The Äspö pillar stability experiment: Part I—Experiment design
The Äspö pillar stability experiment: Part I—Experiment design
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DOI：
10.1016/j.ijrmms.2009.02.010
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发表时间：
2009-07
影响因子：
7.2
通讯作者：
J. Andersson;C. Martin
中科院分区：
文献类型：
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作者：
J. Andersson;C. Martin
进行 äspö 柱稳定性实验是为了检查异质裂隙岩体在受到开挖诱发应力和热诱发应力耦合作用时的破坏过程。岩柱是通过挖掘两个相邻的大直径钻孔而形成的。柱子的载荷是由开挖引起的应力和矩形加热器模式对周围岩石的加热共同作用的。实验采用观察设计方法进行设计。实验体积的表征表明，实验位于裂隙含水岩体中，该岩体被认为是 äspö 硬岩实验室 (äspö HRL) 和芬诺-斯堪的纳维亚地盾的典型特征。使用二维和三维弹性应力分析进行范围计算，以减少远场地应力的不确定性，建立通道的几何形状，以在隧道底部提供升高的均匀应力，并确定支柱的最佳宽度。根据岩体特征，得出由两个直径1.75m的钻孔形成的1m宽的矿柱即可满足设计目标。热模型表明，支柱中的热诱导应力足以将支柱应力提升到引发故障所需的应力大小之上。根据实验设计安装了声发射、位移和热监测系统，没有出现任何问题。三个月内没有丢失任何传感器。实验完成后，对柱子进行激光扫描，揭示了柱子受损的程度。该实验于2002年1月开始，并于2006年成功完成。
The Äspö pillar stability experiment was carried out to examine the failure process in a heterogeneous and fractured rock mass when subjected to coupled excavation-induced and thermal-induced stresses. The rock pillar was created by the excavation of two adjacent large-diameter boreholes. The pillar was loaded by a combination of excavation-induced stresses and heating of the surrounding rock by a rectangular heater pattern. The experiment was designed using the observation design method. The characterzation of the experiment volume showed that the experiment was located in a fractured water-bearing rock mass that was considered typical for the Äspö Hard Rock Laboratory (Äspö HRL) and for the Fenno-Scandinavian shield. Scoping calculations using two- and three-dimensional elastic stress analyses were carried out to reduce the uncertainty for the far-field in-situ stresses, establish the geometry for the access tunnel that would provide a elevated uniform stresses in the floor of the tunnel, and determine the optimum width of the pillar. It was concluded, based on the rock mass characteristics, that a 1m-wide pillar formed by two 1.75m diameter boreholes would meet the design objectives. Thermal modelling showed that thermally induced stresses in the pillar were adequate to elevate the pillar stresses above the stress magnitude required to initiate failure. Acoustic emission, displacement, and thermal monitoring systems were installed according to the experiment design without problems. No sensors were lost over the three month duration. After the experiment was completed, a laser scan of the pillar revealed the extent of the damaged pillar. The experiment commenced in January 2002 and was successfully completed in 2006.