Huang Wanjun, Mao Xuesong, Wu Qian, Chen Linlin
Chang an University, Highway Academy, Xian, 7100000, People's Republic of China.
Luoyang Urban Construction Survey and Design Institute Co., Ltd., Luoyang, 471000, People's Republic of China.
Sci Rep. 2022 Nov 16;12(1):19687. doi: 10.1038/s41598-022-23086-z.
During the spring thawing, the decrease of soil-ice interface strength by temperature may lead to slope instability. For this reason, some researchers have explored the relationship between temperature and soil-ice interface strength. However, previous studies have not systematically explored the change law of strength at the soil-ice interface from negative temperature to 0 °C. Therefore, direct shear tests were conducted at different shear temperatures and different moisture contents. The effects of temperature and moisture content on strength, cohesion, and internal friction angle are analyzed, while the shear failure mechanism of specimens at different temperatures is discussed according to the location of the shear failure surface. The results show that: Shear properties of soil ice specimens are related to the unfrozen moisture content. The strength of the sample decreases with increasing temperature, and the change in strength is most significant from - 2 to - 0 °C. The strength reduction in this range is from 21.8 to 74.8%, and the higher the moisture content the more obvious this phenomenon is. The shear index tends to decrease with the increase of unfrozen water content, and the greater the increase of unfrozen water, the faster the decrease of both, especially in stage 2. When the temperature is higher than - 5℃, the failure surface is located above the soil-ice interface, and the strength of the specimen is similar to that of the frozen soil. When the temperature is - 10℃, the shear damage surface appears at the soil-ice interface, and the strength of the specimen is determined by the strength of the soil-ice interface.
在春季解冻期间，温度导致的土冰界面强度降低可能会引发边坡失稳。因此，一些研究人员探索了温度与土冰界面强度之间的关系。然而，以往的研究尚未系统地探究从负温到0℃土冰界面强度的变化规律。为此，开展了不同剪切温度和不同含水量条件下的直剪试验。分析了温度和含水量对强度、黏聚力和内摩擦角的影响，并根据剪切破坏面的位置探讨了不同温度下试样的剪切破坏机制。结果表明：土冰试样的剪切特性与未冻含水量有关。试样强度随温度升高而降低，在-2℃至0℃强度变化最为显著。该温度区间强度降低幅度为21.8%至74.8%，含水量越高该现象越明显。剪切指标随未冻水含量增加而趋于减小，未冻水增加量越大两者减小越快，尤其在阶段2。当温度高于-5℃时，破坏面位于土冰界面上方，试样强度与冻土强度相近。当温度为-10℃时，剪切破坏面出现在土冰界面，试样强度由土冰界面强度决定。
