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Measuring displacements in model tests typically involves contact-based sensors such as linear potentiometers, where contact between two moving parts occurs at the sensing point. The sensor's finite mass, the limited stiffness of the beams and the clamping mechanism, and the slippage and hinging of the sensor body could affect the object's response and lead to measurement errors. Also, the physical mounting rack required to hold these sensors often obstructs the view and makes significant areas unavailable for conducting some other essential investigations. The advancement in high-speed, high-resolution and reasonably priced rugged cameras makes it feasible to obtain better displacement measurements by image analysis. This paper introduces a non-contact method that works by video recording the projection of laser lines on a test object to measure static and dynamic vertical displacements. The technique produces a continuous settlement distribution along the laser line passing through multiple objects of interest. This paper presents the theory for converting laser line images to displacements. The new method's validity is demonstrated by comparing the results from other measurement techniques: hand measurements, linear potentiometers and three-dimensional stereophotogrammetry.

The horizontal strain in the vacuum preloading/dewatering of dredged slurry is significant to the apparent clogging effect and estimation of surface settlement around a drain; however, it has seldom been investigated in previous studies. In this study, a vacuum consolidation model test assisted by particle image velocimetry (PIV) technology was conducted. The displacement vector field was obtained through PIV analysis and image processing; it was used to visually observe the deformation features around a drain. Based on the displacement field, the vertical/horizontal strains at varied radial distances were calculated to explain the ‘soil pile’ and apparent clogging effect. From the strain distribution with radial distances, a significant lateral compression zone near the drain and an extension zone at farther areas were confirmed. Furthermore, a simple explicit model was established to evaluate the horizontal strain within a prefabricated vertical drain unit cell considering a horizontal attenuated vacuum and compression/extension zone. Finally, this method was applied to predict the horizontal displacement in the model test. The results showed that the proposed method can estimate the lateral displacement of soft clay slurry fairly well.

Large settlement and lateral deformation during construction of a rubble mound, such as a breakwater, over a soft clayey foundation are a challenge. Different mechanisms contribute to excessive settlement of marine clay, including consolidation, the size of the rubble particles, the penetration of individual rock particles and the flow of sludge through the rock pores. Placing a geotextile layer or sand mattress can restrict the amount of material loss caused by these mechanisms. To accurately assess the performance of a geotextile under a rubble mound, eight geotechnical centrifuge tests were conducted. The shear strength of the foundation and the type of the separator layer were the variables considered. The results indicate that the use of a geotextile as basal reinforcement reduced settlement at the breakwater crest and increased stability. In addition, the horizontal displacement of the rubble mound and the clayey foundation decreased remarkably.

With the increasing demand for transportation infrastructure, the construction of urban tunnel systems linking different areas is indispensable. The deformation and the failure process during a tunnel excavation are essential concerns for geotechnical engineers. However, few studies have systematically investigated the effect of the ground loss ratio on tunnel deformation and the inequality between the ground loss ratio and the volume of the settlement trough. An experimental study using the transparent soil testing technique is performed herein for better visualization and digitization purposes. The three dimensional vertical and horizontal deformation patterns of a single tunnel are investigated for both the surface and the stratum right below considering different ground loss ratios. The relationship among the empirical constant of the settlement trough width, buried depth, depth–diameter ratio, and ground loss ratio is presented.

The long-term settlement of calcareous sand foundations caused by daily periodic fluctuations has become a significant geological hazard, but effective monitoring tools to capture the deformation profiles are still rarely reported. In this study, a laboratory model test and an in situ monitoring test were conducted. An optical frequency domain reflectometer (OFDR) with high spatial resolution (1 mm) and high accuracy (±1 μe) was used to record the soil strain responses to groundwater table and varied loads. The results indicated that the fiber-optic measurements can accurately locate the swelling and compressive zones. During the loading process, the interlock between calcareous sand particles was detected, which increased the internal friction angle of soil. The foundation deformation above the sliding surface was dominated by compression, and the soil was continuously compressed beneath the sliding surface. After 26-48 h, calcareous sand swelling occurred gradually above the water table, which was primarily dependent on capillary water. The swelling of the soil beneath the groundwater table was completed rapidly within less than 2 h. When the groundwater table and load remain constant, the compression creep behavior can be described by the Yasong-Wang model with R2 = 0.993. The daily periodically varying in situ deformation of calcareous sand primarily occurs between the highest and lowest groundwater tables, i.e. 4.2–6.2 m deep. The tuff interlayers with poor water absorption capacity do not swell or compress, but they produce compressive strain under the influence of deformed calcareous sand layers.

Designing and the construction of a tunnel in urban areas has their own specific considerations. Usually, excessive settlement caused by tunneling during construction damages the adjacent infrastructures and utilities, especially if the tunnel is excavated by the new Austrian tunneling method (NATM). Thus, it’s important to make accurate predictions and effective control on tunneling-induced settlement. In this study, the soil’s Young’s modulus was modeled using a three-dimensional random field and coupled with a finite difference method (FDM) analysis to reveal the influence of scale of fluctuation (SOF) on the maximum surface settlement (Smax). To generate the field of soil’s Young’s modulus, the Fourier series method is employed and sensitivity studies are further performed via Monte-Carlo simulations (MCS). The results demonstrate both the mean value of Smax and its coefficient of variation (COV) increase from 28 mm to 31 mm and from 0.02 to 0.35 respectively, with an increasing horizontal SOF but they stabilize at higher values of SOF. Furthermore, the probability of failure increases as COV increases for each allowable limit greater than the verification FDM of Smax. It is observed that ignoring the spatial variability of soil’s properties leads to an underestimate of the risk of excessive surface settlement.

The increasing integration of distributed generation (DG) has changed the way modern power systems are planned and operated. However, new market mechanisms at the retail level are still needed to effectively integrate energy resources and emerging market participants in the distribution grid. In this article, a stochastic market clearing and settlement model with distributed renewable energy (DRE) utilization constraints is presented. The proposed model considers the uncertainties associated with the DRE productions in the distribution grid and ensures that a certain portion of the total available DRE at a specified time will be utilized with a high probability. The problem is formulated as a chance-constrained two-stage stochastic programming model that minimizes the expected distribution system operation cost and is solved through a sample average approximation algorithm. Case studies are conducted to verify the effectiveness of the proposed model for different DRE utilization requirements.

