@article{Chen2024, 
author = {Zhimin Chen and Yaohui Liu and Ning Li},
title = {Research on the Shear Characteristics of Moraine under Freeze-Thaw Action and the Surrounding Rock Pressure},
year = {2024},
journal = {Chinese Journal of Underground Space and Engineering},
volume = {20},
number = {2},
pages = {460-470},
keywords = {moraines, freeze-thaw cycles, direct shear test, surrounding rock pressure},
url = {https://www.sciopen.com/article/10.20174/j.JUSE.2024.02.12},
doi = {10.20174/j.JUSE.2024.02.12},
abstract = {Moraines are special rock and soil mass formed by the accumulation of large amounts of debris material transported by glacial action. Due to the geographical and climatic conditions prevailing, freeze-thaw action can pose a challenge to the construction of tunnels through this type of rock, especially in portal sections. The geological conditions of moraine surrounding rocks in Tibet, China, was investigated, and set up a direct shear test of freeze-thaw cycles to study the influence of the number of freeze-thaw cycles and water content on the mechanical properties and indicators of frozen moraine, introduced a comprehensive parameter K for the number of freeze-thaw cycles and water content, fit the formula for the cohesion c. The results show that the freeze-thaw cycles and water content have significant influence on the cohesion c. And proposed a formula for calculating the surrounding rock pressure applicable to the tunnel portal section of moraine surrounding rocks based on the Terzaghi theory. Taking a tunnel of Changlin Railway as an example, the surrounding rock pressure under different conditions was calculated to verify the reasonableness of the formula. The study shows that freeze-thaw cycles and water content are important factors affecting changes in the mechanical properties of moraines, and freeze-thaw action has different degrees of influence on the surrounding rock pressure in the portal section, which should be fully considered in the construction of the project.}
}