Experimental Study On Dynamic Mechanical Properties Of Temperature-water Coupled Sandstone

With the development of infrastructure construction in China,the excavation depth of underground space gradually increases and the temperature increases with the mining depth.The excavation of deep rock mass is often in a special environment full of water.Blasting excavation is one of the main excavation methods of deep rock mass,and the deep rock mass will be subjected to impact load during the excavation process.Most of the underground rock mass is in a state of immersion,and the temperature of water varies with different depths.Therefore,it is of great engineering value to carry out experimental study on dynamic mechanical properties of sandstone under temperature-water coupling.Taking the sandstone of Gubei Coal mine roadway of Anhui Huainan Mining Group as the research object,this paper tested the basic physical indexes of sandstone specimens at normal temperature and after water bath at different temperatures,such as mass,volume,density and longitudinal wave velocity,and compared and analyzed the variation rules of basic physical indexes of sandstone before and after water bath.Dynamic impact compression tests were carried out on rocks under different water bath temperatures and different loading pressures by SHPB apparatus,and the dynamic stress-strain curves,dynamic compressive strength,dynamic strain and elastic modulus were analyzed with water bath temperature and impact velocity.The energy dissipation characteristics of water-saturated sandstone under different impact velocities are analyzed as follows:1.The mass,volume,density,longitudinal wave velocity and other basic physical indexes of sandstone specimens were studied after water bath for 48h(25℃,30℃,35℃,40℃,45℃,50℃,55℃,60℃,65℃,70℃,75℃,80℃,85℃,90℃,95℃).2.Impact compression tests at the same loading rate(impact pressure P=0.3MPa)were carried out on sandstone specimens after water bath by using SHPB test device.The dynamic parameters such as dynamic compressive strength,dynamic strain and dynamic elastic modulus with water bath temperature were analyzed.3.Eight different loading rates of 0.3MPa,0.325MPa,0.35MPa,0.375MPa,0.4MPa,0.425MPa,0.45MPa and 0.475MPa were carried out on sandstone samples of two different water-bearing states(natural water-bearing state and natural watersaturated state in normal temperature water bath)by SHPB test device Dynamic impact compression tests under MPa were carried out to analyze the dynamic parameters such as dynamic compressive strength,dynamic strain and dynamic elastic modulus with impact velocity under two water bearing conditions.4.Analyzed from the points of view of energy dissipation under normal temperature(25 ℃)bath natural saturated sandstone dynamic compressive strength,dynamic strain and dynamic elastic modulus changing with the incident energy,hydrated and sandstone are analyzed,the relationship between the failure pattern of using high-speed cameras observation room temperature water bath natural saturated sandstone in SHPB experiment process from deformation to destruction and analyze its failure characteristics.Figure[41]Table[6]Reference[74]...