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库岸边坡土体受到库水位涨落的周期性影响,其受力过程可描述为在前期固结压力范围内有效应力的多次循环加、卸载过程。通过室内应力路径三轴试验模拟土体孔隙水压力的循环加、卸载,并通过对统一硬化模型的扩展和加、卸载准则的修正,来预测土体的变形发展规律,研究结果表明:循环加、卸载过程中,土体的体积变形呈周期性弹性变化,剪应变呈螺旋上升趋势且增幅随循环次数逐渐减小;卸围压屈服阶段,土体变形呈现体积膨胀的剪胀特征和剪应变增幅加快的脆变趋势,且土体剪切变形在6%左右时即出现实测孔压骤减和峰值强度点;建立压缩曲线系数与加、卸载次数的关系,并修正超固结土的加、卸载准则,扩展后的统一硬化模型能够较好地预测特殊应力路径下岸坡饱和土体的变形特性。
The soil of bank slope is affected by the periodic fluctuation of water level in the reservoir, and its stress process can be described as multiple cyclic loading and unloading processes of effective stress in the consolidation pressure range of the previous period. Through the triaxial test of indoor stress path, the cyclic loading and unloading of soil pore water pressure are simulated, and the law of deformation and deformation of soil body is predicted by the extension of the unified hardening model and the correction of adding and unloading criteria. The results show that: During the unloading process, the volumetric deformation of the soil body changes periodically and the shear strain increases in a spiral upward direction with the increment decreasing with the number of cycles. During the yielding stage of the unloading pressure, the deformation of the soil body exhibits the dilatational characteristics of volume expansion and the shear strain The trend of increasing brittleness is accelerating. When the shear deformation of soil is about 6%, the measured pore water pressure suddenly decreases and the peak intensity point appears. The relationship between the compression curve coefficient and the number of loading and unloading is established, , The unloading criterion and the expanded uniform hardening model can predict the deformation characteristics of saturated soils with bank slope under special stress path.