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In this study, the behavior of soft clay improved with a conductive jute geotextile-encased stone column was investigated, considering the effects of electrokinetic coupling. The study findings suggest that electrokinetic-coupled encased stone columns (e-ESCs) improve the dewatering efficiency, consolidation settlement rate, and shear strength of the soft clay compared to nonelectrokinetic encased columns. After the inclusion of e-ESCs, the time required to remove 50% of the total discharge was decreased by 92% compared to encased stone columns (ESCs). A significant decrease in the volumetric shrinkage and surface cracks was observed for e-ESC-improved soft clay. Further, due to anode corrosion during the process, brass electrodes experienced a 4.25% loss in weight at the end. The consumed power per unit weight of treated soil (Wh/kg) at the end of the test period was 24.03, 19.70, 20.10, and 23.38 Wh/kg for the e-ESC with mild steel, copper, brass, and aluminum anodes, respectively. The findings showed that the choice of anode material affects the characteristics of soft clay, such as undrained shear strength, pore water discharge, flow pattern, and moisture content. Further, a noteworthy modification in the physicochemical properties of clay was observed. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, a mechanical model has been developed to study the behavior of multilayer geosynthetic-reinforced granular fill over stone column-reinforced soft soil. The granular fill and geosynthetic reinforcement layers have been idealized by Pasternak shear layer and rough elastic membranes, respectively. The Kelvin–Voight model has been used to represent the time-dependent behavior of saturated soft soil. The stone columns are idealized by stiffer springs and assumed to be linearly elastic. The nonlinear behavior of the soft soil and granular fill is considered. The effect of consolidation of soft soil due to inclusion of the stone columns on settlement response has also been included in the model. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution and results are presented in nondimensional form. It has been observed that if the soft soil is improved with stone columns, the multilayer reinforcement system is less effective as compared to single layer reinforcement to reduce the total settlement as there is considerable reduction in the total settlement due to stone column itself. Multilayer reinforcement system is effective for reducing the total settlement when stone columns are not used. However, multilayer reinforcement system is effective to transfer the stress from soil to stone column. The differential settlement is also slightly reduced due to application of multiple geosynthetic layers as compared to the single layer reinforcement system. [Copyright &y& Elsevier]

Abstract: The steady-state response of a uniform beam placed on an elastic foundation and subjected to a concentrated load moving with a constant speed has been investigated. The foundation is modeled by using one and two parameters. The mathematical form of the solution is justified by Fourier transform. It is observed that the steady state is not attained at supercritical speed of the load in the ideal undamped case. Numerical results are presented for maximum settlement, uplift and bending moment in the beam. The effect of difference in the modeling of the foundation is shown to be insignificant. [Copyright &y& Elsevier]

In this study, the response of soft clay was assessed during electrokinetic consolidation. The laboratory-based experimental study was conducted in a custom-designed test set-up focusing on soft clay’s engineering and physicochemical response during and at the end of the electrokinetic consolidation. Six electrokinetic consolidation tests were performed under self-weight for 24 h with different voltage gradients. The operational response was investigated by monitoring the electric current and the power consumed during the test. Further, the variation of ohmic heating, volumetric water content, and water potential was continuously measured. The efficacy in enhancing the engineering response is analysed by investigating cumulative discharge, surface settlement, water content, and undrained shear strength of the soft soil. At the end of the test, the effect of electrochemical reactions in altering the soft clay’s pH, microfabric, and mineral phases was investigated. Finally, the quantification of the surface crack was investigated, and their dependence on the applied voltage gradient was established. The study results show substantial enhancement in the engineering characteristics of soft clay. It significantly accelerates the dewatering efficacy, increases the undrained shear strength and surface settlement, and reduces the water content of the soft clay irrespective of the applied voltage gradient. The electrokinetic consolidation increases the temperature of the soft clay. The measured surface cracks give the crack intensity factor of 1.95, 2.10, and 2.15% for the applied voltage gradient of 0.05, 0.10, and 0.15 V/mm, respectively. [ABSTRACT FROM AUTHOR]

This paper pertains to the development of a mechanical model to predict the behavior of a geosynthetic-reinforced granular fill over soft soil improved with stone columns. The saturated soft soil has been idealized by Kelvin–Voight model to represent its consolidation behavior. The stone columns are idealized by stiffer springs. Pasternak shear layer and rough elastic membrane represent the granular fill and geosynthetic reinforcement layer, respectively. The nonlinear behavior of the granular fill and the soft soil is considered. Effect of consolidation of the soft soil due to inclusion of the stone columns has also been included in the model. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution, and results are presented in nondimensional form. Comparison between the results from the present study and the analytical solution using theory of elasticity shows reasonable agreement. The advantage of using geosynthetic reinforcement is highlighted. Results indicate that inclusion of the geosynthetic layer effectively reduces the settlement. Nonlinearity in the behavior of the soft soil and the granular fill is reduced due to the use of geosynthetic reinforcement layer. [ABSTRACT FROM AUTHOR]

A new wave number based approach is proposed for the evaluation of the time-domain Green's function for the railway track idealized as an infinite Euler-Bernoulli beam overlying a Pasternak-type viscoelastic foundation. In the proposed approach, the rail beam response is first computed in the time wave number domain by solving a generalized single-degree-of-freedom system problem using the classical Duhamel integral technique. The Green's function is subsequently evaluated by inverting the so-obtained time wave number solution to the time-space domain. In contrast with the conventional approach, the computational time for evaluating the Green's function using the proposed approach is much smaller. Further, the proposed solution of the Green's function is shown to be convenient for directly evaluating the time-domain response of a rail beam subjected to various types of time-dependent loads. As an illustration, the Green's function is applied to obtain the time-domain response of the rail beam (overlying a viscoelastic layer) subjected to a uniformly moving oscillator by using a novel and simple two-step iterative scheme. The time-domain deflection analysis reveals that the introduction of damping into the oscillator system brings the rail beam response much closer to that associated with the constant moving load idealization. However, if the moving oscillator system is acted upon by an arbitrarily time-varying external vertical load, significantly higher values of rail beam deflections are observed. • Evaluating Green's function for a linear track model using a new wavenumber-based approach. •.Proposed approach is shown to be computationally efficient compared to the conventional track-receptance based approach. • Proposed approach is applied along with a two-step iterative scheme for analyzing the moving-oscillator problem. • Proposed iterative scheme is validated using a recent analytical study. [ABSTRACT FROM AUTHOR]