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Numerous incidents and failures of earth slopes, dykes, levees and embankment dams are caused by internal erosion. At a time of global climate change, rapid pore-water pressure changes in soil masses are frequently induced by extreme rainfall, storm surges, waves, flash floods and so on. Under such complex cyclic hydraulic conditions, the soil erodibility, hydraulic conductivity and subsequent stress–strain behaviour may differ from those under the monotonic seepage condition, and are still poorly understood. In this study, preliminary laboratory tests have been conducted to investigate the development of internal erosion and changes in hydraulic conductivity under one-way cyclic seepage, and the post-erosion stress–strain behaviour. Representative internally stable and unstable soils were tested. The effects of mean hydraulic gradient and cyclic gradient amplitude were investigated in detail. Results show that the erosion development is significantly influenced by both the initial grain size distribution and the pattern of imposed cyclic hydraulic gradient. The cyclic seepage promotes the loss of fine particles and leads to larger hydraulic conductivity. For the internally unstable soil, the eroded soil mass and hydraulic conductivity increased significantly with increasing cyclic gradient amplitude. Nevertheless, the internally stable soil experienced a small amount of particle loss, even under large cyclic gradients. For both types of soil, a larger cyclic gradient amplitude corresponds to a stronger post-erosion contractive shearing behaviour and a smaller critical friction angle.

Seepage-induced instabilities pose a challenge in many geotechnical applications. Particle-scale mechanisms govern the initiation of instability. However, current understanding is based on a macro-scale perspective that draws on continuum mechanics. Recent developments in imaging and numerical analysis can provide the particle-scale fundamental perspective needed to develop a comprehensive insight. This contribution demonstrates the value of combining particle-scale experimental and numerical studies. The experiments consider transparent soil samples created using refractive image matching and monitored by particle image velocimetry (PIV). Three-dimensional pore topology is extracted from a series of two-dimensional images and imported into computational fluid dynamics (CFD) simulations. Permeability is estimated by three distinct approaches: using flow rate, PIV- and CFD-generated data. The flow fields obtained from PIV and CFD are in good agreement considering both flow rate contour plots and flow rate distributions; this demonstrates the successful reconstruction of three-dimensional pore structure and flow-field analysis. The comparison also reveals that the side boundary effects in CFD simulations are constrained within a limited region. The multi-plane results characterise the variance of flow velocity with the three-dimensional pore topology. Finally, the fluid–particle interactions obtained from CFD results show a larger variance in the angular particle packings.

Gum Ghatti (Anogeissus latifolia) is being widely used as an emulsifier, thickener, stabilizer in food, pharmaceutical, and allied industries due to its shelf life, tolerance of heat, and pH stability. Considering the oil & gas industry application, it is ideal for a hydraulic fracturing fluid additive as a direct replacement for Guar Gum. Basically, unlike Guar Gum, it contains less residual hull and it is suitable for low permeability unconventional reservoir; mainly shale gas reservoir, where permeability counts trivial in amount. The polymer of Ghatti aid exceptional rheological properties and help to produce higher molecular weight polymer; which has excellent proppant carrying capacity and fracture propagation. In this paper, the experimental study has been carried out in two different phases. This was achieved through optimization and characterization of hydraulic fracturing fluid which was embedded with gum matrices. In Phase-I, the study was carried out by using Response Surface Methodology (RSM). Wherein, the relation between several explanatory and response variables have been measured. In Phase-II, the characterization was done by using a Scanning Electron Microscope (SEM), Differential Scanning Calorimeter (DSC), Thermo-Gravimetric Analysis (TGA) and also, Fourier-Transform Infrared Spectroscopy (FT-IR). This experimental study will potentially benefit for development of a new hydraulic fracturing fluid. Where Gum Ghatti observed as a satisfactory alternative agent for Guar Gum.

Foam diversion acidizing can effectively solve the problem of acid distribution with severe heterogeneity between and within layers. Based on the foam diversion principle, the gas trap theory, and volume conservation principle, the foam slug diversion acidizing model was established and solved considering the change of bottomhole temperature and deviation factor of foam. The simulation results show that the change of temperature has a great influence on the diversion effect at the initial stage of injection, but a small influence at the middle and late stage. The effect of temperature on the highly permeable layer is greater than that of temperature on the low permeability layer. The deviation factor of foam is mainly controlled by temperature at the initial stage, and by pressure at the middle and late stage, and the whole process shows a downward trend, which has little influence on the diversion effect. The quasi-skin factor of gas trap is the most important parameter that influences the effect of foam diversion. The water saturation of the low permeability layer rises faster than that of the high permeability layer, and the effect of diversion is obvious. The research results have a strong guiding significance for foam diversion acidizing.

Sandstone formations are yet stimulated with mud acid when matrix acidizing is most competent. In terms of high-pressure high-temperature (HP-HT) conditions, the corrosive impact of hydrochloric (HCl) acid prompted the need to explore other alternatives to mud acid. This study examines the efficiency of organic acids in stimulating Sarah sandstone, a tight gas formation of potential. The optimum injection of acid volume was tested on Berea cores. Besides, the mineralogy of outcrop rocks of Sarah formation was identified using X-ray diffraction (XRD) aided by Scanning Electron Microscopy (SEM). Formation mineralogy led to the selection of acetic-hydrofluoric (C₂H₄O₂-HF) and oxalic-HF (C₂H₂O₄-HF) as proper acids for stimulation experiments. Bentonite water-base mud was used to alter the permeability of three fresh Sarah sandstone core samples. The organic-HF acids were used to stimulate two core samples, while mud acid (HCl-HF) was tested in the third core for comparison. Energy-dispersive X-ray spectrometer (EDX) and SEM were utilized to study the impact of acids on porous media. Experiments conducted in Berea core samples led to the execution of five pore volumes (PV) of preflush and one PV of main treatment as the optimum volume during the acidizing trials. XRD and SEM identified pore-filling clay minerals causing the low permeability of Sarah formation. Furthermore, the water-base mud injected decreased the permeability further by 80%. Oxalic-HF and acetic-HF mixtures recovered the initial permeability of core samples by 46% and 35% respectively. SEM-EDX results showed how organic acids have partially unblocked the pathways of the structural pores leading to permeability enhancement. This research not only recommends the use of oxalic-HF acid for acidizing Sarah sandstone formation but also spotlights the ability of organic acids employment as preflush in hydraulic fracturing operations.

