Study on the Dynamic Development Law of Cracks in Expansive Soil Under Dry Wet Cycling

In the middle route project of the South to North Water Diversion Project, the slope of the expansive soil channel is in a dry wet alternating environment. Studying the crack propagation law of expansive soil under the effect of dry wet cycles is of great significance for revealing the instability mechanism of expansive soil slopes. A crack propagation experimental device is designed and used to conduct crack propagation experiments on expansive soil under different dry wet cycles. The water evaporation process and the dynamic development process of apparent cracks over time are systematically measured, and the following conclusions are drawn: (1) The evaporation rate over time under different dry wet cycles can be divided into stable evaporation stage, deceleration rate evaporation stage, and residual evaporation stage. (2) As the number of wet and dry cycles increases, the width of the crack gradually decreases, while the total length of the crack gradually increases. (3) Under the action of dry wet cycles, the surface area crack rate of the soil gradually increases and tends to stabilize. (4) Under multiple dry wet cycles, the particle distribution always develops towards a stable direction, and the humidity stress distribution also develops towards a more advantageous state.