为研究山区深埋隧道塌方机理,以乐西高速大凉山2号隧道工程为工程背景,采用有限元软件MIDAS GTS NX模拟塌方段围岩稳定性,对隧道塌方成因进行分析,提出相应处治措施,并通过现场监测验证其合理性。结果表明：该段处于泥砂岩地层与灰岩地层交界处,节理裂隙发育,岩体松散破碎,裂隙水的渗流使围岩稳定性降低导致隧道塌方；塌方段拱顶沉降量为177.02 mm,拱腰水平收敛量为68.21 mm,围岩变形量较大；围岩塑性区出现在上中台阶掌子面,应变最大值为3.027×10-2,将发生塑性破坏。采用大管棚＋双层超前小导管补强支护对塌方段进行加固,处治效果良好,为后续类似工程提供指导借鉴。
In order to study the collapse mechanism of deep buried tunnel in mountainous area, taking the Daliangshan No.2 tunnel project of Lexi Expressway as the engineering background, the finite element software MIDAS GTS NX was used to simulate the stability of surrounding rock in the collapse section, the cause of tunnel collapse is analyzed, the corresponding treatment measures are put forward, and the rationality is verified by field monitoring. The results show that this section is located at the junction of argillite stratum and limestone stratum, where joints and fissures develop and rock mass is loose and broken. Seepage of fissure water reduces stability of surrounding rock ,which leads to tunnel collapse. The subsidence of the vault in the collapse section is 177.02mm, and the horizontal convergence of the arch waist is 68.21mm. The surrounding rock deformation is large. The plastic zone of surrounding rock appears on the palm surface of the upper and middle steps, and the maximum strain is 3.027×10-2, which means that plastic failure is more likely. The large pipe shed and double-layer advanced small pipe reinforcement support were adopted to reinforce the collapse section, and the treatment effect was good, which provided guidance and reference for the subsequent similar projects.
苗景川,肖鹏帅,洪富义,等. 大凉山深埋软弱围岩公路隧道塌方机理及处治措施[J]. 科学技术与工程, 2023, 23(30): 13143-13149.
Miao Jingchuan, Xiao Pengshuai, Hong Fuyi, et al. Collapse mechanism and treatment measures of deep buried soft surrounding rock highway tunnel in Daliang Mountain[J]. Science Technology and Engineering,2023,23(30):13143-13149.