Stability of Three-Dimensional Slurry Trenches with Inclined Ground Surface: A Theoretical Study

Xiao-Fei Jin,Xiao-Jun Zhu,Shu-Ting Liang

doi:10.1155/2015/362160

Abstract

Stability of slurry trenches is an important issue during the construction of the groundwater cutoff walls and diaphragm walls, and thus gradually draws attention. In this paper, a theoretical method for a three-dimensional trench model with an inclined ground was proposed. Based on the Coulomb-type force equilibrium, a safety factor assessing the stability was derived. The results showed that the existing two-dimensional model was conservative compared to the present three-dimensional model; concretely, a greater inclined angle of the inclined ground and trench length decreased the safety factor. This work could be used to assess the trench stability for both 2D and 3D cases with inclined ground surfaces.

Highlights

Slurry trenches are often used as a hydraulic barrier to prevent the groundwater from flowing into the trenches during the construction of groundwater cutoff walls and diaphragm walls, and the slurry in the excavated trenches plays an important role in providing a lateral supporting force to the trench walls before backfilling
In the early stage, a two-dimensional limit equilibrium method for trench stability based on a simple Coulomb wedge for dry soil conditions was developed [10]; later, the method was extended to account for influences of different levels of slurry in the trench and groundwater in the cohesionless soil [11]
Considering the real case including contribution of the shear forces on the both ends of the failure wedge, three-dimensional method derived from the two-dimensional limit equilibrium theory was already used to analyze the trench stability; Prater [13] and Washbourne [14] proposed planar sides to enhanced existing two-dimensional models

Summary

Introduction

Slurry trenches are often used as a hydraulic barrier to prevent the groundwater from flowing into the trenches during the construction of groundwater cutoff walls and diaphragm walls, and the slurry in the excavated trenches plays an important role in providing a lateral supporting force to the trench walls before backfilling. Based on the Rankin theorem, the trench stability was assessed by considering the pressures from soils, hydrostatic slurry, and groundwater [12] These mentioned methods treated the trench stability as Advances in Materials Science and Engineering a two-dimensional problem and neglected stabilizing forces or shear forces acting on both ends of the failure mass, which may produce conservative results. Considering the real case including contribution of the shear forces on the both ends of the failure wedge, three-dimensional method derived from the two-dimensional limit equilibrium theory was already used to analyze the trench stability; Prater [13] and Washbourne [14] proposed planar sides to enhanced existing two-dimensional models. Extending the two-dimensional model of Li et al [19] to three-dimensional case, we presented an analytical solution of the safety factor and critical failure angle for a slurry-supported trench with an inclined ground, and an example was discussed to illustrate the variation of the safety factor and critical failure angle with different inclined angle, trench length, and groundwater depth

Theory

Example

Findings

Conclusions