Title: “Viscoelastic behavior of rock and jointed rock mass”

Talk at  207 Yantu Building (岩土大楼207室) , Tongji University

9:30am, November 15^th 2010 (周四上午9：30).

Abstract

Rocks contain various defects including voids, fractures, and inclusions and so on at a micro-scale. At an engineering scale, rock joints existing in different forms usually dominate the strength and deformation behavior of a rock mass. Rock masses are generally characterized to be not continuous, not isotropic, not uniform, not homogeneous, not linear and not elastic. However, when analyzing stress wave propagation in rocks and rock masses, this 5-N model is not sufficient, since it is not able to describe energy dissipations in discontinuous rock or jointed rock mass during stress wave propagation. In this study, the viscoelastic property of a sedimentary rock is experimentally investigated. A 3-element viscoelastic model with frequency-dependent parameters is then proposed for the sedimentary rock and jointed rock mass under dynamic loading. Analyses of stress wave attenuation in the sedimentary rock are also performed. It is concluded that the viscoelastic property has significant effects on stress wave propagation which cannot be ignored during dynamic analysis and the present frequency-dependent viscoelastic model is appropriate to describe the dynamic properties of the sedimentary rock. The traditional elastic model is a special case of the present model when the incident wave frequency is sufficient small.