The ballast bed of a high-altitude railway tunnel,which crosses a water-rich Yanshanian diorite fault zone,has triggered upheaval,adversely affecting track smoothness.Considering the train's potential dynamic load and hydraulic coupling conditions at the tunnel base,a multi-scale numerical analysis method is proposed to reveal the macro-and micro-driven mechanisms of ballast bed upheaval under coupled train dynamic load and hydraulic effects.The results indicate that,within 6 seconds of coupled train dynamic load and groundwater action,the porosity of the ballast bed gradually increases from 0.4 to 0.7.As the groundwater head rises from 50 m to 100 m,the pore water pressure at the tunnel base increases by 141％,and the uplift displacement increases by 212％.When the ballast porosity remains constant,the growth rate of pore water pressure at the tunnel base is consistent with that of the water head,yet an increase in ballast porosity intensifies pore water pressure,further exacerbating the upheaval issue.After adopting the remediation measures involving"borehole pressure relief and grouting consolidation",the peak pore water pressure at the tunnel base is reduced by 79.7％,and the peak uplift displacement is reduced to 0.08 mm,substantially mitigating the upheaval problem.The proposed multi-scale simulation method serves as a reference for similar studies.
关键词
铁路隧道/列车动载/地下水/流固耦合/道床隆起病害/多尺度模拟
Key words
Railway tunnel/Train vibration/Groundwater/Fluid-structure coupling/Ballast bed upheaval defect/Multi-scale simulation
维普
万方数据