The Study Of Stability About Loess Foundation Pit Excavation Without Support

In order to quantitative analysis the stability of loess foundation pit, this article starts with stable height and uses theories and numerical simulation to achieve the analysis. According to conventional triaxial compression tests, got soil shear strength indexes, which will be taken into three kinds of theories (active earth pressure is zero, the theory of limit equilibrium and stability number method) and FLAC3D software. Determine the excavation without support maximum stable highly recommended reference value of loess foundation pit, through the comparative analysis of the data. The main contents of this paper are as follows:1) Summarized all kinds of methods for the stability analysis of the slope, and introduced the basic principle and analysis steps of FLAC3D software;2) During the process of conventional triaxial compression tests, by increasing the size of vertical load and confining pressure, simulating the different water content of soil, which is ensure that the soil is saturated to a natural state. When the soil reaches a steady state, gradually reduce the value of confining pressure to simulate the stress change of excavation process. Test stress paths in line with the actual situation of engineering.3) Analyzed for the influence factors on the stability of foundation pit. the theoretical calculation and numerical simulation of FLAC3D are explained:water content is an important factor influencing the stability of loess foundation pit; and, through the comparison of the test results, discover that the change of water content of soil have a great influence on cohesion, while internal friction angle is not.This paper researched the stability of the excavation without support. Get the unbalance force and displacement at the top of the slope. According to the failure depth, unsupported excavation stability height value of loess foundation pit under different water content.Combining three kinds of calculation theories and numerical simulation, got the quantitative analysis of the maximum stable height for excavation of loess without support under different water content. To provide some reference for the future foundation pit engineering, on the same or similar conditions, which has a certain reference value.