Leakage-induced hydraulic and ground responses in a twin-tunnel system are analyzed via the proposed analytical solution on the seepage field. The seepage continuity conditions are rigorously satisfied at the interface between the ground and the tunnel lining, in terms of both water pressure and seepage velocity. The analytical solution is verified by comparing the results of numerical simulations. A detailed parametric analysis is carried out to explore the effect of tunnels’ spatial layouts and degraded waterproof facilities on leakage-induced hydraulic and ground response, including head decline, water inflow and ground surface settlement. Our results show that the often used single tunnel model tends to overestimate the pore pressure on the lining along with water inflow into the tunnel, and underestimate the leakage-induced ground settlement.

A considerable chunk of population in China live in rural areas. To create a suitable living environment in winter, many of them resort to additional solar house to improve the indoor thermal environment. Most of the previous studies focus on how the additional solar house changes the environment, but few try to optimize the size of that house. Therefore, this paper carries out field measurement and numerical simulation to evaluate the indoor thermal environment of a traditional building of Danihe Village, an important residential settlement in Xi’an, northwestern China’s Shaanxi Province, and explores the most suitable size of the additional solar house for improving the indoor thermal environment of the building in winter. The results show that the width of the additional solar house should be controlled within the range of 600–2400 mm, which provides the residents indoor with the best thermal environment. The research results offer a guide for improving indoor thermal environment and reducing indoor energy cost in future.

Tensile strain development in high-density polyethylene (HDPE) geomembrane (GMB) liner systems in landfills was numerically investigated. A new constitutive model for municipal solid waste (MSW) that incorporates both mechanical creep and biodegradation was employed in the analyses. The MSW constitutive model is a Cam-Clay type of plasticity model and was implemented in the finite difference computer program FLAC™. The influence of the friction angle of the liner system interfaces, the biodegradation of MSW, and the MSW filling rate on tensile strains were investigated. Several design alternatives to reduce the maximum tensile strain under both short- and long-term waste settlement were evaluated. Results of the analyses indicate that landfill geometry, interface friction angles, and short- and long-term waste settlement are key factors in the development of tensile strains. The results show that long-term waste settlement can induce additional tensile strains after waste placement is complete. Using a HDPE GMB with a friction angle on its upper interface that is lower than the friction angle on the underlying interface, increasing the number of benches, and reducing the slope inclination are shown to mitigate the maximum tensile strain caused by waste placement and waste settlement.

Due to the shield tunneling underneath, long-term settlements may develop in the existing metro tunnels. The compensation grouting is applied worldwide to stabilize the settlement of ground and existing structures. Few field studies concerning large-diameter shield passing tunnel from below have analyzed the interaction between the compensation grouting and the existing tunnel. This paper presents a case study on the response of the operating metro tunnels to the compensation grouting of an underlying large-diameter tunnel in muddy clay stratum. The tunnel deformations before, during, and after the compensation grouting were monitored and analyzed. The long-term tunnel settlements were mitigated and stabilized by the timely compensation grouting. Smaller settlement rates were observed during the grouting treatment, and the settlement was gradually stabilized three months after the grouting. The grouting holes at the tunnel invert were used initially for better grouting efficiency. The horizontal displacement and convergence developed during the grouting construction and remained stable after the grouting process. Moreover, some limitations of the grouting treatment were discussed. The tunnel settlement in the section close to the center-line of the south-line tunnel cannot be prevented effectively. The differential displacement cannot be reduced by this grouting program.

Consolidating dredged clay slurries using a combination of vacuum pressure and prefabricated horizontal drains (PHDs) is widely used in practice. This is a large strain problem, but there is no existing large strain theory for PHD induced consolidation. A method with explicit equations has been proposed to consider both mechanical and geometrical non-linearities in analyzing PHD induced consolidation. The method considers stepwise variation of properties using imaginary time concept. An imaginary time is determined by the condition of continuity of degree of consolidation before and after changing the properties. Then the method was applied to analyze a large scale model test of vacuum consolidation with PHD. Two analyses were conducted. One considered both the mechanical and geometrical non-linearity (large strain), and another only considered mechanical non-linearity (small strain). The results of large strain analysis agree with the measured settlement curve and excess pore pressures well. While the small strain analysis under-estimated the rate of consolidation significantly. The results from this study indicate that for analyzing PHD induced consolidation of clay slurries considering the effect of large strain is important, and the proposed method can be a useful design tool.

Frost heave and thaw settlement are two critical factors that need to be considered in the design of chilled gas pipelines in cold regions. Due to the variation in seasonal temperature and operating conditions (e.g., pressure and temperature at the compressor stations), the pipeline temperature in some segments might vary from subzero to above zero during winter and summer, respectively. This study examines the freezing and thawing for cyclic and constant temperatures at the pipeline and ground surfaces based on the response of 14 model pipes tested in a geotechnical centrifuge. The cyclic (temperature) operation reduces the frost heave rate per year and causes net settlement in some cases. When the thaw bulb resulting from an above-zero operating temperature is less than the previously developed frost bulb, upward water flow occurs through the thawed soil, which could alter the pipeline–soil interaction behaviour. Five types of freeze-thaw-induced vertical displacement of the pipe have been identified from the centrifuge test results.

In the present paper, the three dimensional (3D) settlement process of two side-by-side free-falling spheres in a water tank was numerically investigated using coupled Smoothed Particle Hydrodynamics (SPH) - Discrete Element Method (DEM) method. The maximum particle Reynolds number, calculated based on the terminal velocity and sphere diameter, is R e m = 2 . 4 × 1 0 4 . The accuracy of the model was firstly validated by simulating the single sphere water-entry, settlement of two circular cylinders arranged in series and two identical spheres settlement side by side problems, respectively. The simulation results exhibited a satisfactory agreement with the available numerical and experimental data in the literatures. Then, the settlement process of two spheres with different sizes and transverse distances were simulated. In particular, the motion patterns of two interacting spheres with different initial gaps and diameter ratios, including motion trajectory, vertical falling distance and flow field, were systematically investigated. The results demonstrate that when initial gap S 0 ∗ S 0 ∗ > 0.75, the interaction between the two spheres are negligible. In addition, the interaction between particles would slow down the settling velocity and affect the terminal settling distance.

