黄土完全软化强度与残余强度的对比试验研究

强菲; 李萍; 李同录

doi:10.13544/j.cnki.jeg.2014.05.09

黄土完全软化强度与残余强度的对比试验研究

doi: 10.13544/j.cnki.jeg.2014.05.09

长安大学地质工程系西安 710054

基金项目:

国家自然科学基金项目（40772181）资助

详细信息

作者简介:
强菲，女，博士，从事黄土边坡工程研究. Email: 382671887@qq.com

中图分类号: TU443
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出版历程
- 收稿日期: 2014-05-30
- 修回日期: 2014-08-25
- 刊出日期: 2014-10-25

COMPARATIVE TEST STUDY BETWEEN FULLY SOFTENED AND RESIDUAL STRENGTHS OF LOESS

Department of Geological Engineering, Chang'an University, Xi'an 710054

摘要

摘要: 为了解决复活蠕滑型黄土滑坡强度参数的取值问题，开展完全软化强度与残余强度的对比试验研究。以山西地区典型黄土为研究对象，采用预压固结法制备饱和重塑试样，并进行反复直剪强度试验获取完全软化强度和残余强度参数。试验结果表明：黄土的完全软化强度以黏聚力为零、颗粒未发生定向排列为主要特征。完全软化强度与二次固结应力和黏粒含量有关。试样在二次固结应力小于300kPa时的应力-应变曲线呈应变软化型，完全软化强度大于残余强度，黏粒含量高的试样应变软化更显著；试样在二次固结应力大于等于300kPa时的应力应变曲线呈理想塑性型，完全软化强度近似等于残余强度。完全软化内摩擦角与残余内摩擦角的差值和预压固结应力、二次固结应力及黏粒含量有关。完全软化内摩擦角与残余内摩擦角的差值随二次固结应力的增大而减小，最终趋于0。当预压固结应力小于300kPa时，内摩擦角差值及黏粒含量对内摩擦角差值的影响随着预压固结应力的减小呈乘幂性增大；当预压固结应力大于等于300kPa时，完全软化强度近似等于残余强度，可用完全软化强度近似代替残余强度。研究结论为复活蠕滑型黄土滑坡稳定性分析时强度参数的取值提供了一定的参考。
- 完全软化强度 /
- 残余强度 /
- 预压固结法 /
- 二次固结应力 /
- 黏粒含量
Abstract: This paper carries out comparative test study between fully softened strength and residual strength. It is to solve the selection problem of the strength parameters of the resurgent and creeping loess landslides. It takes the typical soils of Shanxi province as the research objects and uses the preloading consolidation method to prepare the saturated remolded samples for repeated direct shear test in order to get the parameters of fully softened strength and residual strength. The test results show that the fully softened strength of loess has such special characteristics that its cohesive force is almost equal to zero and its particles have no directional arrangement. The fully softened strength is closely related to the secondary consolidation stress and the clay particle content of the sample. The stress-strain curve of the sample under secondary consolidation stress less than 300kPa is strain softening model which means fully softened strength is greater than residual strength. The samples with higher clay particle contents have more obvious strain softening appearance than the lower ones. The stress-strain curve of the sample under secondary consolidation stress greater than or equal to 300kPa is the ideal plastic model which means fully softened strength is approximately equal to residual strength. The difference between the fully softened friction angle and the residual friction angle has close relationships with the secondary consolidation stress, the preloading consolidation stress and the clay particle content of the sample. The difference between the fully softened friction angle and the residual friction angle decreases with the increasing of the secondary consolidation stress, eventually, tends to be equal to 0.When the preloading consolidation stress is less than 300kPa, the difference between the two friction angles and the effect of the clay particle contents on them appear power law increasing with the decreasing of preloading consolidation stress. When the preloading consolidation stress is greater than or equal to 300kPa, the fully softened strength is approximately equal to residual strength and its parameters can approximately replace the parameters of residual strength. The research results supply a reference to the selection of the strength parameters used in the stability analysis for the resurgent and creeping loess landslides.
- Fully softened strength /
- Residual strength /
- Preloading consolidation method /
- Secondary consolidation stress /
- Clay particle content

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