Experimental study on range of strength limit neighborhood of red sandstone under effect of creep disturbance

In order to obtain more suitable range and division basis of strength limit neighborhood.Red sandstone is used as the research object.Using RRTS- IV rock creep disturbance effect test system developed by ourselves,and the dynamic test and analysis system.Through the test of uniaxial compression creep and its disturbance effect of rock,combined with theoretical analysis,the range and division basis of red sandstone "strength limit field" are studied.Firstly,the difference of long-term strength determined by transverse creep and axial creep is analyzed from two aspects: graded loading creep curve and stress-strain isochronous curve.Then a comparative study of the range of "neighborhood of strength limit" determined by lateral and axial creep of rock is carried out from two aspects: instantaneous disturbance deformation and transformation law of residual disturbance deformation.Finally,through comprehensive analysis,the suitable range and division basis of strength limit neighborhood is obtained.The results show that:compared with the transformation law of axial creep residual disturbance deformation,it is more appropriate to determine the range of strength limit neighborhood by the transformation law of transverse creep residual disturbance deformation,so the threshold value of strength limit neighborhood range of red sandstone is about 32.5 MPa；the difference between the range threshold of strength limit neighborhood determined by long-term strength and the range threshold of strength limit neighborhood determined by transformation law of residual disturbance deformation is about 2.5 MPa. However,as a simple preliminary analysis,it is still of high reference value to define the range of strength limit neighborhood by long-term strength.