Development of a seismic damage evaluation method for embankments considering tensile failure of soil

考虑土体拉伸破坏的路堤震害评价方法的建立

• 批准号: 16310130
• 负责人: SAKAI Hisakazu
• 金额: $ 9.41万
• 依托单位: Ritsumeikan University (2006)National Research Institute for Earth Science and Disaster Prevention (2004-2005)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16310130/
• 关键词: tensile failure; constitute model; hollow-cylindrical torsional shear test; liquefaction; tension crack; particle method; river dike; large deformation; 動的モデル; 短周期地震動; 地震応答解析; 土構造物; 2次災害; 脆性挙動; 有限要素法; 広帯域強振動予測

(1)We studied about the effect of the change and hysteresis of anisotropic elastic constants, on the stress-strain relationship and the crackThe Ortiz model should be improved in case of cyclic loading.Accumulation of experimental data on vulnerability and ductility characteristic of soil is necessary for the establishment of the constitutive model.The number of cracks of soil on the reversed loading tests is larger than in the case of the repeated loading tests, for equal amplitude, hollow-cylindrical torsional shear tests.The relationship between the area of crack and the shear stiffness is strong and is independent of the amplitude of shear test and the difference between the reversed and repeated loading test.The tensile crack has a strong influence on the strength and deformation of soil.(2)Tensile splitting tests of kaolinite clay for different loading rates, show that soil has a larger tensile strength during faster loading. We consider that this effect is induced by suction.(3)We performed 2 dimensional FEM analyses for liquefaction-induced deformation for river dikes based on liquefiable soil layers. The results show that the seismic evaluation by the current methods may overestimate the river dikes safety during a subduction earthquake, and therefore application of the cumulative damage concept is necessary for the seismic evaluation.(4)Our results suggest that the evaluation methodology based on fault rupture process and site effect is useful for the damage estimation of embankments spread over a wide area.(5)We developed the deformation analytical methodology based on the moving particle semi-implicit method for the large deformation estimation of embankment considering tensile failure. Our methodology may be applied for the evaluation of deformed shape of a miniature model with liquefiable ground.

(1)研究了各向异性弹性常数的变化和滞后对应力-应变关系和裂缝的影响。在循环荷载的情况下应改进Ortiz模型。土体脆弱性和延性特性的实验数据积累建立本构模型所必需的。对于等幅空心圆柱扭剪，反向加载试验中的土体裂缝数量大于重复加载试验的情况裂缝面积与剪切刚度之间的关系很强，并且与剪切试验的振幅以及反向和重复加载试验之间的差异无关。拉伸裂缝对土体的强度和变形有很大的影响。 (2)不同加载速率下高岭土的拉伸劈裂试验表明，在较快的加载速率下，土体具有较大的抗拉强度。我们认为这种效应是由吸力引起的。(3)基于可液化土层对河堤液化引起的变形进行了二维有限元分析。结果表明，现有方法的地震评估可能高估了俯冲地震期间河堤的安全性，因此在地震评估中应用累积损伤概念是必要的。(4)我们的研究结果表明，基于断层的评估方法破裂过程和场地效应对于大面积路堤的损伤评估具有重要意义。(5)建立了基于移动粒子半隐式方法的变形分析方法，用于考虑拉伸破坏的路堤大变形评估。我们的方法可用于评估具有可液化地面的微型模型的变形形状。