北疆侏罗系与白垩系泥质砂岩地层TBM卡机研究

Study on TBM Jamming Problems in Jurassic and Cretaceous Argillaceous Sandstone Strata in Northern Xinjiang

  • 摘要: 为研究新疆北部地区侏罗系与白垩系泥质砂岩地层中TBM卡机问题,通过开展岩石力学试验与流变试验获取相关物理力学参数,并进行TBM施工期的数值计算。研究结果表明:侏罗系泥质砂岩的强度、弹性模量和内摩擦角远大于白垩系泥质砂岩的对应值,二者的泊松比、黏聚力相差不大。在持续荷载作用下,侏罗系泥质砂岩的强度会随时间推移显著降低,同时变形会逐步增大;TBM停机后,盾壳所受摩擦阻力会经历缓慢增长到快速增长最终趋于稳定的过程。相较于侏罗系泥质砂岩地层,TBM在白垩系泥质砂岩地层中停机时,盾壳与围岩接触的时间更早,卡机事故发生的时间也更早,白垩系泥质砂岩的蠕变特性比侏罗系泥质砂岩的蠕变特性更显著。TBM停机后,盾壳越长,盾壳所受摩擦阻力越大;超挖量越大,盾壳所受摩擦阻力越小。根据数值计算结果,可以得出各工况下TBM预防卡机的额定推力最小设计值以及安全停机时间。

     

    Abstract: In order to study the TBM jamming issues in the Jurassic and Cretaceous argillaceous sandstone strata in northern Xinjiang, rock mechanical and rheological tests were conducted to obtain relevant physical and mechanical parameters, followed by numerical calculations regarding TBM construction. The results show that the strength, elastic modulus, and internal friction angle of Jurassic argillaceous sandstone are significantly higher than those of Cretaceous argillaceous sandstone, while their Poisson's ratio and cohesion values are similar. Under sustained loading,the strength of Jurassic argillaceous sandstone decreases significantly over time, and the deformation gradually increases. After TBM shutdown, the frictional resistance on the shield shell will experience a process of slow growth,rapid growth, and eventual stabilization. Compared to Jurassic argillaceous sandstone, TBM shutdown in Cretaceous argillaceous sandstone occurs earlier, with the shield-rock contact time and jamming accidents happening sooner.The creep characteristics of Cretaceous argillaceous sandstone are more pronounced than those of Jurassic argillaceous sandstone. After TBM shutdown, the longer the shield shell, the greater the frictional resistance, and the greater the over-excavation, the smaller the frictional resistance. Based on numerical results, the minimum design values for the rated thrust of TBM to prevent jamming and the safe shutdown time under different working conditions are derived.

     

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