Study On Parameters Of EPB Shield Driving And Safety Control Technology Of Shield Tunnel Construction In Mixed Ground

Owning to its safety, economy and speediness and other advantages in construction, Shield Tunnelling method has become one of the main methods of urban subway construction. However, the shield tunnelling method in mixed ground is still a difficult problem in urban subway construction. At present, there are a lot of difficulties existing in the shield tunnelling in mixed ground as follows. The shield type selection is hard in shield tunnelling in mixed ground. The type selection of cutter and the arrangement of cutter head is difficult in shield tunnelling in mixed ground. Besides, the matching relation between the shield driving parameters and geological conditions is ambiguous in tunneling. Moreover, the safety of tunnelling is not easily control. In this article, the above problems will be discussed based on the project of urban subway tunnel engineering of Gaotangshi station to Huangpo station of Guangzhou Metro Line 6. The main research contents and results are as follows:(1)According to the engineering geology and the hydrogeology of based on project and the influencing factor of shield type selection, the type of shield in mixed ground is determined. Meanwhile, based on the configuration of shield tunnelling machine, the adaptability of composite shield tunnelling machine to the disadvantageous geology is systematically analysed.(2)Based on a lot of successful experience in shield tunnelling machine design and construction in mixed ground, this paper studied the structure form of cutter head and cutter’s type and working mechanism. Accordingly the method and basis of cutter head’s structure form selection and arrangement are obtained. At the same time, the principle and method of cutter combination and type selection are determined. Moreover, combined with the cutter wear rule and its influence factors, the control measures of cutter wear are put forward.(3)With the statistical and theoretical analysis of driving parameters such as thrust, torque, rotating speed of cutter head and so on which are acquired by site records of the based on project, the control range and the demand amount of driving parameters is obtained. At the same time, the relation among the driving parameters is determined.(4)By applying 3 Dimension Distinct Element Code method(3DEC) to the numerical simulation of shield tunnelling process under joint strata, it has been clear about the surrounding rock disturbance range and deformation law and stress distribution. Besides, the groud settlement regularity and the segment lining stress distribution patterns are figured out either.In the end, the safety of construction is analysed and proved.