Analysis And Application Of Temperature Effect On The Stability Of Surrounding Rock In Underground Engineering

With the continuous improvement of technical level, the related businesses get their rapid development, such as those with the resources exploitation, water conservancy, transportation, etc., and the space and quantity of underground engineering are increasing day by day. However, the influence of the temperature in underground engineering is inevitable. High temperature in underground not only affects the security and progress of engineering construction, but also can cause lining cracking due to the resulted temperature stress, thus affects the stability of tunnels.This paper combines the field data of Kongzhuang and Zhaolou coal mine, and the data is processed by computer regression analysis to obtain the geothermal gradients of different coal mines. As shown in the analysis: the average geothermal gradient of Zhaolou coal mine is 5.23 °C/100 m, and the Kongzhuang coal mine is 0.49 °C /100 m. Based on the monitoring of Kongzhuang coal mine working face. we reached that the the actual monitoring maximum deformation value of 7432 working face is 26 mm, and that of 7435 tunnel is 16 mm, both are less than 30.778 mm, the ANSYS analysis value. The maximum actual measurement stress is 6.7Mpa. Considering the specific circumstances in field, we use ANSYS to simulate the temperature change of underground tunnel surrounding rock, and get a distribution field of temperature ranging from 20 °C to 35 °C, and a distribution field of thermal strain from 20 °C to 35 °C, as well as a maximum thermal strain which is 0.496 mm. The result also shows a distribution field of heat stress ranging from 20 °C to 35 °C, a maximum stress 1.84 Mpa, as well as a distribution field of heat stress coupling from 20 °C to 35 °C, and the maximum deformation is 31.038 mm. Based on the theoretical analysis of ANSYS, comparing the displacement and stress values in practical engineering application of Kongzhuang coal mine, Due to certain temperature-lowering measures such as ventilation, the actual measured values are all less than the theoretical calculation values. So in the practical construction, we should control the temperature of the engineering environment in order to get an acceptable range of temperature effect on the surrounding rock’s stability, which in turn can avoid the potential safety loophole of unstable surrounding rocks.Through the analysis and the numerical simulation in this paper, the geothermal gradients of Kongzhuang and Zhaolou coal mine are reached. Moreover, by discussing the stability of surrounding rock under different temperatures, this study can provide suggestions for the construction and protection of underground engineering.