Development of Stress Measurement Method for Rock Mass under Severe Condition

恶劣条件下岩体应力测量方法的研制

• 批准号: 08555252
• 负责人: ISHIJIMA Yoji
• 金额: $ 11.58万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08555252/
• 关键词: Borehole Wall Deformation; Change in Borehole Diameter; Axial Strain; Shear Displacement; Coefficient of Sensitivity; Built-in Data Logger; Soft Rock; High Stress Zone; 孔径変化法; 孔軸方向のひずみ; 軟弱な岩盤; 硬岩; コアディスキング; 原位置計測; 地圧計測; 孔壁ひずみ; ダブルボアホール; 悪

In-situ stress measurement is usually cost and time-consuming and can be carried out for rock mass under limited good conditions. The chief investigator developed the theory of the borehole wall deformation method 25 years ago in order to make the measurement simple and to extend the applicable fields. The technology innovation in the measurement field enabled us to develop the stress probes for the borehole deformation method. The main results of the investigation are as follows :(1) The theory was re-examined and it was recognized that the calculation errors can be easily estimated and the probe can be used for rock mass that shows creep behavior since the observation equations are very simple ;(2) Two types of probe were developed. One measures the change in borehole diameter in three directions and the axial strain. Another measures the shear deformation in the two planes which are parallel to the axial direction. The three dimensional stress state can be determined by using these two probes in one borehole ;(3) The probes are mechanically tough and waterproof so that they are easily set at desired depth in a borehole even if is filled by water. The measurement can be carried out as soon as the probe is set with no waiting ;(4) A small built-in data logger was developed. It enabled us to eliminate the cable between the probe and the measurement system out the borehole. This made the possibility of troubles such as cable jamming etc. much less and deeper measurements enable ; and,(5) Stresses at a down hole in soft rock mass, uniaxial compressive strength of rock specimens is between 0.02 and 0.08 MPa, and at a high stress zone, where disking was observed, were successfully measured. This implies that the developed measurement method is suitable for the severe conditions.

地应力测量通常成本高、耗时长，并且只能在有限的良好条件下对岩体进行。为了使测量变得简单并扩展适用领域，首席研究员在25年前开发了井壁变形法的理论。测量领域的技术创新使我们能够开发出用于钻孔变形方法的应力探头。主要研究结果如下：(1)重新检验了理论，认识到由于观测方程非常容易估计计算误差，因此探头可用于显示蠕变行为的岩体。简单；(2)开发了两种类型的探头。一种测量三个方向上钻孔直径的变化和轴向应变。另一个测量平行于轴向方向的两个平面中的剪切变形。通过在一个钻孔中使用这两个探头可以确定三维应力状态；（3）探头机械坚固且防水，即使在充满水的情况下，也可以轻松将其设置在钻孔中所需的深度。探头设置好后即可进行测量，无需等待；(4)开发了小型内置数据记录仪。它使我们能够消除钻孔中探头和测量系统之间的电缆。这使得出现电缆堵塞等故障的可能性大大降低，并且可以进行更深入的测量； (5)成功测量了软岩体的井下应力，岩石试件的单轴抗压强度在0.02～0.08 MPa之间，在高应力区观察到了盘状现象。这意味着所开发的测量方法适用于恶劣的条件。

项目成果

Fujii, Y.: "A Study on Mechanical Backgrounds of Sheeting Joints in a V-shaped Valley" J.MMIJ.Vol.114, No.12 (in Japanese). 869-874 (1998)

Fujii, Y.：“V 形山谷中板材接缝的机械背景研究”J.MMIJ.Vol.114，No.12（日文）。

藤井義明: "あるV字谷におけるシーティングの力学的背景に関する研究" 資源と素材. 114・12. 869-874 (1998)

藤井义明：“V 形谷片的机械背景研究”资源和材料 114・12（1998）。