Radial consolidation analysis of unsaturated soil with vertical drains under various cyclic loadings

2021 ◽  
Author(s):  
Pyol Kim ◽  
Myong‐Chol Ri ◽  
Kil‐Sang Ri ◽  
Myong‐Chol Rim ◽  
Song‐Guk Jong
Keyword(s):  
Unsaturated Soil ◽  
Vertical Drains ◽  
Consolidation Analysis

scholarly journals Consolidation Analysis of Ideal Sand-Drained Ground with Fractional-Derivative Merchant Model and Non-Darcian Flow Described by Non-Newtonian Index

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Zhongyu Liu ◽  
Penglu Cui ◽  
Jiachao Zhang ◽  
Yangyang Xia
Keyword(s):  
Fractional Derivative ◽  
Flow Model ◽  
Soft Soil ◽  
Viscoelastic Behavior ◽  
Vertical Flow ◽  
Vertical Drains ◽  
Saturated Clay ◽  
Implicit Finite Difference ◽  
Consolidation Analysis ◽  
The Ideal

To further investigate the rheological consolidation mechanism of soft soil ground with vertical drains, the fractional-derivative Merchant model (FDMM) is introduced to describe the viscoelastic behavior of saturated clay around the vertical drains, and the flow model with the non-Newtonian index is employed to describe the non-Darcian flow in the process of rheological consolidation. Accordingly, the governing partial differential equation of the ideal sand-drained ground with coupled radial-vertical flow is obtained under the assumption that the vertical strains develop freely. Then, the numerical solution to the consolidation system is conducted using the implicit finite difference method. The validity of this method is verified by comparing the results of Barron’s consolidation theory. Furthermore, the effects of the parameters of non-Darcian flow and FDMM on the rheological consolidation of ground with vertical drains are illustrated and discussed.

scholarly journals Nonlinear Radial Consolidation Analysis of Soft Soil with Vertical Drains under Cyclic Loadings

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Pyol Kim ◽  
Hyong-Sik Kim ◽  
Yong-Gun Kim ◽  
Chung-Hyok Paek ◽  
Song-Nam Oh ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Governing Equation ◽  
Analytical Solutions ◽  
Soft Soil ◽  
Time Dependent ◽  
Vertical Drains ◽  
Consolidation Analysis ◽  
Consolidation Behavior

This paper presents analytical solutions for nonlinear radial consolidation of soft soil with vertical drains under various cyclic loadings. By considering the nonlinear variations of compressibility and permeability expressed by the logarithm relations (e−log σ′ and e−log kh), the governing equation for nonlinear radial consolidation of the soil under equal strain and time-dependent loading is established. The analytical solutions are derived for nonlinear radial consolidation under haversine cyclic loading, trapezoidal cyclic loading, rectangular cyclic loading, and triangular cyclic loading. The presented solution is verified through the degeneration into the existing solutions for nonlinear radial consolidation under constant and ramp loadings, which shows the solution proposed in this paper is more general for nonlinear radial consolidation under time-dependent loading. The nonlinear radial consolidation behavior of the soil with vertical drains subjected to various cyclic loadings is investigated using the solutions developed. The proposed solutions can be effectively utilized in the analysis of nonlinear radial consolidation under various cyclic loadings.

Large-strain elastic viscoplastic consolidation analysis of very soft clay layers with vertical drains under preloading

2014 ◽  
Vol 51 (2) ◽  
pp. 144-157 ◽  
Author(s):  
Ya-Yuan Hu ◽  
Wan-Huan Zhou ◽  
Yuan-Qiang Cai
Keyword(s):  
Constitutive Equation ◽  
Large Strain ◽  
Water Pressure ◽  
Soft Clay ◽  
Constitutive Relationship ◽  
Vertical Drains ◽  
In Situ Conditions ◽  
Consolidation Model ◽  
Clay Layers ◽  
Consolidation Analysis

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.

scholarly journals The role of unsaturated soil mechanics in unconventional tailings deposition

2021 ◽  
Vol 44 (3) ◽  
pp. 1-11
Author(s):  
Paul Simms
Keyword(s):  
Unsaturated Soil ◽  
Soil Mechanics ◽  
Real Field ◽  
Negative Consequences ◽  
Structural Part ◽  
Sulphide Minerals ◽  
History Effects ◽  
Unsaturated Soil Mechanics ◽  
Consolidation Analysis

Desiccation (water loss by drying or freeze-thaw sufficient to generate matric suction), can influence the performance of a tailings deposit both positively and negatively. The significance of desiccation is largest in tailings that have been dewatered prior to deposition, by thickening or filtration. Such tailings can be “stacked” or deposited with a significant slope, which usually implies that a substantial volume of tailings remain above water. Under such conditions the tailings, by accident or by design, may undergo desiccation before burial by fresh tailings. Desiccation can contribute substantially to strength, above and beyond the contribution arising from increase in density, through stress history effects. For some deposits, it is required practice that at least some tailings undergo desiccation to improve, particularly when those tailings for a structural part of a deposit. If, however, tailings remain exposed to the atmosphere in an unsaturated state for some period of time, this may have potential negative consequences through oxidation of sulphide minerals and the formation of acid drainage. This paper describes previous research on the strength gained through desiccation in tailings, and on modelling work that incorporates unsaturated soil phenomena into consolidation analysis. Both types of research are applied to a real field site, providing an example of how novel improvements to tailings management can arise out of application of principles of unsaturated soil mechanics.

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