高寒地区低热水泥混凝土拱坝温控防裂方案  

Temperature control and crack prevention scheme of low heat cement concrete arch dam in high cold area

作　　者：李文伟 江敏敏 向欣 欧阳金惠 周秋景[2] LI Wenwei;JIANG Minmin;XIANG Xin;OUYANG Jinhui;ZHOU Qiujing(China Three Gorges Corporation,Beijing 100038,China;China Institute of Water Resources and Hydropower Research,Bejing 100038,China)

机构地区：[1]中国长江三峡集团有限公司,北京100038 [2]中国水利水电科学研究院,北京100038

出　　处：《南水北调与水利科技（中英文）》2024年第5期967-977,共11页South-to-North Water Transfers and Water Science & Technology

基　　金：三峡集团科研项目(NBZZ20220243);国家自然科学基金重点项目(U2040222)。

摘　　要：高寒地区年平均气温低、昼夜温差大,拱坝易产生温度裂缝,从筑坝材料源头就降低温升,可进一步降低拱坝开裂风险。开展中、低热水泥混凝土拱坝温度场、应力场的对比分析;进行低热水泥混凝土拱坝温控措施优化比选;形成适合高寒地区低热水泥混凝土拱坝的温控防裂方案。结果表明:低热比中热水泥混凝土拱坝最高温度低4.0℃左右,应力最大值低0.7 MPa左右,安全系数从2.48提升到3.65;低热水泥混凝土拱坝可放宽约束区冷却水管间距至1.5 m×1.5 m,强约束区浇筑层厚可从1.5 m放宽至3.0 m,坝体表面流水措施可取消,夏季浇筑温度可放宽至16.0℃,冬季实现常温浇筑;脱离约束区,高温季节5-9月浇筑温度可放宽至18.0℃,层厚对大坝最高温度及应力影响较小,因此可放宽至6.0 m;大坝采用全年永久保温,等效放热系数取β≤3.05 kJ/(m~2·h·℃)。研究结果验证了低热水泥混凝土拱坝抗裂性能的优势,给出高寒地区温控优化措施,实现大坝快速施工,进一步降低了温控和施工成本。The frigid regions were characterized by low annual average temperatures and significant diurnal temperature variations,which made it prone for dams to develop temperature cracks.The conventional high concrete arch dams at that time utilized a mix of"moderate heat Portland cement with 35%Class I fly ash".Despite achieving the then-current advanced level of temperature control measures,the safety factor for concrete crack resistance remained at approximately 1.8.Consequently,it was imperative to conduct research on temperature control and crack prevention,starting from the very source of the materials.With the concrete double-curvature arch dam of a hydropower station in Xizang as its research backdrop,low-heat cement concrete was chosen as the dambuilding material.By reducing the temperature rise from the source of the material,it aimed to further mitigate the risk of cracking.Drawing upon the theories of unstable temperature and stress field calculations,a comparative analysis of the temperature and stress fields between moderate-heat and low-heat cement concrete arch dams was conducted,highlighting the advantages of using low-heat cement concrete for dam construction.Following this,it optimized and compared various temperature control measures for low-heat cement concrete arch dams,ultimately formulating a tailored temperature control and crack prevention strategy suitable for frigid regions.The results indicated that the maximum temperature of the low-heat cement concrete arch dam was approximately 4.0℃lower than that of the medium-heat cement concrete dam,and the maximum stress was reduced by about 0.7 MPa.Moreover,the safety factor was elevated from 2.48 to 3.65.For low-heat cement concrete arch dams,the spacing of water cooling pipes in the constrained zone could be relaxed to 1.5 m×1.5 m,and the thickness of the pouring layer in the strongly constrained zone could be increased from 1.5 m to 3.0 m.The water flow measures on the dam surface could be eliminated,and the pouring temperature in summer could b

关 键 词：低热水泥 混凝土拱坝 温度场 应力场 防裂方案 

分 类 号：TV698[水利工程—水利水电工程] TU411[建筑科学—岩土工程]