Progressive deterioration of tunnel lining in seasonal freezingzone and its engineering influence(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2021年6期
- Page:
- 63-72
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Progressive deterioration of tunnel lining in seasonal freezingzone and its engineering influence
- Author(s):
- WU Yimin1; XU Peng1; HUANG Le2; CAI Zhiyan1; HU Kaixun1
- （1. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China；2. Hubei Provincial Communications Planning and Design Institute Co., Ltd, Wuhan 430051, Hubei, China）
- Keywords:
- tunnel engineering; cold region tunnel; unsaturated freezethaw cycle; lining deterioration; temperature field
- PACS:
- -
- DOI:
- -
- Abstract:
- To study the influence of deterioration of concrete on secondary lining structure after several years of service in the seasonally frozen zone, based on the results of temperature field test in the tunnel, the progressive deterioration model of tunnel lining was established, and the effects of tunnel structure degradation were studied by numerical simulation. Relying on 3 tunnels with different lengths in Wushaoling Tunnel group, Gansu Province, the temperature field of the tunnels was tested by using intelligent temperature recorder and hourly monitoring frequency. The test results revealed that the tunnel lining concrete was subjected to unsaturated freezethaw cycle due to the daily alternation of positive and negative temperatures. Based on the distribution rules of freezethaw cycles in the tunnel, a calculation model was established by using the loadstructure method, in which the lining structure was progressively deteriorated, and the impact of degradation on the lining structure was analyzed. The results show that the number of daily freezethaw cycles experienced by the tunnel lining decreases with the increase of the distance from the tunnel portal, and the lining near the portal can experience hundreds of freezethaw cycles in a year, the number of freezethaw cycles experienced by lining structure decreases from lining surface in the cross section. When the lining surface experiences 138 freezethaw cycles, the lining at the radial depth of 5 cm can experience 77 freezethaw cycles. The deterioration degree of lining concrete is related to the number of unsaturated freezethaw cycles, and presents a gradually weakening distribution from the lining surface to the lining interior, and from the tunnel portal to the middle of the tunnel. With the increase of service life, the progressive deterioration of concrete changes the stress state of the structure, the control principle of the safety factor of lining changes from concrete compressive strength to concrete tensile strength. The safety factor of lining in vault decreases obviously, and the width of tensile zone in vault increases gradually. 1 tab, 16 figs, 22 refs.
Last Update: 2021-12-14