软土中异形地连墙成槽失稳机理研究

随着地下连续墙施工技术发展,“L”形地连墙作为一种常见的异形地连墙被广泛应用于封闭地下围护结构设计施工中。由于成槽过程中,槽段及周边土体的应力变化复杂,“L”形地连墙的稳定性低于常规矩形地连墙。基于上限分析法,对“L”形地连墙成槽施工过程中的稳定性进行研究,提出“L”形地连墙稳定三维机动场模型,计算得出槽壁安全系数,揭示了异形地连墙槽壁失稳机理,并通过参数计算分析地连墙几何形状以及土体性质对槽壁稳定性的影响。对某地连墙工程进行计算,计算结果与现场超声波检测相吻合。研究结果可为异形地连墙的设计施工提供参考和理论依据。

Stability Analysis of Slurry Trench of Irregular Shaped Diaphragm Wall in Cohesive/Frictional Soils

The L-shaped diaphragm wall is broadly used to form an enclosed retaining structure underground. Due to the complicated stress condition during trenching construction, the stability of L-shaped trench is lower than that of regular rectangular trench. In this paper the instability mechanism of irregular-shaped diaphragm wall during the excavation of L-shaped slurry trench is revealed based on upper bound analysis. A 3D kinematically admissible mechanism defining the failure of the L-shaped trench is constructed. The safety factor of the trench and corresponding failure pattern are obtained through upper bound analysis. Moreover, the influences of trench geometries and soil properties on the trench stability are discussed through parameter analysis. The calculation result of a case study is consistent with the field ultrasonic inspection result.