Hydromechanical Evaluation of Flow Behavior in Rock Foundations of Concrete Gravity Dams

9610545 在美国S.在世界范围内，有许多现有的水坝需要检查材料的潜在劣化，以验证是否符合升级的设计要求，或者对性能或安全的长期损失作出反应。 为了应对日益增长的电力需求，世界各地都需要新的水坝。 大坝基础是大坝整体结构性能的关键。 应力水平的变化（例如，来自储层水平或温度的变化）可能是由于接缝打开和关闭而导致渗透率变化的原因。 节理和岩体渗透性影响基础扬压力的大小和分布，以及灌浆和排水帷幕的效率。 扬压力又决定了大坝的抗滑稳定性。 因此，在设计新大坝和/或评估现有大坝时，开发真实的扬压力分布是一个重要的考虑因素，以满足更高的抗震或水力设计要求。 研究内容包括：1）大坝基础下节理张开和闭合的实例研究; 2）洪水条件下实际扬压力分布的发展; 3）大坝基础监测计划的改进; 4）确定基础岩体和大坝/岩石界面的现场尺度流体力学性质; 5）研究大坝几何形状等因素对大坝性能和各种补救措施有效性的影响; 6）加深对节理岩体水流性质和基本特征的认识。 ***

9610545 In the U. S. and world-wide, there are many existing dams that need to be inspected for potential deterioration of materials, to verify compliance with upgraded design requirements, or to respond to long term loss in performance or safety. In response to the increasing demand for electricity, new dams will be needed around the world. The foundations of large dams are key to the performance of the overall structure. Changes in stress levels (e.g. from changes in reservoir levels or temperature) can be responsible for changes in permeability due to joint opening and closure. Joint and rock mass permeability affects the magnitude and distribution of the uplift pressure at the foundation, as well as the efficiency of grout and drainage curtains. The uplift pressure, in turn, determines the stability of the dam against sliding. Thus, development of a realistic uplift pressure distribution is a significant consideration in the design of new dams and/or in the evaluation of existing dams to satisfy higher seismic or hydraulic design requirements. The research includes: 1) case studies of joint opening and closure under foundations of dams; 2) development of realistic uplift pressure distributions under flood conditions; 3) improvements in monitoring plans for dam foundations; 4) determinations of field-scale hydromechanical properties for the foundation rock mass and the dam/rock interface; 5) investigate the influence of factors such as dam geometry on dam performance and effectiveness of various remedial measures; and 6) improve understanding on the nature and basic characteristics of flow through jointed rock. ***