Regional Variation and Influencing Factors of Shear Strength Parameters of Malan Loess in Lüliang Area

Taking the undisturbed Malan loess from 94 sampling points in 29 counties in Lüliang Area as the research object, the undisturbed Malan loess was subjected to direct shear tests and undisturbed loess wetting water content and salt content shear tests to reveal the loess in the area. The regional distribution of loess shear strength parameters in the area is revealed, and the influencing factors of undisturbed Malan Loess shear strength parameters are analyzed. The results show that in the horizontal area, the shear strength parameters c and φ of the undisturbed Malan loess in the Lüliang area are higher on the east side than on the west side; in the vertical space, the correlation between c and φ and the sampling depth is low. The experiment of influencing factors also reveals that c, φ have discrete distribution with natural water content and natural dry density. Under the condition of wetting water content, undisturbed Malan loess c has a good exponential function relationship with wetting water content, φ has a linear negative correlation with wetting water content, and salinity has a positive correlation with c and φ. The effect of salt content on increasing internal friction angle is more obvious than that of cohesion. Compared with salt content, moisture content has a more significant effect on c and φ. This research provides the foundation and necessary conditions for solving the geological disasters in the Loess Plateau of western Shanxi Province.