Research On Artificial Heating Supply Pipe And Engineering Applicability Of Railway Embankment Under Active-temperature Control In Seasonal Freezing Area

Existing measures to prevent frost heave are limited to soil modification.water control,and increasing thermal resistance.However,these measures only delay the development of frost heave and weaken the degree of frost heave deformation;They lack effectiveness and insulation,and the prevention and control efficiency is low.In order to increase the prevention and control measures of embankment frost heave,improve the prevention and control efficiency,and ensure the safety and stability of the train operation.This article relies on the National Natural Science Foundation’s project "Heating Supply Method and Thermal Governing Mechanism of Railway Embankment under Active-Temperature Control in Severe Cold Regions",on the basis of existing research,the "monomer separated artificial heating supply pipe" is proposed,and combined with field tests and numerical simulations to explore the heating effect and heat transfer law of the device to the soil in winter.The main conclusions are as follows:(1)The design method of the separated artificial heating supply pipe is described in detail,and each part of the device is calculated by using Python programming,which makes the device design more standardized,programmed and humanized.(2)Through the analysis of the outdoor test results of the device,it is found that the temperature of the heat pipe wall can reach up to 65 ℃,and the pipe wall temperature gradually increases from the head end to the tail end of the heat pipe under the environmental conditions of this test.The uneven temperature distribution will cause the heating rate of the surrounding soil.Influence,when the heating time is long enough,the soil temperature will tend to be stable.(3)The thermal loss of subgrade soil is calculated by the domain probe and boundary probe in COMSOL and compared with each other to verify the reliability of the calculated thermal loss data.(4)By "implanting" the device into the subgrade model to discuss the heating effect of different burial depths,it is suggested to bury the heat dissipation pipe at 1m below the surface of the bottom layer of subgrade.The working effect of the collector pipe has little influence on the temperature change of the natural formation under the subgrade and will not cause frost heave.(5)Through the short-term field test and simulation of the heating effect of long-term heating on soil,it is concluded that the heating effect of the device under W4S1(compressor working for 4 h and stopping for 1 h)is better,and it can be used as the reference working condition for the site application of the device.In the field test environment,the heating radius of the device for 7 days is about 2 m.Under the condition of simulation calculation,the heating radius of the device for long-term operation is within the range of 2～2.5 m.