Many highways have been built on the eastern coast of China in the past decades. Recently, some engineering problems have emerged after long-term operation. Due to the different properties between the underlying soil and bridge pile foundations, the problem of bumping at the bridge head is inevitable. To study the potential causes and provide insight for future improvement, the settlement of typical highways in the Hangzhou Bay area, which had been open to traffic for more than 10 years, was investigated. After an analytical calculation with the verification of the numerical method and field data, it was indicated that long-term deformation was mainly caused by the poor properties of the lower of the two layers that make up the underlying soil. The trend of the variation of the lower layer keeps increasing at a slow rate during the construction period, resulting in sustained and rapid changes during the following years. Different kinds of ground improvement such as lightweight materials and soil–cement columns generated by deep mixing or jet grouting methods are discussed. The improvement of the lower layer will be more effective. With the analytical method, it is convenient and efficient to calculate and analyse the settlement at different periods, which is significant for design.

The serviceability limit state (SLS) design of foundations typically proceeds by limiting the total settlement of individual foundations and thereby attempting to restrict the differential settlement between pairs of foundations. Due to the uncertain nature of the supporting ground, the magnitude of settlement and differential settlement are random. As it is often the differential settlement that governs serviceability, it is desirable to provide design requirements that suitably restrict differential settlements. This paper investigates, by Monte Carlo simulation, the distribution of the maximum differential settlement between pairs of foundations as a function of the spacing between foundations and the number of foundations — groups of four, nine, or 16 foundations, arranged on a grid — are considered. The effects of the correlations between the equivalent stiffness of the ground under each foundation, as well as between the loads applied to the foundations, on the distribution of the maximum differential settlements and angular distortions are investigated. Ratios of resistance factor to resistance bias factor are presented that can be used to calibrate design requirements on the total settlement of individual foundations that also simultaneously achieve acceptable performance with respect to angular distortion.

This manuscript presents the case study of soft Bangkok clay improvement and simulations using combined vacuum pressures with pre-existing surcharge embankment preloading, including installations of air-tight membranes and horizontal prefabricated drains connected to the top of the PVDs as well as to the vacuum system with a modified air-water separation system. The 17-m-long PVDs were installed from the top of the embankment in a triangular pattern at a spacing of 0.9 m. Monitoring instruments were installed to measure surface settlements, lateral movements, and pore water pressures in the soft clay layer. The subsequent analyses included settlement calculations, settlement predictions using observational methods, flow parameter back-calculations, soil property comparisons before and after improvement, and FEM simulations. The very soft to soft clay was transformed to medium-stiff clay because its undrained shear strengths and maximum past pressures increased, and its water contents, void ratios, and compression indices decreased. The analyses of the degree of consolidation utilized one-dimensional and observational methods as well as a numerical simulation for the prediction of consolidation settlements and comparison to the field data. The results illustrated the effectiveness of the modified vacuum-PVD system. The findings could be used for guidance of similar soft clay improvement projects.

Soil arching and tensioned membrane effects are two main load transfer mechanisms for geosynthetic-reinforced pile-supported (GRPS) embankments over soft soils or voids. Evidences show that the tensioned membrane effect interacts with the soil arching effect. To investigate the soil arching evolution under different geosynthetic reinforcement stiffness and embankment height, a series of discrete element method (DEM) simulations of GRPS embankments were carried out based on physical model tests. The results indicate that the deformation pattern in the GRPS embankments changed from a concentric ellipse arch pattern to an equal settlement pattern with the increase of the embankment height. High stiffness geosynthetic hindered the development of soil arching and required more subsoil settlement to enable the development of maximum soil arching. However, soil arching in the GRPS embankments with low stiffness reinforcement degraded after reaching maximum soil arching. Appropriate stiffness reinforcement ensured the development and stability of maximum soil arching. According to the stress states on the pile top, a concentric ellipse soil arch model is proposed in this paper to describe the soil arching behavior in the GRPS embankments over voids. The predicted heights of soil arches and load efficacies on the piles agreed well with the DEM simulations and the test results from the literature.

Vacuum preloading has been widely used to improve soft soils in coastal areas of China. An increasing amount of evidence from field operations has shown that conventional vacuum preloading is prone to clogging in prefabricated vertical drains (PVDs) and demands a large volume of sand fills. In recent years, air-boosted vacuum preloading has been developed to overcome these limitations; however, this method still requires more data to verify its performance. In this study, a field test for air-boosted vacuum preloading was conducted, and a large-strain two-dimensional (2D) finite element (FE) model was developed and validated against the field test data. Then, a series of FE parametric analyses was performed to assess key factors, i.e. the air injection pressure, the injection spacing, and the characteristics of cyclic injection, which affect the performance of the air-boosted vacuum preloading. The results showed that the ground settlement and lateral displacement of the soils increased due to an increase in the injection pressure, a decrease in the injection spacing, or increases in the number and duration of the injection cycles. Based on the parametric analyses, an empirical formula for ground settlement prediction was proposed and compared with a case history reported in the literature, showing good agreement.

In the event of earthquake-induced liquefaction, structures with shallow foundations can suffer excessive settlement and rotation. In this paper, the rotational response of structures with shallow foundations resting on liquefiable layers with thickness equal to or smaller than the width of the foundation is examined through a series of dynamic centrifuge experiments. Moment–rotation backbone curves are extracted and the corresponding evolution of rocking stiffness with increasing rotation is depicted, in normalised terms. A stiffness attenuation relation is proposed, which can be used for simplified predictions of maximum and residual rotation using rotational spring and dashpot models. Two such examples are presented, one using an iterative, equivalent-linear rotational spring approximation, and one using Masing's rules for cyclic response, extended with Pyke's hypothesis.

Surface settlements caused by twin tunneling are a major interest in underground space engineering. Most prevailing studies have investigated the surface settlements observed over twin tunnels constructed in clay. Yet, less attention is given to the twin tunnels excavated in silty sand, which is the focus of this study. A comprehensive field monitoring scheme was designed in the Hangzhou metro line six project to measure the surface settlements during twin tunneling by adopting earth pressure balance shields. The influence of four shield operational parameters, namely, face pressure, tail grouting pressure, penetration rate, and pitching angle on the surface settlements due to twin tunneling are explored. In general, the total settlement profiles observed over twin tunnels follow an inverted bimodal shape. The post-settlement observed over the 1st tunnel due to the 2nd tunnel excavation is non-trivial when the twin tunnels are spaced closely. Low face pressure and tail grouting pressure can induce excessive peak surface settlements during twin tunneling in silty sand.

