# Soil and Rockfill Dams Safety Assessment for Henan Province: Monitoring, Analysis and Prediction
## 4 Results  
Deformation monitoring was conducted on 17 dams in Henan Province using the PS-InSAR technique. The cumulative deformation maps of each dam from March 2017 to September 2021 were obtained, as shown in Figure 7. The red ellipse represents the location of the master dam for each soil and rockfill dam. Figure 7: _Cont._  
Through deformation monitoring results, it can be observed that among the 17 large-scale soil and rockfill dams in Henan Province, there are three dams with relatively small deformation: The deformation on both sides of the Wuyue Reservoir dam is relatively small, with slight deformation in the middle. The Pohe Reservoir Dam and Nanwan Reservoir Dam show slight overall deformation, reaching \(-46\) mm, \(-30\) mm, and \(-31\) mm, respectively. The left side of the Yahekou Reservoir Dam demonstrates an upward trend, and the right side displays distinct evidence of subsidence, reaching \(-45\) mm. Dams with severe deformation on the left side include Songjiachang Reservoir Dam, Zhaopingtai Reservoir Dam, and Banqiao Reservoir Dam, reaching \(-66\) mm, \(-56\) mm, and \(-34\) mm, respectively. Dams with deformation in the middle include Luhun Reservoir Dam and Gushitan Reservoir Dam, both reaching \(-39\) mm. Dams with deformation on both sides include Nianyushan Reservoir Dam, reaching \(-37\) mm. Dams with severe deformation on the top include Zhaikou Reservoir Dam and Boshan Reservoir Dam, reaching \(-75\) mm and \(-22\) mm, respectively. Dams with overall deformation include Shishankou Reservoir Dam and Baiguishan Reservoir Dam, reaching \(-37\) mm and \(-71\) mm, respectively, and the most severe deformation can be found in Xiaolangdi Reservoir Dam, Yanshan Reservoir Dam, and Baisha Reservoir Dam, reaching \(-86\) mm, \(-142\) mm, and \(-173\) mm, respectively. The deformation of the middle part of Xiaolangdi Reservoir Dam is larger than that of the dam abutment on both sides. The deformation on the left side of Yanshan Reservoir Dam is serious, and the deformation decreases from left to right. The overall deformation of the Baisha Reservoir Dam is serious. From the deformation monitoring results, it can be found that all 17 large-scale soil and rockfill dams in Henan Province have various degrees of deformation. Therefore, it is important to pay close attention to these water conservancy projects. Analysis from soil and rockfill dam materials and anti-seepage structure types, soil and rockfill dams can be roughly divided into three categories: homogeneous dams, sloping wall dams, and core wall dams. Among them, core wall dams are the most commonly used type for large reservoirs in Henan Province. They feature a seepage control structure located in the center of the dam, with the sides of the dam slope supporting and protecting the internal core wall. This design provides a stable structure and good seismic performance, making it unique compared with the other two types of soil and rockfill dams. According  
Figure 7: Deformation of large soil and rockfill dams in Henan Province. (**a**) Shishankou Reservoir Dam; (**b**) Yahekou Reservoir Dam; (**c**) Wuyue Reservoir Dam; (**d**) Nianyushan Reservoir Dam; (**e**) Songjiachang Reservoir Dam; (**f**) Zhaopingtai Reservoir Dam; (**g**) Nanwan Reservoir Dam; (**h**) Zhaikou Reservoir Dam; (**i**) Yanshan Reservoir Dam; (**j**) Pohe Reservoir Dam; (**k**) Baiguishan Reservoir Dam; (**l**) Luhun Reservoir Dam; (**m**) Gushitan Reservoir Dam; (**n**) Boshan Reservoir Dam; (**o**) Baisha Reservoir Dam; (**p**) Xiaolangdi Reservoir Dam; (**q**) Banqiao Reservoir Dam. to the monitoring results, the deformation degree of dams with core walls is often smaller than that of dams without core walls. Because the soil mass in the core wall area is solid, and the gap is very small. Moreover, the core wall has the characteristics of low seepage, which can well block the water seepage to retard the deformation of the soil layer.