Study on the influence of high-speed railway tunnel construction blasting on integrity of gas storage ore layers

In order to ensure the safe and efficient construction of the tunnel and the safe and stable operation of the gas storage, taking the Baofengsi tunnel of the Shanghai-Chongqing-Chengdu high-speed railway and Huangcaoxia gas storage as the support project, the finite difference software FLAC^3D is used to simulate the tunnel construction blasting. The distribution law of strata displacement and vibration velocity after blasting is obtained, and the influence of tunnel construction blasting on the integrity of gas storage ore layers is analyzed. The results show that: ①the deformation of the surrounding rock is negatively correlated with the distance from the tunnel, the deformation of the gypsum rock in Leikoupo formation is the largest, followed by the T₃j₄⁴ gypsum rock formation, and the T₃j₄² gypsum rock formation is relatively the smallest. Controlling the charge amount can effectively reduce the disturbance of the formation by construction blasting. ②After blasting, plastic deformation occurs only around the tunnel and in the upper part of the Leikoupo formation, and tunnel construction blasting has little influence on the airtightness of the gas storage and will not lead to fault activation. ③The simulated maximum instantaneous peak vibration velocity is about 3.60 cm/s, which appears in the gypsum rock formation of Leikoupo formation. The maximum instantaneous peak vibration velocity is lower than the allowable blasting vibration safety standard stipulated in the current blasting safety regulations, and the tunnel construction blasting has little influence on the underlying gypsum rock formation.