To study the variation in pile–soil stress and settlement of a pile–net composite foundation in a collapsible loess area, a test section of the Gansu-Ningxia section of the Yinxi high-speed railway was analysed using an earth pressure box, a liquid level settlement system and a single-point settlement instrument. The monitoring results showed that for, the pile–net composite foundation, the earth pressure in the embankment was significantly affected by the geogrid and the soil arching effect. The geogrid enhanced the soil arching effect between the piles, resulting in an increase in earth pressure between the piles on the embankment. With an increase in the embankment filling height, the pile–soil stress ratio and load sharing ratio of the cement–fly ash–gravel (CFG) pile and cement–soil compaction (CSC) pile increased gradually and the pile–soil stress ratio of the CFG pile was greater than that of the CSC pile. The settlement patterns of the CFG pile top, CSC pile top and the soil between the piles was saddle-shaped. The settlement of the CSC pile was found to be much less than that of the CFG pile.

It is found through centrifuge model tests that the cyclic lateral load on a pile reduces the shaft friction and induces additional pile settlement. A theoretical model using the load-transfer method was proposed for the settlement prediction of cyclic laterally loaded piles in dry sand. A simple formula was established to quickly predict the pile settlement in practical engineering. The theoretical model provided a reasonable estimate of the pile settlement, while the predictions from the proposed quick prediction formula were relatively conservative. A new concept of ‘settlement-controlled design’ was proposed to advance the methodology for the design of a pile by considering potential settlement after many cycles of lateral loads. According to the design plane derived from this study, it was suggested that the design-state points should be limited to the convergent zone.

The critical size hypothesis states that pelagic larvae (vertebrate or invertebrate) must reach a critical size to begin metamorphosis and settle to their suitable reef habitat; however, there have been few critical tests of its broader validity. If there were a narrower range of ages at settlement relative to size, then the data would conform to a critical age hypothesis. It would also be predicted that size or age would be truncated respectively at the lower limit for each hypothesis. These hypotheses were tested for 2 species of coral reef fish from the Great Barrier Reef. Variation in age at settlement forPomacentrus coelestiswas greater than that of size at settlement for fish collected in waters of different temperatures, and the size distribution was truncated at a size of ~9.3 mm; accordingly, we accepted the critical size at settlement hypothesis for this species. In contrast,Scolopsis bilineatusmet one criterion to reject the critical size hypothesis, based on variation, but truncation in size was found. Variation in age aligned with a critical age at settlement hypothesis. There was a variable relationship between age at settlement and size for both species. Strong evidence is provided that growing fast in the plankton and settling quickly may be advantageous for fish. For both species, settlers with a short planktonic larval duration, and sometimes small size at settlement, had grown faster in the plankton and may have experienced better conditions. Differences in pre-settlement growth are likely to affect the maximum size at which fish can settle and post-settlement survivorship.

The heterogeneity of soil is an advantage as well as a disadvantage at the same time. The well graded soil possesses more density and stability then uniformly graded soil, but at same time because of uneven distribution of soil underneath the foundation soil may behave differently to different soil conditions. The soil beneath the foundation cannot be accessed directly therefore methods like pin piles came into the picture. The piles having diameter less than 300 mm are termed as pin piles. Under this portion of study the gain in strength by soil under the foundation of existing structure was noted down by an experimental method. The structure and subsequent conditions were simulated in the laboratory. The quantity and spacing of pin pile are interrelated. In the analysis the pin piles are inserted in the periphery of the existing footing in one line and footing size remains constant throughout the experiments, therefore the more spacing means less number of pin piles and vice versa. The distance between pin piles is termed as pitch length as measured from center to center. The distance from the outermost edge of footing is termed as edge distance also taken as variable. The experiments were designed in MiniTab 9.0 for suitable combinations of variables. The settlement of soil at 25 mm was considered a failure and optimized quantity and spacing of pin piles were determined. The positive effects of pin piles were observed when inserted in the periphery of existing footing.

Dynamics of ocean boundary currents and associated shelf processes can influence onshore/offshore transport of water, critically impacting marine organisms that release long-lived pelagic larvae into the water column. The western rock lobster, Panulirus cygnus, endemic to Western Australia, is the basis of Australia's most valuable wild-caught commercial fishery. After hatching, western rock lobster larvae (phyllosoma) spend up to 11 months in offshore waters before ocean currents and their ability to swim, transport them back to the coast. The abundance of western rock lobster puerulus (settlement phase post phyllosoma) has historically been observed to be positively correlated with the strength of the Leeuwin Current, and an index of puerulus numbers is used by fisheries managers as a predictor of subsequent lobster abundance 3–4 years later. In 2008 and 2009 the Leeuwin Current was strong, yet a settlement failure occurred throughout the fishery prompting management changes and a rethinking of environmental factors associated with their settlement. Thus, understanding factors that may have been responsible for the settlement failure is important for fisheries management. Oceanographic parameters likely to influence puerulus settlement were derived for a 17 year period to investigate correlations. Analysis indicated that puerulus settlement at adjacent monitoring sites have similar oceanographic forcing with kinetic energy in the offshore and the strength of the Leeuwin Current being key factors. Settlement failure years were synonymous with “hiatus” conditions in the south-east Indian Ocean, and periods of sustained cooler water present offshore. Post 2009, there has been an unusual but consistent increase in the Leeuwin Current during the early summer months with a matching decrease in the Capes Current, that may explain an observed settlement timing mismatch compared to historical data. Our study has revealed that a culmination of these conditions likely led to the recruitment failure and subsequent changes in puerulus settlement patterns.

