摘要
对无明显墙式结构的正削式隧道门,现行规范没有现成的设计方法及结构检算模式。采用三维有限元数值分析方法,针对两种在洞口段的不同施工方法(明挖工法和暗挖工法),对隧道门洞口段的力学特性及设计方法进行了研究。研究结果表明:洞口段长度取42m进行整体设计比较合理;在洞口28m范围内的浅埋段,拱顶围岩压力随着埋深的增大而逐渐增加,且暗挖工法产生的围岩压力最大,铁路规范计算结果次之,明挖工法产生的压力最小;采用明挖工法施工时,在纵向上,洞口段42m范围内衬砌拱顶表现出纵梁弯曲特征,部分仰拱处于弯拉状态,内力呈空间效应,均需要对横、纵向内力进行结构检算;采用暗挖工法施工时,只需进行横向内力检算即可。在成洞条件允许的情况下,建议使用暗挖工法进行隧道洞口段施工,可有效改善隧道洞口段结构受力。
For up bamboo-truncating tunnel portal without obvious wall-style structure, there is no existent design method and structure checked mode in present code. In this paper, aiming at bored method and open-cut method for portal section, 3D FEM numerical analysis method is adopted to study the mechanical behaviors and design method of tunnel portal section. The research results show that： Choosing 42 m as the length of portal section and designing as a whole could be reasonable; In the shallow burying section of the extension of 28 m, the surrounding rock pressure of lining crown increases with the increase of depth of tunnel; and pressure of the bored tunneling method tunnel is maximal, the calculation result following the method of the railway tunnel code is the second; and the pressure of the open-cut method is minimal; When taking open-cut method, in the longitudinal direction of the extension of 42 m of portal, the mechanical behaviors of lining crown shows some characters of stringer bending, part of crown is in bended-pulled state; the internal force shows a three-dimensional effect, and the internal force of the direction both transversal and longitudinal should be checked for structure; when taking bored method, the internal force checking is only considered for transversal direction; when the excavation condition allows, the bored method is suggested to do portal tunneling by the reason that this tunneling method can improve mechanical behaviors of tunnel portal structure effectively.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2006年第11期2071-2075,共5页
Rock and Soil Mechanics
基金
铁道部建设司标准设计科研项目(No.建技科字2001-1号)
关键词
隧道
正削式隧道门
结构应力
数值模拟
设计方法
tunnel
up bamboo-trnncating tunnel portal
structural stress
numerical simulation
design method
