Mechanical response and failure characteristics of dam prototype specimens under real hydrostatic pressures in underground reservoirs
The stability of the underground reservoir dam body under water pressure conditions is crucial for the long-term safe operation of abandoned mine water storage power stations.Therefore,in response to the actual groundwater pressure environment,an independently designed and developed servo-shaft-water pressure joint test device was created,and mechanical tests on dam bodies under different water pressures were conducted.The affecting ways of the environmental water were analysed,the evolution process of the joint action structure between the shaft and water pressures was clarified,and the theoretical strength trend of the dam body was determined.Furthermore,the effect law of the water pressure on the mechanical performance of dam body specimens was ascertained,and the characteristics of microscopic fracture surfaces and macroscopic failure modes were explored.The results indicate that the real water pressure environment affects the dam body specimens through both hydrochemical and hydrostatic pressure influences,encompassing seven aspects of reinforcement and weakening effects.The specimen water environment consists of three parts:external confining water,penetrating pore water,and enclosed pore water.During specimen saturation and loading processes,the interaction of water media and crack propagation mutually influences each other,with a greater water pressure leading to increased infiltration and impact effects.The real water pressure environment alters the specimen damage and effective porosity,thereby affecting lateral effective stress and specimen strength.As the water pressure in the actual environment increases,the stress-strain curve exhibits a significant yield fluctuation,where the strength decreases first and then increases,while the axial strain continues to decrease.The energy consumption by the testing machine on the specimen gradually decreases,but the proportion of dissipated energy increases rapidly.After the increase in water pressure,the number of crack nuclei at the fracture surface decreases,with the main fractures occurring sequentially as transgranular fracture,intergranular fracture,and shear failure.The number of fine cracks increases,and the specimen failure pattern undergoes a transition from tension to shear to shear-shear,becoming increasingly complex,accompanied by brittle collapse sounds.The research outcomes can enhance the accuracy of underground reservoir monitoring and assessment,providing theoretical and experimental foundations for the construction of abandoned mine water storage power stations.
mining engineeringabandoned minesunderground reservoir dam body specimenreal water pressure environmentfracture surfacehydraulic fracturing mechanism
万方数据
维普
