Compressibility and crushability of calcareous soils

The crushability of soil can have important consequences for engineering design. An obvious example is the low shaft capacity of driven piles in calcareous material, where compression and crushing of the soil leads to low normal effective stresses at the pile-soil interface. This paper describes the results of a study of the crushability of two calcareous soils, one offshore and one coastal, from the Western coast of Australia. Stress levels of up to 55 MPa were applied, in a high-pressure oedometer. Different crushability criteria were explored, and a modified criterion proposed based on the average grain size above 0.005 mm. This criterion leads to a clear relationship between the pressure applied and the degree of crushing, with a limited relative breakage of about 0.4 at high stress levels.