Research on stability analysis of structural loess slopes based on combined tensile-compression-shear strength theory

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The long-term stable existence of western high and steep loess slopes is closely related to the special structural properties of loess, and there are often tensile stress areas at the top of the slope. It is important to evaluate the stability of upright slopes by reasonably considering the tensile strength of loess. Based on the combined tensile-compressive-shear strength theory of structural loess, the structural parameter field, displacement increment contour distribution field and small principal stress distribution field law characteristics of an upright slope are analyzed and studied by using the finite method of strength discounting. The results show that when there is no load or constant load on the top of the slope, the structural parameter distribution field and displacement increment contour field of the slope show an obvious “slip zone”, and the “slip zone” becomes more and more shallow with the increase of water content; when there is a uniform load on the top of the slope, the slip zone becomes more and more shallow with the increase of water content. When there is a uniform load at the top of the slope, the “shear zone” becomes more and more shallow with the increase of load intensity, and the surface uniform load intensity is bigger with the same water content, and there is a risk of local sliding; when there is no load at the top of the slope or the load remains unchanged, the small main stress field of the slope has different degrees of tension zone penetration, and the smaller the water content is, the bigger the tension zone is, and the amplitude is also bigger; when the slope has no load at the top of the slope or the load remains unchanged, the small main stress field of the slope has different degrees of tension zone penetration. The smaller the water content is, the larger the tensile zone is, and the amplitude is also large; when there is a uniform load on the top of the slope, the location of the tensile zone on the slope changes, shifting from the original back edge of the slope surface to a certain range on the top of the slope, and with the increase of the load strength, the tensile zone becomes smaller and smaller, and with the increase of the water content, the tensile zone also becomes smaller and smaller.