复合锚杆隔离桩隔离技术的理论与实践

Theory and Practice on Isolation Technique of Multi-anchor Isolation Pile

通过对发明的"复合锚杆隔离桩"技术在北京地铁国贸桥站建设过程中首次应用的全过程进行了系统的回顾与总结,从理论和实践两方面对该项技术进行了探讨。研究表明:(1)复合锚杆桩在垂直方向上又不受力,其连成一片则发挥了隔离墙的作用;(2)锚杆桩体与注浆加固后的桩周土结合成一体,保证了原桥桩摩阻力不受损失,提高了隧道开挖体的稳定性;(3)高压注浆与锚杆安装工艺的结合,使桩侧及桩端阻力、土层承载力及变形模量等得到了提高,形成的隔离桩墙具有较高的侧向承载能力。

The overall process of the first application of ＂multi-anchor isolation pile＂ technique in Beijing subway construction at World Trade Center bridge station is systematic reviewed and summarized. Simultaneously, this technique is deeply discussed from the aspects of theory and practice. The research result shows that （1） multi-anchor pile does not bear force in vertical direction, while their assemblies can play a role as isolation wall; （2） the soil around pile is integrated into a whole system by reinforcement of anchor pile and grouting, subsequently it preserved the frictional resistance of original bridge pile and increased the stability of excavation tunnel; （3） the combination of high-pressure grouting and installation technology of anchor increased the resistances of side and pile end, soil bearing capacity and soil deformation modulus. The formative isolation pile and wall possess relatively high side bearing capacity.