泥岩隧道仰拱长期稳定性分析——以新疆达坂地质区某隧道为例  

Analysis of Long-term Stability of Mudstone Tunnel Invert—Case Study of a Tunnel in Daban Geological Zone in Xinjiang

作　　者：司宁虎 赵春鹏 常洲 晏长根[1] 来弘鹏[1] 鲁志方 谢万烨 SI Ninghu;ZHAO Chunpeng;CHANG Zhou;YAN Changgen;LAI Hongpeng;LU Zhifang;XIE Wanye(School of Highway,Chang′an University,Xi′an 710064;Henan Transport Investment Group Co.,Ltd.,Zhengzhou 450016;Gansu Luqiao Highway Investment Co.,Ltd.,Lanzhou 730030)

机构地区：[1]长安大学公路学院,西安710064 [2]河南交通投资集团有限公司,郑州450016 [3]甘肃路桥公路投资有限公司,兰州730030

出　　处：《现代隧道技术》2023年第6期199-210,共12页Modern Tunnelling Technology

基　　金：国家自然科学基金(51978064);甘肃省交通运输厅科技项目(2023-12);甘肃省科技厅重点研发计划(21YF5FA002).

摘　　要：以新疆达坂地质区某隧道为例,分析泥岩隧道仰拱的长期稳定性。通过基于隧道岩体结构、岩块强度和长期变形监测数据的分析,运用H-B强度准则和BP神经网络算法获取监测隧道岩体的力学和蠕变参数。借助FLAC 3D软件内置的CPOWER模型,建立典型断面的数值模拟模型,以分析泥岩流变效应下不同衬砌支护强度和仰拱曲率半径对隧道仰拱运营期稳定性的影响。结果表明:考虑泥岩流变时,隧道的主要变形是仰拱中心的隆起。初次增大支护强度或减小仰拱曲率半径对改善隧道结构的受力、控制围岩变形以及加快围岩的稳定都产生显著效果;然而,随着支护强度持续增大或仰拱曲率半径持续减小,这种控制效果逐渐减弱。当将支护强度从I16工字钢逐渐增大到双层拱架时,仰拱中心的隆起量仍然有11.14 mm;而将仰拱曲率半径从16 m减小到14 m时,仰拱中心的隆起量从33.7 mm减小到3.37 mm,最终的位移满足隧道后期运营的要求。减小仰拱曲率半径比增大支护强度更能有效地从根本上控制仰拱中心的隆起,同时使围岩和支护结构的受力更加均匀;在施工阶段适当减小仰拱曲率半径后,隧道已处于相对平衡状态,流变效应对隧道的应力状态影响不大。By taking a tunnel in the Daban geological zone in Xinjiang for example,the long-term stability of mud⁃stone tunnel invert has been analyzed.After analysis of the tunnel rock mass structure,rock strength and long-term deformation monitoring data,the mechanical parameters and creep parameters of the monitored tunnel rock mass have been obtained by using the H-B strength criterion and BP neural network algorithm.By using the CPOWER model built in the FLAC 3D software,the numerical simulation model for typical section has been created,so as to analyze how various lining support strengths and invert radius of curvature will affect the stability of tunnel invert under the rheological effect of mudstone in the operation period.The results indicate:with mudstone rheology taken into account,the main deformation of tunnel is the heave at the center of invert.First increase of support strength or decrease of invert radius of curvature will significantly improve the stress state of tunnel structure,inhibit surrounding rock deformation and reinforce the stability of surrounding rock.However,as the support strength continues increasing or the invert radius of curvature continues decreasing,this inhibiting effect gradually becomes weaker.When the support is changed from I16 I-beam to two-layer arch frame,the center of invert still has 11.14 mm heave.When the invert radius of curvature is reduced from 16 m to 14 m,the heave at the center of invert is reduced from 33.7 mm to 3.37 mm,and the eventual displacement meets the requirements for later stage of tunnel operation.Compared with increasing the support strength,reducing the invert radius of curvature will fundamentally inhibit the heave at the center of invert,and also allow more even stress on surrounding rock and support structure.When the invert radius of curvature is properly reduced in the construction stage,the tunnel is in a relatively balanced state,and the rheologi⁃cal effect does not significantly affect the stress state of the tunnel.

关 键 词：泥岩隧道 H-B强度准则 蠕变参数反演 长期稳定性 仰拱曲率半径 

分 类 号：U452[建筑科学—桥梁与隧道工程]