Study On The Adaptability And Design Of The Layout For Thrust System Of Shield Machine Under Sudden Load

Shield tunneling machine is a large-scale tunneling equipment integrating excavation?support,lining and slag discharge,and it is used on underground construction.In the process of tunneling,sudden load is very likely to happen when the propulsion system encounters the working conditions like Soft-hard alternating formation,boulders group and weak surrounding rock etc..As a result,it will cause many engineering problems such as malfunction,collapse of hydraulic system,short-term runaway of attitude,risking the quality of tunnel construction and the safety of machinery.Based on the genetic mechanism for the sudden load and the layout theory of the propulsion system,this paper studies the adaptability of propulsion system under the sudden change load.The research includes the following parts:The external force distribution of the tunneling machine is analyzed,mathematical model of sudden load is established,the causes and influencing factors of the sudden load of the propulsion system is studied,and the mechanical balance equation of the propulsion system is established.Based on the mathematical model of tunneling machine,in order to make sure the hydraulic cylinder thrust acting on the top of the segment are uniform and the thrust fluctuation is minimal,two indexes were set up including thrust relative variation coefficient and thrust fluctuation ratio to measure the adaptability of the propulsion system under the sudden load.And through the theoretical analysis,the scope of the adaptability of shield thrust system is explored under different layout,and the specificity of uniform propulsion system is pointed out.The adaptability of shield machine in the Wehrhahn-Lin in Dusseldorf,Germany was analyzed,and the hydraulic cylinder layout with better adaptability of the project was solved by multi-objective optimization algorithm.The calculation results were compared with the current layout scheme to verify the feasibility of the adaptability theory of non-uniform propulsion system under sudden load.Shield machine virtual prototype is established based on one engineering case,and the prototype model is verified by using the theoretical analysis and numerical simulation,uniform propulsion system and non-uniform propulsion system adaptability index changes are researched by using the virtual prototype model of propulsion system under three mutations in the external load.Then the adaptability of the propulsion system in different layouts is discussed and suggestions about propulsion system layout are given for different operating conditions.