Study On Optimization And Application Of Deformation Monitoring For Large Foundation Pit Engineering

Deformation monitoring of foundation pit is a very important part of underground engineering construction. Because the stress of the underground engineering is very complicated, and the design parameters of geotechnical engineering are ideal, so we need to understand the deformation state and stability of supporting structure, and according to the monitoring results to determine the safety of foundation pit. A large number of engineering practice shows that the method of monitoring the effective and accurate, can make the construction and design to achieve a more good effect, to improve the construction efficiency, save investment cost and ensure the safety and so on have a very important role.The retaining structure of foundation pit is characterized by the requirement of the deformation and strength of the structure itself, but also to meet the requirements of the deformation control of the surrounding environment. If you want to understand the construction process in a timely and accurate support structure and the deformation of the surrounding buildings and the state of safety, it must be achieved through monitoring. And the key monitoring items and monitoring points are set up, and the deformation and working state of the foundation pit can be reflected by the limited monitoring data. Then the comprehensive analysis of the monitoring data, once found abnormal or important part of the deformation, deformation rate is too large, we can take measures to prevent the occurrence of accidents.This study relies on a large long foundation pit project, the project the variety of bracing structure of foundation pit, collected a plenty of construction, design and monitoring data, to establish a "key priority areas, taking into account the comprehensive and optimal layout settings, focus on monitoring project" based implementation of the on-site monitoring, to ensure the safety of foundation pit and the effectiveness of the early warning. In this paper, the deformation state of foundation pit excavation process is simulated by using rock soil numerical analysis software MIDAS/GTS, and the monitoring scheme is determined. The test results are compared with numerical simulation and construction. Finally, the failure mode of supporting structure is summarized. The main results are as follows:(1) respectively on four typical underground engineering branch of the support structure section: soil nailing timbering, bored pile support segment, SMW support support segment and cement soil mixing pile support segment under different construction conditions in the numerical simulation and based on the numerical simulation results are monitoring optimization suggestions.(2) the construction live, monitoring data and numerical simulation of soil nailing wall timbering, bored pile support segment, SMW support support segment and cement soil mixing pile supported support segment of the deformation rules and monitoring project effectiveness analysis, optimization of construction scheme and monitoring project settings.(3) based on the deformation law and failure mode of the supporting structure of foundation pit, the research and analysis should be used to monitor the working condition of the foundation pit supporting system, and find out the monitoring method.