Impacts of Drained Conditions and Degree of Reconsolidation on Postcyclic Mechanical Behaviors of Laterite Clay

The mechanical behaviors of subgrade soils will change after cyclic loading, resulting in a modification of foundation bearing capacity and the development of additional settlement. Recognizing this, cyclic triaxial tests were conducted to remolded laterite clay, and reconsolidation was allowed. During the process, the cyclic loading was applied under undrained and partially drained conditions, respectively. Results show that the variations of both postcyclic undrained strength and elastic modulus versus degree of reconsolidation are different: the postcyclic elastic modulus increases with an increase of the degree of reconsolidation, while the undrained strength decreases a little under the condition of the large degree of reconsolidation. Furthermore, there are specific degrees of reconsolidation, making the postcyclic undrained strength and elastic modulus equal to the corresponding test results of the specimen without reconsolidation. Moreover, the greater the number of cycles, the larger the elastic modulus of the specimens with full reconsolidation, and the lower the elastic modulus of the specimens without reconsolidation. The undrained strengths of the specimens with full reconsolidation are all higher than those of the specimens without cyclic loading, whereas those of the specimens without reconsolidation are all lower. In addition, both postcyclic undrained strength and elastic modulus between cyclic loading under undrained and partially drained conditions are compared: the elastic moduli of the specimens under partially drained conditions are greater than those obtained under undrained conditions, while the undrained strengths obtained under partially drained conditions are equal to that under undrained conditions at a certain number of cycles.