岩溶区隧道衬砌结构力学性能的影响因素

Investigating the Factors Influencing the Mechanical Behavior ofTunnel Lining Structures in Karst Regions

为了探究岩溶区隧道开挖过程中隧道衬砌结构受力性能的影响因素,基于有限元软件,研究分析了隧道衬砌结构力学性能的主要影响因素,其中着重研究溶洞尺寸变化、隧道衬砌结构净距的变化、所处位置及形状变化等因素下隧道衬砌结构的受力与变形。结果表明:通过有无溶洞的研究分析表明,隧道衬砌结构附近有溶洞时,会导致隧道衬砌结构的受力和变形改变,且溶洞与隧道间的净距越大,衬砌结构的位移越小;溶洞与隧道衬砌结构的净距相同时,溶洞尺寸越大,隧道衬砌结构的位移也越大;溶洞高跨比越大,衬砌内力值越大,当高跨比为5时,衬砌内力值达到最大;当高跨比越偏离1时,衬砌变形越大,当高跨比为0.2时,衬砌变形最大;当溶洞直径大于0.6D,隧道与溶洞间距小于0.3D,溶洞高跨比为5或0.2时,溶洞对隧道结构力学性能的影响较为显著,此时衬砌结构的最不利点位于拱脚与拱底之间且最不利点发生塑性破坏。

In order to explore the influencing factors of the mechanical properties of tunnel lining structures during tunnel excavation in karst areas,based on finite element software,the main influencing factors of the mechanical properties of tunnel lining structures were studied and analyzed,with a focus on the stress and deformation of tunnel lining structures under factors such as changes in cave size,changes in net distance from tunnel lining structures,and changes in location and shape.The results show that through research and analysis on the presence or absence of karst caves,the presence of karst caves near the tunnel lining structure can cause changes in the stress and deformation of the tunnel lining structure,and the larger the net distance between the karst caves and the tunnel,the smaller the displacement of the lining structure;When the net distance between the karst cave and the tunnel lining structure is the same,the larger the karst cave size,the greater the displacement of the tunnel lining structure;The larger the height to span ratio of the karst cave,the greater the internal force value of the lining.When the height to span ratio is 5,the internal force value of the lining reaches its maximum;When the height to span ratio deviates from 1,the deformation of the lining increases.When the height to span ratio is 0.2,the deformation of the lining is the largest;When the diameter of the karst cave is greater than 0.6D,the distance between the tunnel and the karst cave is less than 0.3D,and the height to span ratio of the karst cave is 5 or 0.2,the influence of the karst cave on the mechanical properties of the tunnel structure is more significant.At this time,the most unfavorable point of the lining structure is located between the arch foot and the arch bottom,and the most unfavorable point undergoes plastic failure.