The adjustment of crop planting structure can change the process of water and material circulation, and thus affect the total amount of water and evapotranspiration in the irrigation district. To guide the allocation of water resources in the region, it is beneficial to ascertain the effects of changing the crop planting structure on water saving and farmland water productivity in the irrigation district. This paper takes Yingke Irrigation District as the background. According to the continuous observation data from 2012 to 2013, Based on the modified Soil and Water Assessment Tool (SWAT) model and taking advantage of monthly scale remote sensing EvapoTranspiration (ET) and crop growth parameters (leaf area index and shoot dry matter), we tested the simulation accuracy of the model, proposed irrigation efficiency calculation methods considering water drainage, and established the scenario analysis method for the spatial distribution of crop planting structure. Finally, we evaluated the changes in water savings in irrigation district projects and resources, the irrigation water productivity and the net income water productivity under different planting structure scenarios. The results indicate that the efficiency of irrigation has increased by 15~20%, while considering drainage, as compared with conventional irrigation efficiency. Additionally, the adjustment of crop planting structure can reduce regional evapotranspiration by 14.9%, reduce the regional irrigation volume by 30%, and increase the net income of each regional water area by 16%.

Local anchor failure can trigger progressive collapse of excavations, during which capping beams and walers, as key load-transferring components, experience significantly increased internal forces. However, the evolution of their mechanical responses remains unclear. In this study, large-scale physical model tests were conducted to systematically investigate the effects of anchor parameters (prestress, failure rate, and installation height), external hazard scenarios (local over-excavation and surface surcharge), and capping beam connection strength on the mechanical responses of capping beams and walers. The results show that applying prestress increases the lateral stiffness of the retaining structure and reduces the bending moment increase in the capping beam. Intermittent instant failure is the most unfavorable condition for the capping beam, inducing larger bending moments than rapid instant failure or slow failure. When anchors are installed at the waler level, the bending moment in the waler is significantly larger than that in the capping beam when anchors are installed at the capping beam level. Local over-excavation subjects the capping beam to larger shear forces at the edges of the over-excavation zone, making it susceptible to shear failure; accordingly, shear strengthening should be implemented at these locations, and strict control over the extent of over-excavation is required. Under surface surcharge, the critical load-bearing component varies with anchor installation height: when anchors are installed at the capping beam level, the retaining piles should be strengthened, whereas when anchors are installed at the waler level, the waler should be strengthened. The wall–anchor support system exhibits superior integrity compared to the pile–anchor system. Capping beam connections effectively disperse failure loads and reduce the increase in axial forces of adjacent anchors. Furthermore, I-steel connections for inter-panel strengthening can further enhance structural stability and increase the number of anchor failures required to trigger progressive collapse. These findings provide a scientific basis for the progressive collapse-resistant design of anchor-supported excavations.