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In the process of treating the dredged slurry under vacuum preloading combined with the prefabricated vertical drains (PVDs), a dense “soil column” with low permeability will be formed around the PVD, which results in a poor drainage condition and an unsatisfactory treatment (i.e., the clogging effect). In this study, in order to predict the consolidation behavior of dredged slurry with different initial water contents, the compressibility and permeability of dredged slurry with different initial water contents are investigated. Based on the compression and permeability curves obtained by laboratory tests, the analytical solution to soil consolidation under vacuum preloading is derived. Both the clogging effect and the effect of the initial water content on the initial effective stress are considered. The developed analytical solution is validated through a series of consolidation tests of dredged slurry under vacuum preloading with different initial water contents. It shows that at a given vacuum preloading, the dissipation rate of excess pore water pressure in the dredged slurry decreases as the initial water content increases. The proposed analytical solution presents reliable predictions on the variation of settlement and degree of consolidation with time in the dredged slurry with different initial water contents under vacuum preloading.

Laboratory tests have been carried out for simulating dredged-slurry treatment combining air-booster and conventional vacuum preloading methods. Settlement plate, micro pore water pressure transducer and miniature vane shearing instrument are adopted for monitoring the settlement, the pore pressure dissipation and the soil strength during the test. The tests results demonstrate that the air-booster vacuum-preloading method can significantly improve the soil strength, pore-water pressure dissipation and settlement. In particular, the real-time responses of pore-water pressure during the air-pressurizing process have been obtained that, in combination with the numerical simulations, help derive the reinforcement mechanism of the air-booster vacuum preloading method, which involves using micro cracks generated by splitting soil between the booster tube and PVD using the pressurised air. Those cracks improve the soil permeability, and have lasting effect even after air pressuring ceased.

Introducing the prefabricated horizontal drains (PHDs) into the permeable geotextile tubes has been reckoned as an efficient and economical method of dewatering slurries with high water contents. However, its application is limited by the poor understanding of the fundamental consolidation mechanism, often resulting in overconservative designs. With the proposed two-dimensional plane-strain consolidation model, a semi-analytical solution calibrated by laboratory test results is obtained. Furthermore, parametric analyses, for example, PHD pave rate, and element aspect ratio, along with the soil anisotropy coefficient, are also conducted to achieve the optimum design requirement. A critical condition corresponding to the optimum effectiveness of this consolidation technique is found, beyond which the consolidation efficiency decreases gradually. The greater the abovementioned parameters are, the later and milder the efficiency reduction occurs. The consolidation efficiency can keep at a high level until the end of consolidation when the values of these parameters are great enough. In the end, design charts and design recommendations are provided with immediate benefits for practical engineers. Key words: consolidation, slurry, horizontal drains, geotextile tubes, laboratory tests, Introduction Due to rapid modernization in China, the clayey slurries dredged from rivers or coastal regions were nearly 6 billion [m.sup.3] in 2016, increasing by 30% per year at least [...]

