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董青, 苏杰, 周正华, 李小军. 基于对数骨架曲线的时域本构及其应用[J]. 岩土工程学报, 2020, 42(8): 1491-1498. DOI: 10.11779/CJGE202008014
引用本文: 董青, 苏杰, 周正华, 李小军. 基于对数骨架曲线的时域本构及其应用[J]. 岩土工程学报, 2020, 42(8): 1491-1498. DOI: 10.11779/CJGE202008014
DONG Qing, SU Jie, ZHOU Zheng-hua, LI Xiao-jun. Time-domain constitutive model based on logarithmic skeleton curve and its application[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(8): 1491-1498. DOI: 10.11779/CJGE202008014
Citation: DONG Qing, SU Jie, ZHOU Zheng-hua, LI Xiao-jun. Time-domain constitutive model based on logarithmic skeleton curve and its application[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(8): 1491-1498. DOI: 10.11779/CJGE202008014

基于对数骨架曲线的时域本构及其应用

Time-domain constitutive model based on logarithmic skeleton curve and its application

  • 摘要: 土层非线性地震反应分析的等效线性化方法会严重降低某一中频段增大相应的高、低频段的地震动非线性效应,且土体的塑性变形影响无法体现,尤其软弱土层、薄覆盖层场地地震反应分析结果与实际观测不符。从一维土层场地时域非线性地震反应分析出发,提出一种基于G/G0,λγ试验曲线确定的对数骨架曲线的函数表达式,其特点是渐近线上升较缓慢。基于Mashing准则,以加卸载转折点应力应变为参考应力应变点建立了对数动骨架曲线本构函数表达式。在此基础上,提出了基于对数动骨架曲线土体本构的交叠差分格式一维土层时域非线性地震反应分析方法,并以Microsoft Visual C++ 6.0为开发平台,自行编制了一维土层地震反应分析程序Soilresp1D,开展了于软弱土层、薄覆盖层场地和场地影响台阵场地的时域非线性地震反应计算分析。与基于双曲动骨架曲线本构的时域分析结果、等效线性化分析结果以及实际地震动观测记录对比,展现了提出的对数动骨架曲线本构的可行性及合理性。同时,对比结果表明,基于对数动骨架曲线本构的土层时域非线性地震反应分析方法适用于不同类型场地的地震反应分析,且尤其表现为对数动骨架曲线本构滞回圈较宽、阻尼比退化系数较大,更好地体现了实际土体的非线性和塑性特性。

     

    Abstract: The equivalent linearization method for seismic nonlinear response of soils will overestimate its high-and low-frequency nonlinear effects, and the plastic deformation of soils can not be reflected, especially for soft soil layer sites and thin overburden sites. The functional expression for logarithmic skeleton curves is proposed based on the test curves to analyze the time-domain nonlinear seismic responses, and the characteristic of the new skeleton curve is that the asymptote rises slowly. Based on the Mashing criterion, a logarithmic dynamic skeleton constitutive model is established with loading-unloading turning points as reference points. On this basis, a 1D time-domain seismic response method for soil by using the overlapping difference scheme is proposed. The corresponding program Soilresp1D is developed taking Microsoft Visual C++ 6.0 as the platform, and it is used to analyze the nonlinear seismic response of soft-soil layer sites and thin overburden sites and Eureka Canyon Road site. By comparing with the results of time-domain analysis based on the hyperbolic dynamic skeleton constitutive model, the equivalent linearization analysis and the actual seismic response observation, the feasibility and rationality of the proposed logarithmic dynamic skeleton curve are verified. The results show that the nonlinear seismic response method based on the logarithmic dynamic skeleton constitutive model can be applied to the seismic response analysis of different soil-layer sites. It is especially shown that the area of the hysteresis loop of the logarithmic dynamic skeleton curve and the damping degradation coefficient are larger, thus the damping effect and the plastic property of soils are better reflected.

     

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