The Research Of Some Problems In The City Underground Shield Construction Survey

The city underground as the modern vehicle is the important symbol and window of city modernization. All of the big cities in the world including our important and primary cities in China are zealously programming and preparing to construct the city underground . Shield tunneling has some advantages compare with the traditional construction methods of underground runnel: less ground task, less effect on the ambience, high automatization and rapid construction. With the maturity of shield construction method which is long distance, big diameter, deep depth and complex section, more and more attentions are paid to shield construction method, and it is becoming the most important construction method of underground tunnel. Having been worked for many years , the asymmetric subsidence has already threatened the safe run of underground trains because it traverses different relief cell and is affected by dynamic load.This paper aims at the construction safety and work requirement of underground runnel, and integrates the new technology of modern engineering survey in order to discuss the shield tunnel survey and the underground deformation monitoring. The paper introduces the character of breakthrough error distribute of shield underground tunnel, the method and root mean square error formula of range finder silo height transfer, and deduces the equations of correlative the freely set station method and the composite conducting wire method, then proposes the reliminary plan to resolve the asymmetric subsidence of underground tunnel.