Vacuum preloading combined with prefabricated vertical drains (PVDs) system has been widely used to improve the soft clay with high water content. Clogging is usually formed around the PVDs during the vacuum preloading, impeding the propagation of the vacuum pressure and slowing down the consolidation process. To understand the forming mechanism of the clogging, particle image velocimetry (PIV) technique and particle tracking velocimetry (PTV) technique were adopted in the model test of vacuum preloading test. Through this study, three stages can be identified from the results of water volume discharge rate and maximum displacements versus time. In the first stage, the soil around the PVD is horizontally consolidated, which leads to the rapid formation of clogging. In the second stage, the formation of clogging slows down due to the loss of vacuum pressure, which further reduces the drainage. In the third stage, the clogging tends to be stable, and the drainage consolidation rate is significantly reduced. PTV results show that there is a difference in the displacement of large and small particles during improvement. Two methods were proposed to estimate the thickness of clogging zone, reflecting a growing layer of clogging zone compressed around the PVD. This study provides new insights to investigate the formation mechanism of clogging during vacuum preloading test. Key words: vacuum preloading, particle image velocimetry, particle tracking velocimetry, clogging, dredged slurry. Le prechargement sous vide combine au systeme de drains verticaux prefabriques (PVD) a ete largement utilise pour ameliorer l'argile tendre a forte teneur en eau. Un colmatage se forme generalement autour des PVD pendant le prechargement sous vide, empechant la propagation de la pression du vide et ralentissant le processus de consolidation. Afin de comprendre le mecanisme de formation du colmatage, la technique de velocimetrie par image de particules (PIV) et la technique de velocimetrie par suivi de particules (PTV) ont ete adoptees dans le test modele de l'essai de precharge sous vide. Cette etude permet d'identifier trois etapes a partir des resultats du taux de decharge du volume d'eau et des deplacements maximaux en fonction du temps. Dans la premiere etape, le sol autour du PVD est consolide horizontalement, ce qui conduit a la formation rapide de colmatages. Dans la deuxieme etape, la formation de colmatage ralentit en raison de la perte de pression du vide, ce qui reduit encore le drainage. Dans la troisieme etape, le colmatage tend a etre stable, et le taux de consolidation du drainage est considerablement reduit. Les resultats de la PTV montrent qu'il existe une difference dans le deplacement des grandes et petites particules pendant l'amelioration. Deux methodes ont ete proposees pour estimer l'epaisseur de la zone de colmatage, refletant une couche croissante de zone de colmatage comprimee autour du PVD. Cette etude fournit de nouveaux elements pour etudier le mecanisme de formation du colmatage pendant l'essai de prechargement sous vide. [Traduit par la Redaction] Mots-cles: prechargement sous vide, velocimetrie par image des particules, velocimetrie de suivi des particules, colmatage, boue de dragage., Introduction Vacuum preloading combined with prefabricated vertical drains (PVDs) has been widely used to improve the engineering property of the dredge slurry (Chai et al. 2005; Chu et al. 2006; [...]

Treating the high water-content sludge with vacuum-assisted prefabricated horizontal drains (PHDs) placed inside, geotextile tubes have the advantage of multiple drainage paths, and geomembrane tubes have the superiority of high vacuum maintenance. Therefore, converting the geotextile tube into a geomembrane tube during slurry dewatering is an effective measure for greater dewatering efficiency and better dehydration effect. In this study, a profound plane-strain consolidation model considering two-dimensional seepage is developed for explaining the dewatering mechanism of sludge in the geo-tubes. Analytical solutions are given and validated by the experiment. The impact of major variables on tube efficiency is further discussed to reference the practice design. Parametric analyses reveal the critical time corresponding to the optimal efficiency of the geotextile tube, after which its consolidation efficiency decreases significantly. However, the consolidation efficiency of a geomembrane tube increases throughout the duration. Consequently, a switching point corresponding to the iso-efficiency state of the geotextile tube and geomembrane tube can be determined for the tube conversion. [ABSTRACT FROM AUTHOR]

The use of prefabricated horizontal drains (PHDs) with combined surcharge and vacuum preloading is an effective improvement approach for dredged clayey slurries. However, there is no large-strain analysis method for PHD-induced consolidation of high-water-content sludge, even though it is a typical large-strain problem. This study develops a two-dimensional plane strain model based on Gibson's large-strain theory, considering horizontal and vertical flows, nonlinear hydraulic conductivity, and compressibility during the consolidation process. The alternative direction implicit (ADI) difference method is used to solve the governing equation. The proposed model is verified by the data from an analytical one-dimensional (1D) large-strain model and from field measurements. Compared with the improved small-strain models, the proposed model produces a slower consolidation of sludge. Furthermore, the analyses incorporating geometrical and mechanical nonlinearities show that, in comparison with the external load and the horizontal permeability, the spacing of the PHDs (horizontal and vertical) and the vertical permeability are more crucial factors significantly impacting consolidation efficiency. Specifically, smaller PHD spacing and greater vertical permeability lead to a more efficient consolidation. [ABSTRACT FROM AUTHOR]

