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Intact rock propertt'es <br />Table 11.3: Values of the constant m; for intact rock, by rock group. Note that values in <br />parenthesis are estimates. <br />167 <br />Rock Class Gmup Texturo <br />type Coarse Medium Fine Very fine <br /> Congloroetate Sandstone Siltstone Claysmne <br /> clastic (22) 19 9 4 <br /> - Greywacke.- <br /> (18) <br /> Chalk <br /> <br /> Organic <br /> Coal <br /> (8-21) <br />w Brescia Sparitic Micritic <br />y Non- Carbonate (P0) Limestone Limestone <br /> clastic (10) g <br /> Chemical Gypstoae . Anhydrite <br /> 16 13 <br />V Non Foliated Marble Hornfels Quartzite <br /> 9 (19) 24 <br /> <br /> Migmatite Amphibolite Mylonites <br />~ Slightly foliated (30) 25 - 31 (~ <br /> <br /> Foliated" G~i~ Schists Phyllites <br />~ Slate <br /> 33 4 - 8 (10) 9 <br /> Granite Rhyolite Obsidian <br /> 33 (16) (19) <br /> Light <br /> Granodiotite Dacite <br /> (30) (17) <br />m Diorite Andesite <br />~ (28) 19 <br />~ Dark X <br />to Dolerite .Basalt <br /> 27 <br /> Norite <br /> 22 <br /> Extrusive Agglomerate Brescia Tuff <br /> pyroclastictype (20) (18) (15) <br />" These values are for intact rock specimens tested normal to bedding or foliation. The value <br />of m;will be significantly different if failure occurs along a weakness plane. <br />1n deciding upon the value of a~; for foliated rocks, a decision has to be made on <br />whether to use the highest or the lowest uniaxial compressive strength obtained from <br />