隧道原位扩建施工力学与围岩松动圈演变规律:以广西贺州—巴马高速公路廷心隧道原位扩建工程为例  

Construction Mechanics and Evolution of Surrounding Rock Loose Circle of In-situ Tunnel Expansion:Taking the In-situ Expansion Project of Tingxin Tunnel on Hezhou-Bama Expressway in Guangxi as an Example

作　　者：黄成年 吴逸飞 许煜林 林志[3] 伍汉 吴森阳 HUANG Cheng-nian;WU Yi-fei;XU Yu-lin;LIN Zhi;WU Han;WU Sen-yang(Guangxi Xinfazhan Communication Group Co.,Ltd.,Nanning 530001,China;Chongqing Fengjian Expressway Co.,Ltd.,Chongqing 404699,China;State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China;China Merchants Chongqing Highway Engineering Testing Center Co.,Ltd.,Chongqing 400065,China)

机构地区：[1]广西新发展交通集团有限公司,南宁530001 [2]重庆奉建高速公路有限公司,重庆404699 [3]重庆交通大学山区桥梁及隧道工程国家重点实验室,重庆400074 [4]招商局重庆公路工程检测中心有限公司,重庆400065

出　　处：《科学技术与工程》2024年第24期10520-10527,共8页Science Technology and Engineering

基　　金：国家自然科学基金(52078089,52274176);重庆英才创新创业领军人才项目(CQYC20220302517);重庆市自然科学基金创新发展联合基金(CSTB2022NSCQ-LZX0079);重庆市自然科学基金(cstc2021jcyj-msxmX1075);交通运输部项目“三峡库区奉建高速公路安全智能建造科技示范工程”(交办科技函[2021] 581号)。

摘　　要：交通量的激增导致的早期建成的高速公路隧道已不能满足通行需求,通过高速公路原位改扩建形式来解决这个问题。但是目前在隧道原位扩建时的围岩松动圈演变规律、应力重分布规律还不明确,常常会导致大变形甚至塌方等安全事故、工程质量等诸多问题。针对隧道原位扩建施工力学与围岩松动圈演变规律,采用离散元软件GDEM建立新建两车道、三车道及四车道的模型和“两扩三”及“两扩四”的隧道模型,并模拟结果与现场应力监测分析定性对比验证,开展公路隧道原位扩建施工力学行为与围岩松动圈展开研究。结果表明:围岩应力大小顺序为拱顶<拱腰<拱脚,开挖宽度增加或者围岩等级的降低会导致围岩应力增大;在相同开挖宽度下,新建隧道的围岩应力小于原位扩建隧道;隧道围岩的松动圈随着围岩等级的降低而逐渐扩大,其形态由“点”形扩大为“耳”形,再扩大为“蝶”形;当围岩等级相同,新建隧道围岩松动圈范围小于扩建隧道的围岩松动圈范围。扩建隧道施工会使围岩从原来多次应力重分布的基础上再进行多次应力重分布,而这种应力的复杂演变将导致了新建隧道和扩建隧道的应力、应变场将完全不同,同时扩建隧道导致原本已经处于稳定状态的围岩松动圈再次向外扩张。The early-built highway tunnels cannot meet the traffic demand due to the surge in traffic volume,and in-situ expansion of the highway is adopted to address this problem.However,the evolution law of the loose rock zone and the stress redistribution law during in-situ tunnel expansion are not clear yet,which often leads to safety accidents and engineering quality problems such as large deformations or even collapses.In order to study the mechanical behavior of in-situ tunnel expansion and the evolution law of the loose rock zone,the discrete element software GDEM was used to establish models of newly built two-lane,three-lane and four-lane tunnels,as well as“two expansions and three lanes”and“two expansions and four lanes”tunnel models.The simulation results were qualitatively compared and verified with on-site stress monitoring analysis to study the mechanical behavior of highway tunnel in-situ expansion and the evolution law of the loose rock zone.The results show that the stress of the surrounding rock mass is in the order of crown<haunch<invert,and the increase in excavation width or the decrease in rock mass grade will lead to the increase in rock mass stress.Under the same excavation width,the stress of the surrounding rock mass of the newly built tunnel is smaller than that of the in-situ expanded tunnel. The loose rock zone around the tunnel gradually expands with the decrease in rock mass grade, and its shape changes from “point” to “ear” and then to “butterfly”. When the rock mass grade is the same, the loose rock zone around the newly built tunnel is smaller than that of the expanded tunnel. The expansion of the tunnel will cause the rock mass to undergo multiple stress redistributions on the basis of the original multiple stress redistributions, and the complex evolution of this stress will result in completely different stress and strain fields between the newly built tunnel and the expanded tunnel, while the expansion of the tunnel will cause the loose rock zone around the rock ma

关 键 词：隧道 原位扩建 围岩松动圈 围岩荷载 

分 类 号：U451[建筑科学—桥梁与隧道工程]