铁路隧道单双线分岔过渡段地震动力响应研究

发布时间：2018-09-13 16:23

【摘要】：分岔隧道通常由大跨段、连拱段和小净距段组成,其结构型式和围岩应力分布较为复杂,是设计和施工的重难点工程,在地震中易发生严重的震害。因此,研究高烈度地震区分岔隧道的地震动力响应及其抗减震措施具有重要的工程价值和意义。本文以成兰铁路杨家坪隧道单双线分岔过渡段为工程背景,通过数值计算研究了该分岔隧道的地震动力响应,并对其抗减震措施进行了研究,提出了适合该工程的抗减震措施。本文的主要工作和研究成果如下:(1)通过数值计算对比分析了有无中隔墙两种工况下分岔隧道的中隔墙和中岩柱的地震动力响应的差异,研究表明:连拱隧道中隔墙所受拉应力峰值和压应力峰值均比小净距隧道中岩柱大,中隔墙所受切应力较中岩柱大;随着中岩柱宽度的增大,压应力的最大值由中岩柱边角位置逐渐转移到中岩柱的中心位置,推荐采用有中隔墙的方案。(2)建立杨家坪隧道单双线分岔过渡段三维数值模型,研究其地震动力响应,研究表明:各隧道拱顶与仰拱的水平相对位移较大;各隧道的对角线相对变形在分岔口、连拱段和小净距段过渡时有明显突变;大拱段和双洞单线段的纵向相对位移变形较小;挡头墙的变形较大,易发生震害;中隔墙与中岩柱过渡段靠近中岩柱一侧拱肩和拱脚处内力峰值存在较大突变;连拱段和小净距段左、右拱脚和拱腰处衬砌结构受力较大;挡头墙处拱脚和拱腰位置的内力相对较大,是抗震的薄弱部位。(3)研究了注浆范围、挡头墙参数和减震缝参数三种措施的抗减震效果。研究表明:注浆范围越大,结构内力和位移越小,注浆范围取挡头墙前后4m效果最好;挡头墙材料刚度越小,结构内力越小;设置减震缝能使其周边一定范围的结构内力得到显著的降低,对于较远处位置的衬砌结构的内力则影响不大(4)隧道拱脚位置,特别是靠近中隔墙和中岩柱一侧的拱脚部位是抗震的薄弱部位。
[Abstract]:Bifurcation tunnel is usually composed of long span section, multi arch section and small net distance section. Its structure type and stress distribution of surrounding rock are more complex, which is the most difficult engineering in design and construction, and it is easy to occur serious earthquake damage in earthquake. Therefore, it is of great engineering value and significance to study the seismic dynamic response of the bifurcation tunnel in the high intensity seismic area and the measures to resist and reduce the earthquake. In this paper, taking the transition section of Yangjiaping tunnel of Cheng-lan railway as the engineering background, the seismic dynamic response of the bifurcation tunnel is studied by numerical calculation, and the measures to resist and reduce the earthquake are studied, and the anti-seismic measures suitable for the project are put forward. The main work and research results of this paper are as follows: (1) the difference of seismic dynamic response between middle partition wall and middle rock column of bifurcation tunnel under two working conditions is analyzed by numerical calculation. The results show that the peak values of tensile stress and compressive stress in the middle wall of the multi-arch tunnel are larger than those in the middle rock column of the tunnel with small net distance, and the shear stress of the middle partition wall is larger than that of the medium rock column, and with the increase of the width of the middle rock column, the shear stress of the middle wall is larger than that of the middle rock column. The maximum compressive stress is gradually transferred from the edge corner position of the middle rock column to the center position of the middle rock column. It is recommended to adopt the scheme with a middle partition wall. (2) the 3-D numerical model of the transition section of Yangjiaping Tunnel with single and double lines bifurcation is established and its seismic dynamic response is studied. The results show that the horizontal relative displacement of the arch roof and inverted arch of each tunnel is large, the relative deformation of diagonal line of each tunnel has obvious abrupt changes during the transition of bifurcation, multi-arch and small net distance, the longitudinal relative displacement of large arch and double-hole single line is small, and the relative deformation of the diagonal line of each tunnel is relatively small during the transition of bifurcation, multi-arch and small net distance. The deformation of the retaining head wall is large, which is prone to earthquake damage, the peak value of internal force near the side arch shoulder and arch foot of the middle rock column in the transitional section of the middle partition wall and the middle rock column is abrupt, and the lining structure at the left, right arch foot and arch waist of the continuous arch section and the small net distance section is subjected to more stress. The internal force of arch foot and arch waist at the head wall is relatively large, which is the weak part of earthquake resistance. (3) the anti-seismic effect of grouting range, retaining wall parameter and damping joint parameter are studied. The results show that the larger the grouting range is, the smaller the internal force and displacement of the structure are, the better the effect is before and after taking the retaining head wall in the grouting range, the smaller the material stiffness of the retaining head wall is, the smaller the internal force of the structure is. The internal force of the structure in a certain range around it can be significantly reduced by setting the damping joint, but the internal force of the lining structure in the farther position has little effect (4) on the position of the arch foot of the tunnel. Especially the arch foot near the middle wall and the middle rock column is the weak part of earthquake resistance.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U459.1

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