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降雨及地下水位上升所引起的滑带土含水率变化是造成其抗剪强度降低与滑坡稳定性下降的重要因素。为研究滑带土在不同含水状态的强度特性，采集三峡库区藕塘滑坡的滑带土作为研究对象，分别使用压力板仪法、盐溶液湿度控制法和双分量空气湿度控制法制备低吸力段、中吸力段与高吸力段的滑带土样品。通过自主研制的非饱和土抗拉、抗剪多功能试验装置测试了不同基质吸力状态滑带土样品的抗拉与抗剪强度，结果表明低吸力段滑带土在拉伸和剪切过程中表现出黏性，而中高吸力段土样拉伸和剪切破坏表现为脆性。土样的单轴抗拉强度与抗剪强度变化趋势与基质吸力变化趋势类似，均随着含水率降低呈非线性单调增大，其中抗拉强度和抗剪强度在221.6 MPa基质吸力状态下分别可达279.8和204.9 kPa。而当土体完全饱和时，土样的抗拉强度与抗剪强度仍分别有46.0和32.3 kPa。滑带土抗拉与抗剪强度的相关性可通过基于吸应力理论的扩展摩尔-库伦强度准则准确描述。基于单轴抗拉强度与吸应力理论计算所得的抗剪强度预测值与通过剪切试验获取的抗剪强度测试值基本吻合，通过该方法测试和计算非饱和滑带土在不同含水率状态抗剪强度可大幅降低时间和试验成本。
Abstract：Variations in the moisture content of sliding zone soils, resulting from rainfall and rising groundwater levels, significantly contribute to the reduction of shear strength and the stability of landslides.This study investigates the strength characteristics of sliding zone soils under different moisture conditions by analyzing soil samples collected from the sliding zone of the Outang landslide in the Three Gorges Reservoir area.Various methods, including a pressure plate apparatus, salt solution humidity control, and dual-component air humidity control, were employed to prepare soil samples with low, medium, and high suction states.A multifunctional testing device for unsaturated soils was utilized to measure the tensile and shear strength of these soil samples under varying matrix suction conditions.The results indicate that the low-suction sliding zone soils exhibit ductile behavior during both tensile and shear processes, whereas the medium-to high-suction soils demonstrate brittle failure.Trends in uniaxial tensile and shear strength closely resemble those of matrix suction, exhibiting a non-linear monotonic increase as moisture content decreases.Notably, at a matrix suction of 221.6 MPa, the tensile and shear strengths reach 279.8 and 204.9 kPa, respectively.Even when fully saturated, the tensile and shear strength values remain at 46.0 and 32.3 kPa, respectively.The correlation between the tensile and shear strengths of sliding zone soils can be accurately described using an extended MohrCoulomb strength criterion based on suction stress theory.The predicted shear strength values calculated by suction stress theory and uniaxial tensile strength tested under various matrix suction conditions align closely with the experimental results.This methodological approach offers a significant reduction in both the time and costs associated with testing and calculating the shear strength of unsaturated sliding zone soils across different moisture states.
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基本信息:
DOI：10.13578/j.cnki.issn.1671-1556.20250149
中图分类号:P642.22;TV697.3
引用信息:
[1]王猛,张凯锋,王菁莪.三峡库区藕塘滑坡滑带土抗拉与抗剪强度关联机制[J].安全与环境工程,2026,33(01):30-38.DOI:10.13578/j.cnki.issn.1671-1556.20250149.
基金信息:
国家自然科学基金项目(41502280); 湖北省自然科学基金项目(2022CFB001)