Abstract: In either a engineering construction or a natural environment, the processes of shrinkage and cracking of soil due to water loss are affected by multiple factors, and the interactions among the factors are very complex. Among these factors, changes in temperature conditions affect the beginning and ending of cracking, which plays a vital role. But there is little information about the influence of internal viscosity and sand ratio on crack development. In this study, a series of indoor evaporation tests are carried out under different environmental temperatures and sand content conditions. By recording the internal water loss and the development of surface cracks, the crack ratio and the geometric shape of the crack networks are quantitatively analyzed using relevant graphic analytical software, which allows to explore the influence mechanism of different temperatures and sand contents on soil shrinkage and cracking. The finding may provide some references for the evaporation and crack development of sand-clay mixture in practical engineering and environment. The results show that: (1) The existence of sandy soil led to changes in the internal structure of the soil and changes in some water conveyance channels, which prolonged the migration path of free water; (2) The existence of sand resulted in early cracking of the soil surface, which is less affected by sand contents and related to whether it contains sand or not; (3) The higher the sand content in the soil, the shallower the depth of crack development and the shorter the extension length of crack. At the same time, the width of a crack is inversely proportional to sand content; (4) Under the condition of the same sand content, the higher the environmental temperatures, the higher the water evaporation rates and the width of cracks formed on the soil surface, i.e., surface cracks, are generated in advance to a certain extent.

Key words: environmental temperature, sand content, moisture movement, evaporation rate, fracture development