The soil slopes alongside the roads, embankments etc. often lead to mishaps as they are prone to slide or collapse due to their instability. Soil nailing is remedial measure to such unstable soil slopes and thus to prevent such mishaps. In this research, a physical model of soil nailed slopes has been established and is tested for stress and strain with different flexible facing materials under the application of load using a hydraulic jack. Then the settlement and displacement of the soil nailed slopes with different facing materials is also calculated and compared. The several flexible facing materials used were HDPE Geomembrane Sheet, Geocomposite and Biaxial Geogrid and were compared with the soil slope without facing. This research shows that different flexible facing materials have different behaviour in terms of strain and displacement under the similar magnitude of load. And it is obtained that flexible facing materials can be a good replacement to rigid facing materials for non-critical structures and an economical and effective way to strengthen existing soil slopes and stabilize them with as they are less costly than the rigid materials. Among all flexible materials that used in this research Geocomposite has high strength of 1.23 N/mm2 and less vertical and horizontal displacement.

Pin piles have been principally utilized to uphold components of footing to counteract the static and dynamic loadings. Pin piles have been utilized adequately in numerous uses of ground improvement to increase the bearing capacity of soil. The purpose of this study is to observe the behaviour of different types of soil when pin piles were inserted in the vicinity of square footing. The diameter of pin pile, edge distance and pile to pile distance were taken as variables to study the effect of pin pile. Both the soil behaves differently to the pin piles. Although, the insertion of pin piles in clayey soil is difficult but as clays are sensitive to the settlement the pin piles can play a vital role in improvement in load bearing capacity even inserted up to shallow depth. Pin piles also show significant improvement to restrict the lateral movement of cohesion less particles of sandy soil. This paper holds the comparison of both clayey and sandy types of soil subjected to pin piles insertion in the periphery of existing footing through a laboratory model.

Various building infrastructure projects around the world have resulted in a major rise in waste materials production such as concrete, fly ash, plastic, rice husk, foundry sand, and other materials, raising disposal issues. In soft clay, stone columns are a traditional ground improvement technique. Crushed concrete is abundant and comes from the removal of old buildings as well as waste concrete from new construction. As a result, construction waste recycling is important, both in terms of reducing the amount of open land needed for landfilling and in terms of environmental protection by resource conservation. Laboratory tests were conducted in this research to examine the influence of crushed concrete columns and crushed concrete by adding 6% sodium silicate columns on characteristics of soft soils (kaolin soil). The finding was that adding sodium silicate to crushed concrete gave a better degree of improvement as compared with crushed concrete columns in both cases (flouting and end bearing). But in flouting case show bearing ratio increased by 367% and in end bearing case increased by 611% as compared with bearing ratio of untreted soil at failure.

International audience; Monte Torretta (Pietragalla, PZ) represents one of the most interesting and less known settlements of ancient Lucania. The site was investigated in the last 50 years by several archaeological activities, but no result has been published so far. In order to study and disseminate the archaeological value of the site, the Université Paris 1 Panthéon‐Sorbonne and the Humboldt‐Universität zu Berlin has established the joint Pietragalla Project. The project is based on a multidisciplinary approach, which aims at studying the settlement and at recovering the lost information obtained by the previous archaeological works. The first geophysical activities conducted on the site offer important results, which increase the knowledge of the site and will help the archaeologists in their future investigation. Through the comparison and integration of different geophysical methodologies, including ground penetrating radar, electrical resistivity tomography and geomagnetic measurements, various information was obtained in proximity of the fortification walls and the two main gates of the site. Moreover, geological and geomorphological interpretations highlighted important information on the archaeological site. The obtained results show the importance of geophysical activities in a context strongly damaged by rural activities of the last century. From an archaeological point of view, the geophysical surveys conducted in 2017 and 2018 show a dense building activity within the area enclosed by the walls. Thanks to these results, we are now able to understand the settlement pattern in the longue durée, at the least for the western part of the infra‐muros area.

Reducing differential settlement between bridges and their embankments caused by an earthquake is necessary to maintain traffic, especially emergency vehicles accessing affected areas. The confined-reinforced earth (CRE) method has been proposed to strengthen the subgrade layer at the bottom of a road pavement and to ultimately reduce road surface unevenness. The method uses granular soil, geogrid layers and confining tie rods. This study presents model experiments designed to investigate the effects of embedded geogrid lengths on CRE behavior under differential settlement and cyclic (vehicle) loads. The CRE was constructed on a fixed plate to simulate a bridge abutment, and on a movable plate to simulate the settlement of an embankment. The results showed that the surface settlement distribution and the maximum surface slope of the CRE decreased with an increase in embedded geogrid length until the geogrids are sufficiently long. Beyond this length value, the deformation only changed slightly. The tensile strain in the geogrids also increased with increased embedded geogrid length under settlement, and the maximum tensile strain increased linearly with increasing settlement. The increment of tensile strain due to the cyclic load was larger for lower geogrid layers than for upper geogrid layers.

Jet grouting is one of the most widely applied soil improvement techniques. It is suitable for most geotechnical problems, including improving bearing capacity, decreasing settlement, forming seals, and stabilizing slopes. One of the difficulties faced by designers is determining the strength and geometry of elements created using this method. Jet grouted soil-cement columns in soil are a complicated issue because they are dependent on a number of parameters such as soil type, grout and water flow rate, rotation and lifting speed of monitor, nozzle jetting force, and water to cement ratio of slurry. This paper discusses the effect of the water-cement ratio on the physical and mechanical characteristics of soilcrete. In the laboratory, sandy soil mixed with cement grout with water-cement ratio varies from (0.7:1 to 1.4:1). To evaluate the characteristics of soilcrete, 96 specimens were prepared in the laboratory and tested at different curing times. The results indicate that the Uniaxial Compressive Strength (UCS) of soilcrete decreases with increasing the (W/C) ratio of the grout, where the soilcrete strength of W/C ratio of 0.7 is higher about 237% of W/C ratio of 1.4 at 28-day; the evolution of the (UCS) is proportional to the logarithm of the curing time; the ratio between the modulus of elasticity (Etg50) to the maximum UCS varies from 113 to 175; when the water-cement ratio increases, the dry density of soilcrete decreases, as a result, the (USC) of soilcrete decreases.

