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赖小玲, 叶为民, 王世梅. 滑坡滑带土非饱和蠕变特性试验研究[J]. 岩土工程学报, 2012, 34(2): 286-293.
引用本文: 赖小玲, 叶为民, 王世梅. 滑坡滑带土非饱和蠕变特性试验研究[J]. 岩土工程学报, 2012, 34(2): 286-293.
LAI Xiao-ling, YE Wei-min, WANG Shi-mei. Experimental study on unsaturated creep characteristics of landslide soils[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(2): 286-293.
Citation: LAI Xiao-ling, YE Wei-min, WANG Shi-mei. Experimental study on unsaturated creep characteristics of landslide soils[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(2): 286-293.

滑坡滑带土非饱和蠕变特性试验研究

Experimental study on unsaturated creep characteristics of landslide soils

  • 摘要: 在库水位变动及降雨入渗作用下,一方面,滑坡土体在饱和与非饱和状态之间转化,土体强度和变形具有非饱和土的特性; 另一方面,滑坡变形发展大都经历了一个时间过程,具有流变特性,因此,考虑吸力(含水率)作用的非饱和土蠕变特性对于水作用下的坡体长期稳定性研究具有非常重要的意义 。 以 三峡库区 某大型滑坡滑动带土为研究对象,开展了一系列非饱和三轴蠕变试验 ,给出了不同偏应力荷载,不同基质吸力条件下的蠕变试验曲线。试验结果表明,同一偏应力荷载下,随着吸力逐渐减小,蠕变变形及蠕变速率均不断增加,且随偏应力荷载的增加增幅更大。在此基础上,建立了各级吸力水平下滑动带土的 Mesri 蠕变模型,即剪应力–应变关系采用双曲线模型,应变–时间关系采用幂函数。接着,通过建立吸力与 Mesri 模型参数 — 初始排水切线模量 之间的函数关系,构建了滑动带土的应力–吸力–应变–时间模型。最后,通过该模型的预测值与试验值的对比分析,发现模型能较合理地预测滑坡滑动带土的蠕变特性。

     

    Abstract: Under the impacts of reservoir water level fluctuation and rainfall, the strength and deformation of slope soils, on the one hand, have features of properties of unsaturated soils; on the other hand, they exhibit time-dependent behaviour s. Therefore, it is indispensable to investigate the time-dependent behaviours of unsaturated soils to better account for the long-term stability of slopes under the effects of water. A series of suction-controlled triaxial creep tests on sliding zone soils of some landslides in Three Gorges Reservoir Area are performed. Creep curves with different values of deviator stresses and matric suctions are presented and discussed. The test results indicate that the creep strain as well as the creep strain rate at constant deviator stress increases gradually with the decrease of the matric suction. Moreover, for the increasing values of the deviator stress, a wider variation of the creep strain as well as the creep strain with suction is obtained. Then, the Mesri creep model for experimental creep strain with different suction values is established. In the model, a hyperbolic function is adopted for the stress-strain relationship and a power function for the strain-time relationship. Finally, an expression for the relationship between the suction and the initial tangent modulus <>Ed is derived. Based on this, a model of stress-suction-strain-time of specimens is developed. The comaprative results indicate that predicted results using the model are in reasonable agreement with the experimental data .