考虑疏干带非饱和土影响下基坑降水引起地面沉降的计算  

CALCULATION OF SETTLEMENT CONSIDERING UNSATURATED SOIL INFLUENCE ON THE DEWATERING OF FOUNDATION PITS

作　　者：吴意谦 朱彦鹏[1,2,3] 

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050 [3]西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050

出　　处：《工程力学》2016年第3期179-187,共9页Engineering Mechanics

基　　金：国家科技支撑计划项目(2011BAK12B07);国家自然科学基金项目(50978129)

摘　　要：大多数基坑底面低于地下水位面,在开挖前需要进行降水工程为施工提供干燥、安全的环境。由于降水历程中孔隙水压力消散和有效应力的增加,周围土体会产生固结压密,同时在基坑周围形成地下水的降落漏斗,最终导致地层的不均匀沉降,对坑周道路、建筑物及地下管线造成危害。在忽略土体的侧向变形及群井效应的前提下,引入非饱和土的有效应力原理,根据裘布依假定求出基坑降水后地下水位的降落曲线方程。采用分层总和法分别计算水位降落曲线上下非饱和土与饱和土的地面沉降量,叠加后得到最终坑周地面沉降量。结合数值模拟计算及工程实例监测数据对比分析,表明该方法具有较高的工程实用价值。As the bottom of most foundation pits is below the underground water level, dewatering is necessary to provide a dry and safety environment for the construction before excavation. Dissipation of pore water pressure and increasing of the effective stress in soil cause consolidation of the soil and the depression-cone around the pits These can bring the non-uniform consolidation settlement which would influence the roads, buildings and underground pipelines around the foundation pits. By ignoring the lateral displacement and the effect of the group wells, the effective stress principle of unsaturated soil was induced and the equation of the water-table depression was solved on the supposition of Dupuit presupposition. Then the settlement of the soil layers above and below the cone of water-table depression was calculated respectively based on the layer-wise summation method, and the actual settlement was the sum of them. Comparison of numerical simulation results with monitoring results of the engineering examples show that the calculation method is of practical engineering value.

关 键 词：基坑降水 沉降 有效应力原理 非饱和土 监测 数值模拟 工程实例 

分 类 号：TU473[建筑科学—结构工程]