Coupled Hydraulic And Mechanical (HM) Analysis Of Water Inrush Induced By Fault And Karst Collapse Column

The direct cause of the water inrush during underground mining is the mining-induced rockmass damage and resultant catastrophe of seepage characteristics. Study and master the law of the mining-induced rockmass structure fractured evolution is of great significance to determine the occurrence of mine water inrush and make a control strategic decision of mine water disaster. It was studied extensively and obtained many significant achievements by scientist of rock mechanics and mining engineering in our country, which plays an active role in guiding for controlling mine water disaster.In fact, under the guidance of the existing theory of hydraulic fracture, waterproofing measures can not completely explain water inrush mechanism. So it is necessary to study the mining-induced rockmass fissure evolvement and resultant catastrophe of seepage characteristics.Under the support of the National Fundamental Research Program (973 Program) of China, this paper focuses on study the water inrushes using the numerical simulation. The following work is included:(1) The works begins with proposing a constitutive law for rock failure under coupled hydromechanical conditions based on the coupled hydromechanical test of rock when the rock heterogeneity, as well as the coupling between deformation and fluid flow, is incorporated. This constitutive law is implemented into a commercial FEM software named COMSOL Multiphysis (CM) using the MATLAB programming, and is used for evaluating the water inrush possibility.(2) According to the hydrogeological and tectonic conditions at a working space where a fault is encountered, the water inrush process is numerically reproduced, based on which the possibility for water inrush is assessed. According to the numerical simulations under different dimension of waterproof pillars, the reasonable size of waterproof pillar for safe mining is obtained. (3) The numerical model is used for evaluating the water inrush possibility induced by a Karst subsidence column at Fan'gezhaung Colliery in China. The real mechanism responsible for the water in-rush process that is associated with the position and conductivity of the Karst subsidence column is clarified based on the numerical simulations.