Study On The Acoustics Characteristic Of Layer Rocks

Ultrasonic diffusing speed in medium reflects physical and mechanics characters of medium. Ultrasonic testing technique in rock mass medium is a new technique which has been developed during near thirty years. It realized physical and mechanics characters, structure and stress state of rock mass by testing the change of acoustics parameters of sound wave signal after penetrating rock mass, which got recognition in domestic and overseas geotechnical engineering fields.Layer rocks are crude mass made of manifold different attribute thickness and component which were assembled according to some ways. Under long geologic effect, in situ stress, water, temperature and man-made effect, microcosmic damage and macrostructure were brought in rock mass, so its characteristics are very different from the single rock. The relationships between groovy physical and mechanics parameters of layer rocks and elasticity wave speed are not only an academic pro but also an applied problem. It is very significant to outspread study home on the relationships between groovy physical mechanics parameters of layer rocks and elasticity wave speedFirstly, longitudinal wave speed of basalt, granite, limestone and layer rocks made of above rocks with different density were tested by RSM-SY5 sound wave test apparatus; then monaxial compression test was carried out while corresponding rock wave speed of every grade load was tested by sound wave apparatus; men elasticity modulus of rock were calculated according to stress-strain curve, corresponding diversified physical and mechanics parameters and acoustics parameters of rock were obtained;on this base, recursive analysis method was carried out, mutial relationships between density, stress, elastic and longitudinal wave speed of rock with different lithology and layer rocks were studied, contrast and analysis were put up and mathematic models of diversified relationships were built; at last, contrast and analysis were earried out about academic calculative value and real value in engineering, which showed that mathematic models had some applicability in engineering, which were validated preferably.It was revealed by the research result that longitudinal wave speed of single rock and layer rocks were increasing along with the increase of density and pertinence was existed between wave speed and density which got better line fitting; whether single rock or layer rocks, longitudinal wave speed was increasing along with the increase of stress during loading process. Because in the loading process, nricrocosmic crannies in rock were closed along with the changes of stress state. In the same stress condition, wave speed of basalt was the biggest, limestone was the second and granite was the smallest but layer rocks were among them In the same loading process, increased proportion of basalt, granite, limestone and layer rocks were 23.34%, 24.39%, 24.08% and 17.87% respectively. Increased proportion of single rock was different but similar, while increased proportion of layer rocks was minished dearly. Conelatrve coefficient of multinomial fitting was the highest between wave speed and stress; longitudinal wave speed of rock was increasing along with the increase of elasticity modulus, better pertinence was existed between wave speed and elasticity modulus. In the four different function fittings, Correlative coeffiicient of multinomial fitting was the highest between wave speed and elasticity modulus.