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| Asymmetric floor heave mechanism and pressure relief control in composite bottom-slab roadways based on the "three-hinged arch-spring" model |
| XU Xiaoding1，2，ZHOU Yuejin1，GAO Yubing2，FU Qiang2，WEI Xingjian2 |
| (1. State Key Laboratory of Deep Rock Mechanics and Underground Engineering，China University of Mining and Technology，Xuzhou，Jiangsu 221008，China；2. State Key Laboratory of Deep Rock Mechanics and Underground Engineering，China University of Mining and Technology，Beijing 100083，China) |
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Abstract In order to solve the problem of asymmetric floor heave of roadway and the potential of inducing kinetic events in dynamic pressure roadways，this paper established a "three-hinged arch-spring support" model based on the geometry and force characteristics of asymmetric roadway deformation，and analyzed the energy dissipation characteristics of the system and the sufficient discriminatory conditions for abrupt destabilization at the cusp of the total potential energy function of the system. The research showed that：The deformation of the equilibrium curve takes two forms when along path I，the deformation is linear and progressive，and no large energy release kinetic event occurs. When along path II，the deformation is a non-linear and abrupt floor heave of roadway，where the lithology，dimensions and lateral stress of the roadway bottom are the key factors affecting the system instability，and the floor slab kinetic event can be prevented by pressure relief. Therefore，the technique of cutting the roof to unload the floor heave of roadway is proposed，the mechanism of pressure unloading is analyzed，and pressure unloading tests are carried out in the Caojiatan coal mine. The results prove that cutting the roof is done by changing the support form of the overhanging roof plate to shorten the collapse step of the roof plate，thus realizing the horizontal and vertical pressure unloading and the release of the collected energy in the quarry，and the horizontal pressure unloading is more obvious than the vertical，thus effectively controlling the deformation of roadway floor.
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