Stability analysis and protective measures for the sacrificial pits at Sanxingdui Site

Maintaining structural stability is a prerequisite for the safe conservation of archaeological sites. To ensure the structural stability of the sacrificial pits during the excavation process at the Sanxingdui Site, a study was carried out on the influencing factors and protective measures of the sacrificial pits stability. Firstly, a high-precision three-dimensional model was constructed based on the three-dimensional point cloud data of the pit body and the measurement results of the pit top unloading fractures. Subsequently, the Delaunay triangular decomposition method with constraints was employed to establish a three-dimensional grid model incorporating the spatial structure of the fractures. Finally, the horizontal displacement or vibration speed of the pit body under layered excavation, equipment loading, crowd standing, and earthquake action was calculated using the ABAQUS software. Based on the results above, the influence of various conditions and scenarios on the stability of the pit body was analyzed. On this basis, targeted preventive and control measures were adopted to maintain the stability of the pit body. The above research findings indicate that the equipment loading scenario with the long or short side less than 1.5m from the edge, the crowd standing scenario with the long side less than 0.3m or the short side less than 0.2m from the edge, and the earthquake action scenario with a magnitude of VI or above are the most unfavorable conditions for the structural stability control of the pit body. The middle part of the long side of K3, K6+K7, and K8, especially the location of the unloading fractures, is the key object of structural stability control. Therefore, on the one hand, we utilize routine management to implement necessary prevention and control of human-controllable factors such as equipment loading and crowd standing. On the other hand, we employ temporary support structures to cope with natural uncontrollable forces such as earthquakes. Through the combination of proactive prevention and passive control measures, the structural deformation of the pit body has been effectively controlled.