【摘要】 砂卵石地层作为一种典型的力学性质不稳定地层,因其结构松散、孔隙大、黏聚力小,盾构施工风险高。而大直径盾构在全断面砂卵石地层中掘进时,因对土体扰动大,更易造成地表沉降,加大了施工难度。结合北京地铁新机场线08标某区间大直径盾构不仅要穿越全断面砂卵石地层又要近距连续下穿丰双、大李铁路实例,从设备适应性改造、试验段掘进分析、加固措施、参数控制、现场实测等方面论述了砂卵石地层大直径盾构顺利掘进并且有效控制地面沉降的风险控制技术。更多还原

【Abstract】 Because of loose structure,large porosity and low cohesion,sandy gravel stratum is a stratum with unstable mechanical properties and high risk of shield construction. When the large diameter shield tunnels in the full-face sandy gravel stratum,it is more likely to cause surface settlement due to large disturbance to the soil,which increases the construction difficulty. Based on the practical project that large diameter shield not only passes through full section sandy gravel stratum,but also crosses under Fengshuang and Dali Railway in close distance continuously of Beijing Metro New Airport Line 08 section,this paper discusses the risk control techniques for successful excavation and effective control of surface subsidence and railway settlement in sandy gravel stratum from the aspects of equipment adaptability,analysis of test section monitoring,reinforcement measures,parameter control and field monitoring.更多还原