深基坑开挖的数值模拟分析及支护优化

Numerical Simulation Analysis and Support Optimization of Excavation of a Deep Foundation Pit

基于合肥市蜀山区某蓄水池基坑工程,根据实际工程资料,结合现场地质勘测并通过MIDAS/GTSNX有限元分析软件对其进行数值模拟。分析基坑开挖时出现的基坑围护结构位移、基坑底部隆起以及基坑外侧表面土体沉降的变形机制及影响因素,研究结果表明:该基坑开挖工程的各项围护结构位移均在预警值以下,基坑外侧表面土体沉降均在预警值以下,围护结构水平位移随着地连墙厚度增大而减小,但水平位移减小到一定程度趋于稳定,在地连墙厚度为1200mm时效果最佳。支护结构中锚杆的水平向夹角并非越大越好,在25°时效果最佳,此时支护结构变形有所减小。

Based on the foundation pit project of a reservoir in Shushan District Hefei City,according to the actual engineering data,on-site geological survey and numerical simulation through MIDAS GTS NX finite element analysis software were taken.The deformation mechanism and influencing factors of the displacement of the foundation pit envelope structure,the uplift at the bottom of the foundation pit and the soil settlement on the outer surface of the foundation pit were analyzed.The results show that the displacement of the envelope structure of the excavation project is below the warning value,the soil settlement on the outer surface of the foundation pit is below the warning value,and the horizontal displacement of the enclosure structure decreases with the increase of the pile diameter of the enclo-sure pile,that is,the thickness of the ground wall,but the horizontal displacement decreases to a cer-tain extent and tends to be stable,and the effect is best when the thickness of the ground wall is 1200mm.The horizontal angle of the bolt in the supporting structure is not the greater the better,and the best effect is at 25°,where the deformation is reduced.