基于正交试验的深基坑变形影响因素及特征机理研究

Research on the Influence Factors and Characteristics of Deformation of Deep Foundation Pit Based on Orthogonal Experiment

运用正交试验原理,以深基坑的地连墙的插入比、地连墙刚度、内撑横间距、一次开挖深度为因素,把深基坑开挖后地表最大沉降、坑底最大隆起以及地连墙最大水平位移作为分析基坑变形的三个指标,利用数值模拟方法对太原地铁车站深基坑的稳定性特征进行了分析。采用直观分析和多元回归分析的方法揭示了各因素在深基坑开挖变形过程中的影响机理及重要性次序。结果表明：在其他施工方式和支护参数保持不变的条件下,地表沉降、坑底隆起和墙体水平位移的最显著影响因素均为地连墙的插入比,地表沉降和坑底隆起的其他影响因素依次为内撑横间距、地连墙刚度、一次开挖深度。墙体位移的其他影响因素依次为内撑横间距、一次开挖深度以及地连墙刚度。采用多元回归方法得到了深基坑变形与各个因素之间的相关规律,并得出地连墙插入比的理想范围是0.7~0.8的结果。

Considering the insertion ratio of wall,rigidity,internal support transverse spacing and the excavation depth as factors,the principle of orthogonal test and numerical simulation were used to analyze the stability of the Taiyuan Metro station foundation pit. And the maximum settlement of ground surface,maximum bottom uplift and even the walls of the maximum horizontal displacement were treated as indicators. Besides,the influence mechanism and order of importance of various factors in the process of deep foundation pit excavation were analyzed by the method of direct analysis and multiple regression analysis. The results show that： with the same construction method and support parameters,it is the insertion ratio that has a marked impact on all indicators. Other factors of the surface subsidence and the heave are the distance between the inner,the rigidity of the ground and the excavation depth. However,the secondary factors of the displacement of walls are the distance between the inner,the excavation depth and the rigidity of the ground. By using multiple regression method,the correlation between deformation and various factors of deep foundation pit is obtained,and the ideal range of the wall insertion ratio is 0. 7 ~ 0. 8.