Experimental Research On Seepage Characteristics And Seepage Damage-failure Mechanism Of Sandstone Under Strong Seepage Field

The seepage field formed by the strong rainfall will accelerate the damage and failure of the weak rock mass which is the important inducement factor of the landslide,debris flow and collapse.Therefore,it is of great theoretical and practical significance to study the seepage characteristics and damage-failure characteristics of weak rock mass under strong seepage field.Based on the RLW-2000M coal rock triaxial rheological testing machinein state key laboratory of coal mine disaster dynamics and control of Chongqin University,the seepage characteristics and seepage damage characteristics of sandstone under strong seepage flow field are studied by using the weak rockstone as the research object.The specific research contents are as follows:(1)Saturated sandstone samples are prepared by collecting,drilling,cutting,grinding and soaking.The test scheme is determined according to the stress-strain curve and the actual situation of the test equipment.(2)A total of 16groups of sandstone samples are subjected to seepage failure test.Under the condition of constant confining pressure of 10MPa,each group of samples are applied 120kN,140kN,160kN and 180kN load,and at the same time,the seepage pressure of 3MPa,5MPa,7MPa and 9MPa are applied respectively until the specimen damage and failure,then obtain the relevant test data.(3)The effect of seepage time and seepage pressure on the seepage characteristics of sandstone including seepage flow,seepage rate and permeability coefficient of sandstone is studied by selecting the test results related to seepage characteristics.(4)The effect of seepage time,seepage pressure and load on the seepage deformation characteristics including axial strain,radial strain,volume strain and strain rate of sandstone is studied by selecting the test results related to the deformation characteristics of seepage flow.(5)The effect of seepage pressure and load on the failure deformation and failure mode of sandstone is studied by selecting the test results related to deformation damage characteristics.(6)The elastic modulus is chosen as the damage variable,and the elastic modulus is calculated and analyzed based on the variation of stress-strain curve during the test.The influence of the action time,seepage pressure and load on the elastic modulus of sandstone is studied.(7)Based on the elastic modulus method,the damage degree of the specimen is obtained by the changing law of the elastic modulus of the specimen,and the damage law of sandstone with time under strong seepage is analyzed.