人工冻结砂土与结构接触面冻结强度试验研究

 为探究人工冻结砂土与结构接触面冻结强度影响因素及其规律，揭示冻结强度形成机制，利用自行研制的大型冻土直剪仪开展冻结强度试验研究。结果表明：人工冻结砂土与结构接触面冻结强度受接触面温度、法向应力、粗糙度等因素影响显著；冻结强度均随接触面温度降低而增大，其中极限冻结强度随接触面温度降低而线性增大，残余冻结强度随接触面温度变化呈现持续稳定、先波动后稳定及循环波动3种典型规律；冻结强度均随法向应力增大而增大，其中极限冻结强度与法向应力关系符合莫尔–库仑定律，残余冻结强度随法向应力变化呈现同样3种典型规律；冻结强度均随粗糙度增大而增大，其中极限冻结强度与粗糙度满足对数函数关系，残余冻结强度曲线波动式循环周期随粗糙度增大而增大。进一步揭示接触面冻结强度形成机制，并对残余冻结强度呈现黏滑现象作出合理解释。通过接触面冻结强度多影响因素综合分析，给出极限冻结强度与接触面温度、法向应力、粗糙度的经验公式，可用于预测极限冻结强度值。

Experimental study on adfreezing strength of the interface between artificial frozen sand and structure

To explore the influential factors，regular patterns and mechanism of adfreezing strength on the interface between artificial frozen sand and structure，an experimental study was conducted with the large-scale direct shear apparatus developed in-house. All the adfreezing strengths were found to be affected notably by many factors， such as freezing temperature，normal stress and roughness，etc. The adfreezing strengths increased with decreasing temperature. The ultimate adfreezing strength presented a linear relation with the temperature，and the residual adfreezing strength varied with the temperature and presented three typical regular patterns. The adfreezing strengths increased with increasing the normal stress. The relation between the ultimate adfreezing strength and the normal stress was in line with Mohr-Coulomb criterion，and the residual adfreezing strength varied with the normal stress and also presented the same three typical regular patterns. The adfreezing strengths increased with increasing the roughness. The relation between the ultimate adfreezing strength and the roughness satisfied a logarithmic function. The fluctuation cycle about the residual adfreezing strength curves increased with increasing the roughness. In addition，the internal mechanism of adfreezing strength was revealed. The stick slip phenomenon in the residue adfreezing strength was also explained. Through the regression analysis of multiple factors affecting the adfreezing strength，an empirical formula for the adfreezing strength related to the temperatures，normal stress，and roughness was derived.