Model Test Study on In-service Karst Highway Tunnel

 

Rao Jun-ying1*, Fu He-lin1, Liu Yun-si1, Yin Quan1, Zhang Hai-ming2

* Corresponding author; rao-ale@163.com
1. School of Civil Engineering, Central South University, Changsha, Hunan 410004, China
2. College of Civil Engineering and Mechanics, Xiangtan University, Xiangtan, Hunan 411105, China

 

 ABSTRACT

This article, based on the Baishan Tunnel, optimized the selection for the similar materials of karst caves filler, surrounding rock and lining,carried out a study on similar model test to in-service karst highway tunnel with the geometric similarity ratio of 1/40. Then, the distribution law and trend of surrounding rock pressure were revealed. Subsequently, the mechanical behaviors of the surrounding rock were discussed after endowing some treatment to these caves. The results show that: ?the ? surrounding rock from Baishan Tunnel can be properly simulated by the mixture of barite powder, plaster powder and cement with the proportion of 1:12:2; ?applying the lower elastic modulus material, compared to surrounding rock, to fill those karst caves, which will lead to greater compression deformation under the same load; ?when these caves were laid nearby the spandrel, haunch and springing, karst caves will cause unsymmetrical pressure to tunnel lining. Although, those caves have been filled, which should be attached great importance during the tunnel service.

Keywords: in-service tunnel; highway tunnel; karst cave; similar model test

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