地下结构地震反应规律和抗震设计方法研究

发布时间：2018-08-28 10:06

【摘要】：随着城市轨道交通系统,尤其是地铁的大规模建设,城市轨道交通系统的安全问题已经成为重中之重。地铁系统要在长时间的运行周期内保证安全,就必须具有良好的抗震性能。对于地下结构抗震问题,模型试验和数值计算是必不可少的两种手段,合理且简便的抗震设计方法是研究所要达到的目标,而地下结构周围土体材料的非线性动力本构模型是研究中的难点。本文对地下结构的地震反应规律和抗震设计方法进行了深入研究,取得了如下研究成果:(1)土的本构模型。根据Hardin和Drnevich提出的土体动应力-应变关系曲线以及其在非等幅往返荷载作用下的Pyke修正,结合Dafilias和Popov等人提出的边界面理论,构造了基于Hardin曲线的土体边界面本构模型,并在ADINA中利用自定义材料的二次开发实现了该本构模型。(2)二维有限元动力计算。采用Opensees对饱和砂土场地的地震反应进行了非线性动力有限元分析,并通过改变土性、地震动幅值、持时、频率等因素后数值模拟的对比,分析了各因素对可液化场地地震反应的影响;然后对饱和砂土中带中柱箱型隧道的地震反应进行了输入不同幅值地震动时的动力计算,分析了场地和结构的加速度反应及其频谱特性、场地的永久变形、隧道的变形和位移、以及隧道的内力分布,揭示了可液化土层中箱型隧道的地震反应规律和震害机理。(3)饱和砂土中地下结构地震反应振动台试验。完成了饱和砂土中地下结构地震反应的振动台试验,从孔压、土层加速度、土层频谱、地下结构加速度、地下结构频谱、动土压力和地下结构应变等方面分析了试验结果,并观测了宏观的试验现象,分析了饱和砂土场地以及其中埋置的地下结构的地震反应规律。(4)三维有限元动力计算。在Opensees计算平台中建立了穿过饱和砂土和粘土分界面箱型隧道的三维有限元模型并且进行了动力数值计算,对比分析了分界面两侧的土层和隧道的地震反应,此外,亦分析了沿隧道纵向地表竖向位移、隧道变形和隧道内力的分布,揭示了饱和砂土和粘土对隧道地震反应的不同作用,探索了穿过饱和砂土和粘土分界面的箱型隧道的地震反应规律和震害机理,对实际工程建设中此类隧道的抗震研究具有重要意义。(5)地下结构横截面抗震设计方法。详细介绍了反应位移法的原理和具体内容,以动力时程计算的结果作为参照,比较了几种地基弹簧参数取值方法计算结果的准确性;然后在反应位移法的基础上提出了大震下地基弹簧参数取值的非线性修正,并对其计算结果进行了验证;最后又依据地基弹簧参数取值的非线性修正,进而提出了基于反应位移法的地下结构简化pushover分析方法,并根据一具体算例对其计算结果进行了验证。(6)地铁隧道纵向抗震设计方法。介绍了几种常见的隧道纵向抗震设计方法,例如,BART法、质点-弹簧模型法和反应变位法等;然后将桩-土相互作用的p-y曲线弹簧引入到了地铁隧道的纵向抗震设计中,建立了超长隧道-地基土相互作用的p-y弹簧模型,并且通过对该模型的Pushover分析给出了地铁隧道的一种纵向弹塑性设计方法;最后通过多点激励对超长隧道-地基土相互作用的p-y弹簧模型进行了动力数值计算,得到了隧道纵向内力和变形的一些规律。
[Abstract]:With the large-scale construction of urban rail transit system, especially the subway, the safety of urban rail transit system has become a top priority. To ensure the safety of subway system in a long period of operation, it is necessary to have good seismic performance. In this paper, the seismic response law and seismic design method of underground structures are studied deeply, and the following research results are obtained: (1) soil constitutive model Based on the dynamic stress-strain curves proposed by Hardin and Drnevich and Pyke correction under non-uniform amplitude cyclic loading, and the boundary surface theory proposed by Dafilias and Popov, a constitutive model of soil boundary surface based on Hardin curves is constructed, which is realized by the secondary development of self-defined materials in ADINA. Constitutive model. (2) Two-dimensional finite element dynamic calculation. The seismic response of saturated sandy soil site is analyzed by nonlinear dynamic finite element method with Opensees, and the influence of various factors on seismic response of liquefiable site is analyzed by comparing the numerical simulation of soil properties, amplitude of ground motion, duration, frequency and other factors. The seismic response of box-type tunnel with middle column is calculated under different amplitudes of ground motion. The acceleration response and its spectrum characteristics of site and structure, permanent deformation of site, deformation and displacement of tunnel, and internal force distribution of tunnel are analyzed. The seismic response law and seismic damage of box-type tunnel in liquefiable soil are revealed. (3) Shaking table test of underground structure seismic response in saturated sand. The shaking table test of underground structure seismic response in saturated sand is completed. The test results are analyzed from pore pressure, soil acceleration, soil spectrum, underground structure acceleration, underground structure spectrum, dynamic earth pressure and underground structure strain, and macroscopic observation is made. (4) Three-dimensional finite element dynamic calculation. A three-dimensional finite element model of a box-shaped tunnel crossing the interface between saturated sand and clay is established on the Opensees platform, and the dynamic numerical calculation is carried out. In addition, the vertical displacement along the longitudinal surface of the tunnel, the deformation of the tunnel and the distribution of the internal force of the tunnel are analyzed. The different effects of saturated sand and clay on the seismic response of the tunnel are revealed. The seismic response law and damage mechanism of the box-shaped tunnel crossing the interface between saturated sand and clay are explored. It is of great significance to study the seismic behavior of such tunnels in engineering construction. (5) Seismic design method for cross section of underground structures. The principle and concrete contents of the reactive displacement method are introduced in detail. The accuracy of the calculation results of several methods for selecting parameters of foundation spring is compared with the results of dynamic time history calculation. On the basis of this, the nonlinear correction of the parameters of the foundation spring under large earthquakes is put forward, and the calculation results are verified. Finally, according to the nonlinear correction of the parameters of the foundation spring, a simplified pushover analysis method for the underground structure based on the response displacement method is proposed, and its calculation results are verified by a specific example. (6) Longitudinal seismic design method of subway tunnel. Several common longitudinal seismic design methods are introduced, such as BART method, mass-spring model method and reaction displacement method, etc. Then the p-y curve spring of pile-soil interaction is introduced into the longitudinal seismic design of subway tunnel, and the interaction between super-long tunnel and foundation soil is established. A longitudinal elastic-plastic design method of subway tunnel is given by Pushover analysis of the p-y spring model. Finally, the p-y spring model of interaction between super-long tunnel and foundation soil is calculated by multi-point excitation, and some laws of longitudinal internal force and deformation of tunnel are obtained.
【作者单位】：中国地震局工程力学研究所;
【分类号】：TU93;TU352.11

【相似文献】