Study On The Effect Of The Combined Action Of Heat-Insulating Concrete And Cooling Water On The Ambient Temperature In High Temperature Roadway

In order to reduce the impact of high-temperature surrounding rock on the ambient temperature in the roadway,starting from controlling the heat transfer path from the surrounding rock to the roadway,a method of passive-active joint control of the ambient temperature in the roadway is proposed.The passive method delays the total amount of heat transferred from a part of the surrounding rock to the roadway;the active method reduces the total amount of heat transferred by the roadway and achieves the purpose of lowering the ambient temperature of the roadway.The specific research results are as follows:（1）Through orthogonal experiments,nine sets of expanded perlite,ceramsite and fly ash mixing ratios are obtained.Measure the density and thermal conductivity of nine groups of test blocks during each curing age.Using range analysis,analytic hierarchy process and analysis of variance,the experimental data is comprehensively analyzed to obtain the primary and secondary order of the influence of three factors on the thermal conductivity of the test block:A.Expansion perlite content>B ceramsite content>C fly ash content.When the curing age of the specimen reaches 28 days,a set of mixing ratio A₃B₃C₂with the best thermal insulation performance is finally obtained,and the thermal conductivity is 0.1562W/（m·K）.（2）Improve the heat transfer model of insulated concrete,establish a second-order thermal conductivity calculation heat transfer model,and conduct steady-state analysis.After the reliability analysis of the calculated effective thermal conductivity and the measured value of the test,the result shows that although there is a deviation from the measured value of the test,but within the allowable range of error,the validity of the model is verified,and it can pass the expanded perlite The change of the volume fraction of the dosage is relatively accurate to predict the thermal conductivity of the thermal insulation concrete and the thermal insulation performance of the material,and then better analyze the influence of the thermal insulation material on the ambient temperature in the high-temperature roadway.（3）Establish a physical model of the roadway.Numerical simulations were carried out on nine groups of heat-insulating concrete with different thicknesses to analyze the advantages of heat-insulating performance and the influence on the ambient temperature in the high-temperature tunnel.It is concluded that the best thermal insulation material A₃B₃C₂has the greatest influence on the ambient temperature in the roadway,and the best thickness of the thermal insulation material is 200mm.Compared with ceramsite,the amount of expanded perlite has a greater impact on the thermal insulation performance of concrete.After laying cooling water pipes of different pipe diameters in the axial length,the ambient temperature in the roadway is greatly reduced.Compared with the application of only the best heat insulation material A3B3C2,the ambient temperature of the roadway before and after laying is further reduced by 3.54K.When the best cooling water pipe is selected The diameter is 25mm,and the inlet velocity of the water pipe is 0.6m/s.At this time,it has the greatest impact on the ambient temperature in the high-temperature tunnel.The high-temperature roadway insulated concrete studied in this paper can realize active cooling,which provides a new technical idea and development direction for solving the problem of thermal damage.In addition to excellent heat insulation performance,it also has the characteristics of light weight,durability,and environmental protection,which have good promotion and use value.The study has 43 figures,21 tables,and 102 references.