Study On The Cutters’ Layout Scheme Of Combined Shield Cutterhead

Tunnel boring technology is an advanced method in underground construction,boring machine is more and more widely used in the fields of mining excavation,subway construction and cross-river tunnel. Combined Shield is an equipment whichis between hard rock tunnel boring machine and shield in structure. This kind ofboring machine is mainly applied in the underground condition where hard rock andsoft rock would appear alternately. The research on the cutterhead design is a vital jobfor higher efficiency and lower cost. Combined shield has a lot common with the hardrock boring machine and the shield in boring mechanism, so there must have been asolid foundation for the research of combined shield’s cutterhead system design. Inthis research, the study of cutters’ layout principles on cutterhead is a most importantwork, which directly affects the excavation efficiency and construction cost. Thispaper mainly focuses on the research of cutters’ layout principle design on cutterheadfrom the following aspects.(1) Reviewed a current research situation of boring machine’s cutterhead systemdesign in domestic and abroad, put forward the great importance of research ofcombined shield’s cutters layout principles on cutterhead.(2) Discussed the key problems in this research, which mainly includes theresearch of cutterhead structure design, the respective rock breaking mechanism ofdisc cutter and blade cutter, the rock breaking mechanism of multi cutters, theconfiguration of different cutters and the layout principle of different cutters.(3) Reviewed the geological condition and the cutterhead&cutters configurationin three sections of Guang Zhou NO.3Subway construction, which applied combinedshields for excavating. Established the models of different cutters and cutterhead usedin one of them, studied the installation methods and layout principles of differentcutters.(4) Explored the cutter rock interaction of blade cutter in Discrete ElementMethod code PFC (Particle Flow Code), which mainly focused on the impact of rakeangle, blade angle and cutting depth of cutters on the cutter force and rock breaking.The result is consistent with that concluded from an experiment before. (5) Take the cutters’ layout scheme in Tian-Hua section of NO.3Subway as anexample, established an parameterized model of the cutterhead, researched thecalculation of forces on disc cutters from the rock, the thrust and torque on cutterheadfrom disc cutters, conducted an static analysis of the cutterhead structure in ANSYS,confirmed the rationality of the cutters layout scheme in this section, and put forwardof flow chart of cutters’ layout scheme design.(6) Prospected the future work of the research on cutters layout scheme design ofcombined shield.