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Experimental Research for Block Stability on Dam Outer Slope Under the Condition of Exceeding Standard Flood

Author(s): Huojian Liu; Yun Li; Xiaogang Wang; Long Zhu

Linked Author(s): Yun Li, Xiaogang Wang

Keywords: Exceeding standard flood; Convenient block; Model tests; Shape optimization; Water drag force

Abstract: Using geotextile materials to lay on the downstream of dam before the exceeding standard flood can effectively delay the dam breach time and enhance the competence in fending off the dam breach risk. In this paper, the method of using convenient block and soil nail to fix geotextile material was put forward for the emergency protecting of earth-rock dam under the condition of overtopping. Model tests and theoretical analysis were used to study the instability mode and water drag force acted on single block by water flow on back slope of earth-rock dam under the overtopping condition. The test results showed that water drag force acted on single block increased gradually along the back slop of dam; As to main instability mode, the cuboid block was sliding while the streamline block was overturning; Water drag force acted on single cuboid block increased with the increase of upstream face area, and the water jump was more obvious near the block; Water drag force acted on streamline block changed little with the increase of upstream face area, and the flow pattern was steady near the block, but the stability of streamline block was greatly influenced by uplift force. Therefore, cuboid blocks with flat and smaller area of upstream face were recommended for the urgent protecting of earth-rock dam in practical situation under the same conditions. For estimating drag force acted on cuboid blocks on back slop of dam surface conveniently, an empirical formula was proposed at different water depths of overtopping and in different areas of upstream face, which had high practical and reference value in engineering applications.


Year: 2013

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