基于OpenSees的地震动对软土震陷影响研究

Influence of Ground Motions on Seismic Subsidence of Soft Soil Based on OpenSees

摘要:

软土具有高灵敏度、低强度等特性，在地震过程中极易产生震陷。基于OpenSees数值模拟方法对软土场地的震陷反应进行非线性动力有限元分析，通过改变地震动峰值加速度、频谱特性、输入方式来研究其对软土震陷的影响。结果表明，地震动峰值加速度对地基土的不均匀震陷有显著影响，地震动峰值加速度越大，震陷量显著增大，震陷影响深度更大，对水平地表造成的破坏范围也更大；地震动频谱特性对软土震陷有重要影响，当地震动卓越频率与场地自振频率相近时，其幅值越大，产生的震陷越严重；水平、竖向同时输入地震动的方式能更好地反映土体的振动及震陷响应。该研究成果对探索软土震陷的机理有一定的指导意义。

Abstract:

Soft soils have characteristics of high sensitivity and low strength and are easily subject to seismic subsidence during earthquakes. In this study, the nonlinear dynamic finite element analysis of the seismic subsidence response of soft soil site was performed based on the OpenSees numerical simulation method. The results show that the peak acceleration of ground motion has a significant effect on the uneven seismic subsidence of foundation soil. As the peak acceleration of ground motion increases, the amount of seismic subsidence, the impact depth of seismic subsidence, and the damage to the horizontal surface also increase. The characteristics of the ground motion spectrum have an important impact on the soft soil earthquake subsidence. If the predominant frequency of ground motion is similar to the natural frequency of the site, the larger the amplitude, the more serious the seismic subsidence is. Simultaneous input of horizontal and vertical ground motions can better reflect the vibration and seismic subsidence response of the soil. The results have a certain guiding significance for exploring the mechanism of seismic subsidence of soft soils.