Abstract: The new No. 5 unit of Dahua Power Plant has run more than three years. Over the period of unit maintenance, the backplane-cracks and washout, erosion, abrasion on the concrete surface has continuous found in volute flow passage.This article brief summarize volute cracks, erosion-corrosion phenomenon as well as the treating processes, and the verification result of their causes are discussed and analysed. Moreover, it put forward the requirements of operation management to volute flow passage structure of unit such as volute, in order to have positive reference function to other similar engineering.

Key words: inlet passage of the volute of new units, cracks erosion, treatment, extension project of Dahua hydropower plant

摘要： 大化电厂新投产的5号机组运行3年多来，历年机组检修期间，连续发现蜗壳进口过水流道存在底板裂缝和混凝土表层被冲刷、淘蚀、磨损现象。对蜗壳裂缝、冲蚀缺陷现象及处理过程分别进行简要概述，并对其产生原因的核查分析结果进行简要探讨、分析，提出对蜗壳等机组过水流道结构的运行管理要求，以期对其他类似工程起到较好的借鉴作用。

关键词: 新机组蜗壳进口流道, 裂缝冲淘, 处理, 大化电站扩建工程