基于随机介质理论基坑降水引起地表沉降计算

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。

Calculation of ground settlement caused by foundation pit dewatering based on random medium theory

in order to calculate the ground settlement caused by precipitation amount, the use of precipitation funnel precipitation area curve for saturated zone and the seepage zone, considering the change of moisture content of saturated zone caused by severe changes in the soil, in turn, led to its effective gravity stress change, consider the effect of seepage force and seepage area, based on calculating the stress changes in precipitation amount of compressed soil element, and through calculation of the random medium theory foundation pit surrounding soil settlement. Engineering practice shows that the calculated value is close to the measured value on the whole, the measured value is 15% higher, and the influence of precipitation is greater within 1.5 times of the excavation depth of the foundation pit. The research content can provide reference for estimating the ground settlement caused by foundation pit dewatering.