考虑拱效应深基坑支护结构土压力分析

针对基坑支护结构土压力的研究以数值模拟为主，而解析理论应用需要完善研究现状，提出一种用于计算基坑支护结构土压力的解析方法。根据填土中土拱效应的作用以及土拱成形的基本理论，结合极限平衡分析方法，应用摩尔圆理论确定了基坑端壁间稳定土拱的轨迹方程，并且得到基于土拱形状所围滑裂土体的体积，确定出基坑支护结构土压力的解析表达式，最后进行了算例分析，研究结果表明土体的物理属性决定了有效滑裂土体的边界。提出的解析方法是深基坑计算土压力的一种新的解析方法。

Analytical solution of earth pressure on supporting structure of deep foundation pit considering arching effects

Although numerical simulation is the prominent method for calculating earth pressure on the foundation pit, it is not handy to do calculating whenever and wherever possible as analytical solutions do. An analytical solution of earth pressure is performed to estimate the mechanical response of backfilled openings, emphasize the effect of load transfer along the interface at the corner of foundation pit. The arc between adjacent corners of pit is formed as parabolic whose original rake ratio at corner can be determined as a function of friction angle in soil. Based on the formation of stable arch in soil, a sliding block behind retaining structure can be determined as a parabola prism truncated by sliding plane. Finally, a formula of active earth pressure is deduced in light of limit equilibrium theory. The results indicate that the arching effects developed in the backfill greatly influence the resultant force on the supporting structure. The analytical results are compared to experimental ones and the discussion that follows highlights some of the key factors influencing the resultant force on the supporting structures.