软硬不均地层复合盾构的研究及掘进技术

STUDY ON COMPOSITE SHIELD AND CONSTRUCTION TECHNIQUE IN COMPLEX UNEVEN STRATA

针对广州地铁二号线越秀公园—三元里区间的软硬不均地层的盾构施工,提出复合盾构的设计思想,并对复合盾构的功能及技术参数进行研究,分析刀盘、刀具与地质的适应性。研究复合盾构掘进模式的原理、掘进参数及模式之间的转换技术,解决了软硬不均地层的掘进难、效率低、成本高、地层变形不易控制等技术难题。为了有效地控制掘进方向和盾构姿态,分析盾构掘进方向偏差的原因,研究相应的控制方法,达到了防止管片裂损和控制错台的目的。为防止黏性地层掘进的“泥饼”现象及富水地层掘进的“喷涌”现象的发生,研究相应的渣土改良技术。通过盾尾环形间隙同步注浆技术的研究及采用可靠的技术措施,并加强施工监测,及时变更掘进参数,控制地层的变形,确保京广铁路正常运营及临近建构筑物的安全。

Based on the shield tunnel construction in complex strata in Guangzhou second tunnel line,an idea of composite metro shield machine is brought forward,and the shield function and its technique parameter are studied and analyzed with the adaptability of cutterhead,cutter,geological condition.The excavation mode theory,the transition between different excavation modes and different excavation parameters are studied,and some technical problems,such as the excavation difficulties problem,the low efficiency problem,the high cost problem,the trouble in distortion control of the shield excavation,are solved.Furthermore,in order to control the excavation direction of the shield more effectively and avoid the cracking and the dislocation of segment,the reason of direction warp is analyzed;and some control methods are presented.In order to avoid mud in clay strata and water gushing in water-enriched geology,the technique of sediment improvement is studied.In order to guarantee the security of nearby building and the routine traffic condition of Beijing—Guangzhou Railway,some credible techniques,such as synchronous grouting technique,construction monitoring technique,the variation of excavation parameters to control tunnel deformation,are adopted.