This paper presents a profound solution for a novel method of dewatering dredged sludge using a combined geotextile tube and vacuum-assisted prefabricated horizontal drains. Firstly, an analytical model was proposed to provide a basis for the design of the proposed approach. This two-dimensional plane-strain consolidation model was based on Gibson's large-strain theory, incorporating the horizontal and vertical flows with consideration of the self-weight, nonlinear compressibility, and hydraulic conductivity of soil. Secondly, the numerical solution obtained using the alternative direction implicit method was compared with the existing one-dimensional model for verification. Thirdly, a field trial was carried out to evaluate the performance of the proposed approach and analytical model. Finally, the effects of various major design parameters on the consolidation efficiency of the tube system were also investigated through a parametric study to establish an optimal design. This study showed that a higher consolidation efficiency and an earlier optimal efficiency point could be achieved when decreasing the horizontal drain interval and increasing the tube height. Furthermore, surcharge preloading induces a more significant effective stress increment in soil than vacuum preloading of the same magnitude. [ABSTRACT FROM AUTHOR]

A very soft clay layer is highly compressible and exhibits significant creep under loading. The classical linearly elastic constitutive relationship and small-strain assumption are not suitable for the consolidation analysis of very soft clays. This paper presents a new large-strain consolidation model that incorporates the Yin-Graham elastic viscoplastic (EVP) constitutive equation for use in studying the consolidation of very soft clay layers with vertical drains under preloading. First, the large-strain fluid continuity equation and the EVP constitutive equation are incorporated into a quadratic differential equation of pore-water pressure and its integral terms. Second, the alternating-direction implicit (ADI) method and virtual node method are adopted to obtain the finite difference solution. A computer program named 'BSSDS' is developed for large-strain EVP consolidation analysis of clay layers with vertical drains, taking into account the complicated in situ conditions, such as resistance of vertical drains, smear effects, variation of permeability with void ratio, and multilayered soils. Third, the new large-strain numerical method is applied to the consolidation modeling of very soft clay layers with vertical drains under preloading at a site that is part of the Hong Kong-Shenzhen Western Corridor Link Project. It is found that the foundation settlements of the new large-strain EVP consolidation model have good agreement with the measured data. Finally, three different consolidation models are used to calculate the average degree of consolidation and settlements of the clay layers. The analysis shows that it is essential to consider both large-strain compression and creep effects in the analysis of very soft clay layers with vertical drains under loading. Key words: soft clay, consolidation, elastic viscoplastic model, large strain, vertical drain. Une couche d'argile tres molle est consideree comme tres compressible et presente du fluage significatif lors de sollicitations. La relation lineaire elastique constitutive classique et l'hypothese des faibles deformations ne sont pas appropriees lors de l'analyse de consolidation d'argiles tres molles. Cet article presente un nouveau modele de consolidation a grande deformation qui integre l'equation constitutive elastique viscoplastique (EVP) de Yin-Graham pour l'etude de la consolidation dans des couches d'argile tres molle avec des drains verticaux, soumises a des pre-charges. Premierement, l'equation de continuite des fluides a grande deformation et l'equation constitutive EVP sont integrees dans une equation differentielle quadratique decrivant la pression interstitielle et ses termes integraux. Deuxiemement, la methode implicite de direction alternative (IDA) et la methode du noeud virtuel sont adoptees pour obtenir la solution de la difference finie. Un programme informatique appele BSSDS a est developpe pour l'analyse de consolidation EVP a grande deformation de couches d'argile ayant des drains verticaux, en considerant les conditions in situ complexes, telles que la resistance des drains verticaux, les effets de souillures, la variation de la permeabilite selon l'indice des vides, ainsi que les sols multicouches. Troisiemement, la nouvelle methode numerique a grande deformation est appliquee pour la modelisation de la consolidation de couches d'argile tres molle avec des drains verticaux et soumis a des pre-charges sur un site qui fait partie du projet de Corridor Ouest Hong Kong-Shenzhen. Il est demontre que les tassements de la fondation selon le nouveau modele de consolidation EVP a grande deformation correspondent bien avec les donnees mesurees. Enfin, trois modeles de consolidation differents sont utilises pour calculer le degre de consolidation moyen et les tassements des couches d'argile. L'analyse montre qu'il est essentiel de considerer la compression a grande deformation et les effets de fluage lors de l'analyse de couches d'argile tres molle ayant des drains verticaux et soumises a des solicitations. [Traduit par la Redaction] Mots-cles: argile molle, consolidation, modele elastique viscoplastique, grande deformation, drain vertical., Introduction With rapid economic growth, the demand for infrastructure construction over reclaimed lands and soft marine clays has continuously increased in the coastal areas of many countries and regions. In [...]

