scholarly journals Effects of Gouge Fill on Elastic Wave Propagation in Equivalent Continuum Jointed Rock Mass

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3173
Author(s):  
Ji-Won Kim ◽  
Song-Hun Chong ◽  
Gye-Chun Cho
Keyword(s):  
Wave Propagation ◽  
Rock Mass ◽  
Rock Joint ◽  
Physical And Mechanical Properties ◽  
Jointed Rock ◽  
Rock Joints ◽  
Shear Joint ◽  
Equivalent Continuum Model ◽  
Particulate Soil ◽  
Equivalent Continuum

The presence of gouge in rock joints significantly affects the physical and mechanical properties of the host rock mass. Wave-based exploration techniques have been widely used to investigate the effects of gouge fill on rock mass properties. Previous research on wave propagation in gouge-filled joints focused on analytical and theoretical methods. The lack of experimental methods for multiple rock joint systems, however, has limited the verification potential of the proposed models. In this study, the effects of gouge material and thickness on wave propagation in equivalent continuum jointed rocks are investigated using a quasi-static resonant column test. Gouge-filled rock specimens are simulated using stacked granite rock discs. Sand and clay gouge fills of 2 and 5 mm thicknesses are tested to investigate the effects of gouge material and thickness. Comprehensive analyses of the effects of gouge thickness are conducted using homogeneous isotropic acetal gouge fills of known thickness. The results show that gouge fill leads to changes in wave velocity, which depend on the characteristics of the gouge fill. The results also show that particulate soil gouge is susceptible to preloading effects that cause permanent changes in the soil fabric and contact geometry and that increased gouge thickness causes a more significant stiffness contribution of the gouge material properties to the overall stiffness of the equivalent continuum specimen. The normal and shear joint stiffnesses for different gouge fill conditions are calculated from the experimental results using the equivalent continuum model and suggested as input parameters for numerical analysis.

Analytical Study of Cylindrical P-Wave Propagation across Jointed Rock Masses

2014 ◽  
Vol 988 ◽  
pp. 502-507 ◽  
Author(s):  
Shao Bo Chai ◽  
Jian Chun Li ◽  
Hai Bo Li ◽  
Ya Qun Liu
Keyword(s):  
Wave Propagation ◽  
Rock Joint ◽  
Jointed Rock ◽  
P Wave ◽  
Displacement Discontinuity ◽  
Linear Elastic ◽  
Transmission And Reflection Coefficients ◽  
Conservation Of Momentum ◽  
Elastic Rock ◽  
Transmission And Reflection

According to the displacement discontinuity method and the conservation of momentum at the wave fronts, analysis for cylindrical P-wave propagation across a linear elastic rock joint is carried out. Considering the energy variation for wave propagation in one medium, the wave propagation equation was derived and expressed in an iterative form. The transmission and reflection coefficients are then obtained from the equation. By verification, the results agree very well with those from the existing results.

scholarly journals Experimental Study on Hydromechanical Behavior of an Artificial Rock Joint with Controlled Roughness

2019 ◽  
Vol 11 (4) ◽  
pp. 1014
Author(s):  
Seungbeom Choi ◽  
Byungkyu Jeon ◽  
Sudeuk Lee ◽  
Seokwon Jeon
Keyword(s):  
Rock Mass ◽  
Rock Joint ◽  
Great Influence ◽  
Rock Joints ◽  
In Situ Tests ◽  
Joint Roughness ◽  
Artificial Rock ◽  
Geometric Conditions ◽  
Bedding Planes ◽  
Hydraulic Aperture

Rock mass contains various discontinuities, such as faults, joints, and bedding planes. Among them, a joint is one of the most frequently encountered discontinuities in rock engineering applications. Generally, a joint exerts great influence on the mechanical and hydraulic behavior of rock mass, since it acts as a weak plane and as a fluid path in the rock mass. Therefore, an accurate understanding on joint characteristics is important in many projects. In-situ tests on joints are sometimes consumptive in terms of time and expenses so that the features are investigated by laboratory tests, providing fundamental properties for rock mass analyses. Although the behavior of a joint is affected by both mechanical and geometric conditions, the latter are often limited, since quantitative control on the conditions is quite complicated. In this study, artificial rock joints with various geometric conditions, i.e., joint roughness, were prepared in a quantitative manner and the hydromechanical characteristics were investigated by several laboratory experiments. Based on the results, a prediction model for hydraulic aperture was proposed in the form of ( e h / e m ) 3 = exp ( − 0.0462 c ) × ( 0.8864 ) J R C , which was a function of the mechanical aperture, joint roughness, and contact area. Relatively good agreement between the experimental results and predicted value indicated that the model is capable of estimating the hydraulic aperture properly.

Verification of UDEC Modeling 1-D Wave Propagation in Rocks

2011 ◽  
Vol 90-93 ◽  
pp. 1998-2001
Author(s):  
Wei Dong Lei ◽  
Xue Feng He ◽  
Rui Chen
Keyword(s):  
Wave Propagation ◽  
Analytical Solution ◽  
Transmission Coefficient ◽  
Method Of Characteristics ◽  
Rock Joint ◽  
Rock Joints ◽  
Dynamic Problems ◽  
The Method Of Characteristics ◽  
Elastic Rock ◽  
D Wave

Three cases for 1-D wave propagation in ideal elastic rock, through single rock joint and multiple parallel rock joints are used to verify 1-D wave propagation in rocks. For the case for 1-D wave propagation through single rock joint, the magnitude of transmission coefficient obtained from UDEC results is compared with that obtained from the analytical solution. For 1-D wave propagation through multiple parallel joints, the magnitude of transmission coefficient obtained from UDEC results is compared with that obtained from the method of characteristics. For all these cases, UDEC results agree well with results from the analytical solutions and the method of characteristics. From these verification studies, it can be concluded that UDEC is capable of modeling 1-D dynamic problems in rocks.

scholarly journals Seismic response of rock joints and jointed rock mass

1996 ◽  
Author(s):  
A. Ghosh ◽  
S.M. Hsiung ◽  
A.H. Chowdhury
Keyword(s):  
Rock Mass ◽  
Seismic Response ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Rock Joints

A Constitutive Model for Rock Joints under Cyclic Loading

2011 ◽  
Vol 243-249 ◽  
pp. 2211-2215
Author(s):  
Dong Mei Yang ◽  
Xiang Bo Qiu
Keyword(s):  
Constitutive Model ◽  
Mechanical Behaviour ◽  
Rock Joint ◽  
Joint Stiffness ◽  
Constitutive Models ◽  
Jointed Rock ◽  
Rock Joints ◽  
Cyclic Loads ◽  
Loaded Rock ◽  
Good Agreement

Cyclic loads are commonly encountered in geotechnical engineering; however most constitutive models do not account for the effect that such loads can have on the mechanical behaviour of soils and rocks. This work is concerned with the behaviour of jointed rock and, as the overall mechanical behaviour of jointed rock is usually dominated by the mechanical behaviour of the joints, it is focused on the behaviour of rock joints under cyclic loads. In particular, an extension of the existed constitutive model for cyclically loaded rock joints is presented. Variations of rock joint stiffness in both the normal and the shear directions of loading due to surface degradation are taken into account. The degradation of asperities of first and second order is considered, while a new relation is proposed for the joint stiffness in the normal direction during unloading. Numerical simulation results show good agreement of model predictions with existing experimental results.

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