Verification of the basal guided wave theory in reduced friction of large rock avalanches and its development

大型岩石崩塌减摩基底导波理论的验证及其发展

• 批准号: 09680444
• 负责人: KOBAYASHI Yoshimasa
• 金额: $ 1.47万
• 依托单位: Hiroshima Institute of Technology
• 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 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680444/
• 关键词: rock avalanche; debris avalanche; plug flow; deposit structure; 岩屑流堆積物; 流動化; 境界波

In accordance with the research plan the head investigator first derived the slide velocity that causes instability in the base of a landslide. As a result it was found that the slide velocity threshold for instability is on the order of 10 m/s that is easily attained by landslides(Kobayashi, 1997).The cooperative investigator, on the other hand, surveyed debris avalanche deposits at several sites including Iwasegawa, Kaida, and Mt. St. Helens and found evidence for a boundary layer in the bottom of the debris-avalanche deposits. He also found that the flow mechanism of the debris avalanches, at least in the final stage, may be seen as plug flow(Takarada, 1999).Cooperative study by the head and cooperative investigators encountered a difficulty, since the cooperative investigator left Japan for study during the term of the project. However, they exchanged information and views by E-mail frequently and the research was promoted greatly (a part of the mails included in the main report).Along with original study of the project the head investigator made a review of the movement mechanism of large rock avalanches, and examined the validity of his own hypothesis(Kobayashi, 1999).It may be concluded that mechanism of a rock avalanches should be divided into those in the developing , flowing and depositing stages ; i.e. no unique mechanism can work through the whole stages. In this respect our hypothesis, basal guided wave theory, also cannot be an exception and it should be used only in the accelerating stage till the slide velocity exceeds the instability threshold.

根据研究计划，首席研究员首先推导出导致滑坡底部不稳定的滑动速度。结果发现，滑坡的不稳定滑动速度阈值为10 m/s左右，这在滑坡中很容易达到（小林，1997）。另一方面，合作调查员调查了岩濑川、海田、山等几个地点的雪崩堆积物。圣海伦斯，并发现了在碎片雪崩沉积物底部的边界层的证据。他还发现，泥石流的流动机制，至少在最后阶段，可以看作是活塞流（Takarada，1999）。由于合作研究者在项目期间离开日本进行研究，因此负责人和合作研究者的合作研究遇到了困难。但是，他们通过电子邮件频繁地交换信息和观点，极大地促进了研究（主要报告中包含的部分邮件）.沿着项目的原始研究，首席研究员对大型岩石雪崩的运动机制进行了回顾，并检验了他自己假设的有效性（小林，1999）。可以得出结论，岩崩的机理应分为发展、流动和沉积三个阶段，即没有一种独特的机理可以贯穿整个阶段。在这方面，我们的假设，基础导波理论，也不能是一个例外，它应该只使用在加速阶段，直到滑动速度超过不稳定的阈值。

项目成果

Kobayashi, Y.: "Long runout landslides riding on a basal guided wave" Proc.Itern.Symp.Geology and Environment, IAEG 1. 761-766 (1997)

Kobayashi, Y.：“基础导波上的长滑坡”Proc.Itern.Symp.Geology and Environment, IAEG 1. 761-766 (1997)

Takarada, S. et al.: "Depositional features and transportotion mechanism of valley-filling Iwasegawa and Kaida debris avalanchos, Japan" Bull. Volcand.60. (印刷中) (1999)

Takarada, S. 等人：“日本岩濑川和凯达碎片雪崩的沉积特征和迁移机制”Bull.60（出版中）。

Kobayashi, Y.: "Long runout lanlslides riging on a basal guidcd wave" Proc. Interm. Symp. Geology and Environment, IAEG. 1. 761-766 (1997)

Kobayashi, Y.：“基础导向波上的长跳动兰斯滑梯索具”Proc。

宝田晋治・鹿野和彦: "Reckslide-debris avalanche of May 18, 1980, Mount st. Hclens volcano, Washington by H. Glicken" 地質調査所月報. 49/2-3. 55-106 (1998)

Shinji Takarada 和 Kazuhiko Kano：“1980 年 5 月 18 日，华盛顿州圣赫克伦斯火山的 Reckslide 碎片雪崩，作者：H. Glicken”地质调查月报 49/2-106 (1998)。

宝田晋治・鹿野和彦: "Rockslido-debris avalanche of May 18,1980,Mount St-Helens Volcano,Washington by H.Glieken" 地質調査所月報. 49/2-3. 55-106 (1998)

Shinji Takarada 和 Kazuhiko Kano：“1980 年 5 月 18 日，华盛顿圣海伦斯火山的岩石滑坡碎片雪崩，H.Glieken”地质调查月报 49/2-106 (1998)。