Study On Mechanical Properties And Creep Properties Of Fractured Rocks With Different Water Content

In nature,the existence of fractured rock masses is very common and will have a direct impact on engineering construction.At the same time,a series of physical and chemical reactions will occur during the long-term coupling process of rock mass and water,which will significantly reduce the strength of rock mass medium,which in turn induces rock mass deformation and failure,which can easily cause engineering accidents and threaten the life safety of construction personnel.In this paper,sandstone is used as the prototype,and similar materials are selected from ordinary Portland cement: river sand: clay: water at a matching ratio of 1:1.7:0.08:0.45 to make fracture-like rock specimens with fracture angles of 30°,45°,60°,and fracture thickness of 0.3mm and 0.6mm,and then obtain rock-like specimens with different moisture content states by dryer drying,natural conservation and complete immersion.Indoor experimental research was carried out to analyze the mechanical properties and creep characteristics of fracture-like rocks with different inclination angles and thicknesses under the influence of moisture content,so as to provide reference for research in the field of rock engineering.(1)Uniaxial compression test and triaxial compression test are carried out for rock specimens and complete specimens with different moisture content.The peak stress of the complete specimen under the conditions of uniaxial compression and triaxial compression test was significantly higher than that of the rock-like specimen containing precast fractures.The peak stress and elastic modulus of rock-like specimens increased with the increase of precast fracture angle,decreased with the increase of precast fracture thickness,and decreased with the increase of moisture content.The cohesion of rock-like specimens increased significantly with the increase of precast fracture angle,and showed a trend of decreasing first and then increasing with the increase of moisture content.The cohesion of rock-like specimens in natural and dry states increased with the increase of precast fracture thickness,while the cohesion of rock-like specimens in the water-saturated state decreased with the increase of precast fracture thickness.The internal friction angle of rock-like specimens increases with the increase of precast fracture angle,decreases with the increase of precast fracture thickness,and decreases with the increase of moisture content.(2)Uniaxial creep compression test was carried out on rock specimens with different moisture content and fractures.The transient strain of uniaxial creep of rock-like specimens increases with the increase of precast fracture angle,and decreases with the increase of moisture content.The steady-state creep rate of uniaxial creep showed a trend of first increasing and then decreasing with the increase of precast fracture angle,and increased with the increase of precast fracture thickness and decreased with the increase of moisture content.(3)The peak stress of uniaxial compression test rock specimens after creep is greater than that of the same type of direct uniaxial compression rock specimens,and creep plays a strengthening role.Figure 44 Table 12 Reference 81...