Research On Adaptabilityevaluation System Of Open Andearth Pressure Balancedual-mode Shields

To address the alternating geological conditions of hard rock,upper soft and lower hard,and soft rock encountered during the construction of the same tunnel,a dual-mode shield machine with both open-type TBM and EPB modes has emerged.Its characteristics of high equipment utilization,broad geological adaptability,and low construction cost have gradually gained popularity.However,the dual-mode shield machine may also encounter issues that do not match the actual requirements,so it is necessary to establish an adaptability evaluation system for the open-type and EPB dual-mode shield machine.This article summarizes the factors influencing the adaptability of the dual-mode shield machine,uses the analytic hierarchy process to determine the weights of evaluation indicators,establishes the membership function of influencing indicators using fuzzy mathematics,and establishes the adaptability evaluation system for the open-type and EPB dual-mode shield machine using the fuzzy comprehensive evaluation method.The main research work and achievements of the paper are as follows:（1）Analyze and summarize the factors influencing the adaptability evaluation of the open-type and EPB dual-mode shield machine,and take 20 influencing factors from the aspects of shield design,shield parameters,geological hydrology,construction safety,and construction efficiency as the preliminary evaluation indicators of the dual-mode shield machine.（2）Compare the advantages and disadvantages of various adaptability evaluation methods,determine the fuzzy comprehensive evaluation method for establishing the adaptability evaluation system of the open-type and EPB dual-mode shield machine,use the analytic hierarchy process to determine the weights of the influencing indicators,and use fuzzy mathematics to determine the membership function of the influencing indicators.（3）According to the hierarchical principle,construct the adaptability evaluation system of the dual-mode shield machine.The target layer is the adaptability of the open-type and EPB dual-mode shield machine,the criterion layer is the five aspects of influencing factors,and the indicator layer is the 20 influencing factors.According to the total weight ranking of the influencing factors,the order is as follows:composite strata,fault crushing zone,surface subsidence,earth pressure of the soil chamber,tool arrangement,tunnel depth,surrounding rock strength grade,total thrust of the cutter head,cutter head rotation speed,tool wear,cutter head opening rate,surrounding rock deformation,tunnel water inflow,cutter head torque,mode selection,cutter head structure,parameter use,advance speed,harmful gas,and mode switching.To eliminate the negative impact of indicators with small weights,the influencing factors in the bottom 6 positions of the ranking list need to be removed before determining the membership function.（4）Summarize the method for establishing the adaptability evaluation system of the open-type and EPB dual-mode shield machine,specifically:1)determine the influencing factors and classify them;2)the research object of the evaluation system is the target layer,classify the influencing factors into the same criterion layer based on similar characteristics,and use the influencing factors as the indicator layer of the evaluation system;3)use the analytic hierarchy process to determine the weights of each criterion,determine the weights of the indicators in the corresponding criterion layer,and use the same method to obtain the weight of the evaluation indicator in the target layer.Remove evaluation indicators with small weights according to the total ranking.4)After screening the evaluation indicators,use fuzzy mathematics to construct the membership function.5)Using the fuzzy comprehensive evaluation method,determine the[0,1]parameters of each evaluation indicator based on the membership function,perform matrix calculation with the weights of the indicators,and obtain the final adaptability and adaptability evaluation level after weighting.（5）An adaptability evaluation was conducted on the TBM and shield sections of the dual-mode shield tunneling machine used in the Anshan section of Qingdao Metro Line 8.The adaptability of the TBM section was rated as"strong adaptability"with a fitness value of D₁=0.89462,while the adaptability of the shield section was rated as"basic adaptability"with a fitness value of D₂=0.65885.The lower adaptability of the shield section was mainly attributed to factors such as rock strength,parameter usage,soil chamber pressure,and tool usage.