粉土–混凝土接触面冻结强度试验研究

土与结构物接触面冻结强度是寒区构筑物基础切向冻胀力计算及抗冻拔模型建立的重要参数。为解释土与结构物接触面冻结强度形成机制,探究其影响因素及变化规律,针对粉土–混凝土接触面开展多种含水率、温度及干密度条件下的正交直剪试验研究。试验结果表明:(1)试验设计的控制因素对抗剪强度影响的主次顺序为:含水率>温度>干密度,低温、高含水率、低干密度条件下,接触面的抗剪强度试验达到最佳;(2)含水率、温度对接触面的抗剪强度影响显著,接触面抗剪强度随含水率及温度绝对值的增大而增强,且二者对接触面抗剪强度的影响具有交互作用;(3)随法向压力增大,含水率对接触面抗剪强度的增强作用逐渐变小,而温度对接触面抗剪强度的增强作用仍能得到提高。基于试验结果进行讨论,给出了土与结构物接触面冻结强度形成及破坏机制的一种解释,研究结果可为切向冻胀力计算和抗冻拔模型的建立提供参考。

Experimental study on the adfreezing strength of the interface between silt and concrete

The adfreezing strength of the interface between soil and structure is an important parameter for the calculation of the tangential frost-heave forces and the establishment of the anti-freeze model in cold regions. In order to explain the formation mechanism of the adfreezing strength of soil-structure interfaces and to explore its influencing factors and changing rules,orthogonal direct shear tests were carried out under various conditions of moisture content,temperature and dry density. The test results show that the order of the influencing factors on the shear strength is moisture content,temperature and dry density and that the interface shear strength test is the best under the condition of low temperature,high water content and low dry density. The moisture content and temperature have significant interactive influence on the interface shear strength. The interface shear strength increases with rising the moisture content and the absolute value of the temperature. With increasing the normal pressure,the effect of the moisture content on the interface shear strength decreases gradually,while the effect of the temperature can still be promoted. Based on the experimental results,an explanation is given for the adfreezing strength formation and failure mechanisms of the interface between soil and structure. The research results can provide reference for the calculation of tangential frost-heave forces and the establishment of anti-freeze model.