Large-strain consolidation analysis of PVD-installed soft soil considering the discharge capacity variation according to depth and time

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ba-Phu Nguyen ◽  
Ananta Man Singh Pradhan ◽  
Tan Hung Nguyen ◽  
Nhat-Phi Doan ◽  
Van-Quang Nguyen ◽  
...  
Keyword(s):  
Numerical Solution ◽  
Discharge Capacity ◽  
Large Strain ◽  
Soft Soil ◽  
Monitoring Data ◽  
Two Dimensional ◽  
Content Type ◽  
Prefabricated Vertical Drain ◽  
Consolidation Rate ◽  
Consolidation Behavior

Purpose The consolidation behavior of prefabricated vertical drain (PVD)-installed soft deposits mainly depends on the PVD performance. The purpose of this study is to propose a numerical solution for the consolidation of PVD-installed soft soil using the large-strain theory, in which the reduction of discharge capacity of PVD according to depth and time is simultaneously considered. Design/methodology/approach The proposed solution also takes into account the general constitute relationship of soft soil. Subsequently, the proposed solution is applied to analyze and compare with the monitoring data of two cases, one is the experimental test and another is the test embankment in Saga airport. Findings The results show that the reduction of PVD discharge capacity according to depth and time increased the duration required to achieve a certain degree of consolidation. The consolidation rate is more sensitive to the reduction of PVD discharge capacity according to time than that according to the depth. The effects of the reduction of PVD discharge capacity according to depth are more evident when PVD discharge capacity decreases. The predicted results using the proposed numerical solution were validated well with the monitoring data for both cases in verification. Research limitations/implications In this study, the variation of PVD discharge capacity is only considered in one-dimensional consolidation. However, it is challenging to implement a general expression for discharge capacity variation according to time in the two-dimensional numerical solution (two-dimensional plane strain model). This is the motivation for further study. Practical implications A geotechnical engineer could use the proposed numerical solution to predict the consolidation behavior of the drainage-improved soft deposit considering the PVD discharge capacity variation. Originality/value The large-strain consolidation of PVD-installed soft deposits could be predicted well by using the proposed numerical solution considering the PVD discharge capacity variations according to depth and time.

Analysis of consolidation behavior of PVD-improved ground considering a varied discharge capacity

2018 ◽  
Vol 35 (3) ◽  
pp. 1183-1202 ◽  
Author(s):  
Yun Tae Kim ◽  
Ba-Phu Nguyen ◽  
Dae-Ho Yun
Keyword(s):  
Numerical Analysis ◽  
Discharge Capacity ◽  
Linear Distribution ◽  
Content Type ◽  
Prefabricated Vertical Drain ◽  
Vertical Hydraulic Conductivity ◽  
Consolidation Rate ◽  
Nonlinear Distribution ◽  
Test Embankment ◽  
Good Agreement

Purpose It is well-known that consolidation rate of prefabricated vertical drain (PVD)-installed ground is closely related to the discharge capacity of PVD, which decreases with an increase in effective stress. This paper aims to present consolidation behaviors of PVD-improved ground considering a varied discharge capacity of PVD. Design/methodology/approach A simple equivalent vertical hydraulic conductivity (k′ve method) was proposed in plane strain numerical analysis, in which the effect of decreased discharge capacity with depth was considered. Numerical analysis was applied to analyze field behaviors of test embankment of soft mucky deposit. Findings Finite element method results indicated that consolidation behaviors of PVD-improved soil with a nonlinear distribution of discharge capacity with depth were in a good agreement with the observed field behaviors, compared with those with a constant discharge capacity and a linear distribution of discharge capacity. At a given time and depth, the consolidation rate in the case of discharge capacity with a nonlinear distribution is lower than that of a linear or constant distribution. Practical implications A geotechnical engineer could use the proposed method to predict consolidation behaviors of drainage-installed ground. Originality/value Consolidation behaviors of PVD-installed ground could be reasonably predicted by using the proposed method with considering effect of discharge capacity reduction.

Consolidation behavior of dredged ultra-soft soil improved with prefabricated vertical drain at the Mae Moh mine, Thailand

2020 ◽  
Vol 48 (4) ◽  
pp. 561-571 ◽  
Author(s):  
Dong Huy Ngo ◽  
Suksun Horpibulsuk ◽  
Apichat Suddeepong ◽  
Menglim Hoy ◽  
Artit Udomchai ◽  
...  
Keyword(s):  
Soft Soil ◽  
Vertical Drain ◽  
Prefabricated Vertical Drain ◽  
Mae Moh ◽  
Consolidation Behavior

An analytical solution for consolidation of PVD-installed deposit considering nonlinear distribution of hydraulic conductivity and compressibility

