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舒荣军, 孔令伟, 王俊涛, 简涛, 周振华. 考虑先期卸荷影响的花岗岩残积土湿化特性试验研究[J]. 岩土工程学报, 2022, 44(S1): 154-159, 165. DOI: 10.11779/CJGE2022S1028
引用本文: 舒荣军, 孔令伟, 王俊涛, 简涛, 周振华. 考虑先期卸荷影响的花岗岩残积土湿化特性试验研究[J]. 岩土工程学报, 2022, 44(S1): 154-159, 165. DOI: 10.11779/CJGE2022S1028
SHU Rong-jun, KONG Ling-wei, WANG Jun-tao, JIAN Tao, ZHOU Zhen-hua. Mechanical behavior of granite residual soil during wetting considering effects of initial unloading[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(S1): 154-159, 165. DOI: 10.11779/CJGE2022S1028
Citation: SHU Rong-jun, KONG Ling-wei, WANG Jun-tao, JIAN Tao, ZHOU Zhen-hua. Mechanical behavior of granite residual soil during wetting considering effects of initial unloading[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(S1): 154-159, 165. DOI: 10.11779/CJGE2022S1028

考虑先期卸荷影响的花岗岩残积土湿化特性试验研究

Mechanical behavior of granite residual soil during wetting considering effects of initial unloading

  • 摘要: 边坡开挖引起的卸荷作用可能会影响后续降雨入渗过程中土体的增湿力学行为,而以往的湿化试验研究对此考虑不多。为此,针对花岗岩残积土开展了一系列(先)卸荷剪切-(后)湿化试验,探究围压和先期卸荷程度对土体湿化特性的影响。此外,还进行了(先)湿化-(后)卸荷剪切试验以考察开挖与降雨次序的影响。试验结果表明:花岗岩残积土具有湿化变形各向异性,水平方向湿化变形潜能大于竖直方向;湿化变形总体水平随固结围压的增大而提高;随着先期卸荷程度的增大,轴向与剪切湿化应变逐渐增大,“湿胀”增强,侧向湿化变形由收缩向膨胀转变;开挖与降雨次序对土体变形特性具有重要影响,与先降雨后开挖工况相比,先开挖后降雨时土体轴向应变和剪应变较大而侧向应变和体应变较小;土体湿化之后的强度性能随先期卸荷程度的增大而降低,且主要表现在黏聚力方面。

     

    Abstract: The unloading caused by slope excavation may affect soil behavior during the subsequent rainfall-induced wetting. However, the previous wetting tests do not greatly consider this fact. For this reason, the unloading-wetting tests are carried out on granite residual soil, and the effects of consolidation pressure and stress ratio (reflecting the degree of the initial unloading) are investigated. The influences whether excavation takes place before or after rainfall are studied. It is found that the granite residual soil shows notable anisotropy during wetting, and the horizontal deformation is greater than the vertical one when wetted under isotropic stress condition. The overall level of wetting deformation increases with the increase of consolidation pressure. As the degree of the initial unloading increases, the wetting-induced axial and shear strains increase, the wetting-induced dilatancy becomes stronger, and the initially compressive lateral wetting deformation changes into extensional somewhere. Whether excavation takes place before or after rainfall makes a difference to the deformation behavior of soil. The soil specimen in the unloading-wetting tests shows larger axial and shear strains but smaller lateral and volumetric strains, compared with that in the wetting-unloading tests. The increasing degree of the initial unloading causes the strength properties, mainly cohesion, of wetted soil to decrease.

     

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