Experimental Studied On The Short-and Long-term Mechanical Behaviors Of Black Sandstone Sample Under Partial Immersion In Water Condition

Water is one of the most important factors affecting the safety of rock mass engineering.It has an important impact not only during the construction process,but also throughout the life cycle of hydropower dams and slope care projects.In the past,although a large number of scholars have studied the physical and mechanical properties of rocks in the water environment,the results obtained can be described as full of enthusiasm.However,almost all of the researches have focused on the study of rocks in the dry and immersion areas,but the study of rocks in some of the immersion areas is awkward.In addition,previous studies have almost always considered water content as the only factor to evaluate the rock water environment,but ignored Non-uniformity of moisture distribution inside the rock.Therefore,in order to study the rock in part of the immersion area and explore the influence of different water distribution patterns on the physical and mechanical properties of the rock mass,the black sandstone drilled in Sichuan Province is taken as the research object,and the following experimental research are carried out by means of the RMT-150 C digitally controlled electro-hydraulic servo test machine.:(1)Before studying the partial immersion characteristics of black sandstone,the water absorption experiment was first carried out to obtain the immersion time-water content curve of black sandstone,and the uniaxial compression test was carried out on the black sandstone samples under dry and saturated conditions respectively to acquire the basic mechanical parameters such as the E and ? of the black sandstone.(2)The study was performed that the short-term and long-term mechanical behavior of black sandstone with different soaking heights under partial soaking.First,the black sandstone was partially immersed for a long enough time.The height of the immersion part was 0,1/8,1/4,1/2 and 1 of the height of the black sandstone,and the uniaxial compression test and creep test were carried out.In addition,a complete set of comparative tests for complete immersion at the same moisture content is carried out: according to the previous immersion time-water cut curve,the black sandstones are completely immersed separately,and they are made to have the same water content as the partially immersed black sandstone.Axial compression test and creep test,two tests were compared.(3)The study was performed that the short-term and long-term mechanical behavior of black sandstone with different soaking time under partial soaking.The black sandstones with black sandstone heights of 1/8,1/4,1/2 and 1 were soaked for 10 min,40 min,3 h and 10 h,respectively,and uniaxial compression test and creep test were carried out to observe and analyze the experiment result.(4)The study was performed that the short-term and long-term mechanical behavior of black sandstone with different soaking angles under partial soaking.The black sandstones with the soaking angles of 0°,30°,45°,60° and 90° were immersed for 10 h respectively,and then the water content was tested and uniaxial compression test was carried out to observe and analyze the test results.