Well killing remains to be the critical technological stage before proceeding with workover operations. Well killing using Visco-Elastic Gel (VEG) has been found to preserve and reinstate the filtration characteristics of bottom-hole formation zone efficiently. Since, these methods exclude the possibility of penetration of well-killing fluids into the reservoirs, the natural permeability of the reservoir retained. In this article, the authors have reported for the first time about a new VEG with controlled fracture times that remains appropriate for killing oil wells associated with both terrigenous carbonate reservoir operations. A distinctive feature of the proposed technology using a VEG with adjustable degradation times (can vary from 3 to 120 h) is that it requires a relatively smaller volumes of the composition in comparison with that of the conventional technologies. As a result, a significant reduction in the negative impact on the reservoir is achieved resulting from a relatively low penetrating ability of the proposed VEG. High structural properties of the VEG make it possible to reliably block the overlapped reservoir interval and it excludes the penetration of process fluid into the reservoir. In addition, it also eliminates the flow of formation fluid from the reservoir, which is absolutely necessary for trouble-free repairing work. It was found from the present study that the use of a breaker of a particular, single type does not provide the desired results and in the present study, the authors have deduced a relatively complex breaker based on peroxyhydrate and citric acid with a 1:1 ratio. The introduction of the encapsulated peroxyhydrate at the stage of preparation of the VEG ensures monodispersity of its dispersion characteristics. The developed VEG was successfully tested in 32 wells of oil fields in the Perm Krai fields in Russia. The well killing technology developed and described in this article using a VEG with adjustable destruction times has successfully been applied in the fields of the Perm Krai. The economic effect from the application of this technology was found to be $6.000 per well.

The underground thermal fluid is one of the significant factors controlling the formation and quality of reservoirs. The Huangliu Formation (N1h) in YF1 area of the central depression belt in the Yinggehai Basin, South China Sea, is characterized by intense thermal fluid activities related to mud diapir and large-scale shallow-water gravity flow deposits. The multi-episodic invasion of high-temperature and CO2-rich thermal fluid into the formation induces complex water-rock reaction during diagenetic process, providing a preferable investigation opportunity for revealing how thermal fluid affects reservoir quality. This study characterizes the reservoirs in the formation through core and thin section analyses as well as physical property test. The reservoirs are dominated by fine-grained sandstone characterized by medium porosity (15.2–21.3%) and lower permeability (0.56–15.75mD). Based on an analysis of casting thin section, cathode luminescence (CL), scanning electron microscope (SEM), carbon and oxygen isotope, inclusion test, and electron-probe microanalysis (EPMA), we systematically investigate the diagenetic patterns and pore evolution process for the reservoirs in the formation. The episodic invasion of thermal fluid occurred approximately 0.4 Ma ago plays an important role in controlling reservoir development: The CO2-rich formation water induces massive late-stage dissolution, resulting in a higher proportion of dissolved pores (38.7–46.4%), which improves the porosity of reservoirs at a depth of 2600–3100 m. Nevertheless, the late dissolution together with carbonate cementation occurred in closed diagenetic system blocks most seepage channels. Furthermore, the relatively high level clay mineral transformation in the YF1 area leads to a higher content of authigenic illite (44–62%) in the formation. Massive authigenic illite severely blocks the pore throats in fine sandstone, reducing permeability. This study offers an insight to the understanding of mud diapir-derived thermal fluid affecting and controlling the quality of reservoirs in some areas of the Yinggehai Basin.

Tight sandstone reservoirs are widely developed in the Mesozoic Yanchang Formation of the Ordos Basin, China. There is a lack of understanding on the sedimentary setting, source-reservoir relationship and oil accumulation conditions in this area. In this study, through the comprehensive analysis of the distribution of tight oil, we evaluated the properties and petrological features of reservoir, geochemical characteristics of source rocks, the source-reservoir relationship, as well as the trapping, preservation and accumulation conditions of tight oil in the Chang 7 Member, and predicted the sweet spots of tight oil in the study area. The results show that the Chang 7 Member is a typical low-porosity and ultra-low permeability reservoir with great tightness, small pore throat and high capillary pressure, and must have been of near-source accumulation. The source rocks are mainly developed in the Chang 73 submember, and the reservoirs mainly occur in the Chang 71 and Chang 72 submembers, forming a combination mode of “lower source rock and upper reservoir”. Sandbodies with good connectivity and fractures being well developed in local areas are the main hydrocarbon transport systems. The abnormal high pressure caused by hydrocarbon generation and pressurization is the main driving force of tight oil accumulation. The mode of hydrocarbon transportation is dominated by the vertical or lateral migration from underlying source rocks or adjacent source rocks to reservoirs within a short distance. Following the integrated evaluation of lithology, physical properties and oil saturation of reservoirs and geochemical characteristics of source rocks, we grouped the sweet spots of Chang 7 Member into three types: Type I, Type II and Type III. Among others, the Type I sweet spots are the best in terms of porosity, permeability and source rock thickness and hydrocarbon enrichment which should be the focus of oilfield development. This study lays an important foundation for the economic and efficient development of tight oil in the Chang 7 Member of Heshui area, and has important implications on tight sandstone reservoirs in other regions of Ordos Basin in China.

Several sets of Paleozoic tight reservoirs are developed in the Central Uplift of the South Yellow Sea Basin. A qualitative analysis of the microscopic pore structure of the tight reservoir rocks was carried out through cast thin slice and scanning electron microscopic image observation. Based on reservoir petrophysical properties, thirty core samples in the Central Uplift of the South Yellow Sea Basin were selected for high-pressure mercury intrusion (HPMI) analysis, which was then combined with fractal calculation to classify and evaluate the tight reservoirs. The analysis of the HPMI curves and related parameters shows that the Paleozoic tight reservoirs can be divided into three types: Type-A, Type-B and Type-C. Type-A sandstone reservoirs contain pores with size mostly ranging between 0.01 and 0.1 μm, followed by pores with size range of 0.001–0.01 μm, and relatively fewer pores larger than 0.1 μm. The Type-B reservoirs are carbonate rocks with extremely heterogeneous pore size distribution, which is closely related to the development of dissolution pores and microfractures. Type-C sandstone reservoirs are dominated by nanopores and submicron pores that distribute more heterogeneously than pores in Type-A reservoirs. The pore distribution in sandstone reservoirs shows significant fractal characteristics and is closely related to the pore size. The heterogeneity of nanopore distribution has a negative correlation with porosity and median pressure and a relatively weak correlation with permeability. Our study has important implications for petroleum exploration in the South Yellow Sea Basin.

