倒虹吸地涵混凝土结构施工期温控敏感性分析

Sensitivity analysis of temperature control for concrete structure of inverted siphon underground culvert

针对倒虹吸地涵混凝土结构的特点以及施工期易产生裂缝这一问题,阐述了影响混凝土温度和应力的主要因素,认为此类结构施工期开裂与浇筑分层、间歇时间、寒潮冷击、昼夜温差、表面保温和冷却水管密切相关。以实际工程为依托,采用三维非稳定温度场和应力场的有限单元法以及水管冷却的精确算法,对温控影响因素进行敏感性研究,认为浇筑分层和间歇时间对混凝土结构整体性和协调变形能力有较大影响,寒潮冷击和昼夜温差对表面防裂极为不利,适当保温和冷却水管能大幅提高混凝土的抗裂能力。此外,根据研究结果,对某工程提出具有针对性的温控防裂措施。

In view of the character of concrete structure of inverted siphon underground culvert and the problem of concrete crack in the period of construction,this paper introduced the main factors which influence the temperature and stress of concrete structure,and the main cause of crack is closely related to placing delaminating,interval time,cold wave strike,diurnal amplitude,superficial thermal insulation and cooling pipe.A case is presented where the 3D FEM simulation of thermal field and stress field of concrete and the numerical algorithm of pipe cooling are adopted to study the sensitivity degree of these factors.It is considered that placing delaminating and interval time greatly Influence the Integrity Deformation Compatibility of concrete structure,and cold wave strike and diurnal amplitude induce adverse effects to crack prevention of surface,and suitable thermal Insulation and cooling pipe greatly improve anti-crack performance of concrete structure.Finally,the paper put forward temperature control measures for crack prevention based on the research results.