Study of Defect Distribution Regularity in Existing Tunnels
and the Classification of Tunnel Environments
（1 Department of Civil Engineering, Southwest Jiaotong University, Emei 614202;
2 Key Laboratory of Transportation Tunnel Engineering, Ministry of Education,
School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031）
Abstract：
For existing tunnels, there are many hazards that affect the durability of the tunnel structure. Based on a survey of nearly 2000 tunnels located in the Chengdu Railway Bureau, it was determined that construction time, conditions of the surrounding rock, classification of the environment, and lithology of the surrounding rock are the obvious factors affecting the distribution regularities of tunnel defects. This study is focused on the prevention of defects in surrounding rock of grades IV and V, the areas with developed ground water, and weak rock masses. Through field sampling and analysis, the human factors related to tunnel defects are discussed in terms of design, construction, and operation maintenance. Because of the particularity of tunnel structures, the current classification of environment is no longer suitable for tunnels and a new classification for general tunnel environments is discussed considering three basic indicators: the development of ground water, humidity inside the tunnel, and the lithology of the surrounding rock. Some countermeasures are put forward.
.Study of Defect Distribution Regularity in Existing Tunnels
and the Classification of Tunnel Environments[J] MODERN TUNNELLING TECHNOLOGY, 2013,V50(4): 35-41
2013, Vol. 50 