Monitoring And Analysis Of Foundation Pit Construction Based On Underground Continuous Wall And Mixed Support System

Under the general trend of underground rail transit development,more and more cities have made subway construction one of the key points of urban infrastructure construction.In recent years,due to the shortage of professional and technical personnel and engineering management experience,subway pit engineering accidents have occurred frequently.For underground clear-cut stations,the monitoring work during the excavation of foundation pits and the timely handling of hidden dangers can avoid accidents to a large extent.This article mainly discusses the construction monitoring situation of subway opencut stations based on underground continuous walls and mixed support system through practical engineering,and expands the basic requirements of monitoring,the principle of measuring point arrangement,the processing of monitoring results,the classification of supports and The respective characteristics of concrete support and steel support,etc.,and from four aspects of monitoring purpose,monitoring equipment and measuring point layout,measuring methods and requirements,and monitoring result analysis,the monitoring items of subway foundation pits such as surface settlement,pipeline settlement,groundwater level A total of nine aspects,including monitoring and supporting shaft force monitoring,are elaborated.Finally,the on-site measured data are collated to analyze the results and reasons,and the main conclusions are as follows:(1)The maximum settlement position of the surface around the foundation pit appears 5m away from the underground continuous wall.Between 5m and 45 m from the continuous wall of the underground,with the increase of the distance from the underground continuous wall,the settlement value of the monitoring point gradually becomes smaller and tends to be stable.(2)Before the excavation of the foundation pit to the design base elevation,the deep horizontal displacement of the underground continuous wall generally increases with the increase of the excavation depth of the foundation pit,below the base elevation of the foundation pit design,and the overall horizontal displacement value of the deep pit The upper side decreases as the depth of the pit increases.The deformation of the underground continuous wall presents a "bow shape".(3)The maximum horizontal displacement of the underground continuous wall appears at the upper position of the basement,between 0.5 and 1.0 m,and the horizontal displacement at the bottom of the underground continuous wall is not zero.