输水隧洞TBM预制管片混凝土配合比优化设计

Optimization Design of Concrete Mix Proportion for TBM Precast Segments in Water Conveyance Tunnel

菲律宾卡利瓦大坝项目输水隧洞具有小断面、长距离、高埋深等特点,处于高地应力、地震区,地质条件复杂,采用双护盾TBM单向施工,管片混凝土强度等级和国内常用管片的相同。笔者分析输水隧洞TBM预制管片混凝土配合比优化的理由,阐述优化设计思路,并根据混凝土原材料性能试验结果,对外加剂掺量、用水量、砂率和总灰量进行优化。结果表明,配合比优化后,每立方米混凝土的胶凝材料用量可减少40 kg,混凝土性能得到一定提高,为预制管片生产提供技术支撑。

The water conveyance tunnel of Kaliwa dam project in Philippines has the characteristics of small section,long distance and high buried depth.It is located in high ground stress and seismic area with complex geological conditions.Double shield TBM one-way construction is adopted,and the concrete strength grade of the segments is the same as that of common segments in China.The author analyzes the optimization reasons for the concrete mix proportion for TBM precast segments in water conveyance tunnel,expounds the optimization design ideas,and optimizes the percentage of chemical admixture,water consumption,sand ratio and total ash content according to the performance test results of concrete raw materials.The results show that after the optimization of the mix proportion,the binder content used per cubic meter of concrete can be reduced by 40 kg,and the performance of concrete can be improved to a certain extent,which provides technical support for the production of precast segments.