77 / 2021-09-18 17:05:41

A coupled stress-seepage-damage model and its application in water inrush from faults

stress-seepage-damage;,water inrush,rock fracture,water inrush channel

Mining-induced fractures often constitute water inrush channels, which lead to mine water inrush accidents. In this paper, a coupled model of stress-seepage-damage based on micromechanics is established, which simulates the initiation and propagation of cracks in rock materials and their interaction with fluid flow. The method combines the continuous damage model with the effective stress principle, in which the elastic modulus and permeability are related to the damage variables. The model is implemented by COMSOL code based on finite element method, and the reliability of the model is verified by the axial compression-seepage test of standard rock samples. According to the actual geological conditions of F13 fault in Wugou Coal Mine, Anhui Province, the damage of floor rock mass and the risk of fault water inrush in 1033 mining face with 50m, 40m, 30m and 20m waterproof coal pillars are predicted. When the coal pillar width is 30m or 20m, the fault, the surrounding rock of the fault and the failure zone of the floor constitute the water inrush channel. The model provides an intuitive understanding of the rock failure and evolution of water inrush which are difficult to observe, and will be helpful to preventing water inrush disasters in practical engineering.