地铁盾构下穿多股道铁路路基变形控制优化研究

为研究盾构下穿铁路时不同加固方案的效果,通过FLAC~(3D)数值模拟,在分析盾构参数对地表沉降影响的基础上,对比研究D型梁加固和管棚注浆加固2种股道加固方案的特点,得到如下结论:地层损失率越低、盾构密封舱内压力越大,地表沉降越小,针对不同工程,应对比选取最佳密封舱内压力以保证整体沉降最小;D型梁的隔离作用优于管棚注浆,但其施工会对股道造成较大扰动;D型梁加固具有一步到位的效果,后期安全系数更高,复杂工程中,D型梁的适用性强于管棚注浆;管棚注浆和D型梁2种加固方案,管棚注浆的经济性和可操作性更强,2种股道加固方案都满足变形要求时,宜优先采用管棚注浆加固;管棚注浆无法满足股道变形要求时,宜考虑D型梁加固。

Study on Optimized Deformation Control of Shield Tunneling Crossing under Railway Subgrade

In order to study the effect of different reinforcement schemes to allow the shield tunneling passing under the railway, the characteristics of D-type beam reinforcement and pipe-shed grouting reinforcement are compared through FLAC~(3 D) numerical simulation based on the analysis of the influence of shield parameters on the ground settlement. The following conclusions are obtained: The lower the loss rate of the formation, the greater the pressure of the shield chamber and the smaller the surface settlement. For different projects, the optimal sealing chamber pressure should be selected to ensure the minimum settlement. The isolation effect of the D-type beam is better than that of the pipe shed, but its construction may cause large disturbance to the channel. The D-type beam reinforcement has one-step effect, and the safety factor is higher in the later stage. In complex engineering, the applicability of D-type beam is stronger than that of pipe shed. Of the two kinds of reinforcement schemes of pipe shed grouting and D-beam, the economical efficiency and operability of pipe shed grouting is stronger. Of the two kinds of reinforcement schemes, the pipe shed grouting has higher economical efficiency and operability. When both kinds of reinforced road reinforcement schemes meet the deformation requirements, the pipe shed grouting reinforcement should be prioritized. When the pipe shed grouting cannot meet the deformation requirements of the strand, the D-type beam reinforcement should be applied.