The ratio of lateral to vertical stress at zero lateral strain (k sub 0) is a soil characteristic that is important in several geotechnical applications. At present, no unanimity exists as to how k sub 0 should be calculated or how it is influenced by stress history. The uncertainty regarding this soil characteristic may be reduced through improved measurements. At present, triaxial testing and confined compression tests are used. Triaxial testing is cumbersome and limited to certain soil types. Confined compression tests ignore the presence of wall friction and thus may introduce unknown factors in the measurement. A new confined compression tester is described that measures wall shear stresses along with vertical and horizontal stresses. Confined compression tests on ottawa sand, alluvial sand, crushed limestone, and coal and cparisons with k sub 0 tests conductedin triaxial apparatus on replicate specimens of the two materials are included. The new test device shows promise and should lead to improved methods for evaluating k sub 0 in soils and provide a tool for achieving an understanding of how stress history influences this important soil characteristic. This paper appears in transportation research record no. 1278, Dynamic testing of aggregates and soils andlateral stress measurements 1990.
Samenvatting