Research On Deformation Caused By Dewatering And Excavation Of Deep Foundation Pit In Nanning Qingxiushan Metro Station

Collapse is one of the common accidents during the construction of mountain tunnels.Once a collapse accident occurs,it will not only delay the construction period,but may also cause huge property losses and casualties,which will adversely affect the entire society.Therefore,in order to avoid the occurrence of collapse accidents,the evaluation of the collapse risk of mountain tunnel construction is of great significance to ensure the smooth progress of construction safety.In this paper,the statistical analysis by the main factors of a large number of actual construction of mountain tunnel collapse.Then,using the intuitionistic fuzzy analytic hierarchy process,combined with the gray cloud model theory,a risk assessment model for mountain tunnel construction collapse is established.Finally,relying on the Python language,develop a mountain tunnel construction collapse risk assessment software.The main work content and research results are as follows:(1)Through statistical analysis of actual engineering cases of mountain tunnel construction collapse,it is concluded that there are four main influencing factors of mountain tunnel construction collapse: hydrogeological factors,natural factors,tunnel factors and human factors,and for the influence of various factors on the mountain tunnel construction collapsed to do a qualitative analysis.The results show that the surrounding rock grade,bias pressure,groundwater,rainfall,tunnel depth,survey accuracy,construction standardization,monitoring timeliness,construction management level and other influencing factors are highly sensitive,more likely to cause collapse accidents.(2)Based on the quantitative and qualitative analysis of factors affecting mountain tunnel construction collapse,a risk assessment index system for mountain tunnel construction collapse was established.In order to make the weighting not subjective,the research adopted the intuitionistic fuzzy analytic hierarchy process(IFAHP)to weight the risk indicators.Combined with the gray cloud model theory,a risk assessment model of mountain tunnel construction collapse based on the IFAHP-ash cloud model is constructed.The mountain tunnel construction collapse risk assessment model is applied to the Chang Dianling tunnel construction collapse risk assessment,and the risk level of the main risk factors that cause the tunnel collapse during the tunnel construction and the total risk level of collapse are obtained.The risk assessment results determined by the application of the risk assessment model are basically consistent with the actual risk situation during the construction of the Chang Dianling Tunnel,indicating the feasibility and effectiveness of the assessment model.(3)Finally,based on the Jet Brains Py Charm development tool,relying on the Python language,the mountain tunnel construction collapse risk assessment software is developed to realize the intelligent assessment of the mountain tunnel construction collapse risk.The intelligent evaluation software for the collapse risk of mountain tunnel construction is applied to the collapse risk assessment of Changdianling tunnel construction,and the evaluation results are consistent with the traditional calculation results.It shows the practicability and reliability of the evaluation software,which can provide a reference for the risk evaluation of similar projects and promote the construction of tunnel projects in my country.