摘要
为了研究无中导连拱隧道先行洞与后行洞之间的最佳纵向间距,以香格里拉至丽江高速公路开达古隧道无中导连拱隧道段为工程背景,运用有限元数值模拟方法对隧道开挖过程进行了模拟,分析纵向间距分别为10,20,30,40 m这4种工况时隧道竖向沉降、水平收敛以及塑性区分布的影响规律,并与现场纵向间距为20 m的监测数据进行对比。结果表明:当纵向间距为10 m时对应的隧道变形最大,纵向间距20,30,40 m对应的隧道变形较小,且这3种纵向间距对应的隧道位移与塑性区分布无太大区别,尤其是纵向间距为30 m和40 m时,其对应的隧道位移与塑性区分布已基本趋于一致,因此从减少施工对土体扰动、围岩稳定及缩短施工工期方面综合性考虑,先行洞超前后行洞的最佳超前距离建议取值20~30 m;不同纵向间距下位于后行洞的测点的拱顶累计沉降曲线变化规律基本一致,均为开始缓慢增加,随后出现拐点,累计沉降快速增加呈减速递增趋势,直至最后趋于稳定,且随着纵向间距的增加,拐点出现的位置不断向后推移;不同纵向间距对应的无中导连拱隧道塑性承载区分布均主要集中在后行洞右侧拱脚位置处,因此在施工过程中应注意对该处进行加固处理;通过对拱顶沉降时程曲线的观察可以看出,初支闭合成环后,拱顶沉降速会明显减小,因此在实际施工过程中应尽早将初支闭合成环。
In order to study the optimal longitudinal spacing between the first tunnel and the second tunnel of the double-arch tunnel without middle pilot,on the background of the Kaidagu double-arch tunnel section without middle pilot on the Shangri-La-Lijiang expressway,the tunnel excavation process is simulated by using the finite element numerical simulation method,and the influence rules of the vertical settlement,horizontal convergence and plastic zone distribution of the tunnel are analyzed under the conditions of the longitudinal spacing of 10,20,30 and 40 m respectively,which are compared with the monitoring data with a longitudinal spacing of 20 m.The result shows that(1)when the longitudinal spacing is 10 m,the corresponding tunnel deformation is the largest,while the tunnel deformations corresponding to the longitudinal spacings of 20,30 and 40 m are smaller,and the tunnel displacements corresponding to the 3 longitudinal spacings are not much different from the distribution of plastic zone,especially when the longitudinal spacings are 30 m and 40 m,the corresponding tunnel displacements and the distribution of plastic zone have basically become consistent,therefore,from the comprehensive consideration of reducing the soil disturbance caused by construction,surrounding rock stability and shortening the construction period,the best advance distance of the first tunnel ahead of the second tunnel is recommended to be 20-30 m;(2)when the longitudinal spacings are different,the change rules of the cumulative settlement curves of the arch crown at the measuring points of the second tunnel are basically the same,which are slowly increasing at the beginning,followed by inflection points,and the rapid increases of the cumulative settlements show the trends of slowing increasing until they finally become stable,and the positions of the inflection points continue to move backward with the increase of the longitudinal spacings;(3)the distributions of plastic bearing areas of multi-arch tunnels without middle pilot correspo
作者
白宏达
张伟
王安民
王少飞
喻佳
BAI Hong-da;ZHANG Wei;WANG An-min;WANG Shao-fei;YU Jia(Yunnan Transport Consulting Co.,Ltd.,Kunming Yunnan 650041,China;Yunnan Transportation Planning and Design Institute Co.,Ltd.,Kunming Yunnan 650041,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2023年第2期153-161,共9页
Journal of Highway and Transportation Research and Development
基金
云南省科技和人才平台计划项目(2017HC025)
云南省交通运输厅科技创新及示范项目(云交科教便[2019]36号)。
关键词
隧道工程
纵向间距
数值分析
连拱隧道
现场监测
tunnel engineering
portrait spacing
numerical analysis
double-arch tunnel
field test
