黄土地层土压平衡盾构刀盘堵塞风险研究

Study on the Risk of Clogging of Cutterhead in Earth Pressure Balance Shield Tunneling in Loess Stratum

为探究黄土地层土压平衡盾构渣土的黏附特性,取西安市引汉济渭二期工程现场渣土样品开展液塑限联合测定试验、搅拌黏附试验及流动度试验,分析三种添加剂对黄土的平均黏附比、稠度指数及流动度的影响。研究结果表明:对于砂-黄土混合土样,随着砂含量增加,土样平均黏附比降低且流动度增大;对于伊利土-黄土混合土样,随着伊利土含量增加,土样平均黏附比降低,稠度指数逐渐增大,土样流动度有小幅上升;对于蒙脱土-黄土混合土样,随着蒙脱土含量增加,土样平均黏附比略有降低,稠度指数先增大后基本处于0.75左右,流动度呈先上升后下降的趋势。总体而言,向黄土中掺入砂有良好的减黏效果,掺入伊利土和蒙脱土均会加大堵塞风险,其中蒙脱土影响更为显著。本研究结合三种指标综合评价渣土黏附特性及盾构掘进堵塞风险,研究结果可为相似工程提供参考。

To explore the adhesive characteristics of muck from EPB shield tunneling in loess stratum,a series of tests were conducted using muck samples in the second phase of the Hanjiang-to-Weihe River Water Diversion Project in Xi′an.These tests include the liquid and plastic limit combined test,stirring adhesion tests,and fluidity tests.The study analyzes the effects of three different additives on the average adhesion ratio,consistency index,and fluidity of loess.The results show that:for sand-loess mixed samples,as the sand content increases,the average adhesion ratio decreases while fluidity increases.For illite-loess mixed samples,as the illite content increases,the average adhesion ratio decreases,the consistency index gradually increases,and fluidity shows a slight increase.For montmorillonite-loess mixed samples,as the montmorillonite content increases,the average adhesion ratio slightly decreases,the consistency index first increases and then stabilizes around 0.75,and fluidity first increases and then decreases.Overall,adding sand to loess effectively reduces adhesion,while adding illite or montmorillonite increases the risk of clogging,with montmorillonite having a more significant impact.This study comprehensively evaluates the adhesion characteristics of muck and the risk of shield tunneling clogging using three indicators,providing a reference for similar engineering projects.