渝黔铁路极高地应力隧道施工控制技术

Construction Control Technique for High Geostress Tunnel in ChongqingGuizhou Railway

研究目的:渝黔铁路天坪隧道长为13.928 km,是全线控制性工程,地质情况极为复杂,其中进入斜井施工后,发现出现初支变形严重、底板隆起等现象,经实测判定该地段为极高地应力区,易发生大变形现象。因此,应研究安全可靠的施工措施完成高地应力区段的施工。研究结论:通过在天坪隧道的施工实践,总结出以下施工措施确保极高地应力施工安全质量:(1)应增加预留变形量,确保高地应力软岩变形后不侵限;(2)应加强监控量测,预测围岩变形量,以便指导施工;(3)应及时调整支护参数,动态适应围岩;(4)当初支变形速率7 d连续小于1 mm/d时,及时施作二次衬砌混凝土;(5)本研究结论可为类似高地应力隧道施工提供参考与借鉴。

Research purposes： Tianping tunnel of Chongqing- Guizhou railway is 13. 928 km long, and is the key workpoint. The geostress conditions of Tianping tunnel is very complicated. When entering the construction of inclined shaft, the deformation of initial supports and baseboard was serious, by measuring the crustal stress, the inclined shaft was judged extreme- high geostress zone, which was apt to effect large deformation. So the problem was what reliable construction methods was adopted to safely pass the high geostress zone.Research conclusions：By the construction practice of Tianping tunnel, the paper summarized the following construction methods to guarantee the safety and quality of high geostress zone ： （ 1 ） Increase the deformation allowance to guarantee that the deformation of soft rock under high stress was not not beyond limit. （2）Strengthen monitoring measurement and predict the deformation of the surrounding rock to guide the construction. （3） Timely adjust support parameter and dynamically adapt the surrounding rock. （4）Timely cast the secondary linings, when deformation rate was continuously less than 1 mm/d for seven days. （5）The research conclusion can provide references and lessons for constructions of similar high geostress tunnels.