隧道衬砌厚度不足的健康判据试验研究

针对目前隧道健康诊断指标判据不统一的现状，采用室内相似模型试验，结合实际工程实例，研究了隧道支护结构衬砌减薄状态下围岩与支护结构破坏规律与极限承载能力，得出了隧道支护结构在相应的受力状态下健康状态判据。结果表明：隧道衬砌支护结构的位移特征以拱肩的压入和拱顶的挤出为主，随着拱顶衬砌支护结构减薄量的增加，支护结构衬砌与围岩之间的接触应力逐渐减小，结构的承载能力逐渐下降，隧道拱顶部位的位移增加，其柔性逐渐增大，隧道拱顶内侧被压溃，外侧受到拉力作用而开裂，随后隧道拱腰和边墙出现裂纹，最后逐渐扩展贯通；隧道承载力曲线呈现明显的“S”型，据此可以划分为承载力缓慢退化阶段、快速退化阶段和退化完成阶段，相对应的阶段可以划分为隧道结构的健康等级与级别，为工程应用提供了参考依据

Experimental research on tunnel health criterion of deficiency in lining thickness

In the light of the not unified present situation of the tunnel health criterion, using lab similar model test and combining with engineering practice, the failure law and ultimate bearing capacity of surrounding rock with supporting structure in the state of deficiency in lining thickness are studied; and the health criterion under corresponding force state is concluded. The results show that the displacement character of lining is spandrel inpressing and vault extruding; contact stress decreases gradually between lining and surrounding rock; structure bearing capacity gradually decreases with the deficiency in thickness increasing; with the displacement increasing and the structural flexibility increases gradually; the inside vault was crushed and the outside crazed as tension action; subsequently, the hance and side wall appear cracks and propagation and coalescence at last. The results show that the bearing capacity curve expresses S-shaped characteristics; it can be divided into slow, fast and complete degradation basis on the variety of velocity; and it is uniform to the health grades and levels of tunnel structures so as to provide reference for engineering application