桩墩扶壁复合土钉墙工作性状数值分析

针对软土地区采用桩墩扶壁复合土钉墙围护结构的基坑,按实际工况进行了开挖支护的三维非线性有限元模拟,其中土体采用修正剑桥弹塑性模型,计算结果与现场实测数据能较好地吻合,表明本文研究方法是可行的。现场实测数据与四种不同型式复合土钉墙围护结构基坑开挖的数值计算结果,均表明三维基坑开挖存在明显的“角部效应”;在复合土钉墙中设置灌注桩墩与锚杆对于减小灌注桩、搅拌桩、锚杆、土钉及周边土体变形及内力有是利的,且灌注桩墩的影响效应要超过锚杆,故在深基坑开挖中采用桩墩扶壁复合土钉墙支护结构是合理有效的。

Numerical Analysis of Working Behaviors of Composite Soil Nailed Wall with Bored Piles in Deep Excavation

According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate the deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the soil’s constitutive relationship during the simulation. The results from the numerical simulation are fitted well with the field data, which indicate that the research approach used in this paper is reliable. Based on the field data and numerical results of the deep excavation supported by four different composite soil nail walls, the significant corner effects are found in the 3D deep excavation. If the bored piles or anchors are considered in the composite soil nailed wall, it is good for decreasing the deformation and internal force of bored piles, cement-soil mixing piles, anchors, nails and soil around the deep excavation, and the effects due to bored piles are more significant than that deduced from anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.