Geotechnical engineering;  foundation pits;  soil rebound;  short-term stress history;  pile anchor support structure;  earth pressure;  Exposure time

In the pile anchor support structure, the calculation of earth pressure does not consider the displacement of the supporting structure and the unloading rebound of the soil at the bottom of the pit, which can lead to a small calculation value of earth pressure in the active area and a large calculation value of soil pressure in the passive area, which reduces the safety level of the supporting structure. Based on the theory of elastic long pile and classical earth pressure, considering the rebound effect of excavation and the short-term stress history of soil in the construction process, the evolution process and calculation method of soil pressure of pile anchor support structure are studied, and the correlation between the "inverse zero distribution" mode, "zero distribution" mode, "zero distribution" mode, "trapezoidal distribution" mode and "rectangular distribution" mode of earth pressure is proposed, as well as its influencing factors and evolution mechanism. It is pointed out that the calculation of soil pressure of pile anchor support structure should comprehensively consider the influence of excavation speed, exposure time of each working condition and soil rebound characteristics