南京饱和细砂液化后大变形条件下动剪切模量衰减特征研究

发布时间：2018-02-03 16:56

本文关键词： 南京饱和细砂液化流动特大变形剪切模量衰减循环加载幅值初始剪应力比　出处：《岩土力学》2017年12期 　论文类型：期刊论文

【摘要】：针对南京饱和细砂液化后特大变形条件下(双幅剪应变接近100%)应力-应变关系特征,分析了有效围压和初始静剪应力比等因素对南京饱和细砂初始液化后特大变形条件下应力-应变关系曲线的影响规律,即在液化后多次循环加载条件下零有效应力阶段、剪胀阶段和反向卸载阶段的剪切模量随单向流动累积变形的衰减特征。结果表明:有效围压、初始静剪应力和循环加载幅值对南京饱和细砂初始液化后特大变形条件下应力-应变关系曲线在零有效应力阶段和剪胀阶段的剪切模量大小及其衰减特征的影响不明显,而对反向卸载阶段的剪切模量大小和衰减特征的影响相对较大。随着有效围压和加载幅值分别增大,南京饱和细砂初始液化后特大变形条件下应力-应变关系曲线反向卸载阶段剪切模量都有明显增大的趋势,同时其剪切模量随后续循环加载次数的衰减速度也变快。但随着初始剪应力的增大,该阶段剪切模量随后续循环加载次数的衰减速度有减慢的趋势。同时,基于试验结果,给出了南京饱和细砂初始液化后特大变形条件下应力-应变关系曲线在不同阶段的剪切模量与单向流动累积变形有关的衰减函数及其拟合参数确定方法。
[Abstract]:According to the Nanjing post liquefaction saturated fine sand under the condition of large deformation (twin shear strain 100%) stress-strain relationship characteristics analysis of the effective confining pressure and initial static shear stress ratio and other factors on Nanjing saturated fine sand under the condition of large deformation after initial liquefaction stress-strain curve of the influence of the after repeated liquefaction under cyclic loading conditions of zero effective stress stage, the attenuation characteristics of the shear modulus and shear dilatancy phase reverse unloading stage with one-way flow of accumulated deformation. The results show that the effective confining pressure, stress amplitude and cyclic loading on Nanjing saturated fine sand under the condition of large deformation after initial liquefaction stress-strain curve at zero effective shear modulus and shear force size stage and expansion stage and its effect is not obvious attenuation characteristics of initial static shear, while the reverse unloading stage of shear modulus size and attenuation characteristics with relatively larger impact. The effect of confining pressure and loading amplitude were increased, Nanjing saturated fine sand under the condition of large deformation after initial liquefaction stress-strain curve of reverse unloading stage shear modulus are obviously increased, and the decay rate of shear modulus with subsequent cyclic loading time becomes much faster. But with the increase of initial shear stress attenuation. The speed of the stage of shear modulus with subsequent cyclic loading time has slowed down the trend. At the same time, based on the test results, given Nanjing saturated fine sand under the condition of large deformation after initial liquefaction stress-strain curves at different stages of shear modulus and one-way flow method to determine the attenuation function and its fitting parameters related to the cumulative deformation.

【作者单位】：南京工业大学岩土工程研究所;
【分类号】：TU43
【正文快照】： 砂土液化引起的场地侧向流动变形将会导致地面滑移达到数米的量级。例如,1964年的新泻地震和1983年的日本海中部地震的震害调查中,倾斜砂土场地的地面位移达到了12.71 m[1];1971年美国圣费尔南多地震中地面侧向位移达到了3 m多;1995年日本阪神大地震中,在大阪、神户沿海回填土

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