The assumption that the gas is a connected phase leads to underestimation of the gas pressure in municipal solid waste (MSW) landfills. In this study, the high gas pressure is shown, by way of field investigations and laboratory experiments, to be caused by foam in the landfills. The field investigations indicated that environmental disasters that have occurred at several landfills in China were caused by high gas or pore pressures. During drilling in these landfills, it was found that a mixture of foam and leachate was ejected from the borehole. The laboratory experiments indicated that foam generation in the landfills was attributable to the two-stage anaerobic biodegradation behaviours of MSWs. Volatile fatty acids (VFAs) decreased the surface tension of the leachate, enabling it to generate foam. The foam's composite index was adopted to evaluate foaming ability and foam stability of the leachate. Meanwhile, the liquid film in the foam divided the gas into a disconnected phase and remarkably increased its flow resistance. An experimental apparatus was designed to compare quantitatively the flow resistances of foam and gas in MSWs. When the foam and gas were injected into a saturated waste column at the same rate, the pressure drop of the foam (412 kPa) was 2·54 times that of the connected-phase gas (162 kPa), thereby resulting in lower residual liquid saturation for foam displacement. The unsaturated permeability coefficient of the foam was about an order of magnitude lower than that of the gas. Owing to the low permeability of waste to foam and continuous gas generation, high gas pressures are easily developed in wet landfills.

This paper reports on analysis of an experimental study that aimed to determine the apparent gas permeability in cracked concrete. There is a lack of research on this topic in the international literature, due to the difficulty of performing reliable experimental testing for gas permeability. The principal interest of this work is to present new and reliable experimental results. Analytical functions between the evolution of the apparent crack permeability and the apparent crack opening are also proposed. These functions appear to be relevant in consideration of Poiseuille theory.

This study analyzes the characteristic numerical analysis of membrane electrode assembly in Proton Exchange Membrane Fuel Cell (PEMFC) with bipolar plate, flow channel, gas diffusion electrode, and proton exchange membrane. The numerical solution focuses on discussing the effects of different parameters, including permeability, porosity, and operation voltage, on various mass fractions, current-voltage curve, and power-voltage curve. The results show that as the porous medium with high gas permeability is an important factor that affects the mass fraction of hydrogen. Regarding the analyses of various porosities, the fuel cell performance can be effectively promoted with larger ratio of porosity and permeability. However, increasing the porosity will affect the electrical conductivity and increase the flooding of water, which will block the flow channel and reduce efficiency.

A pre-compacted MX80 bentonite/Callovo-Oxfordian (COx) claystone mixture has been proposed as a candidate sealing material in a French deep geological repository for high-level radioactive waste. An in-depth understanding of the hydraulic property of this material is essential for accessing the over-pack corrosion and nuclide migration along the gallery. In this study, water flow in the compacted bentonite/claystone mixture was investigated by carrying out infiltration and water retention tests under constant-volume conditions alongside detailed microstructure observation. The evolution of total water hydraulic conductivity with suction was experimentally determined based on the instantaneous profile method. It was observed that the measured total hydraulic conductivity increased slowly at high suctions, then quickly at low suctions and finally approached the saturated value. A new method was developed based on the evolving pore structure, accounting for both vapour and liquid-water hydraulic conductivities. The total hydraulic conductivity predicted by the proposed method agreed well with the measured value, indicating the reliability of the predictive method. The vapour hydraulic conductivity was larger than the liquid-water one at a suction larger than 15·2 MPa, while liquid-water hydraulic conductivity became dominant at a suction lower than 15·2 MPa. In addition, based on the predicted vapour and liquid-water hydraulic conductivities, a numerical model was set up to simulate the water infiltration process. Comparison between the simulation and the measurement showed close agreement, validating the two-phase water flow mechanism in the bentonite/claystone mixture.

Micro-cracks are inherently present in concrete, leads to debilitation of structures. Methods used for managing micro-cracks have a certain degree of toxicity and also possesses certain drawbacks that made them not completely efficient. Bacterial technique when used in fresh concretes results in calcite precipitation in voids and consequently improves the strength and lowers permeability of concrete. Bio- cement is the combination of Bacillus pasteurii 5% and nutrients Urea, Calcium Lactate 95%. In this study by adding 0.5, 1, 1.5 and 2% Bio- cement by weight of cement and observed compressive strength, flexural strength values after 7 and 28 days of curing for M25 grade of concrete.

Characteristics of the natural open fractures on the oil and gas reservoirs is crucial in drilling and production planning. Direct methods of fractures studies such as core analysis and image log interpretation are usually not performed in all drilled wells in a field. Therefore, in absence of these data, the indirect methods can play an important role. In this study, an integrated algorithm is introduced to identify the fractures and estimate its permeability employing conventional well logs. First, open fractures were identified and their properties including density, aperture, porosity and permeability were estimated using FMI log. Subsequently, the fracture index log (FR_Index) was estimated utilizing conventional logs including density, micro-resistivity, sonic (compressional, shear and stoneley slownesses), and caliper logs. After that, the fracture index permeability was estimated by improving the FZI permeability equation. The coherence coefficient between two estimated fracture permeability logs is 0.66. A good correlation is observed on the high permeability zones, but the lower correlation on the low permeability zones. It is notified that, in the high fracture permeability zones, the conventional logs are heavily impacted by fracture permeability. However, due to lower vertical resolution of conventional logs compared with the image logs, the conventional logs are less influenced by less dense fracture zones. However, this algorithm can be used with acceptable accuracy in all uncored and image log wells.

One the promising and emerging enhanced oil recovery techniques in both sandstones and carbonates is Engineered Water Injection (EWI). However, few studies discussed the field-scale applications of this technique in heterogeneous carbonate formations. This paper is an extension of our previous work of the EWI technology at core-scale. This research numerically investigates heterogeneity effect on EWI technique in carbonates at field-scale using five-spot models. Three synthetic five-spot sector models were considered including homogeneous, heterogeneous with permeability channeling, and heterogeneous with gravity underride. The results showed that EWI improves both volumetric and displacement sweep efficiencies compared to conventional formation water injection (FWI) for all models investigated. Also, tracer method is recommended for better estimation of volumetric sweep efficiency as opposed to fractional flow method. Moreover, secondary EWI outperforms other techniques including secondary FW and tertiary EWI. In addition, the observed delay in tertiary EWI can be reduced by increasing well injection pressure and sulfate concentration in the engineered water. An optimum sulfate concentration of 25,000 ppm is recommended for achieving the highest oil recovery by EWI. This study gives more insight into understanding the performance of the EWI technique at field-scale. Recommendations for boosting the performance of this technique have been discussed, which assure more certainty and lower risk.

Due to the progressive use of landfills and the challenges about their effect on their surrounding environment, the hydraulic and gas permeability of the landfill liners has always been a great concern for geotechnicians. Clay-based materials are usually used as the main material for landfill liners. Various additives are implemented to control the hydraulic and gas permeability of these clay liners under different climate conditions. The attempt of this research was to investigate the effect of using four types of geo-fibers, including ordinary and web polyester, polypropylene, and polyvinyl alcohol fibers, on reducing the hydraulic and gas permeability under wet and dry conditions. In this regard, two sets of water and gas permeability tests were performed for clay–fiber mixtures with 0.2, 0.4, and 0.6 weight percentages of fiber additives. The results showed an initial decrease and then a growth in the permeability coefficients by increasing the fiber dosages, resulting in an optimum percentage for each fiber type. Among the fibers used in this study, polyvinyl alcohol fiber with 0.2 weight per cent performed best by reducing the permeability coefficient by approximately 65% and 75% for hydraulic and gas permeability coefficients under wet and dry conditions.