Lime treatment combined with vacuum preloading has been used in the treatment of dredging slurry for many years. Previous studies have indicated that particle grading, which is one of the essential properties of slurry, could affect the pore-size distribution and compression characteristics of slurry and thus affect the efficacy of the lime treatment and vacuum preloading. However, the effect of particle grading has not yet been examined quantitatively. This study investigated the compressibility of lime-treated slurries with different particle gradings using a one-dimensional oedometer for compression testing. A series of laboratory model tests were carried out to examine the effect of particle grading on the efficacy of lime-treated slurry with vacuum preloading. The results showed that particle grading significantly influences optimal lime content. For clay or low-plasticity silt, the optimum lime content for lime treatment combined with vacuum preloading was found to be 2%. When slurry contains increased silt and sand grains, more lime is required to achieve effective lime treatment. However, excessive lime would reduce the efficacy of lime treatment on the compressibility and permeability of the soil. [ABSTRACT FROM AUTHOR]

Recently, permeable geotextile tubes in conjunction with prefabricated horizontal drains (PHDs) have become increasingly popular for dewatering high water content slurries or sludge. However, how to analyze the consolidation process of the sludge in the geotextile tube so as to provide a proper design and prediction becomes a technical challenge. In this paper, we have proposed a two-dimensional plain-strain consolidation model for sludge consolidation in a geotextile tube under combined fill and vacuum preloading. A semi-analytical solution was obtained and validated through experimental observations. A salient finding of this study is the identification of a critical condition at which the optimum consolidation efficiency is achieved. Consolidation efficiency decreases gradually beyond this critical condition, which arrives later as the PHD pave rate and element height to width ratio increase. Furthermore, this analytical method clearly shows how preloading affects the dewatering process and the effect of fill surcharge is more pronounced than that of vacuum preloading of the same magnitude, owing to the vacuum attenuation and leakage. [ABSTRACT FROM AUTHOR]

Parameters of soil constitutive models are usually identified through laboratory tests. The spatial variability of these parameters is generally not considered due to the limitation of the test scale. This study proposes a data‐driven approach to infer the spatially varying parameter of the modified Cam‐clay model from limited field observations and subsequently improves soil settlement predictions. The observation data and numerical results of random finite element method are assimilated in an inverse modeling process based on the iterative Ensemble Kalman filtering (iEnKF). Different unknown variables and number of observations are used to study their effects on parameter estimations and settlement predictions. The effectiveness of the proposed approach is illustrated through a synthetic partial‐loading test. The results show that the site‐specific spatial variability can be estimated reasonably, and predictions of settlement can be improved by using the inferred parameter field. When the variables to be inferred change from all 60 variables to the selected 17 important variables, the average error of the estimated fields increases, but the variance decreases. A reduction in the observation spacing and an increase in the number of observations lead to a slightly smaller error of the mean and considerably reduced uncertainties of soil parameters. Although the inferred results of parameter field show different accuracies, the corresponding calculated settlements are generally similar and satisfactory. [ABSTRACT FROM AUTHOR]

With the development of the transportation, the bridge approach settlement (BAS) received great attention which can result in structure deterioration of the bridge and road, costly maintenance, and hazardous driving conditions. Therefore, accurate prediction of BAS is important. In this paper, a methodology using the iterative procedure is presented to predict the long-term BAS. In this method, the dynamic deviator stress is obtained by a 3D finite element road model and the settlement is calculated by an empirical model with the dynamic deviator stress. Then, the settlement is used as the excitation of the vehicle model for updating the load in the 3D road model. After several iterative calculations, the long-term BAS can be obtained. The comparison between the iterative method and the empirical method is presented. Also the parametric study of the empirical equation is performed. A simplified equation considering the iterative procedure is proposed for engineering practice. Computed results showed that the permanent settlement predicted by the iterative method is larger than that calculated by the empirical method. Also, the parameters of the empirical equation have great effects on the settlement prediction. The applicability of the new empirical equation is also proved. [ABSTRACT FROM AUTHOR]

