低热硅酸盐水泥大坝混凝土施工关键技术研究  

Key construction technologies of low heat Portland cement dam concrete

作　　者：樊启祥[1] 李文伟[1] 李新宇[2] 

机构地区：[1]中国长江三峡集团公司,北京100038 [2]中国电建集团华东勘测设计研究院有限公司,杭州311122

出　　处：《水力发电学报》2017年第4期11-17,共7页Journal of Hydroelectric Engineering

基　　金：国家重点研发计划项目(2016YFB0303600);国家自然科学基金(51209219)

摘　　要：低热硅酸盐水泥(简称低热水泥)混凝土早期强度发展缓慢,其施工工艺、施工进度、温控措施及其效果等方面与中热水泥混凝土有较大差异。为了论证高拱坝采用低热水泥混凝土的可行性,2013年6月在溪洛渡拱坝30号、31号坝段开展了低热水泥大坝混凝土施工关键技术研究,结果表明,与常规的中热硅酸盐水泥(简称中热水泥)混凝土相比,低热水泥混凝土冲毛时间延后16~20 h、拆模时间延后约24 h,但因大坝混凝土浇筑备仓时间通常在7~10 d左右,采用低热水泥混凝土对拱坝施工进度无影响;在浇筑温度、水管间距、一期通水水温和通水流量基本相同的条件下,拱坝混凝土最高温度采用低热水泥可比中热水泥降低4.6℃,封拱灌浆后的温度回升也较中热水泥混凝土低1.2℃;其他条件相同时,低热水泥混凝土的最大顺河向应力比中热水泥混凝土减小19%?65%,抗裂安全系数普遍提高且均大于2.0;拱坝低热水泥混凝土坝段横缝可以张开,接缝灌浆注入量与中热水泥混凝土坝段相近。截至目前,溪洛渡拱坝采用低热水泥大坝混凝土浇筑的30号、31号坝段尚未发现任何裂缝,低热水泥大坝混凝土施工质量和温控防裂效果优良。The growth of low heat Portland cement dam concrete strength at early stage is slower than moderate heat Portland cement concrete. It causes certain great differences between these two kinds of concrete in construction technology, construction schedule, temperature measure, their effect, etc. Studies on key construction technologies of this low heat concrete were carried out for dam blocks 30 and 31 of Xiluodu arch dam in June 2013 to analyze the feasibility of its application to ultra high arch dams. Compared with moderate heat cement concrete, the green cutting schedule of low heat cement concrete had delayed 16-20 h and its formwork removal schedule had delayed about 24h, but this did not influence the dam construction schedule since the concreting intermission time of dam concrete is usually around 7 - 10 d. And its highest temperature in the dam blocks was 4.6 ℃ lower and its temperature rise after joint grouting was 1.2 ℃ lower in basically the same conditions of placement temperature, spacing between cooling pipes, and temperature and flow rate of cooling water. When other conditions were the same, low heat cement concrete had a peak stream-wise stress of 19% - 65% lower and its safety factors of crack resistance were generally improved, all reaching a level above 2.0. The transverse joints of a low heat cement concrete dam block can be opened and the required amount of joint grouting is close to that of a moderate heat cement concrete dam block. Up to now, no crack has been found yet in the observed twodam blocks of low heat cement concrete.

关 键 词：低热硅酸盐水泥 大坝混凝土 拆模时间 冲毛时间 温控防裂 接缝灌浆 

分 类 号：TV431[水利工程—水工结构工程]