Construction time of secondary lining of large span loesstunnel under viscoelasticity condition(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2021年5期
- Page:
- 86-95
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Construction time of secondary lining of large span loesstunnel under viscoelasticity condition
- Author(s):
- LUO Yanbin; CHEN Jianxun
- (School of Highway, Changan University, Xian 710064, Shaanxi, China)
- Keywords:
- tunnel engineering; large span loess tunnel; primary support; secondary lining; creep; construction time
- PACS:
- -
- DOI:
- -
- Abstract:
- To study the best construction time of secondary lining for largespan loess tunnel,based on the Dunliang Tunnel in Shenfu (Shenmu to Fugu) Highway, the method of field test, numerical simulation and theoretical analysis was used. Firstly, the deformation laws of the tunnel vault settlement were obtained by onsite measurement. Then, the calculation method of optimal construction time based on the safety critical state of secondary lining was proposed. Secondly, according to the theoretical formula of surrounding rock mass deformation under viscoelastic condition, combining with the field monitoring data, the rheological parameters of Kelvin model were obtained. Finally, combined with the calculation method of optimal construction time and Kelvin rheological model proposed in this paper, the optimal construction time of secondary lining of largespan loess tunnel under viscoelastic condition was studied by numerical simulation. The results show that settlement of the vault experienced three deformation stages, rapid deformation stage, sustained deformation stage and slow deformation stage, and the settlement value of each stage was 67.7%, 21.7% and 10.6% of the maximum settlement value, respectively. The viscosity coefficients η of creep parameter viscous element in Kelvin constitutive model is 2.75×1014 kPa·s, the elastic modulus E1 of the spring element in parallel with the viscous element is 138.3 MPa, and the elastic modulus E2 of spring element in parallel with viscous element is 321.5 MPa. The best construction time of secondary lining in deep buried section of grade Ⅴ surrounding rock mass of largespan highway loess tunnel is when the vault settlement rate of primary support is less than 0.3 mm/d. 10 tabs, 12 figs, 27 refs.
Last Update: 2021-09-30