复杂地质铁路隧道敞开式TBM施工挑战及思考

Challenges and Some Thoughts on Open-TBM Construction in a Railway Tunnel with Complex Geologies

为降低复杂地质条件下敞开式TBM施工极易发生的工期延误、成本大幅增加、环保事故等风险,以高黎贡山隧道敞开式TBM施工为背景,结合铁路隧道定额体系和规范标准,针对施工过程中遭遇的卡机、初期支护背后脱空、开挖断面不足、隧道清渣排水困难、弃渣松散系数选择不准、掘进指标不合理以及污水处理能力不足等影响较大的问题,从地质、设计和施工方面进行分析思考,提出以下建议:(1)完善TBM法隧道地质勘察具体要求,明确地质特性,提高TBM设备设计针对性;(2)结合TBM施工特点,优化围岩分级修正项,设置合理预留变形量、增强隧道断面尺寸、支护参数的适应性;(3)弃渣松散系数合理范围为1.5~1.9,复杂地质隧道敞开式TBM施工进度指标结合高黎贡山隧道的TBM利用率14.66%考虑;(4)污水处理综合考虑多种因素,保护生态环境;(5)规范标准与定额体系相结合,及时调整完善,提高概算与进度、成本的匹配性。

During open-tunnel boring machine(TBM)tunneling in complex geologies,the risks of construction period delay,cost increase,and environmental accidents are encountered easily.Accordingly,based on relevant railway tunnel quota systems and standards,some problems such as TBM jamming,hollows behind the primary support,insufficient excavation cross section,difficulty in tunnel cleaning and drainage,inaccurate spoil looseness coefficient selection,unreasonable tunneling indicators,and insufficient sewage treatment capacity encountered during TBM tunneling in Gaoligongshan tunnel are analyzed from the perspective of geology,design,and construction.Some suggestions are proposed as follows.(1)The specific requirements of the geological survey for the TBM tunnel and targeted design for TBM equipments must be improved,and the geological characteristics must be clarified.(2)According to the construction characteristics of TBM,the surrounding rock classification correction items must be optimized,reasonable reserved deformation value must be set,and adaptability of the tunnel cross section size and support parameters must be enhanced.(3)The reasonable range of the slag-loosening coefficient is 1.5~1.9,and construction progress indicators of open TBM must consider the value of 14.66%in the Gaoligongshan tunnel.(4)Multiple factors must be considered for sewage treatment to protect the environment.(5)Both the standards and quota systems must be considered,and the construction must be adjusted in time to improve the matching of budget estimates with schedule and cost.