中老铁路软岩隧道溜塌机理及处治措施研究

Research on Construction Technology of Tunnel Face Slump in Soft Rock Tunnel of China-Laos Railway

以中老铁路玉磨铁路巴罗二号隧道为工程背景,对富水岩溶地区软弱围岩隧道溜塌机理及处治技术进行研究,通过建立隧道围岩溜塌力学分析模型,采用理论计算与有限元计算软件模拟相结合的方法,对隧道掌子面溜塌位置围岩和初支结构稳定性进行分析,并依据分析结果提出针对性的处治措施。结果表明:隧道溜塌位置围岩拱顶沉降值为84.7mm,拱腰水平收敛值为167.4mm,围岩变形量值较大,容易发生溜塌事故;围岩塑性区集中出现在掌子面上下台阶交界处,塑性应变最大值为6.63×10-2,掌子面发生塑性破坏风险较大;初支结构拱腰位置易出现应力集中现象,施工过程中应对此位置进行加固,防止发生失稳破坏。根据隧道施工现场实际情况,结合有限元计算结果,采用混凝土填充结合小导管补强加固处治结构对溜塌段进行处理,隧道溜塌段处治效果较好,为后续施工段相同状况的处理提供了参考。

In Laos barrow of jade grinding rail tunnel engineering ii,of rich water karst region slipped in weak rock tunnel collapse mechanism and treatment technology for research,slipped through the establishment of the tunnel surrounding rock collapse mechanics analysis model,the theoretical calculation and finite element calculation software simulation method of combining the,constraints of the tunnel to slip down position at the beginning of surrounding rock and the structural stability analysis,According to the analysis results,the corresponding treatment measures are put forward.The results show that the settlement value of surrounding rock vault is 84.7mm,and the horizontal convergence value of arch waist is 167.4mm.The deformation value of surrounding rock is large,and it is easy to collapse.The plastic zone of surrounding rock mainly occurs at the junction of upper and lower steps on the face of the face,and the maximum plastic strain is 6.63×10-2.The arch waist of the primary support structure is prone to stress concentration,which should be reinforced during construction to prevent instability failure.According to the actual situation of tunnel construction site,combined with the finite element calculation results,the treatment structure of concrete filling combined with small pipe reinforcement was used to treat the tunnel slide collapse section.The treatment effect of tunnel slide collapse section was better,which provided a reference for the treatment of the same situation in the subsequent construction section.