煤层底板导升突水机理研究

为了进一步认识底板突水破坏机理,将底板隔水层简化为弹性梁,在考虑承压水作用的情况下,运用材料力学理论计算得出采场隔水层底界面由压缩区向卸压膨胀区过渡的岩体最易发生损伤破坏。在此基础上,运用损伤力学理论分析给出了临界损伤变量Dc。运用断裂力学理论建立断裂力学模型,并给出采场隔水层承压水导升裂纹端部应力集中系数的计算公式。最后,从损伤断裂能量角度对裂纹扩展进行了分析,通过简化参数,建立了形成初始宏观裂纹损伤断裂能量释放率计算公式,并分析了初始裂纹损伤断裂能量释放率与其各影响参数的关系,可为底板突水预测预报研究提供理论依据。

Study on Mechanism of Floor Water Inrush Induced by Water Rise along Fractures

In order to further know the failure mechanism of water inrush from floor,the water-resisting layer of the floor was simplified as an elastic beam.In the case of considering the confined-water action and based on the calculation with material mechanics theory,it came to the conclusion that the rock on the bottom interface of the floor's water-resisting layer in the transitional region between compression area and discharging swelling area was prone to damage and fracture.On this basis,analysis was made with the damage mechanics theory and the critical damage variable Dc was determined.The fracture mechanics model was established with the fracture mechanics theory and the calculation formula for the stress concentration factor at the confined-water rise crack end was determined.Finally,the crack expansion was analyzed from the angle of the damage and fracture energy,the calculation formula for the energy release rate of the initial crack damage and fracture was developed by simplify some parameters,and analysis was carried out on relation of the energy release rate of the initial crack damage and fracture with each affecting factor,all of these can be regarded as the theoretical basis for the prediction of floor water inrush.