Study on unified evaluation for in-situ dynamic strength of clays during earthquake

地震作用下粘土原位动强度统一评价研究

• 批准号: 09650553
• 负责人: HYODO Masayuki
• 金额: $ 2.24万
• 依托单位: Yamaguchi University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650553/
• 关键词: marine clay; aging effect; cyclic shear strength; overconsolidated; rate effect; undisturbed sample; earthquake; cyclic triaxial test; 動的強度; 塑性指数; 疑似過圧密; 初期せん断応力; 周波数; 繰越し三軸試験; 載荷周波数; 過圧蜜

For the purpose of this research programme, undisturbed clay samples were taken from alluvial deposits at seven different urban coastal locations in Japan. At several of the Locations samples were taken from many different depths in order to sample different sedimentary environments. The samples were then testes in both undisturbed and remoulded states. A testing programme was devised to separately examine the influence of plasticity index, aging factors, rate effect and overconsolidation ratio on the undrained cyclic stength of the clays. The cyclic data for the normally consolidated samples was used empirically to define the cyclic strength of the clays as an intrinsic function of the plasticity index IィイD2pィエD2. This was then modified taking into account the vertical yield stress ratio σィイD2vyィエD2'/σィイD2voィエD2', degree of aging and geological OCR. The cyclic strength of anisotropically consolidated clays at low initial drained shear stress ratios increased with decreasing plasticity. This reversed as the drained shear stress ratio increased. It was possible to define a simple function for the cyclic strength normalised by the isotropic cyclic strength RィイD2ISOィエD2 against the initial drained shear stress ratio. This function was shown to be dependent on plasticity index IィイD2pィエD2 but stress history.

为了这项研究计划的目的，从日本七个不同城市沿海地区的冲积沉积物中采集了未受干扰的粘土样本。在几个地点，为了对不同的沉积环境进行采样，从许多不同的深度采集了样本。然后在未受干扰和重塑状态下对样本进行测试。设计了试验方案，分别考察了塑性指数、老化因素、速率效应和超固结比对粘土不排水循环强度的影响。利用正常固结试样的循环数据，将粘土的循环强度定义为塑性指数I （γ）的内在函数。然后根据纵向屈服应力比σ′′、老化程度和地质OCR对其进行修正。各向异性固结粘土在低初始排水剪应力比下的循环强度随塑性的减小而增大。随着排水剪应力比的增大，这一情况发生逆转。可以为循环强度定义一个简单的函数，该函数由各向同性循环强度R (R)对初始排水剪应力比进行归一化。结果表明，该函数依赖于塑性指数I γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ。

项目成果

山本陽一、兵動正幸: "粘性土の繰返しせん断特性に及ぼす載荷速度の影響"土木学会論文集. No.645/III-50. 63-76 (2000)

Yoichi Yamamoto、Masayuki Hyodo：“加载速率对粘性土循环剪切特性的影响”，日本土木工程师学会会议记录第 645/III-50 号（2000 年）。

Masayuki Hyodo: "Cyclic shear strength of undisturbed and remoulded marine clays" Soils and Foundations. Vol39,No.2. 45-58 (1999)

Masayuki Hyodo：“原状和重塑海洋粘土的循环剪切强度”土壤和基础。

Hyodo,M.,Yamamoto,Y.and Fujii,T.: "Cyclic shear strangth of marine clay"Int.Symp.on Coastal Geotechnical Engineering Practice. (印刷中). (2000)

Hyodo, M.、Yamamoto, Y. 和 Fujii, T.：“海洋粘土的循环剪切强度”沿海岩土工程实践（2000 年）。

HYODO, M.. YAMAMOTO, Y. and FUIJJ, T: "Cyclic shear strength of marine clay"Int. Symp. on Coastal Geotechnical Engineering, Practice. (in press). (2000)

HYODO, M.. YAMAMOTO, Y. 和 FUIJJ, T：“海洋粘土的循环剪切强度”Int。

Hyodo,M.,Ito,S.,Yamamoto,Y.and Fujii,T.: "Cyclic shear behaviour of marine clay"10th Int.Offdore and Polar Engineering Conference. (印刷中). (2000)

Hyodo, M.、Ito, S.、Yamamoto, Y. 和 Fujii, T.：“海洋粘土的循环剪切行为”第 10 届 Int. Offdore 和 Polar 工程会议（2000 年）。