堆石混凝土流动填充与温升过程原型监测

Flow filling and temperature rise of rock-filled concrete based on prototype monitoring

自密实混凝土在堆石体复杂空隙中的流动填充过程隐蔽性高,难以科学量化评价堆石混凝土的填充效果。本文依托石坝河水库开展了堆石混凝土原型监测试验,通过在典型仓截面的不同点位布设温度传感器,并实时测量混凝土液面高度、跟踪浇筑点位置、记录混凝土覆盖测点时刻,绘制出了不同时刻的混凝土自由液面线。试验结果发现,自密实混凝土的横向自流填充能力非常强,当浇筑点距离截面17 m时已有混凝土流过截面;伴随混凝土浇筑填充过程,截面上下游的自混凝土液面高度基本保持着匀速上升的趋势;沿坝轴线防渗层内的混凝土液面斜率Is约0.06,截面处的上下游液面斜率约0.03~0.08,按理论计算得到的堆石体空隙阻滞系数η约65~173;分析浇筑期温度监测数据,发现堆石体与密实混凝土混合后能很快由最初的非均匀温度分布,达到相对均匀的温度场。本文通过原型试验同步研究堆石混凝土流动填充与温升过程,对后续科学评价密实性与细观温度有重要意义。

Flowing and filling process of self-compacting concrete(SCC) in the complex voids of rockfill is of high concealability, so it is difficult to scientifically quantify the filling effect of rock-filled concrete(RFC). This study conducts an in-situ monitoring and experiment on SCC at Shibahe gravity dam: lay temperature sensors at different locations of a typical section;measure real-time fresh concrete levels;track pouring locations;record the instants of monitoring sensors covered by fresh concrete mixture. And the free surface profiles of fresh SCC are plotted for different instants. The test results show SCC has a great lateral self-flow filling capacity-it can flow and reach the monitoring section 17 m away from the pouring location. In pouring and filling of the fresh SCC, its surface levels upstream and downstream of the section keep a trend of rising at nearly constant speeds. The slope Is of the free surface is about 0.03-0.08 upstream and downstream of the section and roughly 0.06 along the dam axis in the whole impermeable layer. The damping coefficient η of the rockfill voids is about 65-173 in theoretical calculations. Analysis of the temperature data of rockfill-SCC mixture reveals that during pouring, its spatial distribution starts from heterogeneous but approaches relatively uniform soon after mixing. The process of flow filling and temperature rise in the mixture observed in-situ synchronously is of great significance for further quantitative evaluation of RFC compactness and mesoscopic temperature distribution.