A series of one-dimensional incremental load consolidation–hydraulic conductivity tests was performed on reconstituted clays. Based on these tests, together with the test data compiled from the literature, the quantitative interrelation between the variation of hydraulic conductivity in the vertical direction with void ratio and the compression behaviour is established. It is found that the hydraulic conductivity in the vertical direction can be expressed as a function of void index, initial void ratio and void ratio at the liquid limit. The effects of initial void ratio and void index on hydraulic conductivity in the vertical direction for a given clay with a given void ratio at the liquid limit can be comprehensively attributed to the effect of void ratio on hydraulic conductivity in the vertical direction. These two findings introduce the point that the hydraulic conductivity in the vertical direction is a function of void ratio and void ratio at the liquid limit. Empirical equations are proposed to determine the hydraulic conductivity in the vertical direction using void ratio and void ratio at the liquid limit or using effective vertical stress, initial void ratio and void ratio at the liquid limit. These two empirical equations are correlated based on the concept of intrinsic compression. [ABSTRACT FROM AUTHOR]

The design of preloading involves loading schedule design and prediction of post-construction settlement. As the in situ measurement data are usually unavailable during the loading schedule design, it is difficult [...]

Summary: The system of vacuum pressure combined with vertical drains to accelerate soil consolidation is one of the most effective ground improvement methods. The consolidation theories of soft soil improved by vertical drains including void ratio–dependent compressibility and permeability have been widely applied in practice to predict the consolidation behavior. In this paper, analytical solutions of the consolidation of vertical drains are derived incorporating the loss and propagating stage of vacuum pressure. In addition, special solutions are obtained for the cases of instantaneous surcharge loading and staged surcharge loading, based on the general solution. The solution is verified by ignoring the propagating stage of vacuum pressure formation and comparing it with an existing solution. The effects of vacuum pressure loss and propagating stage combined with other parameters are investigated through the ratio between excess pore water pressure and surcharge loading. [ABSTRACT FROM AUTHOR]

The sedimentation process of granular materials exists ubiquitously in nature and many fields which involve the solid-liquid separation. This paper employs the coupled computational fluid dynamics and discrete element method (CFD-DEM) to investigate the sedimentation process of non-cohesive particles, including the hindered settling stage and the deposition stage. Firstly, the coupled CFD-DEM model for sedimentation is validated by the hindered settling velocity at different solid volume concentrations of suspension $$\phi _{0} $$ , i.e., $$\phi _0 =$$ 0.05-0.6. Two typical modes of sedimentation are also presented by the concentration profiles and the equal-concentration lines. Then, the comparisons between mono- and poly-dispersed particle system are detailed. In the sedimentation of the poly-dispersed particle system, the segregation phenomenon is simulated. Furthermore, this segregation effect reduces with the increase of the initial solid concentration of suspension. From the simulations, the contact force between every pair of particles can be obtained, hence we demonstrate the 'effective stress principle' from the view of the particle contact force by giving the correspondence between the particle contact force and the 'effective stress', which is a critical concept of soil mechanics. Moreover, the deposition stage can be simulated by CFD-DEM method, therefore the solid concentrations of sediment bed $$\phi _{\mathrm{max}} $$ on different conditions are studied. Based on the simulation results of $$\phi _{\mathrm{max}} $$ and the theory of sedimentation, this paper also discusses a method to calculate the critical time when sedimentation ends of two typical modes of sedimentation. [ABSTRACT FROM AUTHOR]

