Rock weirs are low-head river restoration structures. The present study comprised two sets of flume tests (i.e. fixed bed and moveable sand bed tests) to investigate the rock dislodgement process, which is a primary cause of the failure of rock weirs. The impacts of approach flow intensity, submergence, void ratio and scour of bed sediment on rock weir dislodgement, and the responses of sediment bed scour at rock weirs to the rock weir dislodgement, are analysed and discussed. Three limits are defined to classify the amount of the rock weir dislodgement: (1) limit I indicates the incipient dislodgement of rock from downstream weir toe; (2) limit II indicates that a few rocks are dislodged from downstream weir face and weir crest; (3) limit III indicates that large numbers of rocks are dislodged from downstream weir face and weir crest, which leads to weir failure. A predictor of each limit is proposed for rock weir design.

岩堰是低水头河流修复结构。本研究包括两组水槽试验（即固定床试验和可移动沙床试验），以研究岩石移动过程，这是岩石堰失效的主要原因。分析讨论了引流强度、淹没度、孔隙比和底泥冲刷对岩堰位移的影响，以及岩堰底泥冲刷对岩堰位移的响应。定义了三个界限来对岩石堰的移动量进行分类：（1）界限I表示岩石从下游堰趾开始的移动；(2) 极限II表示下游堰面和堰顶有少量岩石脱落；(3) 极限Ⅲ表示下游堰面和堰顶有大量岩石脱落，这会导致堰故障。提出了用于岩石堰设计的每个限制的预测器。