Experimental Study On The Influence Of Clay Minerals On The Mechanical Properties Of Loess

The mechanical properties of loess directly affect the safety of site construction,and clay minerals,as an important part of the soil skeleton,have a particularly important impact on the mechanical properties of loess.For this reason,based on three different clay minerals(illite,kaolinite and montmorillonite),this article prepared remodeled samples mixed with different increments of clay minerals,and carried out high-pressure consolidation tests and consolidation quick-shear tests.The effect of the type and increment of clay minerals on the consolidation and shear properties.Get the following conclusions:(1)The compressive strain of remolded loess with different mineral types and increments increases with the increase of vertical stress.When the moisture content is the same,under the same vertical stress,the compressive strain decreases gradually with the increase of mineral increment,while the change law of compressive strain corresponding to the incorporation of montmorillonite with different contents is opposite.When the increment of clay minerals is the same,under the same vertical stress,the compressive strain increases gradually with the increase of water content.In addition,the type and increment of clay minerals do not affect the variation trend of compression curve,and the variation trend is that the void ratio decreases gradually with the increase of vertical stress.However,under the same vertical stress,the void ratio of two remolded loess mixed with illite and kaolinite increases with the increase of clay mineral increment,but the void ratio of remolded loess mixed with montmorillonite decreases with the increase of montmorillonite increment.(2)The change trend of shear stress-shear displacement curve of remolded loess with different mineral types and increments can be roughly divided into three forms:when the vertical consolidation stress is small,the curve is manifested as softening type.With the increase of vertical consolidation stress,the softening curve gradually transforms into an ideal elastic-plastic one.With the continuous increase of vertical consolidation stress,the curve gradually transforms from ideal elastic-plastic to hardening,and the change rule of remolded loess mixed with montmorillonite is more obvious than that mixed with illite and kaolinite respectively.(3)The shear strength of remolded loess mixed with the same kind of clay minerals showed a linear increase trend with the increase of vertical consolidation stress and clay mineral increment,and the corresponding shear strength index of the same sample also increased with the increase of clay mineral content.The shear deformation resistance of remolded loess mixed with illite and kaolinite is relatively stronger than that of remolded loess mixed with montmorillonite.However,for the samples with montmorillonite clay minerals,the variation range of shear strength index is weaker than that of the samples with illite and kaolinite clay minerals,respectively.(4)The compressive yield stress of the illite mineral sample mixed with a particle size of 0.5 μm is larger,and the corresponding resistance to deformation of the sample at the post-yield stage is greater than that of the sample with a particle size of 10 μm illite mineral;The degree of softening of the 0.5 μm illite mineral sample is relatively obvious,and the stress-strain curve is still a softening type under the condition of high consolidation stress and large increment.The addition of 0.5 μm illite mineral increases the residual strength of the sample.The shear strength,cohesion and internal friction angle of the 0.5 μm illite sample are greater than those of 10 μm illite.Mineral samples.The greater the content of illite minerals incorporated,the more obvious the increase in shear strength,internal friction angle and cohesion caused by the small particle size of illite.