Propagation Characteristics Of Stress Wave Propagation In Layered Rock And The Measurement Of The Interface Elastic Modulus

With the rapid development of engineering technology,a large scale of engineering constructions are carried out in our country,All kinds of problems are encountered in the process of many fields,such as hydroelectric projects,traffic engineers,construction engineering,mineral resources mining engineering and defense projects etc.It is great important to obtain the mechanical properties of rock mass and rock mass parameters in the analysis of engineering constructions,construction and engineering stability.In this paper,the experiments of the stress wave propagation were made in the layered rock mass and large thickness structural surface to analyze the stress wave propagation properties and measure the mechanical parameters of larger thickness of the surface structure.In this paper,the field tests on layered rock mass were done in at Wan Town,Xinxiang Henan province.We get conclusions as follows:attenuation coefficient increased with the increase of frequency in garden of Qiwang village,attenuation coefficient present first decrease and then increase with the increase of frequency in Bali Gou Rafting,meanwhile,as frequency increases,the attenuation coefficient increases after stabilizing in Yijian Tian,Qiwang Village.The energy losses were mainly due to the viscosity of the layered rock mass and Spherical spreading when the Stress wave propagated in layered rock mass.The method for measuring the viscosity coefficient of layered rock mass was deduced based on stress wave energy loss and dissipative term of the model.The viscosity coefficient of Qiwang Village was measured for 1.93MPa·s by choosing Maxwell Model within 0.7 m distance from the source,and was measured for 3.96MPa·s by choosing Maxwell Model within 0.7~1.5 m distance from the source.The viscosity coefficient of Bali Gou Rafting was measured for 1.45 MPa·s within 0.7m distance from the source,and was measured for 2.14 MPa·s within 0.7~1.2 m distance from the source.For practical engineering thickness larger macro-structure side,the improved linear elastic displacement discontinuity model was established,and the interface elastic modulus was calculated using customary and improved model,respectively.The results indicated that the interface elastic modulus should be measured using customary model when impedance ratio was larger and the interface elastic modulus should be measured using the improved model when impedance ratio was smaller.The effect of interface thickness to test deviation is analyzed;The test deviation,based on the reflection waveform difference adopting improved model,decreased with the increase of the interface thickness.But,The test deviation,based on the transmission waveform difference adopting customary model,increased with the increase of the interface thickness.Finally,the elastic modulus of 0.02 m thickness surface was measured for 0.16 GPa,the 0.09 m thickness surface was measured for 0.27 GPa based on the reflection waveform difference adopting customary and improved model.And the results of field test and numerical simulation were consistent.