复合地层双模盾构与复合盾构刀具磨损对比

软硬交替复合地层中可采用双模盾构和复合式盾构进行掘进施工。然而目前针对双模盾构和复合盾构在软硬交替地层中的适应性缺乏清晰明确的现场掘进数据进行对比验证，特别是施工参数和刀具磨损方面。基于深圳地铁12号线相似地层的3个相邻盾构区间工程，对比不同盾构机的盾构掘进施工参数、刀具服役情况及岩渣形态，分析刀具磨损的原因及特征，并进一步对比在长距离软硬交叠地层下EPB/TBM双模盾构和复合EPB盾构的掘进效能。结果表明：双模盾构TBM模式在岩质地层中的推进速度可达到双模盾构EPB模式的2倍及复合EPB盾构的3倍。受土仓压力和刀盘转速影响，刀盘推力和扭矩差异较大的双模EPB模式和复合EPB盾构更易造成刀具异常磨损。双模盾构TBM模式滚刀磨损速度更低，其刀具寿命是双模盾构EPB模式和复合EPB盾构的3～5倍，换刀时间占比为后两者的3/8～1/2,EPB/TBM双模盾构总体掘进效能优于复合EPB盾构。双模盾构TBM模式的岩渣中岩片更多且形状细长而扁平，在岩石地层中EPB/TBM双模盾构掘进效率优于复合EPB盾构。

Comparative study on tool wear of dual-mode shield and composite shield in composite strata

Dual-mode shield and composite shield could be used for tunneling in soft hard alternate composite strata. However, at present, there was a lack of clear and definite field excavation data to compare and verify the adaptability of dual-mode shield and composite shield in soft and hard alternate strata, especially in construction parameters and tool wear. Based on three adjacent shield section projects in similar strata of Shenzhen Metro Line 12, this paper compared the shield tunneling construction parameters, tool service conditions and rock slag morphology of different shield machines, analyzed the causes and characteristics of tool wear, and further compared the tunneling efficiency of EPB/TBM dual-mode shield and composite EPB shield in the long distance soft and hard overlapping strata. The results show that: (1) The advance speed of the dual-mode TBM mode in the rock stratum can be twice that of the dual-mode EPB mode and three times that of the composite EPB mode. The EPB mode and composite EPB shield with large difference in thrust and torque of the cutter head are more likely to cause abnormal tool wear due to the influence of the soil bin pressure and cutter head speed. (2) The TBM mode hob of the dual-mode shield has lower wear rate, its tool life is 3-5 times that of the EPB mode of the dual-mode shield and the composite EPB shield, and the tool change time accounts for about 1/2~3/8 of the latter two. The overall tunneling efficiency of the EPB/TBM dual-mode shield is better than that of the composite EPB shield. (3) The rock fragments in the rock slag of the dual-mode shield TBM mode are more thin and flat, and the EPB/TBM dual-mode shield tunneling efficiency is better than the composite EPB shield in the rock stratum.