| Inner Mongolia Dazhun Railway has been opened to traffic for more than 20 years,along the many tunnels have appeared frost damage problem,Such as:lining frost heave,cracking,peeling,leaking water,roadbed water and other ice,etc.These problems will seriously affect the normal operation of the line,serious may lead to a larger security accident.Based on the above reasons,it is very urgent to carry out research on the temperature field distribution and frost heave factors of Dazhun railway tunnel.In this paper,according to the typical cold area tunnel-JiMingYi,Under the premise of checking the characteristics of hydrological geological conditions,engineering characteristics,tunnel freezing and tearing characteristics distribution,Use temperature section to the tunnel,analyzed the distribution of the measured temperature data,and the temperature distribution.This paper analyzes the mechanism of frost heaving and the influencing factors of tunnel,analyzes the size of frost heave force of Jimingyi tunnel,analyzes the factors that influence the frost heave force.;Using ANSYS software to simulate the variation of temperature field of tunnel section under various working conditions;Analyze the influencing factors of tunnel frost heave and combine the geological and engineering characteristics of Jimingyi tunnel to calculate the size of tunnel frost heave force;According to the actual situation of the project frost damage to propose frost damage control measures.Mainly completed the following work:(1)Through the investigation of tunnel geological conditions,meteorological hydrology and engineering characteristics,as well as the study of the characteristics and distribution of frost damage,it can be concluded that the main factors of tunnel freezing injury are "low temperature" and "water" Consider anti-freeze measures.(2)Through the temperature monitoring of different sections and depth of the tunnel,the distribution law of the measured temperature is analyzed.The method of mathematical fitting is used to analyze the change law of tunnel temperature in time and space,and the feasibility of temperature fitting in analyzing the temperature field of tunnel is studied.According to the analysis,it can be concluded that in the winter,The farther away from the tunnel,the lower of the temperature,The deeper the tunnel surface,the higher of the temperature and the lower the temperature amplitude.The same depth in the tunnel of the different parts the temperature is not obvious regularity.(3)The finite element simulation software was used to simulate the temperature field of tunnel section 4 and section 1 with or without insulation layer under different working conditions.Combined with the measured temperature data,analyzed the distribution of the temperature field in the tunnel section with or without the insulation layer,Combined with the measured temperature data,the distribution of the temperature field of the tunnel section under various working conditions is analyzed,which provides the basis for the tunnel control?(4)Based on the law of tunnel temperature distribution and actual engineering characteristics,the size of frost heave force of Jinshiyi No.1 rocky rock tunnel and Jimingyi No.2 rock tunnel are calculated and analyzed.The influence factors of frost heave are analyzed.Through calculation and result analysis,The main factors that influence the frost heaving of the surrounding rock are water,low temperature,surrounding rock condition and lining condition,which can provide theoretical support for reducing frost heave and reducing frost damage.(5)Combined with the characteristics of the project,the type of frost damage and the temperature field of the tunnel,the paper puts forward the practical treatment scheme suitable for the project.We can get that in the distance from the tunnel mouth 100m laying 5cm thick insulation layer,the rest of the frost damage occurred in the laying of 3 cm insulation layer insulation layer thickness,and we can accord to the actual increase in engineering practice;for the freezing injury occurred more serious parts,such as part of the water ice Parts can be grouted by means of drainage reinforcement. |
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