PERMFILE56525

• Permit No: C1984065
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: App. 4.3-1 Initial Geotech Study
• Section_Exhibit Name: APPENDIX 4.3-1 INITIAL GEOTECHNICAL STUDY LOGGING & TESTING EVALUATION
• Media Type: D
• Archive: No

8

C U
2.~c
[9]
Consequently, the determination of U and Tan B or k from Equation
[7] by linear regression methods and the subsequent calculation
of ~' and C using Equation [8] and [9] is perhaps a simpler and
more straight forward method than plotting the Mohr envelope.
Direct Shear Strength. The direct shear strength of a rock
core may be envisioned as the shear strength which results when
the normal stress is zero. In other words, the shear strength
of a rock could be approximated as the cohesion at zero normal
stress. Therefore, an estimate of cohesion may be made by test-
ing a rock core in direct shear. The specific test used in the
study is known as the double shear test and is defined as follows:
D P
~ [10]
•
where P ~ load at failure
A ~ cross sectional core area
Brazilian Tensile Strength. The Brazilian or indirect
tensile strength of a rock is determined by loading a disc of
rock in compression across the diameter. The Brazilian tensile
strength (B) is then computed as follows:
$ 2P [11]
4DL
where P ~ load at failure
D ~ sample diameter
L ~ sample thickness
Flesural Strength. The flexural or outer fiber tensile
strength was determined by a bending test. The test involves
,.
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