Excessive ground surface settlement induced by pit excavation (i.e. braced excavation) can potentially result in damage to the nearby buildings and facilities. In this paper, extensive finite element analyses have been carried out to evaluate the effects of various structural, soil and geometric properties on the maximum ground surface settlement induced by braced excavation in anisotropic clays. The anisotropic soil properties considered include the plane strain shear strength ratio (i.e. the ratio of the passive undrained shear strength to the active one) and the unloading shear modulus ratio. Other parameters considered include the support system stiffness, the excavation width to excavation depth ratio, and the wall penetration depth to excavation depth ratio. Subsequently, the maximum ground surface settlement of a total of 1479 hypothetical cases were analyzed by various machine learning algorithms including the ensemble learning methods (extreme gradient boosting (XGBoost) and random forest regression (RFR) algorithms). The prediction models developed by the XGBoost and RFR are compared with that of two conventional regression methods, and the predictive accuracy of these models are assessed. This study aims to highlight the technical feasibility and applicability of advanced ensemble learning methods in geotechnical engineering practice.

An attempt has been made to delineate and identify the alignment of a new route between two important cities of north India, Haridwar & Roorkee using Geoinformatics techniques. Geo-engineering parameters like slope, aspect, geology, land use, drainage and soil along with some techno-economical parameters have been used for this purpose. Multi-criteria weight method has been applied. Five weighting methods (AHP - Analytical Hierarchy Process, Rank Sum, Rank Reciprocal, Rank Exponent and Ratio Estimation) were applied simultaneously to eliminate biasness in weight assignment to the input parameters. The results show that AHP method is the best and ratio estimation method is the second best method for identification of optimum route alignment. Few more parameters were used for final selection of optimum route viz., minimum construction cost; minimum number of bridges and culverts on that route; maximum number of settlement within 5 km buffers on both sides of route; maximum number of tourist locations like temples, waterfalls, springs etc. within 5 km buffer zone on both side of route. The proposed route between Roorkee and Haridwar towns is only 29.22 km long (includes a 17.10 km long part of the existing road), the new road required is 12.12 km, while the existing longer route between Roorkee and Haridwar is 33 km (instead of 29.22 km). By using multi-criteria weighted methods of route alignment, a length of approximately 3.78 km can be avoided. It was also observed that slope, land use and drainage parameters are more sensitive for route alignment.

The collection and reuse of graywater has become an important strategy for achieving the goal of sustainable development. In this work, an integrated preliminary settlement and filtration process was developed for treating shower water which was obtained from a college bathroom toilet. The system's pollutant removal efficiency was examined for three different filter media: manganese sand, quartz sand and ceramsite. The results showed that for ceramsite, the average removal of turbidity, CODcr, NH3-N, and anionic surfactant was 93.3%, 68.6%, 78.9, and 83.5% respectively. For manganese sand, the values were 84.6%, 61.5%, 57.8 and 59%, while for quartz, they were 88.9%, 47.9%, 39.5% and 51.9%. A cost–benefit analysis revealed that the payback period of graywater recycling systems ranges from 3.16–5.30 years and benefit–cost ratios are in the range of 1.23–1.67, depending on tank size. The proposed system provides a new strategy for enhancing water-use efficiency in buildings in a more decentralized way. HIGHLIGHTS An integrated preliminary settlement and filtration process was developed for shower water treatment.; Ceramsite filtering medium was found to be effective to filter graywater to meet the non-potable standard.; The graywater recycling system is economically viable when the potable water price is higher than 2.52 CNY/m3.

This study integrates different machine learning (ML) methods and 5-fold cross-validation (CV) method to estimate the ground maximal surface settlement (MSS) induced by tunneling. We further investigate the applicability of artificial intelligent (AI) based prediction through a comparative study of two tunnelling datasets with different sizes and features. Four different ML approaches, including support vector machine (SVM), random forest (RF), back-propagation neural network (BPNN), and deep neural network (DNN), are utilized. Two techniques, i.e. particle swarm optimization (PSO) and grid search (GS) methods, are adopted for hyperparameter optimization. To assess the reliability and efficiency of the predictions, three performance evaluation indicators, including the mean absolute error (MAE), root mean square error (RMSE), and Pearson correlation coefficient (R), are calculated. Our results indicate that proposed models can accurately and efficiently predict the settlement, while the RF model outperforms the other three methods on both datasets. The difference in model performance on two datasets (Datasets A and B) reveals the importance of data quality and quantity. Sensitivity analysis indicates that Dataset A is more significantly affected by geological conditions, while geometric characteristics play a more dominant role on Dataset B.

In practice, saddle-shaped settlement is often investigated in the pile group foundation with identical piles. For the purpose of decreasing the differential settlement, uneven-distributed pile groups can be used. This paper provides a simplified approach to capture the behaviour of pile groups with dissimilar pile length or pile diameter. The hyperbolic function was adopted to express the mechanism of the interface between pile and soil. Considering the interaction of piles with dissimilar length, the hyperbolic load-transfer model of individual pile in pile groups composed of dissimilar piles were proposed. The related parameters of load transfer function of pile shaft or pile base of dissimilar piles were determined. To clarify the deformation mechanism of pile-soil system, an iterative approach for the analysis on the behaviour of non-uniformly arranged pile groups was proposed. Comparisons between the present computation results and the finite element simulation results were drawn to check the dependability of the proposed approach. Moreover, taking 3 × 3 pile groups as an example, the bearing characteristics of the centre pile, the edge pile and the corner pile in pile groups with different pile arrangements were analysed. For practical purposes, some suggestions on the pile groups composed of dissimilar piles were given to alleviate differential settlement among each individual pile and decrease the cost of pile groups and the construction difficulties.

Thin-walled steel storage tanks are generally located in coastal areas and therefore are prone to settlement. In investigating the effect of possible settlement types, the effect of local settlement is impressive due to its destructive impacts on the performance and stability of tanks. Hence, the need for laboratory studies to investigate the behavior of thin-walled tanks against this phenomenon becomes clear in advance. Many variables can be evaluated in the study of the effect of local settlement on the behavior of tanks. In this study, the variables of height-to-radius ratio ( L / R ) and settlement-range-to-tank-circumference ratio ( S ) were considered. The effect of top stiffening ring on tank’s behavior was also investigated. A total of 12 unstiffened and stiffened specimens with L / R = 1.0 and 1.5 as well as S = 0.05, 0.08, and 0.13 were tested in this experimental endeavor. All specimens had a radius-to-thickness ratio ( R / t ) of 500. This study shows that increasing of the L / R ratio improves the stiffness, strength, and toughness performances of the tank, while increasing of the S ratio results in the reduction of the aforementioned parameters. The presence of the top stiffening ring plays an important role in controlling the radial displacement and preventing the ellipse of the upper edge of the tank. Accordingly, it is demonstrated that tanks with the top stiffening ring have higher stiffness, strength, and toughness performances compared to the unstiffened tanks.

