干湿循环下饱和红土不排水三轴试验研究

发布时间：2018-02-25 09:34

本文关键词： 干湿循环饱和红土不排水三轴试验剪切特性土-水作用　出处：《工程地质学报》2017年04期 　论文类型：期刊论文

【摘要】：以云南红土为研究对象,考虑干湿循环次数、干湿循环幅度等影响因素,利用TSZ-2型全自动三轴仪,开展干湿循环下饱和红土的不排水三轴试验,研究干湿循环作用对饱和红土剪切特性的影响。试验结果表明:不固结不排水条件下,随干湿循环次数增加和干湿循环幅度增大,饱和红土的应变软化现象增强,应力-应变曲线的初始斜率、孔压峰值增大,剪切峰值、峰值轴向应变、黏聚力、内摩擦角减小;干湿循环次数的影响大于干湿循环幅度的影响。干湿循环下饱和红土剪切特性变化的实质在于红土与水之间的相互作用,包括脱湿过程中水的逃逸作用、红土颗粒的吸附作用、红土体的硬化作用及收缩作用和吸湿过程中水的楔入作用、润滑作用、软化作用及红土体的膨胀作用,干湿循环过程中上述作用不断加深加剧,严重损伤了红土体的微结构,最终改变了饱和红土的不排水剪切特性。
[Abstract]:The undrained triaxial test of saturated laterite under dry and wet circulation was carried out by using TSZ-2 automatic triaxial apparatus, taking into account the influence factors such as the times of dry and wet circulation and the range of dry and wet circulation, taking Yunnan laterite as the research object. The effect of dry and wet cycling on the shear characteristics of saturated laterite was studied. The experimental results showed that the strain softening of saturated laterite increased with the increase of dry and wet cycle times and the amplitude of dry and wet cycle under unconsolidated and undrained conditions. The initial slope of stress-strain curve, pore pressure peak value, shear peak value, peak axial strain, cohesion force and internal friction angle decrease. The effect of dry-wet cycle times is greater than that of dry-wet cycle. The change of shear characteristics of saturated laterite under dry-wet cycle lies in the interaction between red soil and water, including the escape of water and the adsorption of laterite particles during dehumidification. The hardening and shrinkage of red soil and the wedge effect of water in the process of moisture absorption, lubrication, softening and expansion of the red soil body, and the deepening and intensifying of these effects in the process of dry-wet circulation have seriously damaged the microstructure of the red soil body. Finally, the undrained shear behavior of saturated laterite is changed.
【作者单位】：昆明理工大学电力工程学院;
【基金】：国家自然科学基金项目(51568031)资助
【分类号】：TU411

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