Study on The Influence of Freezing and Thawing Cycle and Dry and Wet Alternation on Mechanical Properties and Engineering Application of Loess Slope

This article selects typical high-slope loess along the Baolan high-speed railway as the research object. Firstly, laboratory testing methods are used to conduct direct shear and consolidation tests on loess under freeze-thaw cycles, dry-wet alternation, and their combined effects to study the changes in its mechanical properties. The experiment found that rainfall infiltration is different due to different slopes. The negative pore water pressure at the top of the slope rapidly increased from −176.52 kPa to −139.094 kPa, and the volumetric water content also rapidly increased from 14.11% to 16.63%. The negative pore water pressure at the foot of the slope increased to −76.33 kPa, and the volumetric water content was 22.11%. At a given dry density, as the moisture content increases, regardless of the type of specimen, its cohesion, internal friction angle, and compression modulus gradually decrease while the porosity increment and compression coefficient increase. At a given moisture content, as dry density increases, regardless of the type of specimen, its cohesion, internal friction angle, and compression modulus gradually increase while the increment of porosity and compression coefficient gradually decrease. However, the internal friction angle, porosity increment, and compression modulus response to freeze-thaw action are closely related to initial dry density. At a given dry density and moisture content, as the number of cycles increases, the cohesion and compression modulus of the sample gradually decrease while the increment of porosity and compression coefficient increase.