Stability reserve of loess highway tunnel under high ground stress(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2016年03期
- Page:
- 33-40
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Stability reserve of loess highway tunnel under high ground stress
- Author(s):
- HUANG Jun; DANG Fa-ning; QIN Yuan; GUO Chan-juan
- (1. School of Earth Science and Engineering, Xi’an Shiyou University, Xi’an 710065, Shaanxi, China; 2. School of Civil Engineering and Architecture, Xi’an University of Technology, Xi’an 710048, Shaanxi, China; 3. School of Water Resources and Hydro-electric Engineering, Xi’an University of Technology, Xi’an 710048, Shaanxi, China; 4. Northwest Electric Power Design Institute, China Power Engineering Consulting Group Co. Ltd., Xi’an 710075, Shaanxi, China)
- Keywords:
- tunnel engineering; loess highway tunnel; deformation resistance; stability reserve; confining pressure unloading; safety factor
- PACS:
- U451
- DOI:
- -
- Abstract:
- For a more comprehensive and accurate quantitative assessment on loess tunnel stability under high ground stress, an analytical method via considering stress mechanical properties of materials’ deformation resistance and strength reserve was introduced. Through the triaxial test results in Q3 loess samples, this paper proposed the hyperbolic stress-strain model of undisturbed loess to explore the stability of loess tunnel reserves under high ground stress. By considering the coupling effect of strength resistance and deformation resistance of undisturbed loess, a mapping relation reflecting the stability state of any point of the surrounding rock was established, and the loess tunnel limit state was explored. By using unloading confining pressure test to analog loess tunnel excavation process, the change of the strength resistance and deformation resistance of loess was further studied. Besides, based on the results of the confining pressure unloading test in Q3 loess sample, it fitted the change law of strength, elastic modulus and Poisson’s ratio in the unloading process. Finally the safety factor of loess tunnel was calculated, and the proposed method was applied to a loess tunnel in Pingding to Yangqu expressway in Shanxi. The results show that it is able to get closer to the real deformation field by the hyperbolic model, and to better reflect the stability of loess tunnel. The evaluation results in this method are more consistent with the on-site monitoring conclusions.
Last Update: 2016-06-12