| With the rapid development of China’s economy and the expanding scale of urban construction,deep foundation pit projects such as urban subway and high-rise buildings are emerging,and the design,construction and deformation control of deep foundation pit support engineering have become common problems in underground engineering construction today.It is of great theoretical significance and engineering application value to analyze and study the support scheme of deep foundation pit,overall stability of foundation pit,internal force change of support system and deformation of foundation pit.This thesis takes an actual engineering case in Benxi,Liaoning Province as the research object.The project is located in Xiaodonggou,Minshan District,Benxi City,and the surrounding area is adjacent to the oil and gas joint construction station on Yulong Road,and a pressurized gas transmission line is buried underground between the support pile and the external wall of the oil and gas station,and the surrounding environment is extremely complicated.If improperly considered in design and construction,major safety hazards and safety accidents can easily occur during construction.The main contents of this thesis are as follows:(1)On the basis of collecting the surrounding environment data and hydrogeological data,the support scheme was comprehensively analyzed from the perspectives of safety,economy and construction period,and the optimal scheme of pit support was determined by using hierarchical analysis method and fuzzy comprehensive evaluation method.(2)The support scheme was simulated and calculated by using Rizheng slope design calculation software,and the calculation content included wall force system calculation,column internal force calculation,column The results all meet the requirements of the specification and provide a strong basis for the selection of the foundation pit support scheme.(3)The special construction plan of the foundation pit is prepared according to the design plan,and the deformation monitoring of the foundation pit provides real-time feedback on the internal force change of the support structure,displacement change and deformation of the surrounding adjacent buildings to verify the correctness of the foundation pit excavation plan and environmental protection plan.(4)During the excavation process,the earthwork construction unit did not follow the design plan,resulting in local instability of the pit.In response to this unexpected event,the design plan was timely adjusted according to the pit deformation monitoring data,and the safety of the subsequent service of the accident pit was predicted by using dynamic gray theory and three-time exponential smoothing method.The observation results show that the prediction results are consistent with the actual deformation.It provides a reference and reference for other similar projects in the future. |
