Study On The Evolution Law Of Heat And Water Flow Of Segment Joint Leakage In Subway Tunnel

Shield tunneling has become the best structural form for underground rail transit construction due to its advantages such as fast excavation speed,small construction disturbance,and no impact on ground traffic.The majority of subway tunnel under construction or in operation in China are affected by the uneven distribution of soil quality,uneven settlement of soil,soil erosion and perennial cyclic load,resulting in the occurrence of water leakage at the tunnel segment joints.The tunnel water leakage causes corrosion of concrete segment reinforcement and corrosion behind the segment back,seriously affecting the safe operation of the tunnel.In this paper,based on the coupled law of heat flow and heat flow of segment joint leakage in subway tunnel,the influence of longitudinal seam and circumferential seam leakage on segment and pipe ring temperature under different working conditions is studied from the segment and pipe ring dimensions by means of theoretical analysis,numerical modeling and indoor tests;With reference to numerical simulation,indoor tests are designed to further study and compare the temperature distribution inside and outside the segment under different permeability,water pressure and temperature difference conditions during the joint leakage process,and reveal the temperature change law of the segment during the leakage process.The main research content and conclusions of this article are as follows:1.Establish the numerical simulation calculation model of subway tunnel segment joint leakage,the numerical simulation model of pipe annular seam leakage and the numerical model of pipe annular double longitudinal seam leakage,study the influence of different crack permeability,water pressure and temperature difference on segment temperature,obtain the spatial distribution of subway tunnel segment temperature under different working conditions and the law of change with time,providing data support for subway tunnel operation.2.The self-developed model test system is used to carry out the temperature distribution test of segment joint leakage.The test carries out temperature monitoring through the temperature sensors arranged inside the segment,compares and analyzes the segment temperature distribution under different water temperature,water pressure and permeability conditions during the segment joint leakage process,and compares with the numerical modeling conclusion to reveal the temperature change law of the segment during the joint leakage process.3.Based on numerical simulation and indoor experimental analysis of the temperature transfer and distribution of tunnel segment leakage water,a local temperature gradient grayscale mapping gain method is proposed by using infrared thermal imaging technology to analyze the temperature field of infrared detection images of leakage water.This effectively enhances the contrast of infrared thermal images and significantly improves the detection efficiency of rail transit tunnel segment crack leakage water.