For the newly deposited soil, the consolidation will occur under the self-weight and external load jointly if the soil is treated by the stack pre-pressure method. The soil stress caused by self-weight has a significant influence on its consolidation process no matter the soil is either saturated or unsaturated. However, the soil’s self-weight is ignored in the one-dimensional (1D) consolidation theory for unsaturated soils (Fredlund and Hasan, 1979). In this paper, we derived the semi-analytical solutions for excess pressures and normalized settlement in 1D dimensional consolidation of unsaturated soils considering self-weight. The analytical solutions were obtained by Crump’s method (Crump, 1976), through a computing program coupling the calculation of initial excess pore pressures with the inverse Laplace transform of the obtained solutions. Then, the proposed solutions are verified through a degradation case. Several 2D charts are presented to visualize the solutions, and various examples are employed to discuss the key factors that affect one-dimensional consolidation behavior of unsaturated soils when self-weight is considered. It can be found that the relative excess pore pressure will be restrained for the one-dimensional consolidation when considering self-weight.

In this paper, the seismic performance of wall-type gravel and rubber drains as a liquefaction countermeasure in silty sand has been addressed using a series of 1 g shaking table tests. In these tests, the liquefaction resistance of silty sand was studied by changing soil relative density, silt content, number of walls, and materials of drainage walls. In order to evaluate shear wave propagation, the generation and dissipation of pore water pressure (PWP), and the ground surface settlement, various accelerometers, displacement and PWP transducers were placed. The obtained results indicated that an increase in the relative density and the number of wall-type gravel and rubber drains in liquefiable silty sand reduces the settlement, liquefaction-induced deformations, as well as the excess PWP and eventually improves the liquefaction resistance. Totally, it can be noted that the reinforced silty sand with wall-type gravel drains revealed less excess PWP and settlement than that with wall-type rubber drains.

The engineering of sluice has many functions, such as flood control, irrigation, navigation, and power generation. The safety of sluice structure is the premise of its functions and benefits. Moreover, the deformation behavior of the sluice chamber is closely related to the safe operation of the sluice. Firstly, existing literature on sluice research using FEM is investigated and analyzed to determine the calculation model and influencing factors. Secondly, the global sensitivity analysis method of the sluice chamber is constructed based on the Sobol sequence random sampling method and the global sensitivity analysis method based on variance. Finally, according to the distribution rule of the first-order and total-order sensitivity coefficients in the sluice chamber, the typical locations are determined, and the linear and nonlinear relations between the main influencing factors and the deformation indexes of each location are analyzed. An example shows that the deformation of the sluice chamber is mainly settlement, and the major factor is the deformation modulus of foundation soil. Each index model of sluice deformation can be considered as additive. The research results have significant reference value for clarifying the influence mechanism of the sluice chamber deformation behavior and improving the design, operation management, and safety evaluation of sluice structure.

Population irruptions of the western Pacific crown-of-thorns sea star (Acanthaster sp.) are a perennial threat to coral reefs and may be initiated by fluctuations in reproductive or settlem...

Structures with shallow foundations are susceptible to excessive settlement and rotation in the event of earthquake-induced soil liquefaction. Numerical modelling of the problem remains challenging, due to persisting uncertainties regarding dynamic soil response and soil–structure interaction. In this paper, numerical simulations are employed to study the seismic response of a structure on a shallow mat foundation, resting on a liquefiable sand layer. A coupled hydromechanical analysis is performed employing the finite-differences code FLAC2D, modelling non-linear soil response with the constitutive model PM4Sand. A broad set of element tests on Hostun sand (widely used in centrifuge modelling) are performed and used for extensive model calibration. The calibrated model is then validated against centrifuge test results. The validation is not restricted to the recorded pore pressure, acceleration and settlement time histories, but extends to the deformation mechanisms extracted from centrifuge testing through image analysis, allowing for an in-depth assessment of the numerical simulation. Overall, the analysis is in good agreement with the centrifuge model test. The pore pressure build-up and the final foundation settlement and displacement fields are predicted with adequate accuracy. Although the accumulated displacements are well reproduced, the failure mechanism is not fully captured. This discrepancy is attributed to dissipation-related phenomena, which are not accurately reproduced in the numerical analysis.

The spacing of PVDs is an essential factor affecting the consolidation effect of vacuum preloading. For exploring the influence of spacing of PVDs on the impact of sludge drainage consolidation, FeCl3, a commonly used inorganic coagulant, was used to pretreat the sludge. In the experiment a vacuum filtration test was carried out to determine the optimal addition amount of FeCl3, and then the landfill sludge was pretreated according to the FeCl3 optimal addition amount. And two different spacing of PVDs were used to carry out a vacuum preloading contrast test. Then, the drainage and settlement were recorded, and water content and vane shear strength (VSS) were measured after the experiment. Finally, Mercury intrusion porosimetry (MIP) was carried out to explore the pore characteristics of the sludge further. The main conclusions are as follows: After conditioning by FeCl3, the sludge’s flocculent structure was destroyed, the intracellular water was released, and the effect of drainage capacity was significantly improved. After the spacing of PVDs is halved, the average volume reduction ratio and shear strength increases, and the effect of advanced dewatering and volume reduction of sludge improved significantly, leading to a better consolidation effect. In the progress of vacuum drainage consolidation, halving the spacing of PVDs results in large pores transformation into small pores, and the range of drainage consolidation is greatly expanded.

Six geosynthetic-reinforced soil (GRS) retaining walls supporting bridge approach roads of an overpass bridge in China exhibited a series of structural problems after 18 years of service. Field investigations demonstrated that the major structural problems consist of excessive lateral facing displacement, settlement and damage of facing panels, and pavement cracks above the GRS retaining walls. The structural problems were mainly caused by inadequate backfill compaction behind the facing, rain water infiltration, the settlement of foundation soil, and reinforcement ageing. Among the six GRS walls, a 22-m-long section collapsed after mild rain in July 2016, and the failure surface in the collapsed zone was mainly located 0.5–0.9 m away from the back of facing panels along the wall height. The field investigation found that external water filtration into the backfill behind the facing panels, and the breakage of connection between reinforcement and facing panels were the main causes of the failure. The connection breakage resulted from the ageing of PP reinforcement strips, and the critical issue of PP reinforcement ageing in complex backfill environment was pinpointed. Remedial measures of the failed section and reinforcing techniques of the remaining GRS walls were briefly presented in the end.

