Investigation and modeling of mechanical characteristics of non-uniform and discontinuous rock mass in deep ground by in-situ triaxial tests

原位三轴试验研究深部非均匀不连续岩体力学特性并建模

基本信息

批准号：
13355021
负责人：
TANI Kazuo
金额：
$ 17.97万
依托单位：
National University Corporation Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

In-situ triaxial test method was invented in 1998 for the purpose to measure average stress and strain relationships of rock masses. Since the test specimens are prepared in the ground by rotary drilling, disturbance of the ground is expected to be as practically minimal.In the fiscal year 2001,the advanced version of the test method was devised using CCD for deformation measuring system. This system was expected to allow measurement of strain distribution throughout the test specimen, thus believed to be useful for studying non-uniform or discontinuous rock mass behavior.In the fiscal year 2002,uniaxial as well as triaxial compression devices were developed introducing this CCD measuring system. Furthermore, multi-step loading triaxial test method was investigated to reduce the number of test specimens and to avoid the difficulties of interpreting scattered data.In the fiscal year 2003, a couple of triaxial tests were conducted with CCD measurement using artificial rock specimens. The results demonstrated that the deformation of specimens became progressively localized as the axial compression proceeded. Moreover, test equipment for the field test was improved. The accuracy and speed of deformation measurement were enhanced as ten-fold as the previous version. Selection of site was also made for the field tests and preliminary geological investigation was conductedIn the fiscal year 2004,a series of field tests were carried out at the site of tuff breccia. Average stress and strain relationships were measured for typically non-uniform rock masses. Some laboratory triaxial tests were also done to obtain the complimentary data to study scale effect and some other features of rock mass behavior.

原位三轴试验方法于1998年发明，旨在测量岩体的平均应力和应变关系。由于测试样本是通过旋转钻孔在地面上制备的，因此对地面的干扰预计实际上是最小的。在2001财政年度，使用CCD变形测量系统设计了测试方法的高级版本。该系统预计能够测量整个测试样本的应变分布，因此被认为有助于研究不均匀或不连续的岩体行为。在 2002 财年，开发了单轴和三轴压缩装置，引入了这种 CCD 测量系统。此外，还研究了多步加载三轴试验方法，以减少试验样本的数量，并避免解释分散数据的困难。2003财年，利用人造岩石样本进行了几次三轴试验，并进行了CCD测量。结果表明，随着轴向压缩的进行，试样的变形逐渐局部化。此外，还改进了现场测试的测试设备。变形测量的精度和速度比之前的版本提高了十倍。还选择了现场试验地点并进行了初步地质调查。2004财政年度，在凝灰岩角砾岩现场进行了一系列现场试验。针对典型的不均匀岩体测量了平均应力和应变关系。还进行了一些实验室三轴试验以获得补充数据来研究尺度效应和岩体行为的一些其他特征。