特殊土梁场预制T梁裂缝成因分析及预防

Analysis and Prevention of Crack Formation of Precast T Beam

预制T梁开裂是一个普遍存在的问题,通过系统分析可能产生裂缝的原因,得出配合比、温度作用以及收缩等不会导致T梁的结构性裂缝。对于特殊岩土(滇中红层)具有遇水膨胀失水收缩的特性,在雨季极易造成梁场地基的不均匀变形。提出采用测量桩和千分表定性监测地表变形的方法,对比正常与开裂T梁张拉后的预拱度差异验证了梁场地表不均匀变形导致T梁开裂。总结了膨胀性岩土梁场裂缝防治措施和防水治水的重要性。为今后梁场建设和裂缝防治提供参考。

Cracking of precast T beam is a common problem.Through systematic analysis of the possible causes of cracks,it is concluded that the mix Ratio,temperature action and shrinkage will not lead to structural cracks of T beam.For the special rock and soil(the middle red layer of Yunnan),it has the characteristics of water expansion,water loss and shrinkage,and it is easy to cause the uneven deformation of beam field foundation in the rainy season.The method of measuring pile and micrometer to qualitatively monitor the surface deformation was put forward,and the difference of pre-camber between normal and cracked T beams after tensioning was compared to verify that the uneven surface deformation in the beam field led to the cracking of T beams.The importance of preventing and controlling cracks in the expanded geotechnical beam field and waterproofing and water control is summarized.It provides reference for future beam field construction and crack prevention.