Naoki TOSAKA
Effects of consolidation stress ratio on deformation modulus in saturated sand
Hirofumi TOYOTA
In the previous research, the effects of consolidation stress ratio, K, on the shear modulus for the cohesive soil were examined. The local strain measurement and the bender element test (referred to as the BE test) were conducted using a triaxial apparatus to compare the shear modulus obtained from the two testing methods. As a result, the tendency was different in two examinations. Then, the same types of tests were conducted for sand in the present study. The results obtained were compared with those of the cohesive soil.
The new findings obtained are shown as follows.
1. The results from the sand and the cohesive soil have the same tendency in the BE test. That is, if the effective mean stress is the same, the elastic shear modulus has the same value and is independent of K-value. Therefore, the elastic shear modulus obtained from the BE test is subjected to the effective mean stress.
2. The results from the sand and the cohesive soil have different tendency in the local strain measurement. In the case of the cohesive soil, the elastic shear modulus is subjected to the effective axial stress. In the case of the sand, the elastic modulus is not subjected to the effective mean stress because it tends to become small when K-value increases in the case of K>1. It is newly found that the elastic modulus is subjected to the weighted effective mean stress.
3. The shapes of strain dependency of the secant shear modulus obtained from the local strain measurement were examined. The shape depends on K-value in the case of the sand, while it has similar figures with independence of K-value in the case of the cohesive soil.