非对称开挖条件下基坑变形性状分析

根据现场实际情况，采用有限元分析软件PLAXIS，对基坑在不同挖深差和挖深分界面位置不同条件下的非对称开挖进行了模拟。通过对实际工程进行模拟研究发现，随着挖深差的增加，基坑两侧的地表沉降均增加，开挖深部位的地表沉降和沉降影响范围均大于开挖较浅处；坑底隆起在界面处发生较大的差异变形，挖深差越大，界面处的差异变形越明显；随着开挖分界面向较浅侧移动，开挖深部位的隆起变形逐渐趋于稳定，隆起曲线变化趋势向挖深较浅侧增加。通过研究，可以了解不对称开挖基坑受力及变形的性状和不利因素，从而指导施工，控制不对称开挖的挖深差和界面位置，减少工程风险。

Deformation characteristic analysis of foundation pit under asymmetric excavation condition

Based on the actual condition of engineering, the finite element analysis software PLAXIS is adopted to simulate two different asymmetric excavation conditions of the foundation pit: (1) different excavation depth differences, (2) different excavation interface places. Based on study of practical engineering simulation, with the increase of the excavation depth difference, surface settlement on the two sides both increase; settlement value and effect range on the deep side are also larger than the shallow side. Meanwhile, there is a large diversity deformation of bottom heave on the interface; the deformation difference becomes obvious with the increase of excavation depth difference. With the interface movement to the shallow side, the bottom heave on the deep side tends to be stable; and the variation tendency of the bottom heave increases to the shallow side. Through research, there is a better understanding of characteristic and negative factor of stress and deformation on asymmetric excavation pit, which can guide the construction and control excavation depth difference and interface location of asymmetric excavation, then reduce the engineering risk.