薄壁箱型混凝土结构施工期温度裂缝控制
|
摘要
针对薄壁箱型混凝土结构特点及施工期易产生裂缝的问题,采用三维有限单元法仿真计算某拱式渡槽拱圈的一个浇筑段温度场和应力场,据此研究裂缝成因及开裂机理并提出相应的控制措施。结果表明,薄壁箱型混凝土结构早期的内外温差及腹板和横隔板的约束作用是产生裂缝的主要原因,而采用塑料板保温的温控防裂措施能有效预防裂缝的产生,且塑料板厚度越大,防裂效果越好。
In view of the characteristics of thin-walled box concrete structure and the problem of cracking easily during the construction period,the 3-D FEM was adopted to simulate and calculate the thermal field and stresses field of a pouring section of an arch-shaped aqueduct.Accordingly,the causes and mechanism of cracks were studied and the corresponding control measures were put forward.The results show that the temperature difference between the surface and interior of thin-walled box concrete structure and the restraint action of web and transverse diaphragm are the main factors influencing the occurrence of cracks.The exterior thermal insulation is the effective measure to prevent the concrete structure from cracking,and the greater the thickness of plastic sheets,the better the anti-crack effect.
In view of the characteristics of thin-walled box concrete structure and the problem of cracking easily during the construction period,the 3-D FEM was adopted to simulate and calculate the thermal field and stresses field of a pouring section of an arch-shaped aqueduct.Accordingly,the causes and mechanism of cracks were studied and the corresponding control measures were put forward.The results show that the temperature difference between the surface and interior of thin-walled box concrete structure and the restraint action of web and transverse diaphragm are the main factors influencing the occurrence of cracks.The exterior thermal insulation is the effective measure to prevent the concrete structure from cracking,and the greater the thickness of plastic sheets,the better the anti-crack effect.
引文
[1] 张挺元,李念平.预应力混凝土箱型薄壁结构裂缝成因分析及处理[J].山东水利,2003(3):22,29.
[2] 王振红,朱岳明,于书萍.薄壁混凝土结构施工期温控防裂研究[J].西安建筑科技大学学报:自然科学版,2007,39(6):773-778.
[3] 许朴,朱岳明,贲能慧.倒T型混凝土薄壁结构施工期温度裂缝控制研究[J].水利学报,2009,40(8):969-975.
[4] 丁兵勇,唐瑜莲.气温骤降对薄壁混凝土结构温度应力的影响[J].山西建筑,2014,40(29):52-53.
[5] 朱伯芳.大体积混凝土温度应力和温度控制[M].北京:中国水利水电出版社,2012.
[6] 孙启冀,侍克斌.严寒地区某高RCC重力坝温控设计与优化[J].水利水电技术,2017,48(5):56-60,86.
[7] 陈守开,孟美丽,刘秋常,等.昼夜温差对薄壁混凝土结构温度应力的影响分析[J].水力发电,2011,37(7):27-30.
[8] 袁勇.混凝土结构早期裂缝控制[M].北京:科学出版社,2004.
[2] 王振红,朱岳明,于书萍.薄壁混凝土结构施工期温控防裂研究[J].西安建筑科技大学学报:自然科学版,2007,39(6):773-778.
[3] 许朴,朱岳明,贲能慧.倒T型混凝土薄壁结构施工期温度裂缝控制研究[J].水利学报,2009,40(8):969-975.
[4] 丁兵勇,唐瑜莲.气温骤降对薄壁混凝土结构温度应力的影响[J].山西建筑,2014,40(29):52-53.
[5] 朱伯芳.大体积混凝土温度应力和温度控制[M].北京:中国水利水电出版社,2012.
[6] 孙启冀,侍克斌.严寒地区某高RCC重力坝温控设计与优化[J].水利水电技术,2017,48(5):56-60,86.
[7] 陈守开,孟美丽,刘秋常,等.昼夜温差对薄壁混凝土结构温度应力的影响分析[J].水力发电,2011,37(7):27-30.
[8] 袁勇.混凝土结构早期裂缝控制[M].北京:科学出版社,2004.