Experimental Study On Dynamic Mechanical Properties Of Sandstone Under Confining Pressure

With the development and utilization of underground resources and underground space, the development of geotechnical engineering is becoming more and more fast. At present, the research on the dynamic mechanical properties of rock under normal condition is fruitful, and it is widely used in practical engineering. In rock mechanics, the problem of stability and failure of rock under impact load is still a challenging problem. In many areas of engineering research, regardless of geothermal development and utilization, roadway supporting, coal mine rock blasting operation, or in the city circle deep underground space development and utilization of geological environment and rock mass are in a high stress environment. Therefore, it is of great significance to study the dynamic mechanical properties of sandstone under the condition of high ground stress and simulate the high ground stress environment.The Anhui Huainan mining area Xie Li Dajing deep mining engineering background to determine the coal mine roadway excavation engineering is the most common sandstone as research target. And the static mechanical test system for the static mechanical tests were carried out, in the rock dynamic mechanical test research focuses on the use of straight taper section split Hopkinson pressure bar and upgrading active confining pressure test device. The main research contents and results are as follows:(1) The basic physical properties of the rock are tested, and the tensile test and uniaxial compression tests of sandstone specimens are carried out by static mechanics experiment.(2) To carry out the sandstone under impact loading uniaxial compressive and splitting tensile test, comparison and analysis of the specimen in the impact pressure 0.3,0.4,0.5,0.6,0.7 MPa respectively, to carry out the rock specimen of the dynamic strength and strain rate effect.(3) The failure modes of sandstone specimens under confining pressure were 1,2, 3,4 and 5MPa, respectively, and the stress waveform diagram and strain rate effect were analyzed, and the compressive strength increased with the increase of confining pressure. The strength characteristics and failure modes of sandstone specimens under the impact pressure of 0.3,0.4,0.5,0.6,0.7MPa were carried out.