Analytical approach to the viscoelasto-plastic mechanical response of deep soft rock tunnel considring the rockbolt reinforcement effect

被引：0
|
作者：
Zhao N. [1 ]
Shao Z. [2 ]
Zheng X. [1 ]
Wu K. [2 ]
Qin S. [1 ]
机构：
[1] School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an
[2] School of Science, Xi'an University of Architecture and Technology, Xi'an
来源：
Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics | 2022年 / 54卷 / 02期
关键词：
Deep soft rock tunnel; Dilatancy; Plastic softening; Rock bolt reinforcement; Viscoelastic-plastic model;
D O I：
10.6052/0459-1879-21-447
中图分类号：
学科分类号：
摘要：
The surrounding rock of deep soft rock tunnel shows significant plastic softening and dilatancy characteristics. The ignorance of the coupling influences of these two characteristics in current studies leads to the inaccurate prediction results of tunnel deformation. In order to solve the problem, a viscoelasto-plastic calculation model of deep soft rock tunnel is established, based on the Kelvin-Voigt model and Mohr-Coulomb strength criterion. In this model, the plastic softening and dilatancy of surrounding rock are considered and the restriction effect of tunnel face is introduced as well. Furthermore, a mechanical model of rockbolt-reinforced surrounding rock is established by using the equivalent stiffness method, which takes the rockbolt reinforcement into account. Considering the relationship between plastic radius of surrounding rock and bolt length, analytical solutions for tunnel responses under the six conditions are provided. In addition, the reliability and effectiveness of the theoretical derivation are well validated by comparing numerical and analytical results. Finally, the reinforcement effect of rockbolt is discussed based on the analytical solution and a comprehensive parametric investigation is carried out, including the installation time and stiffness of rockbolt and tunnel excavation rate. Results indicate that without considering the rockbolt reinforcement effect, the excavation rate only poses the influence on the development law of early deformation of tunnel, and its influence on the final tunnel displacement can be ignored. The tunnel deformation will be greatly underestimated without considering the plastic deformation of surrounding rock, resulting in a large gap between the predicted and actual results. When the excavation rate is large, the rockbolt should be installed as earlier as possible, to ensure that the rockbolt can play an effective role inmiting surrounding rock deformation. There exists a sub-linear relationship between bolt stiffness and tunnel displacement, and the increase of rockbolt stiffness can prolong the time required for surrounding rock entering plastic deformation. The results of this paper can provide useful guidance for the similar projects. Copyright © 2022 Chinese Journal of Theoretical and Applied Mechanics. All rights reserved.
引用
收藏
页码：445 / 458
页数：13
相关论文
共 32 条
  • [1] Chu Z, Wu Z, Liu B, Et al., Coupled analytical solutions for deep-buried circular lined tunnels considering tunnel face advancement and soft rock rheology effects, Tunnelling Underground Space Technology, 94, (2019)
  • [2] Tomanovic Z., Rheological model of soft rock creep based on the tests on marl, Mechanics of Time-dependent Materials, 10, pp. 135-154, (2006)
  • [3] Zhang Y, Shao JF, Xu WY, Et al., Creep behaviour and permeability evolution of cataclastic sandstone in triaxial rheological tests, European Journal of Environmental and Civil Engineering, 19, pp. 496-519, (2015)
  • [4] Bui TA, Wong H, Deleruyelle F, Et al., Analytical modeling of a deep tunnel inside a poro-viscoplastic rock mass accounting for different stages of its life cycle, Computers and Geotechnics, 58, pp. 88-100, (2014)
  • [5] Wu K, Shao Z., Study on the effect of flexible layer on support structures of tunnel excavated in viscoelastic rocks, Journal of Engineering Mechancis, 145, 10, (2019)
  • [6] Fahimifar A, Monshizadeh TF, Hedayat A, Et al., Analytical solution for the excavation of circular tunnels in a visco-elastic Burger's material under hydrostatic stress field, Tunneling Underground Space Technology, 25, pp. 297-304, (2010)
  • [7] Shao Zhushan, Wu Kui, Yuan Yuan, Theoretical investigation on rock rheological characteristics in variable temperature field, Chinese Journal of Applied Mechanics, 35, 5, pp. 962-968, (2018)
  • [8] Zhang Dingli, Sun Zhenyu, Hou Yanjuan, Tunnel support structure system and its synergistic effect, Chinese Journal of Theoretical and Applied Mechanics, 51, 2, pp. 577-593, (2019)
  • [9] Guan Z, Jiang Y, Tanabashi Y, Et al., A new rheological model and its application in mountain tunnelling, Tunneling Underground Space Technology, 23, pp. 292-299, (2008)
  • [10] Wu Kui, Shao Zhushan, Qin Su, Study on the interaction mechanism between surrounding rock and liner with highly deformable elements in squeezing tunnels, Engineering Mechanics, 37, 11, pp. 185-194, (2020)
1234