The assessment of rock mass in situ permeability is challenging for large-scale projects such as reservoirs created by dams, where water tightness issues are of prime importance. The in situ permeability is strongly related to the frequency and distribution of discontinuities in the rock mass and quantified by rock quality designation (RQD). This paper analyzes the data of hydraulic conductivity and discontinuities sampled at different depths during the borehole investigations in the limestone and sandstone formations for the construction of hydraulic structures in Oman. Cores recovered from boreholes provide RQD data, and in situ Lugeon tests elucidate the permeability. A modern technique of multivariate adaptive regression splines (MARS) assisted in correlating permeability and RQD along with the depth. In situ permeability shows a declining trend with increasing RQD, and the depth of investigation is within 50 m. This type of relationship can be developed based on detailed initial investigations at the site where the hydraulic conductivity of discontinuous rocks is required to be delineated. The relationship can approximate the permeability by only measuring the RQD in later investigations on the same site, thus saving the time and cost of the site investigations. The applicability of the relationship developed in this study to another location requires a lithological similarity of the rock mass that can be verified through preliminary investigation at the site.

Lining structures are subjected to three-dimensional stress transferred from the overburden soil and rock formation and usually encounter external sulfate attack; permeability and mechanical properties of cement materials are significant for the stability of underground engineering. Geotechnical testing methods were adopted to analyse the evolution of gas permeability, ultrasonic P-wave velocity, uniaxial compression and splitting tensile strength of cement mortar specimens subjected to sulfate attack. With increasing confining pressure, the gas permeability gradually decreased, and the rates and amounts of decrease for the attacked specimens and non-attacked specimens were different. The gas permeability of attacked specimens was greater and more sensitive to the variation of confining pressure ranging from 5 to 20 MPa. Under high confining pressures ranging from 20 to 30 MPa, the rate of decrease in gas permeability was reduced. The ultrasonic P-wave velocity of attacked specimens was visibly lower than that of non-attacked specimens, while their open porosity was higher than that of their counterparts. Both the splitting tensile strength and uniaxial compressive strength decreased after sulfate attack, and the deterioration of the former one was more severe. The experimental results can provide reference material for establishing the long-term stability of concrete structures in a high-sulfate environment.

During earth pressure balance (EPB) shield tunnelling in sandy ground, not only foam but also other conditioning agents need to be injected to reduce the permeability of muck and avoid water spewing out of the screw conveyor. Permeability tests were carried out to study the permeability characteristics of conditioned sand under high hydraulic gradients. A low bentonite slurry injection ratio (BIR) enhanced the workability of foam-conditioned sand. As the hydraulic gradient increased, the initial permeability coefficient of conditioned sand increased, and the initial stable period became shorter or disappeared. The BIR had a more significant effect on the permeability of conditioned sand than the foam injection ratio (FIR), and this effect gradually weakened as the hydraulic gradient increased. The initial permeability coefficient of the foam–bentonite slurry-conditioned sand decreased by approximately an order of magnitude compared with that of the foam-conditioned sand. With the addition of bentonite slurry, suitable sand conditioning can accept a higher water content (w) and lower FIR, resulting in suitable ranges of w and FIR that are more flexible. Finally, the mechanism of stabilizing foam under the action of bentonite slurry was discussed by considering the interaction between foam bubbles and fine particles.

The intrinsic permeability is a crucial parameter to characterise and quantify fluid flow through porous media. However, this parameter is typically uncertain, even if the geometry of the pore structure is available. In this paper, we perform a comparative study of experimental, semi-analytical and numerical methods to calculate the permeability of a regular porous structure. In particular, we use the Kozeny-Carman relation, different homogenisation approaches (3D, 2D, very thin porous media and pseudo 2D/3D), pore-scale simulations (lattice Boltzmann method, Smoothed Particle Hydrodynamics and finite-element method) and pore-scale experiments (microfluidics). A conceptual design of a periodic porous structure with regularly positioned solid cylinders is set up as a benchmark problem and treated with all considered methods. The results are discussed with regard to the individual strengths and limitations of the used methods. The applicable homogenisation approaches as well as all considered pore-scale models prove their ability to predict the permeability of the benchmark problem. The underestimation obtained by the microfluidic experiments is analysed in detail using the lattice Boltzmann method, which makes it possible to quantify the influence of experimental setup restrictions., Deutsche Forschungsgemeinschaft, Projekt DEAL

Due to seasonal climate alterations, the microstructure and permeability of granite residual soil are easily affected by multiple dry-wet cycles. The X-ray micro computed tomography (micro-CT) acted as a non-destructive tool for characterizing the microstructure of soil samples exposed to a range of damage levels induced by dry-wet cycles. Subsequently, the variations of pore distribution and permeability due to dry-wet cycling effects were revealed based on three-dimensional (3D) pore distribution analysis and seepage simulations. According to the results, granite residual soils could be separated into four different components, namely, pores, clay, quartz, and hematite, from micro-CT images. The reconstructed 3D pore models dynamically demonstrated the expanding and connecting patterns of pore structures during dry-wet cycles. The values of porosity and connectivity are positively correlated with the number of dry-wet cycles, which were expressed by exponential and linear functions, respectively. The pore volume probability distribution curves of granite residual soil coincide with the χ2 distribution curve, which verifies the effectiveness of the assumption of χ2 distribution probability. The pore volume distribution curves suggest that the pores in soils were divided into four types based on their volumes, i.e. micropores, mesopores, macropores, and cracks. From a quantitative and visual perspective, considerable small pores are gradually transformed into cracks with a large volume and a high connectivity. Under the action of dry-wet cycles, the number of seepage flow streamlines which contribute to water permeation in seepage simulation increases distinctly, as well as the permeability and hydraulic conductivity. The calculated hydraulic conductivity is comparable with measured ones with an acceptable error margin in general, verifying the accuracy of seepage simulations based on micro-CT results.

