Date of Award


Degree Type


Degree Name

Master of Science - Geology



First Advisor

Wesley Brown

Second Advisor

Chris Barker

Third Advisor

R. LaRell Nielson

Fourth Advisor

Kent Riggs


The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Geotechnical engineering is the branch of civil engineering which works on the principles of soil and rock mechanics to evaluate subsurface conditions, stability of slopes, foundations of structures and construction of earthworks. The main focus of this study was to calculate the strength of Lower Cretaceous Travis Peak Formation rocks of East Texas and to check the accuracy by comparing it with Regression analysis. The parameters which were used were the Uniaxial Compression Test (UCS) and tensile strength.

Core samples were collected at Stephen F. Austin State University Core Lab Repository. Strength tests were conducted at the lab facilities of University of Houston.

Parameters such as load for UCS and tensile strength were experimentally determined using procedures outlined by the International Society of Rock Mechanics (ISRM, Rock characterization testing and monitoring, 1981). In this study, a linear regression analysis was also performed to predict and compare the strength values of the core rock samples from the Travis Peak Formation.

Based on previous studies, it was shown that regression analysis is accurate in providing the strength of rocks. The results obtained from the tests are useful in predicting the strength of rocks from the Travis Peak Formation.

Uniaxial compression and tensile strength tests were performed for 12 samples at the Department of Civil Engineering’s Laboratory at the University of Houston. Before the tests, the samples were cut before into the size of 7.2 to 3.6 in ratio of length to diameter to maintain a 2:1 ratio.

The average value of UCS for the 12 samples was 27.43 MPa. Similarly, the average value for tensile strength for 12 samples was 4.05 MPa. Based on the values which were calculated, these samples were classified as medium strength rocks which belongs to Class D.

Linear Regression analysis was performed using MATLAB software for predicting the strength of core rock samples. The equation for linear regression was in the form of , where y is the tensile strength and x is UCS. The root mean square generated for regression analysis was 0.6378.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



Tell us how this article helped you.


To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.