基于随机介质理论基坑降水引起地表沉降计算

Calculation of Ground Settlement Caused by Foundation Pit Dewater Based on Random Medium Theory

针对基坑降水引起周边土层沉降问题,考虑到土体重度的变化和渗流力的影响,提出了一种以随机介质理论计算地表沉降量的方法。利用降水漏斗曲线对降水周边土层进行划分,基于有效应力原理和固结理论分析了降水前后土体重度和渗流有效应力的变化及微小土单元体压缩量,并通过随机介质理论计算基坑周围地表沉降量。以某基坑降水施工为背景,结合理论分析表明:计算方法得到的地表沉降分布与实测值整体上较为接近,在1.5倍开挖深度范围内精度较高,同时降水引起地面沉降也较大,1倍开挖深度处地面沉降最大值,约为25.53 mm;基坑降水引起周围土体重度的变化是影响地面沉降得主要因素,渗流力影响仅为15%。研究内容可为估算基坑降水引起地表沉降量提供参考依据。

In order to solve the problem of settlement of surrounding soil layer caused by precipitation in foundation pit,a method of calculating surface settlement by random medium theory was proposed.Based on the effective stress principle and consolidation theory,the change of the effective stress and the compression of microsoil units before and after precipitation were analyzed,the surface settlement around the foundation pit were calculated by random medium theory.Based on the foundation pit precipitation construction,combined with the theoretical analysis,it is shown that the surface settlement distribution obtained by this calculation method is relatively close to the measured values as a whole,and the precision is higher in the 1.5 times excavation depth range,and the ground subsidence caused by precipitation is also large.The maximum ground settlement at a depth of 1 times excavation is approximately 25.53 mm.The heavy change of surrounding soil caused by foundation pit precipitation is the main factor affecting ground subsidence,and the influence of seepage force is only 15%.The research contents can provide reference for estimating the ground subsidence caused by ground pit precipitation.