Desiccation cracking bebavior of soils based on digital image correlation technique
摘要
Under dry condition, the soil is prone to evaporation, leading to desiccation cracking. It is of great significance to deeply study the desiccation cracking process of soils to accurately grasp the engineering response characteristics of soils in arid climate environment. In conducting laboratory drying tests on cohesive soils, digital cameras are used to record the dynamic development of surface cracks in real time. By using the digital image correlation techniques, the plane strain field and displacement field of the whole process of desiccation cracking of soils are obtained. The experimental results show that: (1) The cracks are usually generated at the position where the tensile stress is concentrated, and the stress is then rearranged when the surrounding stress is rapidly released, and the cracks tend to intersect with other cracks at right angles. (2) The displacement field and strain field can effectively confirm some movement characteristics of the soils during the desiccation cracking process, thus providing assistance for analyzing the dynamic evolution process of cracks. (3) The soils are divided into different blocks by cracks, each block has its shrinkage center, and the shrinkage center will change with time. (4) The digital image correlation technique can effectively identify the gray scale feature values between different images, obtain the surface deformation information, and provide valid technical means for the study on desiccation cracking characteristics of soils.