Analysis Of Adaptability Of Cutting Pan And Stratum Deformation Caused By Construction Of Φ7m Shield In Compound Ground

With the rapid development of economy and science and technology, the scale of urban construction and the urban rail transit system network is extending continually, the urban rail transit system network is improving continually, shield tunneling has a promising application view. At the same time, train speed lifting is a development trend of urban rail transit to improve ride comfortability. In order to solve aerodynamic problems that accompanied by train speed lifting, it is necessary to increase tunnel section. The design and manufacture technology of Φ7m compound shield tunneling machine with own intellectual property is a key point to consummate high-end device manufacturing system and improve international competitiveness and urban rail transit of our country, so is the continuous improvement of study on environment effect caused by shield tunneling.The operated speed of Shenzhen urban rail transit line11is120km/h, which is the first in China. In this paper, analysis of adaptability of cutting pan and stratum deformation caused by construction of Φ7m shield in compound ground based on Chegongmiao～Hongshuwan running tunnel is presented. The main research content of this paper is as follows.(1) The concept of adverse geological factors of shield tunneling construction in compound ground is presented. Based on the concept, the formation along running tunnel is classified and its distribution range is accounted. The characterization and influence on shield tunneling machine’s function design of adverse geological factors is analyzed, then the function design requirements and the key design parameters of Φ7m shield are presented. Besides, the parameters of CET6950shield show its adaptability.(2) The type, scope and workings of shield cutting pan and shield cutters and placing rules of shield cutters is studied, the designing experience of pre-existing shield cutting pan and the shield construction practice in Guangzhou and Shenzhen are summarized. Based on those above, with mechanical analysis of Φ7m shield cutting pan, the adaptability between compound ground and Φ7m shield cutting pan is verified. Besides, tunneling parameters of shield launching section shows the adaptability of cutting pan.(3) Based on Peck formula, the way to confirm settlement width coefficient is presented. With numerical simulation methods,3-D numerical model of single shield tunnel construction is set up, the influence of depth, thickness and relative location of silt layer above tunnel on surface subsidence is studied.(4) With numerical simulation methods,3-D numerical model of double shield tunnel construction is set up. Taking the compound ratio of formation, the ratio between tunnel diameter and thickness of covering formation and spacing distances of tunnels into consideration, surface subsidence caused by shield tunnel construction in compound formation is studied.