| 摘要: |
| 为研究黏性土剪切断裂韧度，研制了土体剪切断裂韧度测试仪，对黏性土进行了断裂韧度测试，验证了使用线弹性断裂力学来简化土体断裂韧度研究的合理性，并进行相关试验探讨了试样干密度、含水率和剪切速率对断裂韧度值的影响。结果表明：断裂韧度与试样干密度呈正相关，即随试样干密度的增大，土体断裂韧度值也增大，并拟合了两者之间的经验计算式；含水率对断裂韧度有很大影响，当含水率为13%~17%时，断裂韧度随含水率的增加先增后减，即存在一个断裂韧度值最大的最优含水率；当剪切速率在05~60 mm/min时，相对于干密度和含水率而言，剪切速率对断裂韧度值影响较小，同时土体含水率、裂缝深度、试样尺寸等因素均对土体断裂韧度有较大影响，需要对其进行深入研究。 |
| 关键词: 击实黏性土 剪切速率 断裂韧度 裂缝深度 干密度 含水率 |
| DOI： |
| 分类号:TU47 |
| 基金项目:重庆市研究生科研创新项目（CYS14166） |
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| Experimental studies on shear fracture toughness of compacted clay |
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HU Jun-feng
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National Engineering Research Center for Inland Waterway Regulation, Key Laboratory of Hydraulic and Waterway Engineering of Ministry of Education， Chongqing Jiaotong University, Chongqing
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| Abstract: |
| In order to carry out studies of the fracture toughness of the compacted clay, based on a newly developed apparatus, the fracture toughness of the clay is tested in the laboratory. While the rationality of the test methods is verified, researches on the relationships of fracture toughness between dry density, moisture content and shear rates are made. The experiment results show that as the empirical formula, the fracture toughness and the specimen dry density have a positive correlation, and that the fracture toughness will increase with the increase in the dry density of the specimen. The changes in the moisture content are closely related to the test results. When the moisture content of the specimen is between 13% and 17%, with increase in the moisture content, the fracture toughness increases at first and then decreases. There is an optimum moisture content for soil which let the fracture toughness reach a top. When the shear rate is between 05 mm/min and 6 mm/min, the shear rate has a lower influence on the fracture toughness in comparison with the dry density and moisture content. Meanwhile, because the factors such as the soil moisture content, crack depth and the specimen sizes could also have remarkable impacts on the fracture toughness, it is necessary to make studies of the influence factors mentioned above in the future. |
| Key words: compacted clay shearing rates fracture toughness crack depth dry density moisture content |
