摘要
针对南京地铁建设的实际背景和南京软弱地基的特点,以某典型软弱地基浅埋地铁区间隧洞为研究对象,对该软弱场地土的动参数进行了室内外试验研究,给出了各类土的剪切模量比G/Gmax和阻尼比λ与剪应变幅值γ之间的关系曲线,以及各土层的剪切波速;同时,采用等效线性化模型描述土的非线性性能,考虑地基土与地下浅埋隧洞动力相互作用的影响,采用二维有限元整体分析法对软弱地基浅埋隧洞的地震反应进行了数值模拟。计算结果表明:软土地基上的浅埋隧洞在中强地震发生时,在衬砌内引起很大的轴向力、剪力和弯矩,使得软土地基上浅埋隧洞在地震荷载作用下距离洞顶和洞底±35°左右的地方很容易发生剪切和弯剪破坏,这与已有地下隧道的震害是非常吻合的,因此该计算结果对地下区间隧道的抗震设计具有重要的参考价值。
By considering the characteristics of soft soils in Nanjing city, a representative soft foundation is selected to be investigated. Firstly, the curves of dynamic shear modulus ratio G/Gmax and damping ratio versus dynamic strain γ of the soils in this site are obtained by GZZ-1 free vibration column test system improved by Nanjing University of Technology. Secondly, as far as the Nanjing Subways are concerned, the earthquake response of shallow subway tunnels in soft foundation is analyzed by 2D finite element method. In the calculation model, the effect of soil-tunnel dynamic interaction and the nonlinear behavior of soil are considered by the equivalent linear method. It is shown that the force induced by middle and strong ground motions are very large. The damages are very likely to occur at places with central angles of ± 35° or so to the top and bottom of the tunnels. These conclusions are in good agreement with records of seismic damage of subway.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2005年第14期2506-2512,共7页
Chinese Journal of Rock Mechanics and Engineering
基金
结构工程江苏省重点实验室基金资助项目(KJSS0201)
江苏省自然科学基金项目(BK2004124)
关键词
隧道工程
地铁
浅埋隧洞
软弱地基
地震反应
Computer simulation
Earthquake resistance
Elastic moduli
Finite element method
Foundations
Subways
Tunnel linings
