ISSN 1000-3665 CN 11-2202/P
    阮永芬,潘继强,胡经魁,等. 泥炭质土K0固结不同开挖路径应力-应变关系研究[J]. 水文地质工程地质,2023,50(2): 112-121. DOI: 10.16030/j.cnki.issn.1000-3665.202206007
    引用本文: 阮永芬,潘继强,胡经魁,等. 泥炭质土K0固结不同开挖路径应力-应变关系研究[J]. 水文地质工程地质,2023,50(2): 112-121. DOI: 10.16030/j.cnki.issn.1000-3665.202206007
    RUAN Yongfen, PAN Jiqiang, HU Jingkui, et al. An experimental study of the stress-strain relationship of different excavation paths for soft soil K0 consolidation[J]. Hydrogeology & Engineering Geology, 2023, 50(2): 112-121. DOI: 10.16030/j.cnki.issn.1000-3665.202206007
    Citation: RUAN Yongfen, PAN Jiqiang, HU Jingkui, et al. An experimental study of the stress-strain relationship of different excavation paths for soft soil K0 consolidation[J]. Hydrogeology & Engineering Geology, 2023, 50(2): 112-121. DOI: 10.16030/j.cnki.issn.1000-3665.202206007

    泥炭质土K0固结不同开挖路径应力-应变关系研究

    An experimental study of the stress-strain relationship of different excavation paths for soft soil K0 consolidation

    • 摘要: 基坑开挖过程中不同部位的土体会因不同的卸荷力学行为而表现出动态的破坏特性。为研究基坑土体开挖过程中复杂的卸荷应力路径,利用TSZ-1S应力控制式三轴仪分别对湖相沉积的泥炭质土进行固结不排水及K0固结下的加、卸荷试验,并按侧向、轴向、轴侧向同时卸荷等不同卸荷条件制定试验方案,模拟基坑开挖过程中不同部位土体卸荷路径下的应力-应变曲线、卸荷剪切破坏时的强度及初始切线模量等的变化规律。试验结果表明:土体的应力-应变特性与应力路径密切相关,各路径下应力-应变曲线都近似呈双曲线型;卸荷剪切破坏时强度明显低于加荷破坏。对不同卸荷路径下初始切线模量(Ei)的研究发现,Ei受侧向卸荷影响较大,卸荷后Ei有所提高,轴向卸荷对其影响较小。对各应力-应变曲线进行归一化处理,构建了考虑不同归一化因子的归一化方程,以该方程为基础对不同应力路径下的泥炭质土进行归一化处理,并对结果进行了验证,效果良好。本研究可为泥炭质土场地上基坑在不同卸荷路径下的变形参数和本构关系的研究提供参考。

       

      Abstract: In the process of foundation pit excavation, the soil mass in different parts shows dynamic destruction characteristics due to diverse unloading mechanics. In order to study the complex unloading stress path in the foundation excavation, the TSZ-1S stress control triaxial compression apparatus is used to carry out the loading and unloading tests of the lacustrine sedimentary peat soil under the conditions of consolidation undrained and K0 consolidation, respectively, and the test scheme is formulated according to different unloading conditions such as lateral, axial and axial lateral meantime unloading, so as to simulate the stress-strain curves of soil under different unloading paths in the foundation excavation and the variation laws of strength and initial tangent modulus under unloading shear failure. The test results show that the stress-strain characteristics of soil are closely related to the stress path, and the stress-strain curves under each path are approximately hyperbolic. The strength of unloading shear failure is significantly lower than that of loading failure. The study of initial tangent modulus Ei under different unloading paths shows that Ei is greatly affected by lateral unloading, Ei increases after unloading, and axial unloading has little effect on it. The stress-strain curves are normalized, and the normalization equation of peat soil considering different normalization factors is constructed. Based on this equation, the peat soil under different stress paths is normalized, and the results are verified. The results of this work can provide reference for the study of deformation parameters and constitutive relations of foundation pits on peat soil sites under different unloading paths.

       

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