Sensitivity Analysis Of Rock Elastic Modulus

Rock mechanics parameter testing is a basic and key work in geotechnical engineering.Aiming at the shortcomings of rock elastic modulus testing such as high cost and long period,this paper puts forward the subject of"sensitivity analysis of rock elastic modulus".Taking rocks from a mine in Fujian as the research object,rock ultrasonic wave velocity testing,ultrasonic propagation testing and uniaxial compression testing are carried out.By introducing sensitivity coefficient,sensitivity analysis of rock dynamic elastic modulus,rock static elastic modulus and rock static elastic modulus is carried out through in-situ borehole elastic modulus test.The main results are as follows:?1?Rock density and dynamic elastic modulus increase approximately linearly;porosity and dynamic elastic modulus decrease approximately linearly,and porosity is more sensitive to dynamic elastic modulus than density;rock longitudinal and shear wave velocity and dynamic elastic modulus increase approximately exponentially,and shear wave is more sensitive to dynamic elastic modulus than longitudinal wave.The number is 0.011 GPa^-1;the correlation coefficient of waveform increases exponentially with the dynamic elastic modulus,the variation coefficient of waveform decreases exponentially with the dynamic elastic modulus,and the amplitude attenuation coefficient decreases linearly with the dynamic elastic modulus;the amplitude attenuation coefficient is most sensitive to the change of the dynamic elastic modulus of rock,and the sensitivity coefficient is 2.4786 GPa^-1;?2?Rock density increases approximately linearly with rock static elastic modulus;rock longitudinal and shear wave velocity increases approximately exponentially with rock static elastic modulus;rock dynamic elastic modulus increases linearly with rock static elastic modulus,and sensitivity coefficient is 0.0058 GPa^-1;with rock static elastic modulus increasing,correlation coefficient increases approximately exponentially.The variation coefficient and attenuation coefficient decrease with negative exponential function.The amplitude attenuation coefficient is the most sensitive to the change of dynamic elastic modulus of rock,and the sensitivity coefficient is 0.04 GPa^-1.?3?The sensitivity coefficients of P-wave velocity,S-wave velocity and dynamic elastic modulus to the static elastic modulus of rock mass are all below 0.1 GPa^-1,but there are great differences among them.The S-wave velocity is more sensitive to the static elastic modulus of rock mass.With the increase of the static elastic modulus of rock mass,the correlation coefficient of waveform increases exponentially,while the variation coefficient and attenuation coefficient increase exponentially.The amplitude attenuation coefficient is the most sensitive to the dynamic elastic modulus of rock,and the sensitivity coefficient is 0.023GPa^-1.?4?Comprehensive analysis shows that the amplitude attenuation coefficient is the most sensitive to the elastic modulus of rock.The variation of elastic modulus of rock can be analyzed by the amplitude attenuation coefficient,which can be used as the characterization of the elastic modulus test.