CAJ | 학술논문

为了研究城市轨道交通引起的环境振动竖向位移衰减关系中局部放大现象的产生机理，将场地简化为弹性半空间单一覆盖层模型，采用传递矩阵法推导了频率波数域三维层状场地竖向位移的动力格林函数。通过七个半空间与覆盖层的模量比，四个覆盖层厚度，七个激励频率，三个覆盖层阻尼比等诸多因素对局部放大影响的分析，结果表明局部放大受埋藏的主要速度界面控制，局部放大区的位置和放大的强度与该界面两侧的模量比（波阻抗比）、覆盖层厚度、激励的频率及覆盖土层的阻尼比等因素有关。一般来说，速度界面的波阻抗越大，局部放大越强烈；给定其他条件，使直达的表面波与半空间表面折射波越接近同时到达的覆盖层厚度使局部放大越为明显，使两者波峰越靠近的激励频率会引起更为明显的局部放大；覆盖层阻尼比越小，局部放大越强烈。
위료연구성시궤도교통인기적배경진동수향위이쇠감관계중국부방대현상적산생궤리，장장지간화위탄성반공간단일복개층모형，채용전체구진법추도료빈솔파수역삼유층상장지수향위이적동력격림함수。통과칠개반공간여복개층적모량비，사개복개층후도，칠개격려빈솔，삼개복개층조니비등제다인소대국부방대영향적분석，결과표명국부방대수매장적주요속도계면공제，국부방대구적위치화방대적강도여해계면량측적모량비（파조항비）、복개층후도、격려적빈솔급복개토층적조니비등인소유관。일반래설，속도계면적파조항월대，국부방대월강렬；급정기타조건，사직체적표면파여반공간표면절사파월접근동시도체적복개층후도사국부방대월위명현，사량자파봉월고근적격려빈솔회인기경위명현적국부방대；복개층조니비월소，국부방대월강렬。
In order to investigate the forming mechanism of local amplification in rail traffic-induced ground vibration attenuation,the ground was simplified to be a single soil layer covering on an elastic half-space.Dynamic Green's function of vertical ground displacement of a three-dimensional layered site model was derived in frequency domain.The effects of many fators including seven modulus ratios of half space to covering layer,four thicknesses of convering layer,seven exciting frequencies,and three damping ratios of convering layer on local amplification were analyzed.The results showed that local amplification is controlled by an important buried velocity interface,its location and intensity of amplification depend on ratio of elastic moduli of medias in the both sides of the interface,i.e., impedance ratio,thickness of covering layer,exciting frequency and damping ratio of covering;in general,the larger the impedance of the interface,the stronger the local amplification;giving the other conditions,the closer the directly arriving time of surface wave and the arriving time of refraction wave from the interface which are governed by covering layer thickness,the more obvious the local amplification;the closer the peaks of waves which are governed by exciting frequency,the more obvious the local amplification;the smaller the damping ratio of covering layer,the stronger the local amplification.