In the vacuum treatment of dredged slurries via prefabricated vertical drains (PVDs), both filtration and consolidation may happen to dredged slurries when subjected to the vacuum gradient. Similar to the consolidation, the filtration may provide equally useful information on interpreting the constitutive behavior of the slurry. In this paper, a new approach utilizing the filtration process is devised to evaluate the constitutive behaviors of dredged slurries. The approach is composed of a vacuum filtration device and an iterative curve fitting algorithm. Two types of tests, namely step-vacuum filtration and constant-vacuum filtration followed by compression test, must be conducted on the slurry specimens, and only the time variations of the filtrate discharge should be recorded. On the basis of the recorded data, the curve fitting algorithm is adopted for determining the parameters of the constitutive equations. The effectiveness of the proposed approach is verified through comparing the obtained compressibility and permeability of the slurries with the data provided by the oedometer test and with the empirical relationships from different sources. The comparisons demonstrate that the constitutive relationships determined by the present approach can predict the compressibility and permeability characteristics of dredged slurries with an acceptable degree of accuracy.

A theoretical model to predict the water permeability of nano-reinforced cement pastes from the pore structure (including the pore size distribution, pore interconnection, porosity and microcracks) is presented. The model is based on the general effective media (GEM) theory and multifractals, considering both the bridging of microcracks and capillary pores and the filling of nano gel pores of cement pastes reinforced with nano-admixtures. To validate the model, water permeability experiments were conducted using a cementitious composite reinforced with graphene oxide and multi-walled carbon nanotubes. The calculated results showed good agreement with the experimental measurements, with a decrease in the maximum error from 67.8% to 9.7% compared with the previously proposed GEM theory. Moreover, the theoretical calculations suggest that the reinforcing roles of nano-admixtures in cement paste to improve permeability-related properties may be mainly due to bridging effects in microcracks and capillary pores, rather than the filling of nano gel pores. The findings of this study enrich understanding of the mechanism of reinforcing cement-based materials with nano-admixtures. In addition, the permeability of cementitious composites can be measured directly, rather than the use if other using time-consuming methods.

Permeable pavements play an important role in the mitigation of stormwater runoff and urban heat island effect. However, due to low strength and clogging, permeable pavements are always applied in light traffic areas. Therefore, it is necessary to understand the structural performance of permeable pavements under different conditions. In this paper, the performance of two permeable pavement structures (fully-permeable (FP) pavement and semi-permeable (SP) pavement) under dry and wet conditions is analyzed with the finite element method (FEM) modeling and one-third scaled MMLS3 test. A preliminary FEM model was established and empirical values of modulus are used. To make the model more closely simulate the actual conditions of the pavement, the modulus was calibrated according to the MMLS3 test results. The results of resilient strain and calibrated modulus of two structures under dry and wet conditions were analyzed, and the SP structure appears better cracking and moisture damage resistances. The modulus increases firstly and then decreases with the change of loading repetitions, which is considered to be caused by the combined action of further compaction of load and temperature. Since the change rate of surface layer modulus of the SP structure with loading repetitions is higher than that of FP structure, and only the base material of the two structures is different. It can be considered that the base layer modulus will affect the bottom strain of the surface layer, thus affecting the surface layer modulus. Furthermore, by calculating the difference between the base layer and the surface layer, it is found that the smaller the modulus gap between them, the smaller the change rate of the surface layer modulus.

This work mainly studies the effect of fluid phase momentum transfer mechanisms on the acidizing results, including the retardation effect of the porous structure and the interaction between the fluid phase, such as viscous dissipation and inertial effect. The results show that the acid fluid momentum transfer is influenced by the complex porous structure and fluid viscous dissipation. Eventually, the Stokes-Darcy equation is recommended to be adopted to describe the fluid phase momentum transfer in the following numerical simulation studies on the carbonate acidizing process. Based on this model, a parametric research is carried out to investigate the impact of acid on rock physical characteristics on the stimulation process. Increasing the acid concentration appears to minimize the quantity of acid consumed for the breakthrough. The acid surface reaction rate has a considerable impact on the pore volume to breakthrough and the optimum acid injection rate. The influence of permeability on the acidizing results basically shows a negative correlation with the injection rate. The difference between the acidizing curves of different permeability gradually becomes insignificant with the decrease of injection rate. The existence of isolated fracture and vug significantly reduces acid consumption for the breakthrough.

Experiments on infiltration of pressurised soil–foam mixture into saturated sand have been carried out in a laboratory set-up that provides a hydraulic gradient comparable to real tunnels. The soil–foam mixture used was comparable to the excavated soil (soil–foam mixture) that can be expected in the excavation chamber of an earth pressure balance (EPB) shield. It appears that a higher effective foam expansion ratio (FERm) is more effective to form a low-permeability layer in the sand. Since there will be an interaction between air, water and sand in the soil–foam mixture, the infiltration characteristics of the soil–foam mixture are a little different from that of the foam. It was shown that a larger air fraction at a given solid fraction reduces the foam flow in the sand. The water permeability of foam-infiltrated sand decreases with an increasing air fraction and a decreasing liquid fraction for a given solid fraction, and also decreases with an increasing air fraction and a decreasing solid fraction for a given liquid fraction. The situation with high sand fraction should be avoided in the field because there will be no impermeable or low-permeability layer formed at the tunnel face. Furthermore, the water permeability of foam-infiltrated sand decreases with the foam injection ratio (FIR) and an appropriate FIR is important for EPB shield tunnelling in saturated sand.

The paper considers the process of imbibition in a porous medium under the action of capillary forces in microgravity. A description of experiments on the repeated imbibition of an artificial porous medium during parabolic flights is given. In some experiments, the porous medium is homogeneous; in others, the experimental cell contains regions with different permeability. The analysis of non-stationary and convective terms in the equation of momentum conservation and their influence on the imbibition process is carried out. The results of numerical modeling of the process of repeated imbibition under the action of capillary forces under microgravity in an inhomogeneous porous medium are presented. The results of numerical modeling are compared with experimental data.

The stress distribution around a circular borehole has been studied extensively. The existing analytical poroelastic solutions, however, often neglect the complex interactions between the solid and fluid that can significantly affect the stress solution. This is important in unconventional gas reservoirs such as coalbeds and shale formations. In order to address this limitation, this paper presents the development of a poroelastic solution that takes into account the effect of gas sorption-induced strain. The solution considers drainage of the reservoir fluid through a vertical wellbore in an isotropic, homogenous, poroelastic rock with non-hydrostatic in situ stress field. The sorption-induced shrinkage of coal is modelled using a Langmuir-type curve which relates the volumetric change to the gas pressure. The redistributed stress field around the wellbore after depletion is found by applying Biot’s definition of effective stress and Airey’s stress functions, which leads to a solution of the inhomogeneous Biharmonic equation. Two sets of boundary conditions were considered in order to simulate the unsupported cavity (open-hole) and supported cavity (lined-hole) cases. The implementation was verified against a numerical solution for both open-hole and lined-hole cases. A comparative study was then conducted to show the significance of the sorption-induced shrinkage in the stress distribution. Finally, a parametric study analysed the sensitivity of the solution to different poroelastic parameters. The results demonstrate that the developed solution represents a useful tool that can be employed alongside complex flow models in order to conduct efficient, field-scale coupled hydro-mechanical simulations, especially when the stress-dependent permeability of the reservoir is of concern.

