【摘要】 通过对国内15座混凝土大坝裂缝的调查分析及仿真反馈计算归纳总结出了混凝土裂缝的原因，探索了混凝土防裂的途径和措施．提出混凝土热膨胀系数直接影响温度收缩应力，决定热膨胀系数大小的是骨料的岩性，选用热膨胀系数小的骨料有利于降低混凝土内部产生的温度应力．由外部环境造成裂缝危害的主要原因是寒潮袭击，其防范措施为采用“薄层、短间隙、均匀上升”的浇筑方式和妥善的表面防护．其它骤然降温因素毛不容忽视，如遭遇洪水浸泡、冷却管内冷却水与混凝土内部温差过大等．此外，结构设计、分缝分块和施工工艺也要给予充分重视．更多还原

【Abstract】 By means of the investigation on concrete cracking in 15 dams and feedback simulatingcalculations. The cracking causes in concrete dam are found, then the measures for preventing crackare studied. A series of conclusions is as follow thermal expention coefficient of concrete directly affectstemperature contraction stresses, the value of thermal expension coefficient is mainly determined bythe rock propertics of the aggregates in concrete making usc of the aggregate8 Which has smaller ther-mal expension cocfficient in conrete is advantageous to the reduction of the thermal stresses. The sud-den changc in ambient temperature is another factor which causes cracking in concrete dam, the pre-vcnting measures are using such construction way as thin layer, short interval, even going-up in con-crete cast1ng and adopt the propcr surface protection. Other temperature sudden change such as en-countering flood inundation too largcr temperature difference between water in cooling pipe and the in-ternal concrete can not be neglccted- Structural design,construction design and construction technologyshould also be given enough attentions.更多还原