Experimental Study On Dynamic Mechanical Properties And Energy Dissipation Analysis Of Fractured Sandstone

Rocks in nature produce a large number of fractures due to long-term geological movement,which constitute a complex joint structure.These fractures are widely distributed,extend to various rock strata,and have a significant impact on the mechanical properties of rock.With the proposal of the “14th Five-Year Plan” strategy,the state has accelerated the construction of new infrastructure.For example,during tunnel excavation and mine blasting,the rock is subjected to impact load during excavation.Among them,the inclination angle and penetration degree of rock fissures have a significant indigenous influence on the strength and crushing deformation characteristics of the rock mass.Therefore,it is urgent to study the problem of the fractured rock mass.In this paper,the roadway sandstone of Dingji Coal Mine of Huainan Mining Group in Anhui Province was used as the research object,and seven sandstone specimens with different fracture inclinations and six sandstone specimens with different fracture penetrations were prepared.The basic physical indexes such as the quality,height,diameter,and mineral composition of the specimens were tested.The dynamic impact compression tests of sandstone specimens with different fracture inclinations and different fracture penetrations were carried out by using the SHPB test device.The influence law of different fracture inclinations and fracture penetrations on sandstone specimens was systematically analyzed from the aspects of dynamic compressive strength,dynamic strain,dynamic stress-strain curve,fracture morphology,and specimen energy consumption after the test.The main research contents are as follows:1.The SHPB test device was used to carry out the impact compression test at the same pressure loading rate(impact pressure p=0.3MPa)on sandstone specimens with different angles(0°,15°,30°,45°,60°,75°,90°).After the test,the variation laws of dynamic compressive strength,dynamic strain,dynamic elastic modulus,and other mechanical parameters with the fracture inclination angle were analyzed.2.The SHPB test device was used to conduct the same pressure loading rate impact compression test(impact pressure p=0.3MPa)on sandstone specimens with different crack penetration(0,0.1,0.2,0.3,0.4,0.5).After the test,the variation laws of dynamic compressive strength,dynamic strain,dynamic elastic modulus,and other mechanical parameters with crack penetration were analyzed.3.STSJ-4 digital high-frequency vibrating screen machine was used to quantitatively analyze sandstone specimens with different fracture dip angles after the test,and the average particle size and fractal dimension of the specimens were obtained,and the impact failure characteristics of sandstone specimens with different fracture dip angles were analyzed.Flex SEM 1000 SEM was used to measure the fracture morphology of fractured sandstone specimens with different penetration after the test,and the surface structure characteristics of the specimen fracture under impact load compression were observed.4.From the perspective of energy dissipation,the relationship between reflection energy,transmission energy,dissipation energy and incident energy ratio of sandstone specimens with different fracture dip angles and penetration degrees is analyzed,and then the variation law between energy dissipation density and related dynamic mechanical parameters and crushing energy dissipation is explored.Figure [55] Table [10] Reference [66]...