PREDICTION AND ANALYSIS ON THE WEAR LAW AND CUTTING LIFE OF DISC CUTTER OF EARTH PRESSURE BALANCED SHIELD TBM IN COMPOSITE STRATA

Geological conditions changes frequently in the composite strata contained various soft and hard rocks. The serious wear of disc cutter severely restricts the construction efficiency. In order to explore the wear resistant measures and predict the wear extent and cutting life of the disc cutter of earth pressure balanced(EPB)shield TBM in composite strata, the statistical regression method was used to analyze the wear extent and replacement process of disc cutter in the excavation interval of ZDK30+433.76to ZDK31+150.61 of the Guangzhou Metro Line 18. Based on the actual wear extent of disc cutter and the tunneling parameters of EPB shield TBM,the wear coefficient K suitable for the composite strata contained various soft and hard rocks is obtained. Then, the wear extent and the cutting life of disc cutter of EPB shield TBM in the composite strata are predicted and analyzed according to the wear coefficient K and the corresponding disc cutter wear model. Subsequently, measures such as the improvement of disc cutter, the optimization of construction parameters, the majorization of management and the amelioration of residue are proposed to reduce the wear extent of disc cutter. Finally, the optimization of the tunneling parameters of the EPB shield TBM this project is carried out, and the recommended rotation speed for EPB shield TBM under-passing the Shawan waterway is proposed. The study provides engineering experience and theoretical basis for the prediction of disc cutter wear and the choice of tool change opportunity in Guangzhou Metro Line 18 and similar tunnels project in composite strata.