Ring Shear Characteristics Between Aeolian Sand-Loess Mixtures and Steel Interface
YAO Zhihua1,*, ZHANG Jianhua2, XIN Jianping1, MU Rui3
1 Department of Airdrome Construction Engineering, Air Force Engineering University, Xi'an 710038, China 2 China Southwest Geotechnical Investigation & Design Institute Co., Ltd., Chengdu 610052, China 3 Army Logistics Academy of PLA, Chongqing 401331, China
Abstract: The northern side of the Loess Plateau is bordered by many deserts, forming a widely distributed mixed distribution area of aeolian sand and loess. The aeolian sand-loess mixture (ASLM) presents different physical and mechanical characteristics under different proportion conditions, and the interfacial contact mechanical behavior of the ASLM foundation of ten occurs with other materials during field construction, and the relevant research is rarely mentioned at present. This work obtained the maximum dry density of the ASLM under different sand content conditions, prepared circular specimens of the ASLM with the same compaction degree and different sand content, and conducted ring shear tests on the interface between the ASLM and steel under different vertical pressures and shear velocities. The particle distribution properties and particle fragmentation characteristics of different sand content were observed using scanning electron microscopy, and the formation mechanism of resi-dual strength of ASLM with steel in ring shear condition was revealed. The test results show that the physical and mechanical characteristics of ASLM transition from loess to sandy soil with the increase of sand content. When the vertical pressure is less than 100 kPa, the probability of dilatancy of the mixture increases. There is a linear relationship between the interface residual strength and vertical pressure between the ASLM and the steel, which is consistent with the Mohr-Coulomb law. As the sand content increases, the crushing effect of aeolian sand particles increases, and the interfacial residual internal friction angle and the interfacial residual cohesion between the ASLM and steel decrease. An increase in shear rate shorten the contact time between the mixture and the steel interface, making it difficult to exert the contact and bite effects between the two, thereby reducing the residual strength of the interface between ASLM and steel. The research results predict the proportion of loess added to aeolian sand, which can provide useful reference for the treatment of aeolian sand foundation and also provide scientific reference for revealing the construction mechanics of ASLM.
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