Development of cyclic shear deformation characteristics test of soil under extreme nonlinear region

对286个测点在11次地震运动下的地震反应进行了分析，结果表明：等效线性分析中除位移外地震运动指标最大，其次为总应力非线性分析和有效应力分析。利用482次循环剪切变形特性试验数据，验证了双曲模型、R-O模型等常用应力-应变模型的适用性。与双曲模型相比，R-O模型在大应变下的适用性较差。考虑到这一点，提出了一种仅使用参考应变和抗剪强度的应力-应变模型。为了再现地震时的地应力状态和荷载状态，提出了一种新的试验方法。在各向同性应力条件下，K0场地条件下的试验结果与常规试验结果表现出不同的循环剪切变形特征。

Seismic response analysis on 286 sites is made under 11 earthquake motions showed that earthquake motion indices except displacement are largest in equivalent linear analysis, then total stress truly nonlinear and effective stress analyses.Applicability of frequently used stress-strain model such as the hyperbolic and the R-O models are examined by using 482 cyclic shear deformation characteristics test data. The R-O model shows less applicability at large strains than the hyperbolic model. Considering this, a new stress-strai model which uses only the reference strain and the shear strength is proposed.A new test method is developed in order to reproduce in-situ stress state and loading condition during earthquakes. Test results under K0 site condition showed somewhat different cyclic shear deformation charactetistics compared with conventional test result under isotropic stress conditions.