新奥法思想对基坑侧土压力影响

Influence of new Austrian tunneling method on lateral soil pressure of foundation pit

根据新奥法原理,通过引入主应力跃迁值的概念,研究方形基坑开挖过程中土拱形成规律。采用数值模拟和理论分析的方法,对比分析了基坑土压力随深度的分布特征。研究表明,在均质地层中,沿基坑一定范围内会形成水平承载拱,并具有自承能力;考虑土拱的土压力与实测数据最为接近,且均小于理论计算值。得到的结论对于优化支护结构强度,降低工程造价,具有重要意义。

According to the principle of NATM(New Austrian Tunnelling Method),the formation law of soil arch during excavation of square foundation pit is studied by introducing the concept of principal stress transition value. By means of numerical simulation and theoretical analysis,the distribution characteristics of soil pressure with depth of foundation pit are compared and analyzed. The results show that in homogeneous stratum,the horizontal bearing arch will be formed in a certain range along the foundation pit,and it has self-supporting capacity. The earth pressure considering the soil arch is the closest to the measured data and is smaller than the theoretical calculation value. The conclusion is of great significance to optimizing the strength of supporting structure,reducing the cost of engineering and guiding similar engineering design.