某土石坝上游护坡型式改变影响坝顶高程的试验研究

徐麦菊 叶伟 徐章耀 刘永强 马福恒

摘要：针对病险水库除险加固过程中会出现的上游护坡型式改变的情况，基于物理模型试验，研究各工况下干砌石与混凝土两种类型护坡的波浪爬高及越浪情况，确定护坡类型变化对波浪爬高和坝顶高程的影响。以某水库大坝为例，采用1∶15的模型比尺进行了不同护坡型式典型断面的波浪物理模型试验。研究发现，由于干砌石、混凝土两种型式护坡的糙渗系数相差015，干砌石护坡改为混凝土护坡后最大波浪爬高计算值增长056 m，试验值增长06 m，此情况下坝顶的现状高程不能满足规范要求；改变护坡型式后波浪冲击坝顶胸腔而产生的跃浪量也会增加，胸墙收到的最大波浪压力从159 kPa增至178 kPa。试验的成果对类似除险加固工程的设计工作具有借鉴意义。

关键词：土石坝；护坡；坝顶高程；模型试验；糙渗系数

中图分类号：TV641文献标志码：A文章编号：16721683（2018）03014906

Experimental study on effect of the upstream slope protection type change of an earth rock dam

XU Maiju1，YE Wei2，XU Zhangyao3，LIU Yongqiang3，MA Fuheng2

（1.Management Bureau of Zhaopingtai Reservoir，Pingdingshan 467300，China；

2.Dam Safety Management Department， Nanjing Hydraulic Research Institute，Nanjing 210029，China；

3.Management Bureau of Baiguishan Reservoir，Pingdingshan 467301，China）

Abstract：In view of the upstream slope protection type change in the process of the reinforcement of dangerous reservoirs，we conducted a physical model test to study the wave runup and overtopping situation of the dry masonry slope protection type and the concrete type，and determined the effect of slope protection type change on the wave runup and crest elevation.In this paper，we took a reservoir dam for a case study.A wave physical model test of a typical section of the slope protection types was carried out at the scale of 1∶15.The test results showed that the roughness coefficients of the dry masonry and concrete types differed by 015.After the change of slope protection type from dry masonry to concrete，the calculation value of the maximum wave runup increased by 056 m， and the test value increased by 06 m.In this condition，the original crest elevation could not meet the standard requirements.In addition，after the change of slope protection，the wave overtopping will also increase.The maximum wave pressure on the parapet will increase from 159 kPa to 178 kPa.The results of the test can provide a reference to the design of similar reinforcement projects.

Key words：earth and rockfill dam；slope protection；crest elevation；model test；roughness coefficient

20世纪50年代至70年代我国修建了大量水库，由于历史原因及设计施工水平的限制，多数大坝存在病险问题。一般而言，常见的水库病险主要分7个方面：防洪、抗震、大坝结构、大坝渗流、输、泄水建筑结构、金属结构和机电设备及管理设施等[14]。其中，大坝结构病险问题又主要包括护坡破损、坝坡不稳定、断面不足等3个方面。通常，土石坝上游可采用块石、现浇混凝土及预制混凝土块等型式[5]进行护坡整治。以昭平台水库为例，水库除险加固过程中将主坝上游护坡型式由原干砌石改为混凝土面板。……