Damaging effects of earth fissures on high-speed railway bridges: Insights from physical experiments and numerical simulations

Earth fissure is a typical geological phenomenon related to surface rupture. With the rapid development of highspeed railways (HSRs) in recent years, earth fissure disasters pose a serious challenge to the construction and subsequent safe operation of HSRs. Here, we aimed to investigate the damaging effect of earth fissure activities on HSR bridges spanning the earth fissure zone. Taking the Shuixiu earth fissure of Da -Xi HSR as the prototype, a large-scale laboratory physical experiment with geometric model scale 1:20 was carried out to reveal the deformation and failure characteristics of HSR bridges under earth fissure activity. In addition, the damage influence range and damage mode of HSR bridges crossing earth fissures are further determined by numerical simulation. The results show that the earth fissure activity mainly has damaging effects on the structure of HSR bridges near the earth fissure zone, which is mainly manifested as uneven settlement of reinforced concrete pile, bending deformation of box girder and cracking of track slab. The width of the influence zone of Shuixiu earth fissure on the HSR bridge is determined to be 32.4 m. Moreover, the pile -end pressure on the hanging wall side of the earth fissure gradually decreases with the earth fissure activity, while that on the footwall side increases significantly. Most importantly, it is emphasized that a practical long -term monitoring and early warning system of HSR bridge structures should be established to prevent the hazards caused by earth fissure activities. The above understanding will benefit to the design, construction and operation of Da -Xi HSR line, and also provide significant guidance and reference to the construction of HSR bridges in other earth fissure prone areas.