基坑降水及开挖对支护结构变形的影响

Influence of Foundation Pit Dewatering and Excavation on Deformation of Support Structure

为掌握基坑弱承压含水层降水及开挖对SMW桩支护结构变形的影响,该文采用数值模拟和现场监测等手段,研究了徐州市某基坑不同降水工况对支护结构变形及周围地面沉降的影响规律和机理。结果表明:随着基坑降水点与支护结构距离的增大,基坑降水深度逐渐减小,降水效果逐渐减弱,对应支护结构水平位移和基坑外侧土体沉降量也逐渐减小。计算工况降水点与支护结构间距1~7m范围内的变化,基坑内降水高度在7.5~0.5m、支护结构最大水平位移在36~46mm、桩外侧土体沉降在21.0~24.5mm之间变化。

In order to understand the impact of dewatering and excavation in the weakly confined aquifer of a foundation pit on the deformation of the SMW pile support structure,this article uses numerical simulation and on-site monitoring methods to study the influence law and mechanism of different dewatering conditions on the deformation of the support structure and surrounding ground settlement of a certain foundation pit in Xuzhou City.The results indicate that as the distance between the dewatering point of the foundation pit and the supporting structure increases,the dewatering depth of the foundation pit gradually decreases,and the dewatering effect gradually weakens.The corresponding horizontal displacement of the supporting structure and the settlement of the soil outside the foundation pit also gradually decrease.The variation of the distance between the precipitation point and the support structure within the range of 1~7m under working conditions is calculated.The precipitation height inside the foundation pit is 7.5~0.5m,the maximum horizontal displacement of the support structure is 36~46mm,and the settlement of the soil outside the pile varies between 21.0~24.5mm.