| Author: | Au, Chi-kwong |
| Title: | Failure mechanism of rock-like material with random distribution of flaw under uniaxial compression |
| Degree: | M.Sc. |
| Year: | 2000 |
| Subject: | Rock mechanics Joints (Geology) Hong Kong Polytechnic University -- Dissertations |
| Department: | Multi-disciplinary Studies Department of Civil and Structural Engineering |
| Pages: | xi, 93 p. : ill. (some col.) ; 30 cm |
| Language: | English |
| Abstract: | There are many joints in rock mass. Joints may be developed in the relief of tensional or shearing stress acting on rock masses. The cause of the stresses has been variously ascribed to shrinkage or contraction, compression, unequal uplift or subsidence and other phenomena. Basically, Joints are developed in vary angle on rock. When the rock mass sustained a surcharge and when the degree of surcharge increase to a particular level, the cracks will initiate at tip of joints. The length of cracks will grow with increasing force. Finally, the cracks will be coalescence with the neighboring joints. The crack coalescence is the cause of the rock mass failure. Most mathematical models were developed to explain and predict the processes of crack growth, interaction and rock failure in single joint and muti-parallel joints, but relatively few experimental investigations were done to examine the failure mechanism of joints on rock mass in varied angle. The failure mechanism is still not clear. This project examines the failure mechanism of limestone-like material with random distribution(varied angle) of flaw under uniaxial compression, the sample contains random distributed fictional flaws, with various length of flaws. Three main points are observed: (1) The first crack initiation is at the tip of flaw which is near the tension zone (the center part) of the sample under uniaxial compression. (2) The number of crack initiation increases with length of flaws. That is the longer length of flaw, the more number of crack initiations from the flaw tip. (3) The peak strength decreases with increasing length of flaw. The experimental peak strength was compared with an analytical method (the model of Ashby and Hallam) and a numerical method (RFPA). In the comparison, it is found the experimental result has a high degree of correlation with the predicted result by the numerical method. However, less with the predicted result by the analytical method. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b15594476.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 12.53 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/2075