2019 ◽  
Vol 36 (2) ◽  
pp. 707-730 ◽  
Author(s):  
Ba-Phu Nguyen ◽  
Yun-Tae Kim
Keyword(s):  
Hydraulic Conductivity ◽  
Analytical Solution ◽  
Field Measurements ◽  
Soil Disturbance ◽  
Excess Pore Pressure ◽  
Content Type ◽  
Disturbed Zone ◽  
Prefabricated Vertical Drain ◽  
Time Required ◽  
Consolidation Behavior

Purpose It is well known that the prefabricated vertical drain (PVD) installation process generates a significant soil disturbance around PVD. This disturbed zone significantly affects the rate of settlement and excess pore pressure dissipation. However, the characteristics of these zones were still uncertain and difficult to quantify; there remains large discrepancy among researchers. This study aims to develop a simple analytical solution for radial consolidation analysis of PVD-installed deposit considering mandrel-induced disturbance. Design/methodology/approach The proposed solution takes into account the nonlinear distributions of both horizontal hydraulic conductivity and compressibility toward the drain. The proposed solution was applied to analyze field behavior of test embankment in New South Wales, Australia. Findings Both effects significantly increased the time required to achieve a certain degree of consolidation. The effect of hydraulic conductivity on the consolidation rate was more significant than the effect of compressibility variation. And, the increased compressibility in the soil-disturbed zone due to mandrel installation significantly increased vertical strain of the PVD-improved soil deposit. The predicted results using the proposed analytical solution were in good agreement with the field measurements. Practical implications A geotechnical engineer could use the proposed analytical solution to predict consolidation behavior of drainage-installed ground. Originality/value Consolidation behavior of PVD-installed ground could be reasonably predicted by using the proposed solution with considering variations of both hydraulic conductivity and compressibility due to PVD installation.

scholarly journals Numerical Solution of Nonlinear Large Strain Consolidation Based on Non-Darcian Flow

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Xu-dong Zhao ◽  
Wen-hui Gong
Keyword(s):  
Numerical Solution ◽  
Large Strain ◽  
Geometrical Nonlinearity ◽  
Soil Layer ◽  
Slowing Down ◽  
Vertical Strain ◽  
Huge Impact ◽  
Consolidation Rate ◽  
In The Beginning ◽  
Final Settlement

In this paper, based on non-Darcian flow, the governing equation of 1D nonlinear large strain consolidation is established, which comprehensively accounts for vertical strain, soil self-weight, geometrical nonlinearity, continuity of pore water flow, the relative velocity of the fluid and solid phases, and changing compressibility and hydraulic conductivity during consolidation. Then the numerical solution is obtained with the finite difference method (FDM). Verification of the FDM solution shows excellent accuracy. On this basis, we investigate the influence of the non-Darcian flow on consolidation behavior. The results show that the increase of the non-Darcian exponent will accelerate the consolidation rate in the beginning, while slowing down the consolidation rate in the end. However, it has no effect on the final settlement of the soil layer. In addition, boundary drainage conditions have a huge impact on the consolidation rate, whether it is Darcian or non-Darcian flow.

scholarly journals Determination of the time-dependent convection coefficient in two-dimensional free boundary problems

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mousa Huntul ◽  
Daniel Lesnic
Keyword(s):  
Inverse Problem ◽  
Free Boundary ◽  
Numerical Solution ◽  
Input Data ◽  
Free Boundary Problems ◽  
Time Dependent ◽  
Two Dimensional ◽  
Convection Coefficient ◽  
Content Type ◽  
Noisy Input

Purpose The purpose of the study is to solve numerically the inverse problem of determining the time-dependent convection coefficient and the free boundary, along with the temperature in the two-dimensional convection-diffusion equation with initial and boundary conditions supplemented by non-local integral observations. From the literature, there is already known that this inverse problem has a unique solution. However, the problem is still ill-posed by being unstable to noise in the input data. Design/methodology For the numerical discretization, this paper applies the alternating direction explicit finite-difference method along with the Tikhonov regularization to find a stable and accurate numerical solution. The resulting nonlinear minimization problem is solved computationally using the MATLAB routine lsqnonlin. Both exact and numerically simulated noisy input data are inverted. Findings The numerical results demonstrate that accurate and stable solutions are obtained. Originality/value The inverse problem presented in this paper was already showed to be locally uniquely solvable, but no numerical solution has been realized so far; hence, the main originality of this work is to attempt this task.

The Best Perturbation Method for the Parameter Inversion of Two-Dimension Convection-Diffusion Equation

2013 ◽  
Vol 380-384 ◽  
pp. 1143-1146
Author(s):  
Xiang Guo Liu
Keyword(s):  
Inverse Problem ◽  
Diffusion Equation ◽  
Perturbation Method ◽  
Numerical Simulations ◽  
Numerical Solution ◽  
Two Dimensional ◽  
Convection Diffusion ◽  
Convection Diffusion Equation ◽  
Parameter Inversion ◽  
Parametric Inversion

The paper researches the parametric inversion of the two-dimensional convection-diffusion equation by means of best perturbation method, draw a Numerical Solution for such inverse problem. It is shown by numerical simulations that the method is feasible and effective.

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