Long-wavelength P-wave and S-wave propagation in jointed rock masses

Field data suggest that stress level and joint condition af-fect shear-wave propagation in jointed rock masses. Howev-er, the study of long-wavelength propagation in a jointed rock mass is challenging in the laboratory, and limited data are available under controlled test conditions. Long-wavelength P-wave and S-wave propagation normal to joints, using an axially loaded jointed column device, reproduces a range of joint conditions. The effects of the normal stress, loading his-tory, joint spacing, matched surface topography i.e., joint roughness, joint cementation e.g., after grouting, joint opening, and plasticity of the joint filling on the P-wave and S-wave velocities and onS-wave attenuation are notable.The ratio VP /VS in jointed rock masses differs from that found in homogeneous continua. The concept of Poisson’s ratio as a function ofVP /VS is unwarranted, andVP /VS can be interpret-ed in terms of jointed characteristics. Analytic models that consider stress-dependent stiffness and frictional loss in joints as well as stress-independent properties of intact rocks can model experimental observations properly and extract joint properties from rock-mass test data. Thus, joint proper-ties and normal stress have a prevalent role in propagation ve-locity and attenuation in jointed rockmasses