深基坑开挖对周边环境影响范围的数值模拟研究

Numerical Simulation Study on Influence Range of Deep Foundation Pit Excavation on Surrounding Environment

为研究深基坑开挖对周边环境的影响范围,以泉港地下储粮库项目工程为背景,利用三维岩土工程有限元软件PLAXIS3D进行数值模拟,对比了摩尔—库仑(M-C)本构模型和高级硬化本构模型(HS本构模型)对模型沉降变形的影响。同时计算了逐级开挖基坑变形影响范围以及监控点的沉降和水平合位移曲线。研究结果表明:从位移量值来看,基坑开挖引起的水平变形远大于沉降变形,水平变形与沉降变形的比值,约为4∶1;基坑开挖过程中降排水引起的地表沉降变形影响范围较大,但量值较小;而土体开挖引起的变形较大,但变形影响范围有限,仅限于基坑周边一定距离;采用M-C本构模型与HS本构模型,得到的变形规律基本一致。

In order to study the influence range of deep foundation pit excavation on the surrounding environment,taking the Quangang Underground Grain Storage Project as the background,the three-dimensional geotechnical finite element software PLAXIS3D was used for numerical simulation,and the influence of the Moore-Coulomb(M C)constitutive model and the advanced hardening constitutive model(HS constitutive model)on the settlement and deformation of the model was compared.At the same time,the influence range of foundation pit deformation by the progressive excavation and the settlement and horizontal displacement curves of the monitoring points are calculated.The results show that:From the displacement value,the horizontal deformation caused by foundation pit excavation is much greater than the settlement deformation,and the ratio of horizontal deformation to settlement deformation is about 4∶1;during the foundation pit excavation,the influence range of surface settlement deformation caused by dewatering and drainage is large,but the value is small;the deformation caused by soil excavation is relatively large,but the influence range of deformation is limited,which is only limited to a certain distance around the foundation pit;the deformation laws obtained by using M-C constitutive model and HS constitutive model are basically consistent.