基于非对称荷载作用下的基坑变形特性研究

Deformation Characteristics of Foundation Pit under Asymmetric Load

依托合肥市某管廊基坑工程,采用MIDAS/GTS对基坑开挖及支护全过程进行数值模拟,研究了非对称荷载作用下深基坑开挖引起的地下连续墙水平变形规律,模型计算结果与实测数据吻合良好,在此基础上研究了荷载距离D的改变对内支撑轴力及坑外地表沉降的影响.结果表明:非对称荷载作用下,基坑两侧地下连续墙水平变形规律存在很大差异,基坑同一断面内有荷载一侧的水平变形均大于另一侧,最大水平位移出现在距离地下连续墙顶部约为4 m的位置,偏压侧模拟最大值约为8.5 mm,监测最大值约为9.8 mm;基坑变形特性对偏压距离D较敏感,随着偏压距离D不断增加,内支撑轴力和偏压侧地表沉降均有减小的趋势.研究成果以期为相关工程提供参考.

Taking a pipe gallery foundation pit project in Hefei as an example,this paper uses MIDAS/GTS to simulate the whole process of foundation pit excavation and support,and studies the horizontal deformation law of diaphragm wall caused by deep foundation pit excavation under asymmetric load.The model calculation results are in good agreement with the measured data.On this basis,the influence of the change of load distance D on the axial force of inner support and the surface settlement outside the pit is studied.The results show that there are great differences in the horizontal deformation law of the diaphragm wall on both sides of the foundation pit under asymmetric load.The horizontal deformation on the side with load in the same section is greater than that on the other side.The maximum horizontal displacement occurs at the position about 4 m from the top of the diaphragm wall,the simulated maximum value on the biased side is about 8.5 mm,and the monitored maximum value is about 9.8 mm.The deformation characteristics of foundation pit are sensitive to the bias distance D.The axial force of inner support and the surface settlement on the bias side tend to decrease with the increase of bias distance D.The research results are expected to provide reference for related projects.