Filter cake is critical to maintaining the stability of the excavation face of an underwater shield tunnel in a high-permeability stratum. In a high-permeability formation, generating an effective filter cake on the excavation face is difficult with a pure bentonite slurry, which penetrates the ground and may not achieve the required suspension pressure. Determining how to efficiently and quickly form a thin and low-permeability filter cake on the tunnel working face has become a key engineering problem in the construction of slurry shield tunnels in high-permeability strata. In this study, the relationship between slurry viscosity and the slurry pressure gradient of pure bentonite was established by performing slurry permeability experiments. The influence of slurry viscosity on the formation of the filter cake in a high-permeability formation was studied under different pressure gradients. In addition, the effect of additive particle size on the slurry filter cake formation was analyzed by introducing additives with different particle sizes to pure bentonite slurries with different viscosities. The test results indicate that (1) for the pure bentonite slurry, the critical initial pressure gradient can be used as a rough indicator of the formation of the filter cake, and the relationship between the critical maximum pore diameter and the average pore diameter of the formation can be compared to establish and analyze the formation law of the slurry filter cake; (2) adding particles to the slurry can enhance the effect of the pure bentonite slurry; and (3) adding coarse-grained materials can effectively improve the film-forming effect. The slurry is more compact when the particle size is close to the average pore size of the formation.

In this paper, a THMC multi-field coupling triaxial cell was used to systematically study the evolution of gas permeability and the deformation characteristics of sandstone. The effects of confining pressure, axial pressure and air pressure on gas permeability characteristics were fully considered in the test. The gas permeability of sandstone decreases with increasing confining pressure. When the confining pressure is low, the variation of gas permeability is greater than the variation of gas permeability at high confining pressure. The gas injection pressure has a significant effect on the gas permeability evolution of sandstone. As the gas injection pressure increases, the gas permeability of sandstone tends to decrease. At the same confining pressure, the gas permeability of the sample during the unloading path is less than the gas permeability of the sample in the loading path. When axial pressure is applied, the axial stress has a significant influence on the permeability evolution of sandstone. When the axial pressure is less than 30 MPa, the gas permeability of the sandstone increases as the axial pressure increases. At axial pressures greater than 30 MPa, the permeability decreases as the axial pressure increases. Finally, the micro-pore/fracture structure of the sample after the gas permeability test was observed using 3D X-ray CT imaging.

A review of the petrophysical properties involving formation damage is presented. Variation of the end-point saturations with porosity and permeability, fluid disposition, distribution, and entrapment, flow functions, and petrophysical parameters of geologic formations, dependence of the flow functions, such as capillary pressure and relative permeability, on the end-point saturations, wettability, and clay morphology, and temperature and stress effects are discussed. The interrelations between the various factors affecting formation damage are described.

The horizontal distribution and periodic accumulation of hydrocarbon in reservoirs are well understood. However, our understanding on the vertical distribution of hydrocarbon accumulation in reservoirs is not clear and remains mysterious to some extent. We proposed a concept of hydrocarbon accumulation depth limit (HADL) to characterize the hydrocarbon’s vertical distribution in petroliferous basins, which is determined by statistical analyses of the variation trends of reservoir layers’ essential properties, including hydrocarbon saturations (So), movable hydrocarbon ratios (Mo) and dry layer ratio (Ko), when the depth is increased. A total of 80,762 drilling results from 12,237 exploration wells in six representative petroliferous basins in China were collected and analyzed. The reservoir layers’ essential properties So, Mo and Ko and their correlations with porosity, permeability, pore throat radius and thermal evolution degree were investigated. The critical values of So, Mo and Ko that define HADL were quantified to be So=0, Mo=0 and Ko=100. Our study indicates that the HADL in petroliferous basins varies from less than 3,000 m to more than 13,000 m deep, depending on the hydrocarbon composition, reservoir lithology, reservoir age, geothermal gradient, tectonic movement, etc. Two factors play an essential role in the formation and variation of HADL: 1) the depletion of hydrocarbon generation potential of source rocks which cuts off hydrocarbon contribution for reservoirs formation and 2) the termination of differential compaction which eliminates capillary pressure difference between the outer surrounding rocks and inner reservoir layers, ending the dominant driven force for hydrocarbon migration and accumulation in deep and tight reservoir layers. All proven oil reserves of 33.95 billion tons equivalent in China, as well as world’s discovered 52,926 oil and gas reservoirs and their unproved potential resources, are distributed above the HADL we defined.

In the Oil and Gas industry, the implementation of artificial intelligence techniques gives advantages of better use of existing infrastructure. It provides better future outcomes, which makes it an essential technology in the operations of the industry. In this paper, the implementation of artificial intelligence techniques for good planning, determination of reservoir rock properties, drilling optimization and production facilities are reviewed. With precise knowledge of permeability and porosity, reservoir engineers can develop robust reservoir development plan and manage hydrocarbon recovery effectively. For porosity prediction, wire-line log data and seismic attributes are used in artificial intelligence-based models. Permeability prediction has been discussed by considering the different types of well-log data in the modeling of artificial intelligence techniques to predict single-phase fluid. Solution of specific developed problems during the determination of permeability in the actual experiment is also mentioned. Artificial intelligence techniques are used in the design and accurate analysis of the drilling fluid. It assists in the selection of drill bit and drilling-related problems. If a reservoir cannot produce naturally, we can select a suitable artificial lift and design the production system using Artificial intelligence techniques. For EOR methods, SADA and NAVA knowledge base systems are discussed. Artificial intelligence can help in optimizing production, improve production efficiency and recovery of hydrocarbons.

A growing body of evidence suggests that the increase of permeability results in reduced strength and bearing capacity of subgrade. A new microbiological stabilizing method, known as microbial induced calcite precipitation (MICP), was induced into stabilization of the subgrade for fully permeable pavement in this study. This study explored the mechanical and hydraulic properties of unsaturated and saturated fine sand soil stabilized by MICP technology. Instead of bacteria, urease was directly induced into fine sand with pre-mixing method. The results indicated that saturated specimens obtained better moisture stability. Compared with cement stabilized soil, the compressive strength and resilient modulus of unsaturated urease stabilized soil were lower under the same CaCO3 or cement content. What stands out in this study is that the saturated urease stabilized soil was not sensitive to water and had relatively higher strength. In addition, the hydraulic conductivity of urease stabilized soil was significantly higher than that of cement stabilized soil. This study developed a potential subgrade improvement technology for possible application in fully permeable pavement. Urease stabilizing method could be used to help increase the strength and maintain a high hydraulic conductivity.

