复杂环境深大基坑施工对周边环境影响研究

Research on the Impact of Deep Excavation Construction in Complex Environment on the Surrounding Environment

软土具有高含水率、高压缩性、低强度等缺点,因此软土地区深基坑施工是一项极具挑战性的工程任务。本研究以深基坑为研究对象,通过对基坑施工时进行监测揭示了基坑施工过程中地表沉降、深层土体水平位移、周边地下水位以及邻近建筑物沉降的内在规律。研究表明:随着基坑开挖深度和距基坑距离的增加,周边土层应力分布发生明显改变,导致地表沉降量先增加后减少。在距离基坑0m~20m范围内,沉降量逐步增加;而在20m~30m范围内,沉降量则逐渐减少。基坑开挖导致深层土体水平位移,从边缘到中心逐渐增大,随开挖深度加深而增长,尤其在发生管涌后,第七支撑位移显著。A#楼监测点的沉降随靠近基坑而增大,第5号监测点呈现最大沉降。在3号监测点,水位下降是因为隔水层受损,导致地下水渗入基坑,而8号和9号监测点的水位波动,是因为发生了管涌现象,使地下水快速流入基坑。

Soft soil has disadvantages such as high moisture content,high compressibility,and low strength,making deep excavation construction in soft soil areas a highly challenging engineering task.This study takes deep foundation pits as the research object,and through monitoring the construction of foundation pits,reveals the inherent laws of surface settlement,deep soil horizontal displacement,surrounding groundwater level,and adjacent building settlement during the construction process of foundation pits.Research has shown that with the increase of excavation depth and distance from the foundation pit,the stress distribution of the surrounding soil layer changes significantly,leading to an initial increase and then a decrease in surface settlement.The settlement gradually increases within a range of 0m to 20m from the foundation pit.Within the range of 20m to 30m,the settlement gradually decreases.The excavation of the foundation pit causes horizontal displacement of the deep soil,gradually increasing from the edge to the center,and increasing with the depth of excavation.Especially after the occurrence of piping,the displacement of the seventh support is significant.The settlement of monitoring point A#increases as it approaches the foundation pit,with the maximum settlement observed at detection point 5.At monitoring point 3,the decrease in water level is due to damage to the aquitard,causing groundwater to seep into the foundation pit,while the fluctuations in water level at monitoring points 8 and 9 are due to the occurrence of piping,causing groundwater to quickly flow into the foundation pit.