Earthquake induced deformation and failure of soft sediments

地震引起的软沉积物变形和破坏

• 批准号: 10640440
• 负责人: MIYATA Yuichiro
• 金额: $ 1.28万
• 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: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640440/
• 关键词: strain rate; argillaceous sediments; earthquake; progressive failure; vein structure; reccurrence period; Nishizaki Formation; hypocenter; 歪み速度; 平面歪み圧縮試験; 歪みの局所化; 三軸圧縮試験; 間隙水圧

The deformation and failure of soft sediments induced by earthquakes were experimentally investigated with special reference to (A) high strain-rate and (B) repeated inversion of shearing. The following results are demonstrated ;(A) As increasing strain rate from 10^<-3> to 10^0/s, (1) shear strain is not localized, and homogeneously deformed, (2) change from limited progressive failure to simultaneous failure, (3) angle of shear plane (α) decrease from 70°to 50°, and (4) shear strength becomes larger. In these results, relationship between (3) and (4) contradict with each other in the sense of mechanics. In general, higher shear strength means higher internal friction as well as larger angle of shear plane (α). However, these results from plane-strain shear tests seems contrary to usual cases. As one reason, it was suggested that the effective stress between particles is reduces due to high pore pressure. (5) Regardless of strain rate, the amount of pore pressure is almost equal. Therefore, the expected high pore pressure under high strain rate was not realized. (6) Under strain rate less than 10^<-3> s^<-1>, angle of shear plane does not change.(B) Minor fracture array was formed under low strain by repeated inversion of shearing, which is geometrically equivalent to the vein structures found in argillaceous sediments of active plate margin. (1) They are initiated as a conjugate Riedel shear under simple shear before failure with major Riedel shear ; (2) They grow with repetition of stress inversion ; (3) Higher void-ratio and low strain are preferable conditions. (4) The aspect ratio of the shear plane, height to spacing, is controlled by the width of the shear zone.

实验研究了地震诱导的软沉积物的变形和失效，特别参考了（a）高应变率和（b）重复的剪切反转。证明了以下结果；（a）由于应变速率从10^<-3>增加到10^0/s，（1）剪切应变不是局部的，并且均匀变形，（2）从有限的渐进失败到简单失败到简单的失败，（3）剪切平面（3）从70°至50°，（4）剪切强度降低。在这些结果中，（3）和（4）之间的关系在力学意义上相互矛盾。通常，较高的剪切强度意味着更高的内部摩擦以及较大的剪切平面（α）。但是，这些来自平面材料剪切测试的结果似乎与通常的情况背道而驰。作为一个原因，有人建议颗粒之间的有效应力是由于高孔压力而减小的。 （5）不管应变率如何，孔隙压力的量几乎相等。因此，未实现在高应变速率下的预期高孔压力。 （6）在小于10^<-3> s^<-1>的应变速率下，剪切平面的角度不会改变。（b）通过重复的剪切反转剪切在低应变下形成较小的断裂阵列，该剪切的重复反转，这在几何上等同于在活性板边缘的质量质量突出中发现的静脉结构。 （1）它们是在简单的剪切下作为偶联的Riedel剪切作用，然后用大瑞德（Riedel Shear）失败； （2）它们随着压力反演的重复而生长； （3）较高的void-ratio和低应变是首选条件。 （4）剪切平面（高度与间距）的纵横比受剪切区的宽度控制。

项目成果

姉川学利,宮田雄一郎: "未固結砂泥互層における流体の移動過程-宮崎県日南層群の砂泥互層中にみられる流体噴出構造-"地質学雑誌. 107巻・4号(印刷中). (2001)

稻川岳俊、宫田雄一郎：“松散砂泥交替层中的流体运移过程——宫崎县日南群砂泥交替层中的流体喷出结构”《地质杂志》第107卷（印刷版）。 2001）

田中尚、宮田雄一郎: "高速せん断による泥質堆積物の流動変形"地質学雑誌. 105巻5号. 352-363 (1999)

Hisashi Tanaka，Yuichiro Miyata：“高速剪切引起的泥质沉积物的流动变形”地质杂志，第 105 卷，第 5 期。352-363 (1999)

姉川学利,宮田雄一郎: "未固結砂泥互層における流体の移動過程-宮崎県日南層群の砂泥互層中にみられる流体噴出構造-"地質学雑誌. 107巻(印刷中). (2001)

Gakutoshi Anekawa，Yuichiro Miyata：“松散砂泥交替层中的流体运移过程 - 宫崎县日南群砂泥交替层中的流体喷射结构观察”地质杂志（2001 年）。

田中尚,宮田雄一郎: "高速せん断による泥質堆積物の流動変形"地質学雑誌. 105巻. 352-363 (1999)

Hisashi Tanaka，Yuichiro Miyata：“高速剪切引起的泥质沉积物的流动变形”地质杂志，第 105 卷，352-363（1999 年）。

Hisashi TANAKA and Yuichiro MIYATA: "Flow deformation of argillaceous sediments under high strain rate shear."Jour.Geol.Soc.Japan. 105, (5). 352-363 (1999)

Hisashi TANAKA 和 Yuichiro MIYATA：“高应变率剪切下泥质沉积物的流动变形。”Jour.Geol.Soc.Japan。