Experimental Study on Brittle - Ductile Transition in Shear Deformation of Soft Sediments

软沉积物剪切变形脆韧转变的实验研究

• 批准号: 07640604
• 负责人: MIYATA Yuichiro
• 金额: $ 1.41万
• 依托单位: Faculty of Science, 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: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640604/
• 关键词: soft sediments; shear deformation; brittle failure; ductile flow; shear plane; strain localization; strain rate; pore pressure; 塑性変形; せん断破壊; ダクティリティー; 可視化

Deformation of soft-semidents involves brittle failure and ductile flow, both of them including intermediate style occur at the same time of shearing. In this study, critical condition for deformation style was examined experimentally, and following results were obtained ; (1) Shear plane characteristics under uniaxial compression for unconsolodated and semi-consolidated clay show particular differences, such as thin and healed shear plane with less disturbance of primary grain-fabric for unconsolidated clay, while dominant secondary shear developed around the main shear plane for semi-consolidated clay. (2) Visualization technique for local shear strain during deformation and failure by plane-strain compression was developed. (3) Interrelationship between slip failure and plastic flow deformation under shear was categorized from the standpoint of strain-localization ; slip failure followed by strain-localization is likely to occur for more lithified and/or smectite-rich clay, plastic (flow) deformation is still accompanied with slip failure for the other case. (4) Strain-rate and anisotropic fabric as control factors on deformation style were investigated by systematic experiments, and ductile stress-strain behavior, extensive shear strain and flow were shown under high strain-rate, which is more effective than grain-fabric. (5) Its mechanism was explained by physical model involving strain-localization. (6) High pore-pressure expected under rapid shear is, however, difficult to verify in laboratory, and is rmained unsolve.

软内部的变形涉及脆性衰竭和延性流动，包括中间样式包括在剪切的同时发生。在这项研究中，对变形样式的临界条件进行了实验检查，并获得了以下结果。 （1）在单轴压缩下的剪切平面特性，用于非固定和半固结的粘土表现出特殊的差异，例如薄和愈合的剪切平面，对于未固结的粘土而言，原代晶粒的干扰较小，而主要的二次剪切在主剪切面周围围绕半固定的粘土而产生。 （2）开发了变形过程中局部剪切应变的可视化技术，并开发了平面应变压缩的故障。 （3）从应变 - 位置的角度对剪切下的滑动失效与塑料流量变形之间的相互关系；滑动失败后，可能会出现更严格的岩石和/或富含晶状体的粘土，塑料（流动）变形仍伴有其他情况下的滑动衰竭。 （4）通过系统的实验研究了应变率和各向异性织物作为变形样式的控制因子，并且在高应变率下显示了延性应激应变，广泛的剪切应变和流动，这比晶粒更有效。 （5）它的机制是通过涉及应变平局的物理模型来解释的。 （6）然而，在快速剪切下预期的高孔隙压力很难在实验室中验证，并且未解决。

项目成果

伊藤寛之, 宮田雄一郎: "マッドクラックのパターン形成実験" 地質学雑誌.104. 90-98 (1998)

Hiroyuki Ito，Yuichiro Miyata：“泥裂模式形成实验”地质杂志.104（1998）。