Research On Construction Process Simulation And Risk Control Technology Of Covering And Digging Reverse Construction Method For Underground Civil Project

With the process of urbanization,most of the above ground space has been occupied,so more and more people want underground space,but the existence of existing buildings above ground increases the difficulty of underground space development.When we develop underground space,the const ruction process may cause ground settlement,ground horizontal deformation,ground structure settlement and other problems,which will have a certain impact on t he existing buildings.In order to reduce the disturbance to the existing building structure on the ground,cover excavation method and underground excavation method have been proposed.Based on the research of relevant experts and scholars at home and abroad,this paper carries out basic research,and relies on the underground civil air defense project of Luwen Road in Jinan City.The research methods include theoretical analysis,numerical simulation and analytic hierarchy process.At the same time,in order to ensure the safety of structure construction,it is n ecessary to identify and analyze the risk sources in the process of structure cons truction.The risk control technology of this kind of project is studied to reduce the time of encroachment on the surrounding environment and the impact on the surroun ding environment,and the risk control scheme is put forward.The main contents of this paper are as follows:Literature research,study the relevant engineering experience in recent years,and the impact of foundation pit construction on the surrounding environment,and through the selection of technical schemes,determine the rationality of the applicable construction schemes for the project.Based on the surrounding environment,a three-dimensional finite element model of foundation pit-soil-building is established by using the three-dimensional finite element software MIDAS GTS,and the laws of vertical displacement,horizontal displacement,ground settlement and differenti al settlement of surrounding buildings are analyzed.Using the analytic hierarchy process(AHP)based on the fuzzy theory,the risk assessment model of the whole underground structure const ruction process is established.The risk identification and weight control can be carried out through the membership function and expert scoring.A complete risk control model of underground engineering is established to ensure the comp letion of risk tracking and risk control at all stages of construction.Through the above analysis,the following main conclusions are drawn:(1)the construction of cover excavation method has a great impact on the settlement around the foundation pit,and the settlement caused in the construction process accounts for about 50% of the total settlement.Therefore,the construction of cover plate as soon as possible can ensure the closure of the structure as soon as possible and reduce the subsequent settlement.(2)the value of uneven s ettlement is greatly affected by the shape of the building.The longer and narrower the building,the greater the value of uneven settlement.Therefore,when selecting the location of the foundation pit,the construction along the narrow and long construct ion should be avoided as far as possible.(3)the engineering risk evaluation system of luowen road civil air defense project was established.