Rock Stress Measurement by Hydraulic Fracturing with Hemispherical-ended Borehole

半球形钻孔水力压裂测量岩石应力

• 批准号: 03452241
• 负责人: OKAMURA Hiroshi
• 金额: $ 4.42万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452241/
• 关键词: Rock Stress Measurement; Hydraulic Fracturing; Finite Element Method; Hemispherical-ended Borehole Technique; 初期応力; 岩盤計測; 岩盤応力

Recent development in relation to prediction of structural stability of large rock cavern has indicated the need for systematic stress measurements in the field, e.g. systematic measurement of the stress distributions around caverns. In the hydraulic fracturing to determine the state stress at a certain point within a rock mass, the fracture phenomena of a borehole surface, which is a function of the field stress, needs to be measured by applying hydraulic pressure into the borehole. Hydraulic fracturing with hemispherical-ended borehole is very similar to conventional hydraulic fracturing except for the location of applying hydraulic pressure, namely the pressure at the borehole bottom surface which is formed hemispherically. This method has a possibility to measure the three dimensional stress state in rock mass in a single borehole.Firstly, hydraulic fracturing of spherical cavity in infinite rock mass is suggested. Then the fracture phenomena are analyzed by the stress coefficients determined theoretically on the surface of the cavity. It is clarified that two magnitudes and three directions of the principal stresses of rock stress are determined by this method. Secondly hydraulic fracturing with hemispherical-ended borehole is suggested and the stress coefficients are determined by FEM for analyzing fracture phenomena at borehole bottom surface. Finally, analyzing the fracture phenomena on the hemispherical-ended borehole surface under general three dimensional rock stresses, it is made clear that those are dominated by the deferential stress, the directions of principal stresses, the tensile strength of rock mass and so on. It is concluded that the rock stress can be determined by the hydraulic fracturing with hemispherical-ended borehole.

大型岩洞结构稳定性预测的最新发展表明需要在现场进行系统应力测量，例如系统测量洞穴周围的应力分布。在确定岩体内某一点的状态应力的水力压裂中，需要通过向钻孔中施加水压来测量钻孔表面的破裂现象，该破裂现象是场应力的函数。半球形井眼水力压裂与常规水力压裂非常相似，不同之处在于施加水压力的位置，即形成半球形的井眼底面的压力。该方法为测量单个钻孔内岩体三维应力状态提供了可能。首先，提出了无限岩体球腔水力压裂。然后通过理论确定的型腔表面应力系数来分析断裂现象。明确了该方法可确定岩石应力主应力的两个大小和三个方向。其次，提出了采用半球端钻孔水力压裂，并通过有限元法确定应力系数，分析钻孔底面的破裂现象。最后，分析了一般三维岩石应力作用下半球端钻孔表面的断裂现象，明确了其主要受偏应力、主应力方向、岩体抗拉强度等因素的影响。结果表明，通过半球端钻孔水力压裂可以确定岩石应力。

项目成果

K.SUGAWARA,Y.OBARA,K.KANEKO,T.AOKI: "Hemispherical-ended borehole technigue for measurement of absolute rock stress" Proc.of INT.Symp on Rock Stress and Rock Stress Measurements. 207-216 (1986)

K.SUGAWARA、Y.OBARA、K.KANEKO、T.AOKI：“用于测量绝对岩石应力的半球端钻孔技术”Proc.of INT.Symp on Rock Stress 和 Rock StressMeasures。

K.SUGAWARA, Y.OBARA, K.KANEKO and T.AOKI: "Hemispherical-ended Borehole Technique for Measurement of Absolute Rock Stress" Proc. of Int, Symp on Rock Stress and Rock Stress Measurement. 207-216. (1986)

K.SUGAWARA、Y.OBARA、K.KANEKO 和 T.AOKI：“测量绝对岩石应力的半球端钻孔技术”Proc。

尾原 祐三,菅原 勝彦,荒木 秀郎,有賀 義明: "スリーブフラクチャリング法による岩盤応力測定" 材料. 38. 13-19 (1988)

Yuzo Ohara、Katsuhiko Sukawara、Hideo Araki、Yoshiaki Ariga：“套筒压裂法测量岩石应力”材料 38. 13-19 (1988)。

K.SUGAWARA,K.KANEKO,Y.OBARA,H.OKAMURA: "Determination of the State of Stress in Rock by the Measurement of Strains on the Hemispherical Borehole Bottom" Proc.of INT.Symp on Large Rock Caverns. 2. 1039-1050 (1986)

K.SUGAWARA、K.KANEKO、Y.OBARA、H.OKAMURA：“通过测量半球形钻孔底部应变来确定岩石中的应力状态”Proc.of INT.Symp on Large Rock Caverns。

K.Sugawara: "MEASUREMENT OF IN-SITU ROCK STRESS BY HEMISPHERICAL-ENDED BOREHOLE TECHNIQUE" Mining Science and Technology. 3. 287-300 (1986)

K.Sukawara：“通过半球端钻孔技术测量原位岩石应力”采矿科学与技术。