Study on cracking process of coarse-grained soils in central dry zone of Ningxia

In order to investigate the cracking process of coarse-grained soils in pressed sand,coarse-grained gravels（grey-green slate） were used as the objects of study. The physical and chemical properties of coarse-grained gravels under the action of freeze-thaw dry and wet were measured through indoor simulation tests, and the fine morphology of coarse-grained gravels under different treatments was observed by electron microscopy scanning. The results showed that the coarse gravels showed significant fracturing behaviour as the number of cycles increased, with the coarse gravels of2 mm producing more rock chips with greater fragmentation and the release of mineral elements. The EC values in the drench solution increased with the number of cycles, indicating that the mineral ions in the coarse grains were released and dissolved in the drench solution. The analysis of the coarse particle cracking pattern from macroscopic and microscopic perspectives revealed the mechanism of coarse particle cracking and provided theoretical support for further research on soil coarse particle loam formation.