用于共同管沟衬砌的挤压混凝土配合比及关键工艺研究

为使现浇挤压混凝土衬砌共同管沟能在城市建设中得以推广应用,需对用于该衬砌混凝土的配合比及关键施工工艺进行研究,解决挤压衬砌混凝土流动性大,且坍落度长时间保持与早强之间的矛盾,并对挤压施工中的关键工艺进行研究。通过室内试验的方法最终得出满足要求的混凝土配比为W∶C∶F∶M砂∶M石∶M外=180∶343∶86∶673∶1 098∶6.4,挤压压力控制在0.3 MPa,保压时间30 min,混凝土在经过挤压脱水后,1 d强度可达10 MPa以上,28 d强度可达45 MPa以上。该研究成果将为共同管沟挤压混凝土衬砌施工推广提供一定的技术支持。

Mixing Proportion of and Key Construction Technologies for Extruded Concrete Lining of Utility Tunnels

The mixing proportion of and key construction technologies for extruded concrete lining of utility tunnels are studied so as to promote the application of utility tunnels with extruded concrete lining in China. The key of the study is to solve the contradiction between the high flowability and long slump-keeping time of extruded concrete and its early high strength, as well as to solve the problems in the construction of extruded concrete lining. After indoor tests, it is concluded that the mixing proportion of the extruded concrete lining that can meet relevant requirements is W ： C ： F ： Msand ： Maggregate ： Madditive = 180 ： 343 ： 86 ： 673 ： 1 098 ： 6.4, the extrusion pressure should be controlled at 0.3 MPa, the pressure holding time should be 30 min, the 1 day strength of the concrete can reach more than 10 MPa and the 28 day strength can reach more than 45 MPa. The study result can provide technical support for the construction of extruded concrete lining of utility tunnels in China.