不同场地考虑衬垫层影响的填埋场地震响应

Seismic response of municipal waste landfills with bottom liner interface under different site conditions

摘要:

采用薄层土体代替衬垫层，并提出薄层土体相应的动力计算参数，建立填埋场动力计算模型，采用一维多层土体的等效线性解法进行求解，研究了衬垫界面、填埋高度和场地条件对填埋场地震响应的影响规律。计算结果表明，在中震或强震作用下填埋场衬垫处发生较大的剪切位移，限制了地震波的向上传播，忽略衬垫层对填埋场地震响应的影响，会造成较大的误差；当填埋场高度为15m时，填埋场顶部峰值加速度最大，随着填埋高度的增加，填埋场基本周期逐渐增大，远离了共振状态，使得填埋场顶部加速度逐渐减小；最后，通过对比4种场地条件下填埋场的地震响应变化规律可发现场地条件的变化对填埋场的地震响应也有较大影响。

Abstract:

A new calculated model was developed to analyze the seismic responses of MSW landfills. In this model, a geosynthetic liner is replaced by an equivalent soil layer that has characteristics that duplicate the liner interface response under dynamic loads. Then, the effects of liner interface, landfill height and site condition on seismic responses of landfills were studied. The calculated results showed that the shear displacement was very large at the liner interface under medium or strong seismic motion, which limited the propagation of seismic waves. If the effect of the liner interface on the seismic response of the landfill is not taken into account, some errors might occur. It can be seen that the landfill with 15m height showed maximum value of maximum horizontal acceleration (MHA) at the top of the landfill. With the increase of the landfill height, the fundamental period of vibration of the landfill is gradually increasing, and deviating from the resonance range. Thus, the MHA values at the top of the landfills are lower for higher landfills. Additionally, comparing with the calculated results under four different site conditions, it can thus be concluded that different site types have strong effects on seismic responses of landfills.