Study of the Fissures and Microstructure Under Dry-wet Circulation of Expansive and Modification Soil
Expansive soil has the characteristics of developing fissures,and it has great influence on its engineering geological properties.In this paper,it analyzed the macrostructure and microstructure of samples under dry-wet circulation.It reveals the development pattern of sample cracks under the action of dry wet cycles,and it studies the suppression of expansive soil cracking by ionic soil stabilizer,and briefly explored its modification mechanism.The main research conclusions were as follows,under the action of dry wet cycles,the fissures of expansive soil exhibit three distinct stages:slow growth,rapid growth,and slow decline.The dominant microstructure constituents of these two types of samples were flake structure and flat structure,and the connection mode of clay minerals were"surface-surface"and"edge-surface",so the microstructure is flocculation structure.Under the effect of dry-wet circulation,the microstructure of soil samples varied from compaction state to the loose state gradually.After ionic soil stabilizer modification,peak value of the sample fracture area can reduce 20％and the reduction in crack width can reach 30％.The state of clay mineral changed from curled sheet gradually into single chip,the reunion phenomenon,which contained the process of"the clay-pills polymers-micro polymers",occurred and larger reunion piece appeared.Furthermore,the addition of the ISS caused the beneficial changes in the cohesiveness and water stability,and it can effectively suppress the development of cracks in expansive soil and improve its engineering properties.
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