Visualization and sequence photo of tertiary creep under confining pressure

围压下三次蠕变的可视化和序列照片

基本信息

批准号：
15360473
负责人：
OKUBO Seisuke
金额：
$ 4.42万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360473/
关键词：
Visualization Sequence Photo Rock Creep Tri-Axial Compression Test Confining Pressure Visco-Elasticity Constitutive Equation

项目摘要

It is essential for underground development to understand the failure process of rock subjected to tri-axial compression. Therefore, we developed a transparent tri-axial vessel made of an acrylic acid resin, and succeeded in observing the failure process of rock specimens in tri-axial compression test. In this study, tri-axial creep tests of Tage tuff were also conducted within the transparent vessel.A creep test usually requires longer time than a compression test and it is not feasible to take a photograph continuously at every predetermined time interval. Therefore, in this study, the photographing system was developed which cooperated with the existing loading and measuring apparatuses. This system made it possible to take a series of photographs of a specimen in the tertiary creep region. Photographs taken in a tri-axial test were processed to obtain axial and lateral deformations by the computer program developed in this study.After careful examination of axial and lateral deformations, it was found that the creep strain (axial strain) just before failure was nearly equal to the cross sectional width of the stress-strain curve at the creep stress level, and that not only axial but also lateral strain-rates in the tertiary creep region were inversely proportional to the residual time up to the failure. And it was also found that ratio of the lateral and axial strain increases in the tertiary creep region were similar to those of the tri-axial compression test just after the strength failure point.

了解岩石在三轴压缩作用下的破坏过程对于地下开发至关重要。为此，我们研制了丙烯酸树脂透明三轴容器，并成功观察了岩石试件在三轴压缩试验中的破坏过程。在这项研究中，Tage凝灰岩的三轴蠕变试验也在透明容器内进行。蠕变试验通常比压缩试验需要更长的时间，并且在每个预定的时间间隔连续拍照是不可行的。因此，本研究开发了与现有加载和测量设备配合的拍照系统。该系统可以拍摄第三级蠕变区域样品的一系列照片。通过本研究开发的计算机程序对三轴试验中拍摄的照片进行处理，以获得轴向和横向变形。经过仔细检查轴向和横向变形，发现失效前的蠕变应变（轴向应变）接近等于蠕变应力水平下应力-应变曲线的横截面宽度，并且第三级蠕变区域中的轴向应变率和横向应变率均与失效前的剩余时间成反比。还发现，三次蠕变区的横向和轴向应变增加比率与强度破坏点后的三轴压缩试验相似。