家竹箐隧道煤系地层段病害特征及成因分析

家竹箐隧道自1997年建成运营以来,分别于2003年和2013年在煤系地层段发现有衬砌开裂、剥落、掉块、渗水等病害。对病害原因进行调查、分析,主要结论及建议如下:1)隧道的2次病害均发生在大变形处理与非处理的过渡段,病害以衬砌裂损为主;2)隧道区地应力是持续发展、聚集、提高的,既有大变形段的小里程端是地应力的主要聚集、作用区;3)区域构造产生的地应力作用是造成隧道病害的主要原因,围岩软弱、结构偏弱是次要原因;4)预计构造运动造成该隧道煤系地层段地应力的聚集、作用并导致病害的产生存在着6~10年的周期性;5)建议类似地质条件下软质岩高地应力大变形隧道设计及施工加强措施的地段应扩展到大变形两侧一定范围。

Analysis on Characteristics of and Causes for Defects of Coal Measure Section of Jiazhuqing Tunnel

Defects, such as cracks, spalling, falling and water seepage, occurred to the lining of the coal measure section of Jiazhuqing tunnel in 2003 and 2013 respectively. In the paper, the characteristics of and causes for the defects of the tunnel are investigated and analyzed. Conclusions drawn and advices proposed are as follows: 1) The transition section between the large deformation controlled section and the large deformation un controlled section is the main defect section, with the lining cracks as the main defect; 2) The ground stress in the tunnel region develops, concentrates and increases continuously, with the section at the small mileage side of the serious deformation section as the main ground stress concentration and action section; 3) The ground stress is the main cause for the tunnel defects, with the weak surrounding rock and the weak tunnel structure as the secondary causes for the tunnel defects; 4) The tunnel defects in the coal measure section caused by the concentration and action of the ground stress are expected to have a 6~10 year cyclic period; 5) It is suggested that the scope of the strengthening of the weak rock section in similar geological conditions should be extended.