砂性地层土压平衡盾构切刀磨损室内试验研究

Laboratory Experimental Study on the Wear of EPB Shield Cutting Tools in Sandy Stratum

为探究土压平衡盾构切刀磨损规律,使用自制模拟盾构掘进试验设备进行室内刀具磨损试验,运用显微观测和磨损质量统计分析相结合的方法,分析了安装方位、土样石英颗粒含量和改良剂含量等因素对切刀磨损情况的影响规律,结果表明:在切刀磨损过程中,刀具安装朝向影响磨损情况;表面磨损形式、磨损质量变化与安装半径、石英颗粒含量之间均呈现正相关趋势;添加改良剂可以有效减小切刀磨损质量,改善切刀表面磨损发展情况。基于以上规律对Rabinowicz显微切削模型进行修正,引入切削方向修正系数KR和改良剂折减系数Ks用以分别考虑迎土面、背土面刀具磨损差异和实际工程中地层预先处理措施的影响,并对磨粒磨损系数Kα细化分析,得到修正后的土压平衡盾构切刀磨损质量预测公式,可为相关研究和实际工程中刀具磨损问题提供参考。

In order to explore the wear law of earth pressure balance(EPB)shield cutting tools,indoor tests are carried out with self-made test equipment simulating the shield driving process,and the rules of the influence of installation orientation,quartz particle content and conditioner content on cutter wear are analyzed by means of microscopic observation and statistical analysis of wear-induced mass loss.The results show that:in the wear process of cutters,the installation orientation of cutters affects the wear condition;there is a positive correlation between the surface wear form,the wear-induced mass loss and the installation radius,the quartz particle content;and adding conditioner can effectively reduce the wear-induced mass loss of cutters and mitigate the development of cutter surface wear.In view of the above rules,the Rabinowicz micro-cutting model is modified,by which the correction coefficient of cutting direction and the reduction coefficient of conditioner are introduced to consider the wear difference between the front and back of cutters as well as the influence of ground pre-treatment respectively,and the abrasive wear coefficient is analyzed in detail to obtain the modified prediction formula of cutter wear-induced mass loss of EPB shields,which can provide reference for related research and practical engineering.