公路隧道衬砌厚度不足对衬砌安全性影响

针对Ⅲ级和Ⅳ级围岩两种不同的支护形式, 建立衬砌厚度不足计算模型。在有无病害条件下, 比较隧道衬砌各位置的内力和安全系数, 并根据衬砌厚度不足病害程度和宽度, 采用数值计算的方法, 分析公路隧道衬砌厚度不足对衬砌安全性的影响。分析结果表明: 隧道衬砌边墙、拱腰和拱顶的弯矩、剪力和轴力都比较大, 属于病害发生的敏感部位; 隧道衬砌出现厚度不足病害时, 安全系数显著减小; 衬砌安全系数随着病害程度的加剧, 左边墙呈线性减小, 而拱腰和拱顶呈曲线形减小; 衬砌安全系数随着病害宽度的增加, 先是显著减小, 最后又有小幅增长, 但整体呈减小趋势; 随着病害区域从边墙向拱顶转移, 衬砌受影响的范围逐渐增大。

Effect of lining thickness lack on lining safety for highway tunnel

The calculation models of lining thickness lack were set up for surrounding rock Ⅲ and rock Ⅳ. The internal forces and safety factors of tunnel lining at various locations were compared under the conditions of tunnel linings with disease and without disease. Using numerical methods, the effect of lining thickness lack caused by disease extent and range on lining safety were analyzed. Analysis result shows that the values of the bending moments, shears and axial forces at the wall, haunch and vault of lining are large, so these sections are belonging to the sensitive parts to disease. When thickness lack disease appears, the safety factor of tunnel lining significantly reduces. With the increase of disease degree, the safety factor of left wall linearly decreases, but the safety factors of haunch and vault curvily reduce. With the increase of disease width, the safety factor firstly decreases obviously and then increases in small range, but the overall trend is decrescent. With the transfer of disease region from wall to vault, the influenced region of lining increases gradually.