The Key Technology Research Of Shield Construction In Nanjing Subway Of Whole Section Weathered Sandstone

Of shield construction technology in the major applications of underground engineering isbecoming more and more widely in our country, has become the main method of subwayconstruction. With more and more large-scale subway construction in big city, tunnelconstruction will build in complex strata. It put forward higher request to the shield construction.It includes research of shield cutter knives formation adaptability, cutter head torque thrust thekey parameter of reasonable selection and shield promoting effect on the formation and control,etc.Taking Nanjing subway line three Shengtai west road station~Tianyuan west road stationshield interval as the background, through information research, theoretical analysis andexperimental research, on-site validation integrated research methods, combining the wholesection of Nanjing area weathered sandstone formation under the condition of shieldconstruction key technology research. Main research contents are as follows:(1) According to the characteristics of the Nanjing weathered sandstone, in view of theshield cutter hob more severe situation, studies the hob and the interaction mechanism ofsandstone, reveals the mechanism of rock fragmentation of gear hob.(2) According to the actual engineering of Nanjing subway, the introduction of a new typecutting tools, double ball hob, improve the efficiency of shield cutter head broken rock,increased the shield cutter wear-resistant performance, improve the construction speed of shield,shield construction period has been saved.(3) Put forward the whole section sandstone formation of reasonable cutter tools selectionscheme, reduce the degree of wear and tear, and the method of optimizing cutting toolsconfiguration.(4) Research the shield cutter head key parameters such as thrust, torque calculationmethod and the main influence factors, puts forward the method of setting the key parameters ofshield construction.(5) Study the influences of shield advance on surface, reveals the single wire shield withdouble shield, ground surface settlement trough peck the law of the curve. Shield advance onsurface deformation control measures are put forward: to set reasonable parameters for shieldadvance, over break volume control, the use of synchronous grouting, the use of secondarygrouting and other measures.(6) The floatation mechanism and affecting factors of the shield tunnel segment lining, andcombined with practical engineering, the segment buoyancy control measures are put forward.