Migration and settlement of temporary plugging particles of different sizes affect the effect of temporary plugging, which in turn affect the effect of reservoir reconstruction. However, the migration and settlement laws of temporary plugging particles in horizontal wellbore are still unclear. In order to study the migration and settlement laws of temporary plugging particles in horizontal wellbore, a set of multicluster perforation physical model experiment device for horizontal wells was built. Based on this experimental device, the effects of mass ratio, pumping rate, and adding sequence on the migration and settlement laws of temporary plugging particles were studied, respectively. The experimental results show that the 3 mm temporary plugging particles move forward in a leaping manner at the bottom of the horizontal wellbore and the 1 mm particles are distributed in layers in the horizontal wellbore, and the particles are less in the upper part of the wellbore and more in the bottom of the wellbore. The migration trajectory of the two mixed particles is similar to the single. Under different mass ratio, the settlement mass of particles in the perforation clusters at the outlet end is greater than that in the entrance end. When the 3 mm particles account for a relatively large amount ( m 3 mm : m 1 mm = 5 : 1 ), the settlement mass of the particles in the two perforation clusters is greater than other mass ratio conditions. For the same perforation, the settlement mass becomes greater as the proportion of 3 mm increases. When only 3 mm particles are considered, with the increasing of displacement, the mass of particles in the perforation clusters at the inlet end increases, and the mass of particles in the clusters at the outlet end decreases. With the increase of displacement, the sedimentation mass of particles in high angle perforations decreases, while the sedimentation mass in other perforations increases. Adding 3 mm first and then 1 mm particles, the particle settlement mass in the perforation cluster at the outlet end is twice the mass of the particles in the perforation cluster at the inlet end. Reversing the sequence, the settlement masses of the particles in the two clusters are almost equal. The particle distribution in the perforation at different angles has obvious gradation. The smaller the angle, the greater the settlement mass of the temporary plugging particles. This research results will provide reference for temporary plugging and fracturing construction.

Soil replacement is a common technique that can be used to increase the soil bearing capacity and reduce the expected settlement. The thickness of replacement layer depends on many factors such as: the applied stress, original soil properties, material of replacement layer and the cost of foundation works. However, until now the practical thickness of replacement is usually selected based on soil experts’ experience. This study proposed an optimization model to assist geotechnical engineers in predicting the optimum thickness and material type of replacement layer that satisfy the main design requirements, i.e. bearing capacity, consolidation settlement and cost considerations at the same time. The Evolutionary solving method that uses a variety of genetic algorithm and local search methods was used to solve the research problem. Furthermore, the effect of the thickness and properties of clay layer and the depth of ground water table on determining optimum type and thickness of replacement soil were investigated. The study evaluated the relationship between the replacement layer thickness and the total direct cost of foundation works and found that, the notion of increasing replacement thickness to decrease cost limitlessly was not viable and an optimal thickness was usually achieved.

The settlement of the widening of soft soil subgrade highways is typically associated with different treatment positions of cement mixed piles. In order to overcome this, in the current paper we employ the finite element method to simulate and analyze the influence of piles under an existing road slope and under an existing subgrade and new embankment on the settlement characteristics of the subgrade and foundation. In particular, we focus on the influence of the pile length and pile spacing on the subgrade and foundation settlements based on a northern high-speed reconstruction and expansion project. The subgrade and foundation soils in the finite element analysis are considered to be homogeneous, continuous, and isotropic elastoplastic materials. The Mohr–Coulomb ideal elastoplastic constitutive model is implemented as the constitutive soil model. The impact of piles under an existing subgrade and new embankment on the settlement is observed to be more significant than that of piles under the existing road slope. Moreover, the subgrade and foundation settlements increase with the pile spacing under the existing road slope and under the existing subgrade and new embankment. More specifically, an increase of the pile spacing from 200% to 400% of the pile diameter is associated with an increase in the maximum settlement of the foundation surface from 1.76 to 1.85 cm (existing road slope) and from 1.44 to 1.96 cm (existing subgrade and new embankment). In addition, the subgrade and foundation settlements decrease for increasing pile lengths under the existing road slope and under the existing subgrade and new embankment, the pile length increases from 4.7 to 9.2 m, and the maximum foundation surface settlement is reduced from 6.2 to 5.52 cm and from 9.73 to 5.43 cm, respectively. The results can provide reference for future subgrade widening projects.

Settlement schemes are aimed at settling landless people and those displaced by disasters to support socio-economic and environmental development of a country. Eastern Mau Forest Reserve is an important water catchment that has settlement schemes established, which has led to encroachments and degradation of the catchment. This paper, therefore, assesses the implications of human settlements on Eastern Mau water catchment by examining the trends in land use/cover change and river flows for four decades. Primary data was collected from key informant interviews based on purposive sampling whereas secondary data was derived from Landsat satellite images over a 10-year period and analysed using Maximum Likelihood Function from ArcGIS. Data on river flows from River Njoro was obtained from Water Resources Authority Office in Nakuru. Rainfall and temperature data were obtained from Kenya Meteorological Station in Nakuru. Time series analysis is used to understand the trend in river flows over time while Pearson correlation is used to determine relationship between farmlands and river flows. The results indicate a sharp decline in forest cover by 42.7% and an increase in farmlands by 41%. Dense vegetation and farmlands have an inverse relationship as an increase in farmlands lead to a decrease in forest cover. People have settled beyond the established settlement schemes boundaries leading to encroachment and drying up of some rivers. There is also an increase in rainfall and river flows over the years, with monthly river flows increasing in peak flows and declining during low seasons. There is a positive correlation between farmlands and river flows between 1989 and 2020. There is need for regeneration of encroached areas and defining boundary of Eastern Mau to allow initiatives and interventions that help with sustainable management of the catchment area.