| The safe excavation and efficient utilization of mineral resources is a hot topic in recent years.However,with the development of the times,shallow mineral resources have been difficult to meet the needs of human daily life and technological development.Therefore,the excavation of mineral resources has to go deeper.However,various difficulties encountered in the excavation process are gradually increasing,and problems such as complex geological conditions and harsh excavation environment need to be solved by experts.Groundwater and ground temperature are the most common environmental conditions in the construction process.In addition,the pores of the rock itself lead to the complex internal structure of the rock sample,which is more prone to damage and deterioration.Therefore,in this experiment,the prefabricated circular sandstone specimens were treated by temperature-water coupling method,and the SHPB test equipment was used for dynamic load loading.The test has certain reference function for the construction operation of coal mine roadway.The rock samples used in this experimental study were taken from the sandstone of deep roadways in Gubei and Dingji coal mines in Huainan City,Anhui Province.The dynamic load was loaded on the same inner diameter and different temperature ring sandstone specimens and the same temperature and different inner diameter ring sandstone specimens.The basic physical quantities such as mass,inner and outer diameter and density of circular sandstone specimens before and after temperature-water coupling were measured.The dynamic performance of annular sandstone specimens was studied by SHPB test device.The failure modes of ring specimens after different temperature treatments were compared and analyzed.Finally,the XRD and SEM test devices were used to explain the reasons for the change of the dynamic performance of the specimen from the microscopic aspect.The details are as follows:1.The circular sandstone specimens with an outer diameter of 25 mm and an inner diameter of 10 mm were subjected to temperature-water coupling treatment,and the temperature was set at 25 °C(normal temperature)～ 95 °C.The basic physical quantities of circular sandstone specimens after different temperature treatments were measured,and the influence of temperature-water coupling on the deterioration of the specimens was compared and analyzed.Then,the SHPB device was used to carry out the test,and the data collected from the test were calculated and analyzed to obtain the dynamic tensile strength,dynamic peak strain and average strain rate of the ring sandstone specimen.2.The circular sandstone specimens with different inner diameters(0 ～ 25mm)were subjected to temperature-water coupling treatment at 45 °C.Subsequently,the dynamic characteristics of circular sandstone specimens were studied.By changing the clamping mode of the specimen,the dynamic compressive strength and dynamic tensile strength of the circular sandstone specimens with different inner diameters were studied.The influence of dynamic peak strain,dynamic elastic modulus and average strain rate.3.By observing and analyzing the residual fragments of the circular sandstone specimen,the broken form of the circular sandstone specimen is analyzed.The incident energy,reflection energy,transmission energy and absorption energy of the SHPB test device are calculated,and the energy ratio diagram is drawn.The energy dissipation method is used to study the variation law of specimen crushing morphology from the perspective of energy,and further verify the dynamic characteristics of annular sandstone specimens.4.XRD and SEM test equipment were used to observe the composition of the specimen and the apparent morphology of the fracture surface.The influence of temperature and water on the dynamic performance of the ring specimen is analyzed from the microscopic point of view.The fracture mode and failure mechanism of ring sandstone specimens were analyzed.Figure [55] Table [8] Reference [82]... |
PDF Full Text Request