一种适于新疆村镇建筑的简易复合隔震体系研究

According to Xinjiang's regional characteristics of high seismic frequency and the entire area covered by frozen soil, this project try to research a simple composite isolation system for houses in villages and towns, while frost heaving of ground base could be eliminated by the isolation system. The layout of the structure is: pave sand cushion under the foundation of building, set ring beam with some rubber bundles at outdoor ground level and pave a mortar layer with lower strength along the middle height of the ring beam. The working mechanism of the structure is: under small earthquake, only sand cushion play the isolation role, the main sesmic capacity depends on structure itslef.under medium or large earthquake, mortar layer with lower strength is cracked, ring beam is divided into two parts, the main structure integrally slide along with the top ring beam, and rubber bundles are deformed to constrain displacement of main structure, ring beam play the damping role, the composite isolation system is formed. Through paving sand cushion and setting ring beam, the hazard of frost heaving force to building is eliminated. In the project, theoretical analysis, numerical simulation and experimental study would be used as research techniques, the calculation model of composite isolation structure would be established under different earthquake level, the mechanism of damping vibration would be studied, and the effect of arrangement of sand cushion and rubber bundles, temperature would be analyzed. Ultimately, the layout principle, optimal design parameters and related constructional detail measures of composite isolation system would be determined. The system has the advantages of simple structure,convenient construction and low cost. It embodies the seismic principle of towns and villages. In the process of construction of small towns and new socialist countryside in Xinjiang, the composite isolation system will have a wide application prospect.

本项目针对新疆地处地震高发区和冻土区的区域特点，研究一种兼顾消除地基冻胀的村镇建筑简易复合隔震体系。布置方案为：在建筑基底设砂垫层和室外地面标高处布设内置捆绑橡胶束的减震圈梁，圈梁中部预留一道低标号砂浆滑移层。工作机理为：在小震下，仅砂垫层发挥隔震功效，低标号砂浆滑移层未开裂，结构整体抗震；在中、大震下，砂浆滑移层开裂，圈梁一分为二，主体结构随上层圈梁整体滑动，橡胶束变形限位，减震圈梁发挥消能减震功效，与砂隔震垫层共同工作，形成复合隔震体系；基底砂垫层和地圈梁的设置，消除了冻胀力对房屋的危害。项目采用理论分析、数值模拟和试验为手段，研究复合隔震结构在不同地震水平下的计算模型及其减震机理，分析砂垫层、橡胶束布置、温度等因素对减震效果的影响，确定体系的布置原则和最优设计参数，及构造措施。该体系构造简单、施工方便、造价低廉，体现了村镇建筑抗震原则，在新疆小城镇建设和新农村建设中有广阔应用前前景。

针对新疆低层村镇建筑面临地震和地基冻胀的双重危害，提出一种由基底砂垫层与基础滑移隔震层组成的复合隔震体系，该体系在隔震的同时可消除地基冻胀对低层村镇建筑的不利影响，围绕复合隔震体系的抗震性能开展研究，主要开展工作及结论有：1）提出由基底砂垫层和基础滑移隔震层串联组成的复合隔震体系，建立了简化三质点动力分析模型，得到了体系的减震机理。2）对构成复合隔震体系的基础滑移隔震层和基底砂垫层等相关隔震部件的材料性能及构造进行了研究。3）进行了滑石粉改性砂浆滑移隔震墙体、钢珠—改性砂浆滑移隔震墙体、干铺石墨粉滑移隔震墙体等3种隔震构造墙体与普通墙体的低周反复加载对比试验研究。研究表明隔震墙体具有良好的滑移耗能能力，设置低摩擦系数的滑移隔震层改变了墙体的受力破坏机制，隔震墙体在试验过程中始终处于弹性阶段，上部刚度几乎没有退化，即通过水平滑动和橡胶束的限位作用有效保护了上部结构免于破坏。3种配方中的滑移能力依次为石墨粉滑移层、钢珠改性砂浆滑移层、滑石粉改性砂浆层。4）进行了1/4缩尺模型对比振动台试验，包括4栋2层的砌体结构房屋，分别为复合隔震结构、基础滑移隔震结构、基底砂垫层隔震结构，以及普通抗震结构。对比考察了上述四种结构在不同地震输入水平下的动力特性、地震反应特征，以及破坏特点。研究表明，未设置构造柱的普通抗震结构抗震性能较差，设置隔震措施的结构抗震性能较好，其中采用复合隔震体系的结构由于基底砂垫层和基础滑移层的联合工作，其抗震性能最优。5）采用ABAQUS软件对包括普通砌体结构、基础滑移隔震结构、砂垫层隔震结构、复合隔震结构等四种模型进行了不同地震强度输入下的弹塑性时程分析，分析了四种结构动力反应特征的差异，明确了砂垫层—基础滑移复合隔震体系的隔震机理，以及不同烈度区合理的滑移层摩擦系数取值范围。6）基于项目研究成果，初步提出砂垫层—基础滑移复合隔震村镇建筑的设计与施工建议，为工程应用提供依据。