BaCe0.65Zr0.20Y0.15O3-delta - Gd0.2Ce0.8O2-delta (BCZY-GDC) membranes have received increasing attention for their full H-2 selectivity, high thermal and chemical stability, and intrinsic lower cost respect the Pd-based technology. The microstructure of the substrate plays a fundamental role to increase the gas diffusivity through the porous support. In this work, BCZY-GDC ceramics for hydrogen separation application were produced for the first time using ice-templating technique to obtain membrane supports with well-organized aligned porosity and lower pore tortuosity. After slurry composition optimization, the effect of cooling rate on the microstructure was accurately investigated. Samples produced with cooling speed of 30 degrees C/h showed homogeneous microstructures and well-aligned porosity with the best compromise between gas permeability and mechanical properties. Particularly gas permeability values are one order of magnitude higher with respect to the ones registered for tape cast BCZY-GDC substrates with isotropic porosity conventionally used for protonic applications.

The contribution of geomechanics to provide a rigorous quantification of porosity changes and associated permeability changes is often neglected when considering hydrocarbon production. However, it often has significant effects on production rates and ultimate recovery. For the cold heavy oil production with sand (CHOPS) technique, geomechanics is the key for reservoir simulations and promoting successful operations. In fact, the technique employed in CHOPS significantly affects the stress state within the reservoir by inducing “on-purpose” formation damage. It is not only vital to comprehend the behaviour of the reservoir during production, but it is crucial to identify how to harness that behaviour to improve productivity. In order to simulate the mechanical behaviour of unconsolidated sand material, an elastoplastic damage model was formulated. Fluid-flow-geomechanical modelling was then performed for predicting individual well behaviour and overall field performance. The combined effect of fluid-flow and geomechanics improved predictions with respect to oil, water, and gas production rates at key wells. Fluid rates matched satisfactorily most of the wells. In addition, the onset and propagation of equivalent wormhole networks were quantified throughout the production history. This enabled quantification of the volume of produced sand at individual wells. The comparisons between the measured and simulated sand volume rate at well locations showed reasonable agreement. Such calibrated models can then be used for the placement of new wells to optimize production.

The currently in use fluid loss model (American Petroleum Institute (API)) was developed using the Darcy relationship and assuming that there is no changes in the permeability, solid content in the filter cake and filter cake thickness during the 30 min of fluid loss. Hence, in the current API model, the fluid loss is directly propositional to the square-root of time. In this study, a new proposed hyperbolic fluid loss model has been developed based on a time dependent variation in the filter cake properties. Also, the new proposed model has the power to quantify the short-term and long-term fluid losses (more than 30 min). Moreover, the new model has a limit on the total fluid loss compared to the current API model that shows an infinite fluid loss with time. The new model parameters are related to the applied pressure and temperature using nonlinear power models. The new model predictions are verified with the fluid loss results reported in the literature (225 °C and 300 psi) and tests performed in the laboratory at high pressure and high temperature on bentonite drilling muds during this study. The laboratory tests are both limited to 2% and 8% (by weight) bentonite drilling muds at 100 °C and 100 psi (689.5 kPa) up to 420 min (7 hrs) till the end of the fluid loss. The new model predicts the experimental results on maximum fluid loss and changes in the filter cake porosity, permeability, solid content, and thickness with time, pressure and temperature very well.

Floodwaters can damage railway tracks by scouring the ballast, and this can, in turn, lead to dire consequences, including train accidents. Therefore, the accurate prediction of water flow through railway ballast is of significant importance to assess and mediate the risk of ballast damage. In particular, ballast permeability is an important parameter because it controls the flow rate through the ballast. Here we develop a model that includes the random permeability effect using the Karhunen-Loeve expansion. We also allow for the free boundary. The computation is carried out using the finite element method, and it is shown that the same elements can compute the Karhunen-Loeve expansion as are used in the numerical solution of the fluid flow. All calculations are carefully validated against either analytic solutions or results from the literature. It is shown that randomness in the permeability increases the outward flow compared to the constant permeability case. It is also shown that allowing for the free boundary changes significantly the flow characteristics.

Air leakage caused by mining-induced fractures around the borehole and roadway greatly affects the effect of underground gas drainage. Therefore, the study of the air leakage model considering three-dimensional stress and coal elastic-plastic deformation is of great significance to prevent air leakage. In this work, a model of air leakage outside borehole in mining-disturbed coal seam including a fully coupled gas-air flow and coal mechanics model and a mining-induced damage permeability model was developed and verified. The model was used to study the gas-air migration law and air leakage mechanism during gas drainage, and the influence of key parameters including initial permeability and sealing depth on gas drainage effect was analyzed. The results show: (1) The model can be used to characterize the air leakage of pre-drainage boreholes in mining-disturbed coal seams. (2) The gas and air pressure in the severe mining disturbance area rapidly decreased and increased in a short time. (3) Increasing the initial permeability and sealing depth will promote the gas flow in the borehole in the early stage, but the gas concentration will be reduced. The research results provide a scientific theoretical basis for improving the gas drainage effect and ensuring mining safety.

The extent to which groundwater flow affects drainage density and erosion has long been debated but is still uncertain. Here, I present a new hybrid analytical and numerical model that simulates groundwater flow, overland flow, hillslope erosion and stream incision. The model is used to explore the relation between groundwater flow and the incision and persistence of streams for a set of parameters that represent average humid climate conditions. The results show that transmissivity and groundwater flow exert a strong control on drainage density. High transmissivity results in low drainage density and high incision rates (and vice versa), with drainage density varying roughly linearly with transmissivity. The model evolves by a process that is defined here as groundwater capture, whereby streams with a higher rate of incision draw the water table below neighbouring streams, which subsequently run dry and stop incising. This process is less efficient in models with low transmissivity due to the association between low transmissivity and high water table gradients. A comparison of different parameters shows that drainage density is most sensitive to transmissivity, followed by parameters that govern the initial slope and base level. The results agree with field data that show a negative correlation between transmissivity and drainage density. These results imply that permeability and transmissivity exert a strong control on drainage density, stream incision and landscape evolution. Thus, models of landscape evolution may need to explicitly include groundwater flow.

