初始剪应力对饱和粉土液化大变形特性的影响

发布时间：2018-02-14 03:36

本文关键词： 饱和粉土液化大变形初始剪应力比循环剪应力比循环强度　出处：《岩土力学》2017年05期 　论文类型：期刊论文

【摘要】：由于斜坡场地存在初始剪应力的作用,在强地震动作用下比水平场地更易发生液化大变形破坏,研究初始剪应力对土体液化大变形特性的影响是必要的。以饱和粉土为研究材料,开展了一系列单幅剪应变达到50%的循环扭剪试验。试验结果表明:在初始剪应力和循环剪应力的共同作用下,饱和粉土试样均发生孔压达到有效围压的零有效应力状态现象,累计变形呈平缓—急剧的发展模式,土体大变形的产生机制可区分为2种:循环液化和应变累计。随着初始剪应力比的增加,饱和粉土的循环强度呈现先减小后增大的特征,且在初始剪应力比接近循环应力比CSR时其循环强度最低。
[Abstract]:Because of the effect of initial shear stress on slope site, liquefaction and large deformation are more likely to occur under strong ground motion than in horizontal site. It is necessary to study the effect of initial shear stress on the large deformation characteristics of soil liquefaction. A series of cyclic torsional shear tests with single shear strain up to 50% have been carried out. The results show that under the combined action of initial shear stress and cyclic shear stress, the zero effective stress state of pore pressure reaching effective confining pressure occurs in saturated silty soil samples. The cumulative deformation shows a gentle and sharp development pattern, and the generation mechanism of large deformation of soil can be divided into two types: cyclic liquefaction and strain accumulation. With the increase of initial shear stress ratio, the cyclic strength of saturated silt decreases first and then increases. When the initial shear stress ratio is close to the cyclic stress ratio CSR, the cyclic strength is the lowest.
【作者单位】：南京工业大学岩土工程研究所;
【基金】：国家自然科学基金项目(No.41172258,No.514380040)~~
【分类号】：TU43

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