基坑开挖对周边环境的影响分析

为探究基坑降水开挖过程中基坑及周边环境的响应,以西北某实际基坑工程为背景,通过Plaxis 3D软件建立模型,分析了基坑开挖过程中基坑及周边环境产生的变形和围护结构锚杆上力的变化.结果表明:基坑开挖产生的土体变形是一个三维问题,剖面土体的变形受基坑阴、阳角的影响,这种影响的强弱与剖面距基坑阴、阳角的距离有关;在基坑围护结构中,锚杆锚固效果比土钉好30%左右,桩锚支护效果比复合土钉墙好20%左右;下排锚杆比上排锚杆承担更多的主动土压力,其自由段轴力比上排锚杆大;位于复合土钉墙支护段附近的道路受基坑开挖影响,其倾斜方向由最开始的朝坑外倾斜转变为朝坑内倾斜;位于桩锚支护段附近的既有建筑变形均在相关规范允许范围内,周边既有建筑处于安全状态.

Influence of foundation pit excavation on the surrounding environment

In order to explore the response of the foundation pit and the surrounding environment during the excavation of the foundation pit, taking the actual foundation pit project in the northwest as the background, the corresponding model was established by Plaxis 3D software, and the deformation of the foundation pit and its surrounding environment and the change of the force on the anchor rod of the retaining structure during the excavation of the foundation pit are analyzed. The results show that the soil deformation caused by the excavation of the foundation pit is a three-dimensional problem. The deformation of the soil body in the profile is affected by the yin and yang angles of the foundation pit. The extent of this effect is related to the distance between the profile and the internal and external corners of the foundation pit.In the retaining structure of foundation pit, the anchoring effect of anchor bolt is about 30% better than that of soil nail, and the supporting effect of pile anchor is about 20% better than that of composite soil nail wall. The lower row of bolts bears more active earth pressure than the upper row of bolts, and the axial force in the free section is greater than the upper row of bolts. The road near the composite soil nailing wall support section is affected by the excavation of foundation pit, and its inclination direction changes from the initial inclination towards the outside of the pit to the inside of the pit. The deformation of existing buildings near the pile anchor support section is within the allowable range of relevant specifications, and the surrounding existing buildings are in a safe state.