STATISTICAL ANALYSIS OF SHALE DURABILITY FACTORS

The results of a study performed to develop durability tests for shales for use in embankments and swamp fills are presented. Forty-three shale samples, representing all exposed shale units in Ontario, were collected. The samples were subjected to a variety of tests, some standard soundness tests, some recently developed shale durability tests, and some special tests devised by the author. The tests included freeze-thaw durability, Franklin slake test, wet-dry deterioration, modified "rate of slaking", water adsorption at controlled humidities, water absorption, abrasion, and dry bulk density. The results of the tests were statistically analyzed. The principal analytic method was multivariate stepwise regression analysis, but other statistics were also obtained. The stepwise regression analysis picks the testing procedures that have the greatest influence on the desired property and produces a multitest equation that can be used to determine that property. A series of seemingly unrelated tests can thus be used to determine the durability of shales. For instance, wet-dry deterioration is related to and can be calculated from water absorption, freeze-thaw, and abrasion results. The results obtained apply to the variety of shales found in southwestern Ontario. A larger data base may be necessary to extend the conclusions to all shales as a group. (Author)