碾压混凝土分层碾筑无层缝施工新技术研究

通过参加广西岩滩水电站碾压混凝土筑坝的施工实践，结合等建龙滩水电站高坝碾压混凝土设施施工的技术要求，分析研究碾压混凝土筑坝产生层缝的原因，成功探索出了一种混土工作度介于干硬性混凝土拦合物和低塑性混凝土拌合物之间，即VC值小于5s至坍落度小于5mm之间，取名“亚态碾压混凝土拌合物”为筑坝分铺碾物料，以相应最合适的湿地推土机为铺碾设备，并由此在相邻混凝土压实层间形成三角锯齿状相互嵌固，整体胶结的无层缝施工新技术，经作碾压试验，各项技术指良好，试验块四组层面原位抗剪（断）强度平均结果：f‘=1.18,3‘=2.38MPa ,混凝土无层继剪面破坏沿层面结合齿的中间剪断，该项技术已获国家发明专利，专利号ZL98109133．4，名称“碾压混凝土分层碾筑无缝施工技术”，有促进碾压混凝土筑坝技术进步与良好效益。

Research on the Technique of Compacting with Layers and Non-Layer Joints Constructing for Roller Compacted Concrete

This research deals with a key technique of the layer surface binding for roller compacted concrete.Based on construction experences of RCC dam in Yantan project,considering the technical requirements for Logtan high RCC dam to be built soon,this paper analyzed the causes of joints occured between the layers during RCC dam constructing.Used as surfacing material on the layers for dam construction,a mix has been found out sucessfully.It is called sub-RCC mix and has a working condition which situated between stiff mix and low-plasticity mix,that means its VC value in smaller than 5 seconds and slump in smaller than 5 mm.With suitable marsh bulldozer or super-marsh bulldozer as paving and compacting equipment,the new construction technique of non-layer joints has been achieved.The concrete between adjacent compacting layers embeded each other,formed saw-tooth joints and further cemented integrally. Compacting tests shown that each technical parameter can meet the requirements of specification.The average results of shear strength in situ of four group joints in test block are that the friction factor is 1.18,and the cohesion is 2.38MPa.The shear plane failure of concrete with non-layer joints occurs in the intermediate of binding tooth.The technique of compacting with layers and non-layer joints constructing for roller compacted concrete has gained national invention patents registration with patent number of ZL98109133.4.This technique will accelerate RCC damming technology advance and has good benifit.