基于断裂力学理论的隧道衬砌开裂病害分级  

Classification of Tunnel Lining Cracking Disease Based on Fracture Mechanics Theory

作　　者：刘勇 韩宇 LIU Yong;HAN Yu(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang Hebei050043,China;Mass Transit Business Department,China Railway Design Corporation,Tianjin300143,China)

机构地区：[1]石家庄铁道大学土木工程学院,河北石家庄050043 [2]中国铁路设计集团有限公司城市轨道交通事业部,天津300143

出　　处：《中国铁道科学》2019年第3期72-79,共8页China Railway Science

基　　金：河北省高等学校科技项目(Z2012037)

摘　　要：以开裂隧道衬砌为研究对象,基于线弹性断裂力学理论,得到平面应变状态下衬砌结构Ⅰ型和Ⅱ型裂缝尖端应力场及位移场,借鉴混凝土工程经验提出隧道衬砌开裂判据;数值模拟分析不同围岩级别下衬砌结构各部位不同开裂深度时的裂缝处最大主应力、裂缝尖端应力强度因子和稳定性系数。结果表明:当衬砌拱顶开裂时,裂缝尖端主拉应力最大,衬砌结构的稳定性系数最小;当衬砌拱腰和拱脚开裂时,裂缝尖端主压应力最大,衬砌结构的稳定性系数较大;裂缝深度与裂缝尖端应力强度呈正相关关系,与稳定性系数呈负相关关系。以裂缝深度为参量(稳定性系数f)对隧道衬砌开裂病害进行分级:当f<1或主应力超过混凝土材料极限强度时,将衬砌裂缝划分为扩展中裂缝;当f≥1且主应力未超过混凝土材料极限强度,可进一步将1≤f<2,2≤f<10,f≥10时的裂缝依次划分为即将扩展裂缝、亚稳定裂缝及稳定裂缝;并反推出不同等级病害所对应的临界开裂深度。Taking the cracked tunnel lining as the research object,the stress and displacement fields at the compositeⅠ-Ⅱcrack tips of tunnel lining under plane strain state were obtained based on the linear elastic fracture mechanics theory.The criterion for tunnel lining cracking was put forward by referring to the experience of concrete engineering.The maximum principal stress at crack,the stress intensity factor and stability factor at the crack tips of lining structures at different cracking depths in different parts of tunnel lining structures under different surrounding rock grades were analyzed by numerical simulation.Results show that when the vault of lining cracks,the principal tensile stress at crack tip is the largest and the stability coefficient of lining structure is the smallest.When the hance and arch springing of lining crack,the principal compressive stress at crack tip is the largest and the stability coefficient of lining structure is larger.The crack depth is positively correlated with the stress intensity at crack tip and negatively correlated with stability coefficient.Taking the crack depth as a parameter(stability coefficient f),the crack disease of tunnel lining is classified.When f<1 or the principal stress exceeds the ultimate strength of concrete material,the lining cracks are classified as cracks in expansion.When f≥1 and the principal stress does not exceed the ultimate strength of concrete material,the cracks with 1≤f<2,2≤f<10 and f≥10 can be further classified into expansion cracks,metastable cracks and stable cracks sequentially.In addition,the critical crack depths corresponding to the classified diseases are derived reversely.

关 键 词：隧道病害 衬砌开裂 裂缝深度 稳定性系数 病害分级 断裂力学 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]