隧道软弱围岩变形时效性表征及影响因素分析  

Characterization and Influence Factors of the Time-Dependent Behaviors of Soft Surrounding Rock

作　　者：王智超[1,2] 周黎[1] 张学兵[1] 沈明燕[3] WANG Zhichao;ZHOU Li;ZHANG Xuebing;SHEN Mingyan(Hunan Key Laboratory of Geomechanics and Engineering Safety,Xiangtan University,Xiangtan 411105;Hunan Province Key Laboratory of Engineering Rheology,Central South University of Forestry and Technology,Changsha 410004;School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201)

机构地区：[1]湘潭大学岩土力学与工程安全湖南省重点实验室,湘潭411105 [2]中南林业科技大学工程流变学湖南省重点实验室,长沙410004 [3]湖南科技大学土木工程学院,湘潭411201

出　　处：《现代隧道技术》2018年第4期146-154,共9页Modern Tunnelling Technology

基　　金：国家自然科学基金(51308485);湖南省教育厅优秀青年项目(17B260);湖南省自然科学基金(2016JJ2133;12JJ4006)

摘　　要：为研究隧道开挖过程中围岩变形的时效特性,文章构建了能够反映岩石时间相依特性的弹粘塑性模型,且基于软弱砂岩单轴压缩率敏性室内试验获得了模型参数,并将模型通过UMAT子程序成功嵌入到有限元软件ABAQUS中,结合杭长高速公路云峰寺隧道围岩变形监测数据反演确定了本构模型综合参数。对该隧道K106+995断面围岩流变变形三维数值分析结果表明:锚喷厚度依次取15 cm、20 cm、25 cm和30 cm时,其拱顶沉降相对前者依次降低了2.53%、2.11%和1.99%,但对围岩水平收敛变化影响相对较弱;当锚喷厚度增加到一定值后,作用已经很微弱;当上台阶以2 m/d和3 m/d的开挖速度从K106+986断面推进27 m时,K106+986开挖面洞周围岩变形稳定经历的时间则分别为13.5 d和9 d,拱顶处围岩变形分别增加了5.77 mm和4.09 mm,相差1.68 mm,说明开挖速度在短期内所引起的变形之差比较明显,而对围岩变形的长期影响较小。To study the time-dependent deformation characteristics an elastic-viscoplastic constitutive model is established to predict the of surrounding rock during tunnel excavation, time-dependent behavior of soft surrounding rock. The model parameters of the proposed constitutive model are identified by an indoor uniaxial compression rate sensitivity test for weak sandstone, and the elastic-viscoplastic constitutive model is implemented using the finiteelement software ABAQUS by the UMAT subroutine. The modified comprehensive model parameters of the constitutive model are obtained based on the inverse analysis of deformation monitoring data for the surrounding rock of the Yunfeng Temple tunnel on the Hang-Chang highway. The numerical analysis results of the 3D rheological deformation of the surrounding rock of a tunnel on the Hang- Chang highway at the K106＋995 section shows that the crown settlements are reduced by 2.53%, 2.11% and 1.99%, respectively, at thicknesses of anchor and shotcreting support of 15 cm, 20 cm, 25 cm and 30 cm, and the effect on the horizontal convergence of the tunnel is relatively slight and very slight at certain thicknesses. When the upper bench section is driven forward 27 m from K106＋986 at a driving speed of 2 m/d and 3 m/d, the deformation times of the surrounding rock around the holes are 13.5 d and 9 d, respectively. During the excavation process, the crown deformations increase by 5.77 mm and 4.09 mm, respectively. Results show that the excavation speed has an obvious influence on deformation in the short term while it has little influence in the long term.

关 键 词：隧道工程 软弱围岩 变形 弹粘塑性本构 率敏性 锚喷厚度 开挖速度 

分 类 号：TU456.1[建筑科学—岩土工程]