深基坑基底注浆加固效果数值模拟分析

采用高压旋喷注浆工艺对软土地区的基坑底部土体进行加固是保证深基坑施工安全与工程稳定常采用的方法。基于某地铁站监测数据，利用PLAXIS 2D软件建立了其数值计算模型并进行模型校核，对加固和未加固两种工况进行了数值模拟，对比分析了地连墙的位移和弯矩、地表沉降等开挖响应。研究表明，对软土地区基坑进行基底注浆加固，能有效减小地连墙的侧向变形和地表沉降。并针对加固区厚度、地连墙嵌入深度及刚度、软土层厚度4个参数进行了分析与讨论，优化了加固区的合理厚度、地连墙的合理嵌入深度，研究了基坑变形受地连墙刚度和软土层厚度影响的敏感性。

Numerical simulation analysis of jet grouting effect of deep excavation bottom

Jet grouting technology is widely employed as a reinforcement of excavation base in soft soil area. In this study, based on the monitoring data, numerical analysis of a railway station is carried out using PLAXIS 2D software. Firstly, comparison between the reinforced and unreinforced excavation cases is evaluated based on the analysis of deformation, bending moment of diaphragm wall and ground settlement. The results show that the lateral deformation of diaphragm wall and the ground settlement can be effectively reduced by basal grouting reinforcement in soft soil. Then four parameters, namely, the thickness of reinforcement zone, the penetration depth, the stiffness of diaphragm wall and the thickness of soft soil layer, are analyzed and discussed. The reasonable thickness of reinforcement zone and depth of diaphragm wall, and the sensitivity of deformation to the stiffness of diaphragm wall and the thickness of soft soil layer are also investigated.