基坑开挖卸荷影响深度分析

Influence Depth of Unloading During Pit Excavation

目前在基坑设计与计算中,大多只是凭借经验来选取卸荷影响深度.该文通过大量的卸荷应力路径试验,模拟了基坑开挖时坑底被动区土体的受力过程,分析了竖向卸荷条件下土体竖向变形及侧应力的变化.通过对坑底被动区土体回弹应变和侧应力随卸荷比变化规律的研究,得出了基坑开挖工程中卸荷影响深度的估算方法,其结果对基坑工程设计具有一定的参考价值.

In the design and calculation of the excavation engineering, the influence depth of unloading is usually determined based on experiences. In this work, a large number of unloading stress path experiments are performed to simulate the stress propagation process in the passive zone at the bottom of the foundation pit. Vertical deformation and the change in the horizontal stress are analyzed. The method for estimating the unloading depth in the excavation engineering is presented by analyzing relationship between the unloading ratio and the rebound strain and horizontal stress. The result is useful in excavation engineering.