地铁地下车站结构抗震弹塑性工作性态与性能化实用分析方法研究

The subway underground station structures are becoming even more large and complicated, which potential earthquake dangers are not easily perceived. Meanwhile, the seismic rehabilitation of subway underground stations should also be very difficult. In these regards, study on the seismic elasto-plastic performance of subway underground station structures should be very important to its seismic design, and a practical performance-based seismic analysis method should also be developed. Accordingly, in this new research project, the dynamic properties of soft clay in a large strain range will be studied firstly by a combination of different advanced test methods to correct the hardening rules of the existed dynamic elasto-plastic constitutive model developed by applicant earlier, and then some practical expressions will be made for the dynamic parameters of soil in a large strain range. As a result, the numerical modeling methods will be developed to simulate the seismic performance of subway underground structure loaded by the large seismic deformation of around soil in a strong earthquake. By the developed numerical modeling methods, the seismic elasto-plastic performance and the earthquake collapse process of some typical underground station structures will be systematically investigated. Meanwhile, the numerical modeling method and the new research results will be verified and improved by the large-scale model tests developed in this study. Based on the above newest research results, some uniform quantified indicators will be extracted to describe the seismic elasto-plastic performance of subway underground station structures. By using these indicators, the clear seismic performance levels and objectives of subway underground station will be confirmed in this study. At last, based on the newest idea of damage-reduction seismic design, a practical performance-based calculation method will be developed for the seismic design of subway underground station structures. Some new research achievements in this research project can be directly used in the seismic design and the seismic safety evaluation of subway underground structures, which should also drive fast development on the earthquake prevention and disaster reduction of an urban rail transit project.

鉴于地铁地下车站结构的空间尺度大、安全隐患不易发现且震后修复难度大等特点，研究其抗震弹塑性工作性态和性能化实用分析方法尤为重要。首先，本项目通过软粘土动力学特性的多种室内试验联合研究，建立宽应变范围内土体动力学参数的统一经验表达式，完善土体动力学本构模型的硬化准则，实现强震中土体大变形条件下地铁地下车站结构弹塑性工作性态及其地震倒塌的数值模拟分析方法；其次，基于系统地数值模拟，结合创新动力模型试验和现场震害实例分析，探明多种典型地铁地下车站结构的抗震弹塑性工作性态和地震破坏连锁效应，析取其抗震性能的多样化量化指标，确定其抗震性能水准和抗震性能目标；最终，从结构性能化抗震设计理念出发，考虑整体结构和关键构件的不同抗震需求，建立基于性能的地铁地下车站结构实用抗震分析方法。预期成果可直接用于地铁地下结构的抗震设计和地震安全性评价中，并有力推动城市轨道交通防震减灾工作的快速发展。

鉴于地铁地下车站结构的空间尺度大、安全隐患不易发现且震后修复难度大等特点，研究其抗震弹塑性工作性态和基于性能化实用分析方法尤为重要。首先，本项目通过对新近沉积饱和土与橡胶颗粒混合土的动力学特性室内试验研究，建立了宽应变范围内土体动力学参数的统一经验表达式，完善了土体粘弹塑性动力学本构模型的硬化准则，提高了已建本构模型对土体动力大变形的计算效率与精度；其次，考虑周围土压力的等效，基于地下结构抗震性能的层间位移角划分体系确定以位移控制的循环加载曲线，研发了大比尺模型地下结构循环推覆加载的物理模型试验方法，通过开展不同地下结构的循环推覆加载模型试验，进一步揭示了典型地铁地下车站结构的抗震弹塑性工作性态和地震破坏发展过程；同时，基于增量动力分析方法(IDA)，建立了二维土-地下结构非线性动力相互作用的有限元模型，对大开车站的浅埋矩形地下结构的非线性地震反应进行了一系列的数值模拟计算，提出了一种基于概率统计方法的地下结构抗震性能等级划分方法。在此基础上，基于筛选出的地表峰值加速度（PGA）和场地顶底相对最大侧移（PSSRD），以层间位移角（IDR）为地下结构地震损伤指标，提出了浅埋地下结构的地震易损性曲线的建立方法；其次，基于系统地数值模拟，结合大型振动台模型试验、新提出的动力模型试验方法和现场震害实例分析，探明不同场地条件下多种典型地铁地下车站结构的抗震弹塑性工作性态和地震破坏过程，提出了地铁地下车站结构的抗震性能水准和对应的地震破坏特征物理描述；最终，从结构性能化抗震设计理念出发，建立了基于性能的地铁地下车站结构抗震性能评价准则与体系。本项目的研究成果可直接用于城市轨道交通这一重大工程的抗震设计和地震安全性评价中，可对国家级规范《城市轨道交通结构抗震设计规范》和标准《地下结构抗震设计标准》的修订提供重要的科学依据和具体分析方法，同时对我国城市轨道交通工程防震减灾工作具有重要的推动作用。