| 含裂隙膨胀土无侧限抗压强度特征试验研究 |
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| 引用本文： | 李关洋,顾凯,王翔,施斌.含裂隙膨胀土无侧限抗压强度特征试验研究[J].水文地质工程地质,2022,49(4):62-70. |
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| 作者姓名： | 李关洋 顾凯 王翔 施斌 |
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| 作者单位： | 南京大学地球科学与工程学院, 江苏 南京 210023 |
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| 基金项目： | 国家重点研发计划课题子任务(2019YFC1509901)；国家自然科学基金面上项目（41977217） |
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| 摘 要： | 膨胀土易发育大量裂隙，对其工程性质影响显著。引入一种膨胀土试样预制裂隙方法，对特定裂隙形态下膨胀土试样开展无侧限抗压试验，研究了膨胀土强度特征受裂隙形态的影响，并揭示了裂隙的作用机制。研究结果表明：（1）裂隙形态显著影响试样破坏模式，垂直于受力方向裂隙越宽，破坏模式由剪切-拉伸破坏向张拉破坏转变；平行于受力方向裂隙条数...
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| 关 键 词： | 膨胀土 裂隙形态 无侧限抗压试验 强度特征 破坏模式 |
| 收稿时间： | 2021-11-13 |
An experimental study of the unconfined compressive strength characteristics of the expansive soil with cracks |
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| Affiliation: | School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China |
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| Abstract: | Expansive soil is prone to develop a large number of cracks, which have a significant impact on its engineering properties. A prefabricated crack method of expansive soil samples is introduced to carry out the unconfined compression strength on the expansive soil samples under the specific crack morphology. The influence of the crack morphology on the strength characteristics of the expansive soil is examined, and the mechanism of crack action is revealed. The results show that: (1) The crack morphology has a significant effect on the failure mode of the samples. When the cracks become wider, which are perpendicular to the stress direction, the failure mode changes from shear-tensile failure to tensile failure. When the cracks parallel to the stress direction become more and more, the failure mode changes from shear failure to swelling failure. (2) The shape of the cracks perpendicular to the stress direction has a significant effect on the stress-strain relationship of the expansive soil samples. The wider the crack is, the greater the closed strain is. The deeper the crack is, the smaller the initial crack initiation stress is and the greater the strength increment is. The shape of cracks parallel to the stress direction has no obvious effect on the stress-strain relationship. Based on the results, four types of curves are divided, namely, the multi-level rise, fluctuation rise, multi-level decline and standard curve. (3) The direction of crack obviously affects the strength reduction of the cracked soil. The peak strength of the sample containing cracks parallel to the stress direction is close to that of the non-cracked sample. The peak strength and deformation modulus of the sample containing cracks perpendicular to the stress direction decrease with the increasing crack number, and have a good logarithmic function relationship. The peak strain is less affected by crack. This study can provide a theoretical basis for the shallow instability mechanism of the expansive soil slope, and a guidance for the design and construction of the corresponding cracked soil engineering. |
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