Precision controlled vertical actuator for advanced hydro-thermal coupled confined and long term testing for nuclear waste repository geomechanics

女王大学的Diederichs博士从事与岩石在各种载荷和边界条件下的损伤检测和预测相关的研究，以预测地下核废料储存库附近和周围的长期性能。这里要求的设备将成为与设计用于长期储存核废料的竖井、隧道和洞穴周围的挖掘破坏有关的实验工作的关键基石。这种储存库的围岩的长期稳定性和极限渗透性取决于在建造、运营期间和储存库的长期寿命期间控制开挖周围的损害发展水平。块状岩石的长期下限强度与在最终破坏过程中在中等应力水平下观察到的可测量的损伤开始有关。通过单调或循环应力/应变路径测试，可以通过高精度的载荷和应变控制来监控该损伤阈值和随后的损伤在样品中的扩展。在本研究过程中进行的测试需要一个具有高水平可定制控制和灵活物理配置选项的全天候专用执行器/加载框架，包括能够与先前为这项工作以及未来的直接剪切和断裂测试获得的最先进的约束单元集成。这里要求的设备是具有高容量、高刚度和最先进的数字控制技术的伺服控制加载框架，使其能够进行无侧限压缩、三轴、后屈服、直接和间接拉伸、蠕变和断裂韧性测量测试以及循环应变/载荷测试。该系统具有先进的控制器、应用软件和大流量、高响应的伺服液压(阀)，允许使用任何反馈信号组合(例如：轴向载荷、行程和应变、周向应变、油液增强器压力和行程、孔隙流体压力等)来操纵控制回路。在今后4年内，至少有10000名研究生将在所讨论的研究范围内使用该系统，但也将在若干其他项目中以次要身份使用该系统。

Dr. Diederichs at Queen's University is involved in research related to damage detection and prediction in rock under a variety of loading and boundary conditions as a predictor for long term performance adjacent to and around underground nuclear waste repositories. The equipment being requested here will form a critical cornerstone in the experimental work related to excavation damage around shafts, tunnels and caverns designed for long term storage of nuclear waste. The long term stability and limiting permeability of the host rocks for such a repository depend on controlling the levels of damage development around the excavations during construction, operation and over the long term life of the repository. Long term lower bound strength of massive rock has been linked with the measurable onset of observed damage at intermediate stress levels on the way to ultimate failure. This damage threshold and the subsequent damage propagation within the sample can be monitored with highly accurate load and strain control through monotonic or cyclic stress/strain path testing. The tests to be performed during the course of this research require a full time dedicated actuator/load frame with a high level of customizable control and flexible physical configuration options including the capability to integrate with a state-of-the-art confinement cell acquired previously for this work and the future direct shear and fracture testing. The equipment requested here is a servo-controlled loading frame with high capacity, high-stiffness and state of the art digital control technology that makes it possible to conduct unconfined compression, triaxial, post yield, direct and indirect tension, creep and fracture toughness measurement tests and cycled strain/load tests. The system has leading edge controller, application software and high-flow, high-response servo-hydraulics (valves) allow for manipulation of the control loop using any combination of feedback signals (ie: axial load, stroke and strain, circumferential strain, onfining fluid intensifier pressure and stroke, pore fluid pressure, etc). Within the next 4 years at least 10 graduate students will use the system within the context of the research discussed but also in a secondary capacity in a number of other projects.