Abstract
This paper presents numerical failure analysis on cracking of shield machine cutterhead structure during a metro-tunnel construction. The stress intensity factors (SIFs) of surface cracks with different shapes and location angles were analyzed by a finite element simulation method based on linear elastic fracture mechanics (LEFM) theory. The ratios of variation in stress intensity factors of cracks with different shapes were analyzed. The maximum allowable crack depth of the cutterhead panel is 50.23 mm by dynamic stress calculation, and the damage tolerance criterion of the cutterhead panel was proposed. The influence of the Paris model parameter values was analyzed based on mathematical methods. It is proven that the location of the cutterhead cracking angle is mainly determined by the mixed-mode SIF. In practice, the crack section basically expanded into the semi-elliptical shape. The cutterhead structure may directly enter the stage of crack propagation due to welding defects during tunneling. The research results provide a theoretical basis and important reference for crack detection in the key parts of the cutterhead, as well as maintenance cycle determination and life prediction of the cutterhead mileage, both of which have important engineering value.
Highlights
Introduction safetyThe of the cutterhead structure.the construction of hard strata, such cutterhead of a shield machineIn is generally a large welded structure, which is as be welded using steel plate to form a whole structure, and the corresponding position is solitary stone, the problems of excessive wear and fatigue cracking of the cutter reserved to install the disc cutters and scrapers
Paper of demonstrates an engineering case due to fatigue ratio of Without affecting the overall structural accuracy, the model of cutterhead is crack on a certain type of cutterhead, which ensures the safety of the construction process omitted, and the weld seam is rigidized
Without affecting the overall structural accuracy, the model of cutterhead is simeters ofparameters the cutterhead are shown in Table detailed of the cutterhead are shown in Table plified appropriately
Summary
To solveand thisStatic problem, numerical failure analysis was carried out to identify the root. Without affectinglaw thewas overall accuracy, thelife model causes, and the crack-growth appliedstructural to predict the crack-growth of the of cut-cutterh. The characteristics ofofbolt hole,failure chamfer and rounded terhead. Paper of demonstrates an engineering case due to fatigue ratio of Without affecting the overall structural accuracy, the model of cutterhead is crack on a certain type of cutterhead, which ensures the safety of the construction process omitted, and the weld seam is rigidized. The cutterhead model is imported in simplified appropriately. The characteristics of bolt hole, chamfer and rounded corner are and provides reference for similar structures. StructureThe ofcutterhead the cutterhead welded into a whole, a omitted, and theThe weldoverall seam is rigidized
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