为研究渠道下卧土-混凝土衬砌冻结接触面抗剪强度及其随主要影响因素的变化规律，采用直剪仪开展了不同含水率、冻结温度、法向应力及冻结时间条件下渠道下卧土-混凝土衬砌冻结接触面直剪试验研究。结果表明：剪切的初始阶段，接触面存在局部剪应力释放现象，释放量大小受土体含水率、法向应力、冻结时间因素影响，但不受冻结温度的影响；在本试验参数范围内，接触面峰值抗剪强度随着土体含水率、法向应力、冻结时间的增加而增大，随冻结温度的降低而增大；接触面的抗剪强度实质上是冻土中的冰晶与混凝土衬砌接触面之间的胶结力，以及土体与混凝土衬砌接触面之间的黏聚力与摩擦力；峰值抗剪强度大小主要受胶结力影响；黏聚力和摩擦力主要受法向应力、冻结时间的影响。

In order to study the shear strength of the frozen interface between channel bed soil and concrete lining and its variation with the main influencing factors, a series of direct shear tests of the frozen interface between channel bed soil and concrete lining are performed. In these tests, the main influencing factors, such as soil moisture content, freezing temperature, normal stress level and freezing time, have been taken into consideration and then analyzed in detail. The experimental results show that interface existence phenomenon of local shear stress release at the initial stage of the shear tests, the release amount influenced by normal stress and soil moisture content, freezing time, but not affected by the imposed freezing temperature. Within the parameters of this test， the peak shear strength increases with the increase of soil moisture content, normal stress, freezing time, and with the decrease of freezing temperature; Essentially, the shear strength of the interface is cementation force, cohesive force and friction force between channel bed soil and concrete lining. The peak shear strength was mainly affected by cementation force due to frost. Cohesive force and friction force was mainly affected by normal stress and freezing time.

国家科技支撑计划项目（2015BAB07B00）