圆砾地层深基坑工程特性离心机试验研究

Centrifuge Testing Research on Engineering Characteristic of Gravel Deep Excavation

以南宁轨道交通工程为背景,通过离心机试验对圆砾地层深基坑工程进行模拟,获取围护墙体变形、土压力分布及墙后地表沉降等基坑工程特性。研究表明,采用现场取土通过相似级配法制作圆砾地层离心机土层模型可较好地解决土层粒径效应与力学特性问题。试验数据表明,圆砾地层深基坑墙体最大水平位移D为0.96%H^1.49%H(H为开挖深度);主、被动侧向土压力随深度不断增长,均呈三角形分布,土压力大小分别介于理论静止土压力与主、被动土压力之间;地表沉降呈凹槽形曲线分布,最大沉降点发生在距坑边约1.0 H处,地表沉降最大值约1.0 D,开挖主要影响范围约3.0 H。

After a centrifuge testing simulating deep excavation engineering in gravel area based on Nanning rail transit project,the excavation engineering characteristics are obtained,such as the deformation of retaining wall,the distribution of lateral earth pressure and the surface settlement. The research results show that the centrifuge simulating model of gravel which was made of on-site soil by Similar Grading Method could solve particle size effect and mechanical properties problem. From the testing data,the maximum value of retaining wall deformation D equals 0.96% H ~ 1.49% H（ H is excavation depth）. The active and passive earth pressure increase with depth,and show triangle distribution. And the earth pressure value is between theoretical static value and active or passive value. The surface settlement distribute as groove shape curve. The maximum settlement value is 1.0 D which appears at the point about 1.0 H far from the edge of excavation. And the influence range is about 3.0 H.