Abstract：Research purposes: With the rapid construction of the Kunming metro，the shield construction begins to the sectional tunnel． How to make the lectotype of the main shield system to reduce the impact of the shield construction on the environment under the complicated hydrological condition of the sedimentary deposit of the Dianchi Lake and the special construction conditions is an urgent problem to be solved． According to the situation of shield excavation and based on the experience of the shield construction of the metro in other cities，this paper analyzes and discusses the tectotype of the main shield system to be used under the special geological conditions of the Kunming metro．
Research conclusions: The adaptabilities of the lectotype designs of the main shield system to the construction condition，such as physical structure，cutter head，drilling and excavation of shield machine，should be ensured to reduce the excavation risk except the necessary measures should be taken．
2011, Vol. 28 
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