Study on long-term permeability of fracture in rock mass

岩体裂隙长期渗透率研究

• 批准号: 12450411
• 负责人: MATSUKI Koji
• 金额: $ 6.4万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450411/
• 关键词: Permeability of fracture; Shear deformation; Time-dependent closure; Theory of viscoelasticity; Confining pressure test; Control of confining pressure; rock; き裂の閉鎖; き裂のせん断変形; 一般的応力条件; 時間依存性

For prediction and control of the long-term permeability of a fracture in rock mass, it is indispensable to clarify permeable change of an underground fracture with time. The purpose of this study is to establish a method for prediction of long-term permeability of a fracture. For this purpose, firstly, it was carried out that theoretical study of time-dependent closure of a fracture with rough surfaces under constant normal stress. Secondary, the relaxation modulus of rock was measured by using proposed indentation-test system. Finally, the permeable change of a fracture in the rock under both of shear stress and normal stress with time was clarified experimentally and theoretically.Main results obtained in this study are summarized as follows:1) A formula for the relationship between constant normal stress and time-dependent closure as a function of time was derived, based upon the distributions of aperture local minima and their radii. It was shown that the ultimate closure of a fra … More cture under constant normal stress can be estimated from the normal stress-elastic closure curve and the relaxation modulus of rock. The ultimate time-dependent closure was shown to be independent of the normal stress if the elastic closure is linear with the logarithm of the normal stress (Goodman's fracture).2) Indentation-test system for estimating the relaxation modulus and the elastic constant of rock was developed. A Monte Carlo simulation on time- dependent closure of a fracture under constant normal stress was performed by using the fracture model and the measured relaxation modulus.The results qualitatively showed that the time-dependent closure for granite is not dependent on normal stress and that for sandstone is dependent on normal stress. However, simulated time-dependent closure was fairly smaller than that of experimental results. It was thought that this difference was the main causes with the size effect by the difference of contact area.3) Permeability test of a fracture applying shear deformation with constant/uniform normal stress under confining pressure was carried out. Less

为了预测和控制岩石质量裂缝的长期渗透性，不可或缺的是，随着时间的流逝，可以透明地渗透性地改变潜在的骨折。这项研究的目的是建立一种预测断裂长期渗透性的方法。为此，首先，进行的是，在恒定的正常应力下，裂缝的时间依赖性闭合的理论研究。次级，使用建议的凹痕测试系统测量岩石的弛豫模量。最后，在实验和理论上阐明了剪切应力和正常应力下的岩石骨折的可渗透变化。在这项研究中获得的梅恩结果总结如下：1）基于稳定的正常应力和时间依赖性关闭时间之间的关系的公式，该公式是根据Aperture局部Minima和他们的hadii and hadii和他们的hadii的分布得出的。 FRA的最终闭合……可以根据正常应力弹性闭合曲线和岩石的弛豫模量来估计更多的正常应力下。如果弹性闭合与正常应力的对数（Goodman's骨折）。2）用于估计宽松模量和岩石的弹性常数的压力测试系统。通过使用断裂模型和测得的弛豫模量进行恒定正常应力下的骨折闭合，对骨折的时间依赖性闭合。结果是，结果表明，花岗岩的时间依赖性闭合不取决于正常应力，并且对于砂岩而言，该结果取决于正常应力。但是，模拟的时间依赖性闭合要比实验结果小得多。人们认为，这种差异是通过接触面积差异尺寸效应的主要原因。3）在约束压力下施加剪切变形的裂缝的渗透性测试，该裂缝施加了剪切变形，并进行了恒定/均匀的正常应力。较少的