P_1波入射角对建筑基础振动的影响

INFLUENCE OF INCIDENT ANGLE OF P_1 WAVE ON VIBRATION OF BUILDING FOUNDATION

考虑土颗粒和孔隙流体的压缩性以及孔隙流体与土骨架之间的粘性耦合作用，采用修正的Biot模型，对P1波从饱和土体入射到建筑基础的反射和透射时，入射角对不同强度建筑基础的振动特性的影响进行了数值模拟分析。结果表明，对于特定的入射频率（例如100Hz），当P1波垂直入射和掠入射时，基础不产生应力；当P1波掠入射时，基础不产生位移；当基础与土体的强度相近时，基础的位移可以忽略不计；当基础强度超过一定值后，波动产生的最大基础位移和应力基本不变。对于通常的钢筋混凝土建筑，当P1波入射角为30°～50°时，基础容易产生较大的水平剪应力；当入射角小于30°时，基础容易产生较大的竖向应力；当入射角为40°～60°时，基础容易产生较大的水平振动；当入射角为45°-70°时，基础容易产生较大的竖向振动。

The compression of soil grain and pore fluid and viscid coupling of pore fluid and soil skeleton were considered, and amended Biot model was adopted to numerically analyze the influence of incident angle of P_1 wave on vibration characteristics of building foundation with different modules when the reflection and transmission of incident P_1 wave at the interface of saturated soil and building foundation occurred. At the selected incident frequency of 100Hz, the calculated results indicate that there is no stress in the foundation when the incident angle of P_1 wave is 0° or 90°, and no displacement when 90°; there is negligible displacement when the soil and foundation have nearer modules, and the increase of the largest displacement and stress of foundation are not considerable when the module of foundation exceeds a special value. For general reinforced concrete foundation, there is larger horizontal shear stress when the incident angle of P_1 wave is between 30°and 50°; there is larger vertical normal stress when the incident angle is less than 30°; there is larger horizontal vibration when the incident angle is between 40°and 60°, and there is larger vertical vibration when the incident angle is between 45°and 70°.