Characteristic of cyclic loading due to passing wheels is associated with one-way loading without stress reversal, which includes a simultaneous cyclic variation of vertical normal stress and horizontal normal stress lasting for a long period of time and generally takes place in partially-drained conditions. Therefore, it is of great practical relevance to study the deformation behaviour according to the characteristic of traffic loading. In this work, a series of one-way stress-controlled cyclic triaxial tests with a simultaneous variation of the vertical and horizontal stress components during cyclic loading were conducted to investigate the deformation behaviour of natural K-consolidated soft clay in partially-drained conditions. Test results demonstrate that not only the deviator part of the stress rules accumulation but also the volumetric part significantly contributes. While the deviator part of the stress amplitude is held constant, the increase amplitude of cyclic confining pressure will promote the development of both permanent volumetric strain and axial strain significantly. Furthermore, the effects of cyclic confining pressure on the deformation of natural K-consolidated soft clay was quantified. Finally, an empirical formula for permanent axial strain considering the effects of cyclic confining pressure was proposed which can be used for feasibility studies or for the preliminary design of foundations on K-consolidated soft clay subjected to traffic loading. [ABSTRACT FROM AUTHOR]

Abstract: Dynamic vibrations of a circular rigid foundation, which is embedded in poroelastic soil and subjected to incident P waves, are studied by semi-analytical methods in this present work. The motion of the soil is governed by Biot''s dynamic poroelastic theory. A set of potentials are introduced to represent the incident waves, and the scattering waves caused by the foundation are considered based on the decomposition of the total wave field in soil. The soil along the vertical side of the foundation is assumed to be composed of series of infinitesimally thin poroelastic layers, while the soil under the foundation base is regarded as the poroelastic half-space and to be independent of the overlying soil. The interaction problem is solved by Hankel transforms. Then, combining the boundary conditions along the contact surface between the soil and the foundation and the dynamic equilibrium equation of the foundation, expressions of the vertical and rocking vibration amplitudes of the embedded foundation excited by the incident P waves are acquired. Numerical results are presented to demonstrate the influences of embedded depth, foundation mass, pore water in the soil and incident angle on the vibrations of the foundation. [Copyright &y& Elsevier]

Abstract: This paper studies the displacements behind a row of elastic piles in a homogeneous unbounded poroelastic soil after excitation by the passage of elastic waves. Biot’s theory is employed to describe soil behavior. Using a Fourier–Bessel series expansion with the aid of a translational addition theorem, closed-form expressions for the scattering coefficients are developed by imposing continuity conditions at the pile–soil interfaces. The influence of certain parameters, such as pile rigidity and soil permeability on the screening performance of the pile barrier is investigated. Particular attention is focused on the influence of the soil permeability on the screening effectiveness of a row of piles in the frequency domain. [Copyright &y& Elsevier]

Abstract: This paper presents the results of a parametric study investigating the axisymmetric consolidation of a semi-infinite transversely isotropic saturated clay subjected to a time-varying circular pressure at the ground surface. Based on Biot’s governing consolidation equations for transversely isotropic clay, the general solutions have been previously derived by applying the Laplace–Hankel transform technique. A numerical inverting procedure was then used to study the consolidation behavior in the time domain for three loading cases, that is, instantaneous constant, ramp, and cyclical sinusoidal loadings. The obtained numerical results demonstrate that the pore pressure dissipation of the clay under the aforementioned time-varying loadings exhibits different characteristics that require special attention. Under ramp loading, the non-dimensional construction time factor, , significantly influences pore pressure dissipation, while under cyclical loading, pore water pressure changes may lag behind or exceed the period of the cycle, depending on the parameters that characterize the properties of the transversely anisotropic soil. Moreover, the change of soil surface settlement always lags behind the loading period under cyclical loading, which generates a negative pore water pressure. [Copyright &y& Elsevier]

