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.

特别参考（A）高应变率和（B）剪切的重复反演，对地震引起的软沉积物的变形和破坏进行了实验研究，证明了以下结果：（A）随着应变率从 10^< 增加。 -3> 到 10^0/s，(1) 剪切应变不是局部的，并且均匀变形，(2) 从有限的渐进破坏变为同时破坏，(3) 剪切面角度 (α) 从70°至50°，（4）剪切强度变大 在这些结果中，（3）和（4）之间的关系在力学意义上是相互矛盾的。通常，较高的剪切强度也意味着较高的内摩擦力。然而，平面应变剪切试验的结果似乎与通常情况相反，原因之一是颗粒之间的有效应力因高孔隙压力而降低。无论应变率如何， (6) 在应变率小于10^<-3>s^<-1>时，剪切面角度没有变化。 (B) 小裂缝阵列是在低应变下通过反复反转剪切而形成的，这在几何上相当于活动板块边缘的泥质沉积物中发现的脉状结构。 (1) 它们在简单条件下以共轭 Riedel 剪切形式启动。破坏前发生大 Riedel 剪切； (2) 它们随着应力反演的重复而生长； (3) 较高的空隙率和低应变是优选的条件 (4) 控制剪切面的高宽比、高度与间距。剪切带的宽度。

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。