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.

Parametric Study on Cylindrical P-Wave Propagation

2014 ◽  
Vol 621 ◽  
pp. 225-229 ◽  
Author(s):  
Shao Bo Chai ◽  
Jian Chun Li ◽  
Hai Bo Li ◽  
Ya Qun Liu
Keyword(s):  
Wave Propagation ◽  
Rock Joint ◽  
Joint Stiffness ◽  
Jointed Rock ◽  
P Wave ◽  
Wave Source ◽  
Linear Elastic ◽  
Source Distance ◽  
Parametric Studies ◽  
Elastic Rock

Considering the energy variation, cylindrical P-wave propagation across a linear elastic rock joint is analyzed. Then parametric studies are carried out to investigate the effects of the wave source distance,the joint stiffness and the incident waveforms on wave propagation across a jointed rock mass.

scholarly journals Transmission of Normal P-Waves across a Single Joint Based ong‐λModel

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Zhanfeng Fan ◽  
Jichun Zhang ◽  
Hua Xu ◽  
Jianhua Cai
Keyword(s):  
Particle Velocity ◽  
Normal Incidence ◽  
Exponential Model ◽  
P Wave ◽  
Displacement Discontinuity ◽  
Reflection Coefficients ◽  
Joint Stress ◽  
Limit Values ◽  
Transmission And Reflection Coefficients ◽  
Transmission And Reflection

This paper investigates the wave transmission and reflection of an elastic P-wave at a single joint for normal incidence. First, considering a coupled joint (correction parameterλ,0<λ<1), a normal deformation constitutive model of the joint (g‐λmodel) under static or quasi-static loading is introduced and then extended to dynamic loading. The nonlinearity of the joint stress-deformation curve increases with increasingλ. Second, the interaction between the P-wave and the joint is investigated by using the method of characteristics and the displacement discontinuity method to deduce the differential expression of the transmitted wave’s particle velocity. The approximate analytical expressions of the transmission and reflection coefficients are obtained according to the Lemaitre equivalent strain assumption. Third, parametric studies are conducted to evaluate the effects ofλon transmission characteristics for a normally incident P-wave at a single joint. The results show that the particle velocity of the transmitted wave depends onλ. Whenλtakes the limit values 0 and 1, the transmitted wave’s particle velocities are then consistent with the conclusions of the classical exponential model and the Barton–Bandis model. In addition, the transmission and reflection coefficients are discussed with respect toλand also to the ratio of the joint closure to the maximum allowable joint closure.

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.

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

Geophysics ◽  
2009 ◽  
Vol 74 (5) ◽  
pp. E205-E214 ◽  
Author(s):  
Minsu Cha ◽  
Gye-Chun Cho ◽  
J. Carlos Santamarina
Keyword(s):  
Wave Propagation ◽  
Rock Mass ◽  
Normal Stress ◽  
Jointed Rock ◽  
P Wave ◽  
Rock Masses ◽  
S Wave ◽  
Jointed Rock Masses ◽  
Long Wavelength ◽  
Joint Properties

Field data suggest that stress level and joint condition affect shear-wave propagation in jointed rock masses. However, 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 history, 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 on S-wave attenuation are notable. The ratio [Formula: see text] in jointed rock masses differs from that found in homogeneous continua. The concept of Poisson’s ratio as a function of [Formula: see text] is unwarranted, and [Formula: see text] can be interpreted 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 properties and normal stress have a prevalent role in propagation velocity and attenuation in jointed rock masses.

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.

A PHOTOELASTIC STUDY OF STRESS WAVE PROPAGATION IN A QUARTER‐PLANE

Geophysics ◽  
1971 ◽  
Vol 36 (2) ◽  
pp. 296-310 ◽  
Author(s):  
A. N. Henzi ◽  
J. W. Dally
Keyword(s):  
Rayleigh Waves ◽  
Wave Interaction ◽  
P Wave ◽  
Stress Wave Propagation ◽  
Reflection Coefficients ◽  
Stress Distributions ◽  
Full Field ◽  
Transmission And Reflection Coefficients ◽  
Quarter Plane ◽  
Transmission And Reflection

An experimental investigation was conducted on a quarter‐plane loaded with an explosive charge at one point on the boundary. Experimental methods of dynamic photoelasticity and interferometry were used to obtain full‐field data of the dynamic event. Results of the study were obtained for both the P and R‐wave interaction with the corner. Energy reflection coefficients were found for the P‐wave interaction. For the Rayleigh wave, where the response was more significant, transmission and reflection coefficients based on both stress and surface energy were established. Subsurface stress distributions for the transmitted and reflected Rayleigh waves were obtained in the region near the corner.

scholarly journals Transmission, Reflection and Dissipation of Microwaves in Magnetic Composites with Nanocrystalline Finemet-Type Flakes

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3499
Author(s):  
Anatoly B. Rinkevich ◽  
Dmitry V. Perov ◽  
Yuriy I. Ryabkov
Keyword(s):  
Composite Material ◽  
Microwave Absorption ◽  
Nanocrystalline Alloy ◽  
Reflection Coefficients ◽  
Magnetic Composites ◽  
Transmission And Reflection Coefficients ◽  
Wave Interference ◽  
Microwave Losses ◽  
Frequency Dependences ◽  
Transmission And Reflection

The microwave properties of a composite material containing flakes of finemet-type nanocrystalline alloy placed in the epoxy matrix have been investigated. Two compositions have been studied: with 15% and 30% flakes. Frequency dependences of transmission and reflection coefficients are measured in the frequency range from 12 to 38 GHz. The dielectric permittivity and magnetic permeability are obtained, and the microwave losses are calculated. The dependences of transmission and reflection coefficients have been drawn as functions of wave frequency and thickness of the composite material, taking into account the frequency dependences of permittivity and permeability. The regions of maximal and minimal microwave absorption have been defined. The influence of wave interference on the frequency dependence of microwave absorption is studied.

Sign in / Sign up

Export Citation Format

Share Document