In order to study the dynamic response of reinforced pavement on soft clay under traffic loading, cyclic triaxial tests were conducted to investigate the effects of initial deviator stress and load cycles on the softening behavior of clay. The empirical equation for softening of clay was proposed by using regression analysis method. Then the equation was imported into ABAQUS through compiled subroutine. Contact interface elements were used between geogrid and soil. Dynamic response of unreinforced and geogrid reinforced pavement was studied by FEM program ABAQUS in order to investigate the reinforcement effect. FEA results indicate that softening behavior of clay has important effect on the performance of reinforced pavement. Geogrid reinforcement can provide lateral confinement at the bottom of the base layer by improving the interface shear resistance, and improve the stress distribution on subgrade layer. The geogrid reinforcement can reduce the surface deformation and nonuniform settlement. [ABSTRACT FROM AUTHOR]

Abstract: Based on Gibson’s governing equation for one-dimensional finite-strain consolidation of a saturated thick soil layer, a simple semi-analytical method is developed to solve the problem of one-dimensional consolidation by taking into account the varied compressibility of soil under cyclic loadings. The solution in the transformed domain is obtained using the method of Laplace transforms. Thereafter a numerical inverting procedure is applied to study the behaviors in the time domain. The variation of soil compressibility during compression and rebound is paid special attention, and a computer program has been written that enables this facet of soil behavior to be accounted for. The technique used is numerically stable and has proved accurate in predicting consolidation settlements and the distribution of void ratios within soil layers. [Copyright &y& Elsevier]

On the basis of Terzaghi’s one-dimensional consolidation theory, the variation of effective stress ratio in layered saturated soils with impeded boundaries under time-dependent loading was studied. By the method of Laplace transform, the solution was presented. Influences of different kinds of cyclic loadings and impeded boundaries conditions were discussed. Through numerical inversion of Laplace transform, useful illustrations were given considering several common time-dependent loadings. Pervious or impervious boundary condition is just the special case of the problem considered here. Compared with average index method, the results from the method illustrated are more accurate. [ABSTRACT FROM AUTHOR]

The authors of the article "Large-Strain Elastic Viscoplastic Consolidation Analysis of Very Soft Clay Layers With Vertical Drains Under Preloading" that appeared in a 2014 issue of the "Canadian Geotechnical Journal" respond to a report within the issue by Gholamreza Mesri and Cai Wang criticized their research. Topics include design of preloading, the calculation of the void ratio, soil consolidation, and related equations.

A novel sheet-pile groin structure consisting of row piles and a tied sheet has been introduced to resist the impact of tidal bores in recent years. However, the dynamic responses of the structure under tidal bore loads have not been carefully studied before. This paper proposed an analytical solution for the dynamic responses of a sheet-pile groin subjected to transient lateral excitation. To take the flexural and longitudinal vibrations into consideration, the piles and the sheet are modeled by Timoshenko beam (TB) theory and a one-dimensional rod, respectively. The soil around the piles is simulated by the dynamic Winkler foundation model. The excitation is considered by a lateral concentrated point load acting on the front pile. On this basis, the governing equations are constructed in the time domain and solved in the frequency domain, while the time-domain responses are obtained using the inverse Fourier transform. The accuracy of the presented analytical solution is validated by comparison with the results obtained from finite element method (FEM) simulation. The effects of the properties of the sheet, piles and soil on the dynamic responses are investigated through a comprehensive parametric study. • Dynamic responses of the sheet-pile groin subjected to a transient lateral excitation are developed. • The mathematical model takes the flexural and longitudinal vibrations into consideration to simulate the sheet-pile groin. • Velocity responses of the sheet-pile groin in time and frequency domain depend on the stiffness of the sheet-pile. • The higher shear wave velocity of the soil corresponds to a greater resonance frequency. [ABSTRACT FROM AUTHOR]

In this work, the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays.

Biot's two-phase theory for fluid-saturated porous media was applied in a study carried out to investigate the influence of water saturation on propagation of elastic wave in transversely isotropic nearly saturated soil. The characteristic equations for wave propagation were derived and solved analytically. The results showed that there are four waves: the first and second quasi-longitudinal waves (QP1 and QP2), the quasi-transverse wave (QSV) and the anti-plane transverse wave (SH). Numerical results are given to illustrate the influence of saturation on the velocity, dispersion and attenuation of the four body waves. Some typical numerical results are discussed and plotted. The results can be meaningful for soil dynamics and earthquake engineering.