Abstract Based on investigation of closing type blockage disasters and analysis of their relationship to geological disasters, seven structures affected by deformation-induced collapse of the surrounding rock, six structures affected by mud bursts and two structures affected by debris flows inside the tunnels are introduced, and the causes of the disasters are analyzed. The examination shows that: 1) the grade of the surrounding rock where the instability occured due to deformation and collapse were not corrected and either the primary supports were not constructed in time or the the primary support was not intense enough; 2) the soil disc of the soil-isolating rock was broken through because the autologous mud isolating soil disc and compound soil disc were not thick enough or strong enough, or the conditions of the disasters causing mud bursts varied, which led to mud bursts and debris flows; 3) shear fracture failure occurred along the preferred structure planes at mud- isolating joint fractured rock discs and led to mud bursts; and 4) vibrations induced by tunnel construction resulted in instantaneous sinking of clay fill in karst caves and caused mud-isolating rock discs to break and mud bursts to occur.
Abstract：
Based on investigation of closing type blockage disasters and analysis of their relationship to geological disasters, seven structures affected by deformation-induced collapse of the surrounding rock, six structures affected by mud bursts and two structures affected by debris flows inside the tunnels are introduced, and the causes of the disasters are analyzed. The examination shows that: 1) the grade of the surrounding rock where the instability occured due to deformation and collapse were not corrected and either the primary supports were not constructed in time or the the primary support was not intense enough; 2) the soil disc of the soil-isolating rock was broken through because the autologous mud isolating soil disc and compound soil disc were not thick enough or strong enough, or the conditions of the disasters causing mud bursts varied, which led to mud bursts and debris flows; 3) shear fracture failure occurred along the preferred structure planes at mud- isolating joint fractured rock discs and led to mud bursts; and 4) vibrations induced by tunnel construction resulted in instantaneous sinking of clay fill in karst caves and caused mud-isolating rock discs to break and mud bursts to occur.
2018, Vol. 55 