摘要
在岩溶地区,列车振动荷载已成为引起铁路周边地表岩溶塌陷的重要影响因素。为研究新建地铁隧道在岩溶地层中开挖时,列车荷载对隧道、地表及地层的动位移和动应力响应,以贵阳地铁3号线下穿川黔铁路为背景,通过有限元软件建模计算了在最不利围岩和列车动载条件下,隧道拱顶无溶洞、有溶洞和溶洞注浆3种工况的动力响应规律进行对比分析。结果表明:在列车动荷载作用下,溶洞存在及对其注浆加固对地表位移动力响应的影响范围大致为3.3倍洞径以内,有溶洞时地表最大瞬时沉降发生在路基中线与隧道中线交叉处,为2.74 mm,而对其注浆加固后此处的沉降为2.16 mm,减小了21.2%;对溶洞进行注浆加固后隧道支护结构产生了相对更大动力响应,最大瞬时位移和主应力均发生在隧道拱顶,分别为-1.41 mm和-0.36 MPa;地层竖向应力从地表到隧道拱顶衰减最明显的是有溶洞的情况,从-0.076 6 MPa衰减到-0.008 4 MPa,衰减率为89.03%。可见,对铁路与隧道之间的地层溶洞注浆加固后,在保证新建隧道安全的情况下,明显改善降低了列车动载引起的地表瞬时沉降。
In Karst areas,train vibration load has become an important factor that causes surface karst collapse around railway.In order to study the dynamic displacement and stress response of train load to tunnel,ground and stratum when a new subway tunnel was excavated in Karst stratum,taking Guiyang Metro Line 3 crossing Sicuan-Guizhou Railway as the background,the finite element software modeling was used to calculate under the most unfavorable conditions of surrounding rock and train dynamic load.The dynamic response rules of three conditions of no cave above the tunnel,with cave and cave grouting were compared and analyzed.The results show as follows.Under the action of train dynamic load,the influence range of the karst cave and grouting reinforcement on the surface displacement dynamic response is roughly within 3.3 times the diameter of the karst cave.Moreover,when there is a Karst cave under the railway subgrade,the maximum instantaneous settlement of the surface occurs at the intersection between the middle line of the subgrade and the middle line of the tunnel,which is 2.74 mm.After grouting reinforcement of the Karst cave,the settlement here is 2.16 mm,decreased by 21.2 percent.In addition,the maximum instantaneous displacement and principal stress,which are-1.41 mm and-0.36 MPa,occur in the tunnel vault.When there are Karst caves in the stratum,the vertical stress attenuation from the surface to the tunnel vault is the most obvious,from-0.076 6 MPa to-0.008 4 MPa,with a attenuation rate of 89.03%.It can be seen that the ground instantaneous settlement caused by train dynamic load can be significantly improved and reduced under the condition of ensuring the safety of the new tunnel after grouting reinforcement of the Karst cave between the railway and the tunnel.
作者
杜碧涛
刘远明
陈会宇
陈庆芝
陈林全
滕召磊
DU Bi-tao;LIU Yuan-ming;CHEN Hui-yu;CHEN Qing-zhi;CHEN Lin-quan;TENG Zhao-lei(School of Civil Engineering,Guizhou University,Guiyang 550025,China;Key Laboratory of Geotechnical and Engineering Safety of Guizhou Province,Guiyang 550025,China;Guizhou Transportation Planning Survey and Design Academe Co.,Ltd.,Guiyang 550008,China)
出处
《科学技术与工程》
北大核心
2023年第30期13134-13142,共9页
Science Technology and Engineering
基金
贵州省科学技术基金(黔科合基础-ZK[2022]一般082)
贵州省科学技术基金(黔科合基础[2019]1057号)
贵阳城市轨道交通科研项目(GD3-FW-YJ-05-2020-13-ZB)。
关键词
列车荷载
岩溶地层
注浆加固
地铁隧道
数值计算
动力响应
train load
Karst formation
grouting reinforcement
subway tunnel
numerical calculation
dynamic response
