陷落柱波场模拟是研究陷落柱地震波响应及偏移成像的前提，然而传统的结构化网格难以准确表征其复杂的剖面形状和围岩特征，对不规则陷落柱的波场模拟存在误差。为此，构建6个不同剖面形状、围岩特征的陷落柱模型，采用Blossom-Quad法生成非结构化四边形贴体网格。通过Legendre谱元法开展了弹性波地震波场模拟，并对比分析不同陷落柱模型的波场特征。结果表明：Blossom-Quad网格剖分法对复杂陷落柱模型具有较高的适用性，谱元法可以在此基础上获得更加准确的地震波场。陷落柱的柱顶、柱底及地层错断点处会形成绕射波且不规则陷落柱的绕射波更复杂，同时绕射波的形态受陷落柱剖面形状影响。震源位于陷落柱两侧时会形成柱壁反射波，且反射波的形态与陷落柱的柱壁形态基本吻合。除此之外，当陷落柱错断地层界面时，地层反射波受陷落柱影响出现同相轴错断、凹陷、振幅减弱等异常特征，且水平分量波场中的反射波异常较垂向分量更明显。

The simulation of seismic wavefield is a precondition for studying the wave response and imaging of collapse columns. However, traditional structured grids are difficult to accurately describe their complex vertical shape and wall rock features, leading to errors in wavefield simulation for irregular collapse column. Therefore, six models of collapse column with different vertical section and wall rock were constructed, and Blossom-Quad method was used to subdivide non-structured quadrilateral body-fitted grids. Then seismic wavefield was simulated by using the Legendre spectral element method and a comparative analysis about wavefield characteristics of different collapse columns was given. The analysis results show that the Blossom-Quad method has high applicability for complex collapse column models, and spectral element method can obtain more accurate seismic wavefield based on this. Diffraction waves are formed at the top, bottom of collapse column and breakpoint of geological interface, and the irregular collapse columns have more complex diffraction waves. The shape of diffraction waves is also affected by the vertical shape of collapse column. When the source is located on both sides of the collapse column, reflection waves form at column wall and the wall morphology is basically consistent with reflection morphology. In addition, when collapse columns cut off the stratum, the stratigraphic reflection appear abnormity such as discontinuity, indentation and amplitude attenuation of events. And these abnormity of wavefield is more obvious in horizontal component than vertical component.