高层建筑基坑变形内力分析及量测点优化

Analyses of Internal Force for the Deformation of Foundation Pit of High Building and Optimum of Measurement Spot

研究目的:高层建筑的基坑稳定与围护结构变形、土层条件、水文条件密切相关,处理得当,可以控制地表沉降和墙体位移。本文根据数理统计原理建立量测点优化布置原则,借助有限元模拟开挖计算结果,分析基坑开挖位移场分布规律和影响因素,从减小量测误差原则出发,提出量测点优化方案,为施工提供依据。研究结论:通过对条形基坑围护结构变形分析、量测点优化、实测数据分析得出以下结论:围护结构水平位移取决于开挖深度、基坑宽度、土层性质、墙体刚度、入土深度;墙顶位移观测点应设在跨中,从跨中向两侧均匀布设,墙体测点从跨中开始,自上而下设置,在墙的支撑作用点处略高于挖深处设测点;基坑开挖过程中,进行实时监测,预测基坑的变形规律,及时采取预防措施,减少变形速率,确保量测点的优化和基坑的施工安全。

Research purposes： The stability of foundation pit of high building relates closely to the deformation of exterior-protected construction, soil condition and hydrographic condition. The surface subsidence and wall displacement can be controlled effectively if the deformation, soil and hydrographical conditions are treated well. This paper analyzes the distribution regulation and influence factors of the displacement of the foundation pit during excavation through optimal distribution of the measurement spots based on the mathematical statistical principle and with the help of the simulation calculation result of the excavation with finite element, and offers the optimal program for distribution of measurement spots based on the principle of reducing the measurement error for providing the basis for the construction. Research concinsions：Through the analyses the deformation of strip exterior - protected construction for foundation pit, optimum of measurement spots and analyses of the measured data, the followings are concluded： （ 1 ） The horizontal displacement of the exterior - protected construction depends on the excavation depth, width of foundation pit, soil nature, wall rigidity and embedded depth. （2） The measurement spots for the displacement of the wall top should be installed from the span center to both sides evenly, and the measurement spots for the wall should be installed at the supporting place of slightly higher than the deep excavation place with the beginning from the center and from top to bottom. （3） The real - time monitoring should be done in the course of the excavation for predicting the deformation regulation, taking preventive measures in time, lowering the deformation speed and guaranteeing the optimum of measurement spots and the construction safety.