Complex Earth Pressure Balance Shield Cutter Cloth Knife Law And Cutter Cad System Development,

With the increasingly rapid economic development as well as the demand for basic project constructions, shield tunneling has become a main construction method in project, such as the rail transportation, municipal pipelines, irrigation, and natural gas and so on. The cutterhead is a critical component of shield machine and it plays a major role to break rock and support the tunneling interface. The reasonable arrangement of cutters is not only the guarantee of tunneling efficiently and stably, but also the key to balance the forces of cutters, improve tunnel face'stability, and extend the life of cutters and the main bearing. Based on substantial literature, the arrangement law of cutters and the development of cutterhead CAD system on the composite EPB shield are studied. The main researches of this paper can be summarized as follows:(1) The arrangement law of typical cutters of cutterhead on the composite EPB shield is analyzed. Firstly, arrangement mode of disc cutters are analyzed. The numerical simulation of loading serially on two disc cutters has been carried out using UDEC. Then the specific energy consumption of disc cutters is calculated. According to the principle of minimum specific energy consumption, the optimization cut spacing of disc cutters is determined. The feasibility of the numerical simulation method is verified by the cutting experiment and engineering application. Also, two common modes to arrange cutters on the composite EPB shield cutterhead are proposed by analyzing the actual cutterhead.(2) Genetic Algorithm is used here to solve the optimization model of the disc cutters arrangement. According to their structural characteristics, the cutterheads of the composite EPB shield are divided into eight types due to the distribution of cutterhead opening, and then the arrangement area of disc cutters is obtained. A optimization model of disc cutters arrangement is established to minimize cutterhead's unbalanced force and the difference of the rock breaking amount. And it is solved by the subsection method. Taking the disc cutters arrangement design of the cutterhead used in a subway line construction of Shenzhen for example, the result turns out that the optimization model of disc cutters and the Genetic Algorithm to solve this model are both feasible and effective.(3) A cutterhead CAD system for the composite EPB shield is developed preliminary. The basic functions and the corresponding design requirements of the target system are described. The system services 3D software SolidWorks as a development platform and Visual Basic as a secondary development language, then the combination of programming method and template-based approach is used to realize the function of parametric modeling. Furthermore, combined with the engineering demand of a subway line construction of Shenzhen, the cutterhead is designed using the cutterhead CAD system according to the geological conditions.