三门峡大坝双层泄水孔原型噪声观测与底孔改建设计

三门峡大坝泄流排沙孔原为施工导流底孔，其体型不满足黄河高含沙水流的要求，泄水后其斜门槽、工作门槽导轨等部位发生严重破坏。为了查明破坏机理，提出合理的改建措施，于１９８９年对双层泄水孔进行了原型噪声观测。本文介绍了噪声测试水流空化的原理、方法及成果，对照水工模型试验及底孔破坏情况进行了分析，对改建方案进行了论证。此次原型噪声观测为水工建筑物水流空化情况测试和判断提供了新的途径，底孔改建为改善水力条件

Prototype Observation of Noise Level in The Two-layer Discharge Outlet and Design on Reconstruction of Bottom Outlet for Sanmenxia Dam

The shape of bottom outlet which originally used for construction diversion for San-menxia Dam can not satisfy the requirement by heavly burdened water flow which can cause seriousdamages on guide rails and other places on the sloping gate slot and service gate slot after discharging.For finding out the damage mechanism and proposing the reasonable improving measures, prototypeobservation of noise in the two-layer discharge outlet was carried out in 1989. In this paper, the prin-ciple, method and result of cavitation observation in water flow by noise test is introduced, and the re-construction scheme is demonstrated with reference to the hydraulic model test and the damage of ac-tual bottom outlet. This prototype observation of noise level has provided a new way for test and de-termination of cavitation in the water flow passing hydraulic structures. Reconstruction of bottom out-let is a new engineering practice for improving hydraulic condition and preventing cavitation damage.