摘要
Abstract
Due to the construction of perforated pile,the impact load will act on the karst foundation,which may aggravate the existing karst ground collapse or cause the new karst ground collapse.Based on the theory of complete nonlinear dynamic analysis in Flac3D,the impact load is simplified into a triangular load mode,and the binary structure with the cover layer as"sand on top"is taken as the research object.The impact load is applied to the surface of the soil tunnel roof plate,and the displacement of the soil tunnel roof plate at different times is moni-tored to analyze the influence of impact load on the stability of the soil tunnel roof layer.The results show that the shock wave generated by the impact load propagates downward in the form of a spherical surface,and the displacement of the surface application point has a rebound phe-nomenon,and the vertical displacement near the roof plate of the soil tunnel is the largest,which indicates that the ground collapse mechanism under the impact load is the collapse and destruction around the soil tunnel,and the particles of the covering layer gradually lose to the soil tun-nel,and finally cause the ground collapse.In addition,through the analysis of vertical displacement of the roof plate under cyclic impact load,it can be seen that its increase rate is similar and gradually increases.Therefore,with the increase of impact times,the roof of the covering lay-er may produce instantaneous punching failure.关键词
循环冲击荷载/土洞/稳定性/数值分析Key words
Cyclic impact load/Soil cave/Stability/Numerical analysis分类
天文与地球科学
