Influence Of Temperature And Water Content On Dynamic And Static Mechanical Properties Of Sandstone

In recent years,with the implementation of western development strategy,it is very important to study the mechanics property of rock mass in cold area.Due to the comprehensive action of lithology,porosity,temperature,water content,rock stress and other factors,a large number of geotechnical engineering in the development process is difficult.Therefore,it is necessary and of great practical significance to study the mechanical properties of frozen rock.Most of the previous researches on frozen rocks are focused on simple statics conditions,and few studies on the static and dynamic mechanical properties of rocks under the coupling effect of different water content and freezing temperature.Therefore,this paper conducted static and dynamic compression tests on sandstone specimens under different temperature and water content conditions,and explored their stress-strain,energy dissipation rule characteristics,and fracture morphology.Specific work contents are as follows:(1)Several freeze-thaw cycle tests were carried out on sandstone specimens with three kinds of temperature: 20 ℃,-20 ℃,-30 ℃,and three kinds of water content:dry,20% water content and full water content.Non-metallic ultrasonic detector was used to measure the wave velocity before and after freeze-thaw,and its variation rule was summarized.And the static compression test was carried out.The results show that the wave velocity and uniaxial compressive strength of sandstone specimens before and after freezing-thawing are different with different temperature and water content.(2)Uniaxial compression test was carried out on sandstone specimens with three kinds of temperature: 20 ℃,-20 ℃,-30 ℃,and three kinds of water content: dry water content,20% water content,and full water content,and the stress-strain curve,energy dissipation characteristics,and the change law of breakage morphology with the gradient of temperature and water content were explored.The results show that the uniaxial compressive strength of sandstone specimens increases with the decrease of temperature when the water content remains unchanged.Under the condition of constant temperature,the compressive strength increases first and then decreases with the increase of water content.(3)Using SHPB test device,three dynamic impact tests of impact pressure 0.5MPa,0.6 MPa and 0.7 MPa were carried out on sandstone specimens with three kinds of temperature: 20 ℃,-20 ℃ and-30 ℃ and three kinds of water content: dry,20%water content and full water content.The results show that the law of impact strength of sandstone specimens is consistent with that obtained from uniaxial compression test,and the corresponding impact strength increases gradually with the increase of impact pressure.Figure [71] Table [9] Reference [82]...