Measuring desiccation-induced tensile stress during cracking process

Abstract

The desiccation cracking of soil occurs when shrinkage is restricted during the drying process and the induced tensile stress equals the tensile strength. Thus far, experimental estimations of the tensile stress of soil have not been realized, although such estimates are important for predicting crack initiation. This study presents the development of a laboratory-based desiccation stress test to measure the tensile stress generated during the drying process until crack initiation. In this proposed desiccation stress test, the tensile stress is induced during the drying process in the longitudinal direction of bar-shaped specimens with fixed ends. Desiccation stress tests were performed on sandy soil with a rich fine fraction, and the results were verified through photographic observations of crack initiation and comparisons with the results of direct tension tests. The results show that the desiccation stress test yields reliable tensile stress until cracking. The application of the desiccation test results is illustrated via the verification of an existing model of crack initiation by desiccation. The results of the desiccation stress tests are useful for determining the model parameters that significantly influence the development of tensile stress and enable its accurate prediction until crack initiation.