Study on the envelope of stress path during deep excavation

Abstract

In the pit excavation process, soil deformation and earth pressure is highly depending on the loading process of soil. It is essential to characterize soil loading process, as in the form of stress path, during pit excavation process. However, there are two problems existed: Firstly, the stress path of the test is single. There are two stress paths commonly applied to experimental research, i.e., lateral stress reduction with the constant of axial stress and axial stress reduction with the constant of lateral stress. Therefore, the whole process of excavation is calculated by using the software of numerical analysis in this paper. The calculation results are shown as follows. (1) In the process of excavation, the stress paths of soil in different parts are different. (2) In the process of excavation, the stress paths of the soil are not all the stress reduction or increase in the single direction. (3) The main characteristic of soil stress path is the decrease of stress in a certain direction or multi direction in the process of excavation. According to the calculation conclusion, the concept of stress path envelope of foundation pit excavation is proposed. The probability of soil deformation around the foundation pit is large when the stress path outside the envelope of soil is experienced. The soil deformation probability around the foundation pit is small when the soil is subjected to the stress path in the envelope.