摘要
衬砌裂损是隧道常见的病害之一,对隧道结构及行车安全有较大影响,其表现形式主要有衬砌开裂、衬砌变形、衬砌起层剥落。以某运营高速公路隧道病害为工程背景,根据隧道地质条件、设计、施工情况、病害现状及检测结果综合分析病害产生原因,通过数值计算对既有结构的受力状态和安全性展开研究,分别提出相应的加固处治措施,在此基础上研究套拱加固方式对隧道净空富余量的影响。结果表明:(1)仰拱欠厚和衬砌强度不足的施工缺陷是造成该隧道仰拱及衬砌裂损的主要原因;(2)拆换方案能有效解决衬砌裂损及结构病害,但由于病害段围岩软弱,拆换方案对既有结构及围岩扰动大,且病害段为高瓦斯煤系地层,施工风险高,结合本隧道工程实际,推荐采用钢架混凝土套拱进行衬砌加固处治。(3)衬砌混凝土强度越低,结构安全系数越小,MS-Ⅴa衬砌段,混凝土最低抗压强度要求为16MPa,既有结构才能满足规范的安全系数要求;(4)结构安全系数随套拱厚度的增加而增大,病害段MS-Ⅴa衬砌需进行结构加固的混凝土强度Ra范围值为:当9 MPa<Ra<16 MPa时,需采用I10钢架混凝土套拱进行加固,当6.5 MPa<Ra<9 MPa时,需采用I20钢架混凝土套拱进行加固;(5)结合仰拱处治方案及隧道平纵线型指标,通过调整竖曲线的方式整体降低隧道标高,增加限界净空富余,可解决套拱加固导致的净空不足问题。
Lining crack is one of the common diseases in tunnels,significantly impacting the tunnel structure and driving safety.Its main manifestations include lining cracking,lining deformation,and lining peeling.Based on the engineering background of a highway tunnel disease in operation,the causes of the disease are comprehensively analyzed based on the geological conditions,design,construction conditions,disease status,and detection results of the tunnel.Through numerical calculation,the stress state and safety of the existing structure are studied,and corresponding reinforcement measures are proposed.On this basis,the impact of arch reinforcement methods on the headroom margin of the tunnel is studied.The results show that:(1)Construction defects such as insufficient thickness of the inverted arch and insufficient lining strength are the main reasons for the cracking and damage of the tunnel's inverted arch and lining.(2)The demolition and replacement plan can effectively solve lining cracks and structural diseases.However,due to the weakness of the surrounding rock in the affected section,the demolition and replacement plan greatly disturbs the existing structure and surrounding rock,and the affected section is a high gas coal-bearing stratum,resulting in high construction risk.Based on the actual situation of this tunnel project,it is recommended to use steel frame concrete arch for lining reinforcement treatment.(3)The lower the strength of the lining concrete,the smaller the structural safety factor.The minimum compressive strength of concrete for the lining section of MS-Ⅴa is required to be 16MPa,so that existing structures can meet the safety factor requirements of the specification.(4)The structural safety factor increases with the increase in arch thickness.The range of concrete strength Ra required for structural reinforcement of the lining in the diseased section MS-Ⅴa is:when 9 MPa<Ra<16 MPa,I10 steel framed concrete arch is required for reinforcement;When 6.5 MPa<Ra<9 MPa,I20 steel frame concrete arch is required for reinforcement.(5)Combining the inverted arch treatment plan and the horizontal and vertical line indicators of the tunnel,by adjusting the vertical curve to reduce the overall elevation of the tunnel and increase the clearance margin,the problem of insufficient clearance caused by arch reinforcement can be solved.
作者
吴铭芳
曾仲毅
黄义雄
谭勇
Wu Mingfang;Zeng Zhongyi;Huang Yixiong;Tan Yong(Guizhou Transportation Planning Survey&Design Academe Co.,Ltd.,Guiyang 550081,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2023年第S02期942-954,共13页
Chinese Journal of Underground Space and Engineering
基金
黔科合重大专项(字[2018]3011)
关键词
公路隧道
衬砌裂损
强度不足
套拱加固
处治措施
highway tunnel
lining crack
insufficient strength
arch reinforcement
treatment