Rock types, pore structures and permeability are essential petrophysical outputs, and they contribute considerably to the highest degree of uncertainty in reservoir characterisation. These factors have a strong influence on exploration and field development decisions. Core analysis is the best approach for estimating permeability, assigning rock types and characterising pore networks. Wireline logs are the most often employed method for estimating the parameters at each data point of reservoirs since there are more un-cored wells than cored wells. Artificial intelligence, on the other hand, is gaining popularity in the geosciences due to the ever-increasing complexity and volume of available subsurface data. This is also obvious in the demand for faster and more accurate interpretations in order to identify reservoir characteristics in increasingly difficult and complicated petroliferous basins. Artificial Neural Networks and Self-Organizing Maps are examples of machine learning approaches that can be used in both supervised and unsupervised modes for modelling and prediction. Eocene carbonates of Mukta oilfield are the major pay rocks of strong geological heterogeneity in terms of their porosity and permeability relationship with pore structures. This paper outlines a novel method of rock fabric classification, pore structure characterization, flow unit classification and robust reservoir permeability modelling based on an integrated approach that incorporates core measurements, log data and machine learning techniques. The pore structure has been characterised by the combination of conventional core, capillary pressure and nuclear magnetic resonance data. Artificial neural network has added an adequate benefit in accurate permeability modelling by utilizing the concepts of rock classifications and hydraulic flow units.

The pore structure in the high-temperature zone plays a leading role in the permeability of the sinter bed. However, few studies on the bed structure in the high-temperature zone of sintering are due to the difficulty of sampling. Pilot-scale sinter pot tests were conducted to investigate the flame front propagation properties and pore evolution characteristics under different granulation moisture in this paper. Liquid nitrogen was injected to quench the sintering bed. We use X-ray computed tomography to reconstruct the high-temperature zone sinter structures. Results show that the higher porosity of green bed under higher granulation moisture results in faster flame front and more likely channels formation. The porosity of the high-temperature zone increases from 48.40% to 51.50% and 55.68% with moisture increasing from 5.30% to 6.35% and 6.91%. However, the mean length of pores decreases from 1.60 mm to 1.38 mm caused by inadequate coalesce under high moisture conditions.

Understanding of hydraulic heterogeneity of the reservoir is the basis for Enhanced geothermal systems (EGS) optimization. This, however, is challenging, as there are limited well tests available for reservoir characterization. To overcome this challenge, this study developed a methodology for determining hydraulic parameters by integrating the induced micro-seismic data collected during the hydraulic stimulation, and tracer test data in the subsequent trial production period for the first time. The spatio-temporal distribution of induced micro-seismicities is indicative of the hydraulic diffusivity distribution, and is subsequently converted into the heterogeneous distribution of permeability and porosity, by quantitative calibrating models outputs with tracer test observations. This approach was verified and applied to the Habanero EGS, Australia, where the accuracy in calibrating the tracer test responses was improved by over 50%, attributed to the constraints of micro-seismic data. The well placement was then optimized based on new insights of hydraulic parameters in the reservoir. As a result, the electrical power efficiency was increased by 5.59 times in 30 years. The wide existence of tracer and induced micro-seismic data promotes the generality of this methodology to improve the reservoir characterization and well placement optimization for the sustainable development of EGS.

Permeability is one of the principal factors related to durability of concrete. The responsible factor for volume change is permeability. This paper attempt to mechanical and durability study of Supplementary Cementitious Concrete where cement has been replaced by fly ash & GGBS in combination of (30%, 0%), (20%,10%), (10%, 20%) and (0%, 30%).16 such concrete samples has been cast in which water binder ratio introduced as 0.35, 0.40, 0.45 & 50 for each 4 set .cubical and cylindrical concrete 16 samples has been prepared for curing period of 7 and 28 days with replacement of manufactured sand and coarse aggregates. Compressive strength, ultra sonic pulse velocity test (UPV) and Rapid chloride permeability test has been done value at the end of each curing period. The results of this research show that both UPV and compression strength have augmented with supplementary Cementitious materials (SCM) Incorporations. Various empirical models were proposed for pulse velocity and compressive strength. Models for the compressive strength and ultrasonic pulse velocity was developed at individual percentage levels (fly ash or GGBS) and then for each replacement stage four different models (FA percent + GGBS percent) were developed. Similarly after curing for 28 days, Chloride permeability test as per ASTM C1202 has been done. Diverse parameters mathematical models were developed to acknowledge the effect of various factors like SCM incorporations, water binder ratio, replacement of manufactured sand etc., and Models has been tested in full range by data and has strong precision, correlation with experimental data.

Soil is a vital substance for all creatures in the world, soil has vast usage in different part such as agriculture, civil work, foundation, Bridges, Embankment, Buildings, Canals, Tunneling and etc. Soil has different classes and types all types of soil cannot fulfill all requirement of engineering properties and cannot stand against the properties such as mechanical strength, permeability, durability, plasticity, compressibility and etc. among the different classes of soil clay soil is a weak soil which has less shear strength and should be stabilized. Stabilization of soil is a techniques and ways for improvement of engineering and other properties of clay soil, clay soil is really a problematic soil for civil engineering and other field works due to its less strength, shrinkages and swelling behavior. Many waste materials are available for stabilizing and strengthening of clay soil which is economic and beneficial for improvement of clay soil. We accurately analysis and incorporate this research paper base on indirect methodology (Secondary data) and extracted that many waste material such as Nano-Silica, white cement, Fly ash classes family, Lim, Copper slag, Red mud, Blast furnace Slag and so on are available for stabilizing of clay soil which is eco friend, economic and easy found in site and market. Related secondary data are elaborated and suitable techniques of stabilization of clay soil are also discussed.

Ever - increasing utilization and cement requirement have forced the researchers to develop alternate building materials that have eco-friendly nature and will contribute towards less waste management. Industries and governmental agencies are looking towards waste reduction. In this paper, the effect of fly ash percentage on concrete properties is demonstrated. Present work deals with the partial replacement of cement weight by 5–20% fly ash. In the present study, M20 grade concrete and water to cement ratio of 0.5 was used. The properties like workability, water demand, heat of hydration for fresh concrete and compressive strength, permeability, durability for harden concrete were studied and compared with Fly Ash based concrete mix. The fly ash based concrete mix showed promising results from constructional point of view. Hence, from the present study, it can be concluded that Fly Ash concrete mix can be used as a partial replacement of normal concrete mix.

The use of ceramic products (tiles, electrical insulators, sanitary fitting, etc.) in building and structural construction is increasing day by day. Generation of ceramic waste is increased globally due to the fragile nature of ceramic it easily breaks during processing, transportation, and installation. Therefore, researchers are growing interest in using ceramic waste as alternative aggregate materials for construction. While other ceramic product wastes such as sanitary wares and electrical insulators have been extensively investigated, not many findings are available on ceramic wall and floor tiles wastes. Thus, the current study focuses on the mechanical (compression, tensile, flexural, and abrasion) and permeability characterization of waste ceramic wall and floor tiles aggregate concrete. Ceramic tiles were used as crushed coarse aggregate in concrete as a replacement for natural aggregates by the replacement level of 0%, 5%, 10%, 15% 20%, and 25%. From the results, it has been observed that ceramic waste enhances the performance of concrete at a certain level of replacement. Ceramic waste has the potential to use in concrete structures at a certain level of replacement to achieve desirable properties.