中国水利

近年来多起中小型水库土石坝漫而未溃案例突破了土坝“漫顶即溃”的传统认知。针对水头较低、溃坝下游影响较小的中低土石坝，适宜的坝面防护与泄流技术可延缓漫顶溃决过程，在提升大坝防御超标准洪水能力的同时也为下游群众撤离争取了宝贵时间。基于近年典型水库大坝漫顶案例的出险过程特征，从提升中小型水库土石坝防漫顶溃决能力角度，梳理了在设计洪水计算方法、工程措施技术、应急抢险技术、风险监控与预警等方面的研究进展，提出了亟待突破的关键技术难题，包括变化环境下超标准洪水内涵定义、多要素作用下漫顶冲蚀特性与溃决机理、坝面防护新型结构、泄洪能力提升改造、应急抢险技术与装备等。为构建中小型水库土石坝防漫顶溃决技术体系，围绕变化环境下中小型水库设计洪水计算与洪水标准确定方法、土石坝漫顶溃决模拟与临界阈值确定方法、土石坝坝面防护新型结构及泄洪能力提升改造技术、土石坝防漫溃应急抢险技术装备集成与示范等方面提出对策建议，旨在为提升中小型水库土石坝工程韧性与风险防控能力提供技术支撑。

In recent years, several instances where small and medium-sized reservoirs with earth-rock dams experienced overtopping without subsequent failure have challenged the traditional notion that “overtopping leads to inevitable breaching”. For earth-rock dams with low water heads and minimal downstream impact,appropriate dam surface protection and discharge technologies can delay the overtopping failure process.This not only enhances the dam's capacity to withstand floods exceeding standard levels but also provides valuable time for downstream evacuations. Based on the characteristics of recent overtopping incidents in typical reservoir dams, this paper reviews advancements in design flood calculation methods, engineering measures, emergency response technologies, and risk monitoring and early warning systems to improve the overtopping failure resistance of small and medium-sized earth-rock dams. Key technical challenges identified include defining the concept of floods exceeding standard levels in changing environments, understanding overtopping erosion characteristics and failure mechanisms under multiple factors, developing new dam surface protection structures, enhancing flood discharge capacity, and improving emergency response technologies and equipment. To establish a technical framework for preventing overtopping failure in small and mediumsized reservoirs with earth-rock dams, this paper proposes strategies focusing on design flood calculation and standard determination methods in changing environments, simulation of overtopping failure and determination of critical thresholds, development of new dam surface protection structures and technologies to enhance flood discharge capacity, and integration and demonstration of emergency response technologies and equipment. The goal is to provide technical support for enhancing the resilience and risk prevention capabilities of small and medium-sized reservoir earth-rock dam projects.