沉管节段局部块体浇筑试验分析

Study on partial block casting tests of immersed tunnel

港珠澳大桥沉管隧道是我国首次采取工厂化预制沉管管节,混凝土沉管管节在预制过程中裂缝控制是工程中要解决的难题之一,必须在沉管预制施工前进行局部块体浇筑试验,验证混凝土原材料、配合比、施工工艺以及裂缝控制措施的可行性及可靠性。开展K1和K2两件局部块体浇筑试验,得到室内优选配合比在现场浇筑中的基本性能,研究了加冰工艺、不透水模板布、保温保湿养护薄膜及网格布等裂缝控制措施的有效性,通过温度监测得到了高温季节和常温季节下局部块体的内部最高温度、内外温差等关键指标,为下阶段足尺节段浇筑试验提供一定的参考价值。

Hong Kong-Zhuhai-Macao immersed tunnel is the first tunnel in China precasted in factory and few empirical approaches can be used for reference.Controlling and avoiding early age thermal cracking in concrete is a key technology to guarantee the construction quality of the project,and small block tests should be carried out to study the basic performance of concrete,cracking control measures and temperature indexes in different season.Through two small block tests.It studied the basic properties of concrete in different mix ratio,and verified the effectiveness of cracking control measures such as mixing ice,formcloth,curing film and gridingcloth.Furthermore,temperature indexes in different season were obtained through monitoring.All of the works provided some value for the 1/4 quarter full-scale segment tests in future.