施工期乌东德水电站左岸尾水边坡实测变形及支护受力特性

Deformation and supporting force characteristics of left bank tail-water slope of Wudongde Hydropower Station during construction period

乌东德水电站在施工期间,其左岸尾水边坡曾出现过较大变形,为保证水电站的长期正常运行,分析了该期间乌东德水电站边坡岩体变形、锚杆应力、锚索锚固力、表面变形的变化特性,分析了发生变形的主要部位和深度范围,评价了边坡稳定状况,阐释了监测成果与边坡开挖支护的相关性,揭示了边坡发生较大变形的最主要原因。结果表明,变形主要发生在f_(1)断层上盘即向山内侧方向至尾水洞与泄洪洞边坡交界处、高程796~910 m边坡范围内。变形区变形深度一般在10~20 m范围内。边坡的变形与边坡下挖和尾水出口段开挖密切相关。边坡开挖后的卸荷回弹和施工过程中的爆破振动,是导致边坡向坡外产生较大变形的主因。随着设计要求的支护措施逐步实施,边坡变形基本趋于稳定。

During the construction period, the left bank tail-water slope of Wudongde Hydropower Station experienced a large deformation. The safety and stability of the slope are related to the long-term normal operation of the hydropower station. This paper analyzes the characteristics of the rock mass deformation,anchor stress, anchor cable anchoring force, and surface deformation during this period. The main positions and depth ranges of the slope deformation are analyzed, and the slope stability is evaluated. The correlation between the monitoring results and the excavation and support of the slope is explained, and the most important reason for the large deformation of the slope is revealed. The results show that the deformation mainly occurs on the upper part of the fault f_(1), i.e., towards the inner side of the mountain to the junction of the tail-water tunnel and the spillway slope, and at the elevation of 796 m to 910 m. The depth of the deformation zone is generally in the range of 10 m to 20 m. The deformation of the slope is closely related to the excavations of the slope and the tailwater outlet section. Unloading rebound after excavation of the slope and blasting vibration during construction are the main causes for the slope to produce large deformation from inside to outside. With the gradual implementation of the support measures required by the design, the slope deformation has basically stabilized.