Abstract:

The doubleline 6lane segment of Honggu Immersed Tunnel has many characteristics, such as large crosssection, complex structure, mass casting concrete, difference between inner and outer temperatures and temperature stresses and high antiseepage and crack prevention performances. The hydration heat and small circle cracking test are carried out so as to select cementing materials. The mixing proportion of concrete is determined by mechanical property test, durability test and impermeability performance test. The castinsitu test block and temperature test are carried out. The internal temperature variation rules of concrete and effect of cooling pipe are analyzed. The arrangement of cooling pipes during segment prefabrication and relevant temperature control and crack prevention technologies are presented according to temperature control and informatized construction. A series of technologies have been adopted, i. e. concrete temperature control technology, concrete casting technology, time control of cooling pipe and mould dismantling and segment maintaining technology.

Key words: Honggu Immersed Tunnel, mass concrete, temperature stress, mixing proportion, temperature control, crack prevention technology, informatized construction