论文部分内容阅读
针对现有地下结构抗震分析方法用于地铁大型地下结构的可行性研究明显不足问题,根据中国抗震规范的相关规定设计了常见的3种场地类别,考虑输入地震动特性及其强度,通过84种有限元计算工况,分析了土–地铁地下结构非线性动力相互作用体系的侧向变形特征。结果表明,在Ⅱ、Ⅲ、Ⅳ3个场地类别条件下输入加速度峰值较大时(0.3g和0.4g),或者场地类别为Ⅳ类时即使输入很小地震动峰值加速度时,土与结构相互作用系数均小于1,即大型地铁地下结构侧向土体总是“推着”地下结构产生最大相对变形,此时地铁地下结构周围土层的大变形将对地下结构抗震造成不利的影响。反之,将会出现地铁地下车站结构侧向最大变形大于等代土体单元的侧向变形,即地下结构的动力变形将受到周围土层的约束作用,此时将对地下结构的抗震起到有利作用。同时,也给出了场地类别和输入地震动特性对土–地铁地下结构相互作用系数的影响规律。
Aiming at the problem of insufficient feasibility of existing underground structure seismic analysis method for metro underground structures, three kinds of common ground types are designed according to the relevant provisions of China Seismic Code. By considering the characteristics and intensity of input ground motion, Finite element calculation condition, the lateral deformation characteristics of the nonlinear dynamic interaction system of the soil-subway underground structure are analyzed. The results show that the earth interaction with the structure occurs when the input acceleration peak is large (0.3g and 0.4g) under the conditions of Ⅱ, Ⅲ and Ⅳ, or when the ground classification is Ⅳ, even if the input is a small ground acceleration peak acceleration The coefficient is less than 1, that is to say, the lateral soil mass in the large-scale subway underground structure always produces the maximum relative deformation of the underground structure, and the large deformation of the soil layer surrounding the underground structure of the subway will adversely affect the seismic resistance of the underground structure. On the contrary, the lateral maximum deformation of the metro underground station structure will occur more than the lateral deformation of soil units of the same generation, that is, the dynamic deformation of the underground structure will be restrained by the surrounding soil layer, which will play an advantageous role in the seismic resistance of the underground structure effect. At the same time, the influence laws of the type and input ground motion characteristics of ground on the interaction coefficient of soil-subway underground structure are also given.