库水循环加卸载条件下岸坡饱和土体变形特性试验研究

发布时间：2018-05-27 08:45

本文选题：循环加卸载 + 非等向受压　；参考：《水利学报》2015年05期

【摘要】：水库运行期水位每年周期性涨落,岸坡土体在库水循环加卸载作用下会发生不同程度的阶梯状变形。为探求循环加卸载对岸坡深部变形的诱发机理,本文以水库防洪限制水位以下岸坡土体为研究对象,在饱和土应力路径三轴试验过程中,控制非等向受压试样的孔隙水压力周期变化,模拟岸坡土体的水力-力学状态,实时测定土体的周期性变形特性及破坏特征。研究结果表明:等偏应力孔压循环加卸载过程中,试样剪应变为台阶式上升趋势,而体应变是循环的弹性变化;孔压持续增大造成试样破坏呈现脆变和剪胀的特征。最后,结合等偏应力孔压增大条件下粉质黏土的破坏特征与常规三轴剪切试验成果,对比两种应力路径下试样的有效应力比和剪应变的发展过程,分析了其强度差异的内在原因。
[Abstract]:During the operation of the reservoir, the water level fluctuates periodically every year, and the slope soil is subjected to different degrees of step deformation under the action of water circulation loading and unloading. In order to explore the induced mechanism of cyclic loading and unloading on the deep deformation of bank slope, this paper takes the slope soil below the limited water level of reservoir flood control as the research object, in the course of triaxial test of saturated soil stress path, The periodic variation of pore water pressure of non-isotropic compression specimens is controlled, the hydraulic mechanical state of the slope soil is simulated, and the periodic deformation characteristics and failure characteristics of the soil are measured in real time. The results show that during the cyclic loading and unloading of the isobaric stress pore pressure, the shear strain of the specimen is a step upward trend, while the bulk strain is the elastic change of the cycle, and the failure of the specimen due to the continuous increase of the pore pressure is characterized by brittle change and shear expansion. Finally, combined with the failure characteristics of silty clay under the condition of increasing the pore pressure of isodeflection stress and the results of conventional triaxial shear tests, the development process of effective stress ratio and shear strain of the samples under two stress paths are compared. The internal reasons of the strength difference are analyzed.
【作者单位】：三峡大学三峡库区地质灾害教育部重点实验室;湖北省地质局冶金地质勘探大队;
【基金】：国家自然科学基金资助项目(51409149) 湖北省自然科学基金面上项目(2014CFB267)
【分类号】：TU43

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