Shield Cutterhead Opening Rate And Cutterhead Body Structure Optimization Design

In our country, Earth pressure balance (EPB) shield machine is a very huge market demand in infrastructure projects, national defence and so on because of its a lot of advantages, which is fast and efficient, safe and reliable, good construction quality and to have small influence to ground buildings. Cutterhead is the key component of EPB. Cutterhead is the key component of EPB. Aperture ratio and cutterhead body structure are very important in cutterhead design, and They are interactional and intercoupled. But hey are studied Independently from domestic and foreign literatures, and the related research is less. In view of the questions above, aperture ratio and cutterhead body structure are researching parallelly in the paper. In view of EPB cutterhead of some subway section, discrete element and finite element numerical analysis method are used in the aperture ratio and cutterhead body structure optimization in typical soil dao plate boundary conditions, which improve the overall performance of cutter shield. The main research contents are as follows:(1)The first work is to determine the discrete element model parameter before discrete element model simulation of shield cutter mining process. The sand of the formation of a subway construction is as the research object. A large number of parameters by trial and analysis are used to fit the curves of parameters of the macro parameters and microscopic parameters with inversion method of discrete element model parameters. Particle density, porosity, particle stiffness, friction coefficient and other microscopic parameters are inverted approximatively, which lay the foundation for discrete element model of EPB cutterhead.(2) The discrete element model of cutterhead is constructed based on the EPB cutterhedad of a subway construction section. The boundary conditions is established according to the working principle. The evaluation criteria of the EPB cutterhead' discrete element simulation is determined. Shield' tunneling process is simulated in different overall opening rates. The results show that mining' efficiency of cutterhead is improved as aperture ratio increases.The collapse is appeared when the aperture ratio is over 40%. Shield' tunneling process is simulated in different central opening rates. The results show that mining' efficiency of cutterhead is descended as aperture ratio decreases. A large number of particles are gathered in front of cutter center, and the pressure surges. Based on the analysis results above and related literature, a cutterhead with optimized overall and central aperture ratio is found, which is a basis for the following work.(3) After determining the external load, a simplified three-dimensional model of cutterhead is established by SolidWorks. ANSYS Workbench is usd to simulate cutterhead structure whose design parameters are cutterhead plate thickness, cutterhead thickness and Propping diameter and whose optimizing targets are cuuterhead's stress, strain and weight. Results show that the optimized chtterhead'stress and strain decrease and so is the weight.