## 4 Analysis of Results
### Analysis of Subsidence Monitoring in the Area along the Great Wall  
An analysis of Figures 4 and 5 uncovers four noteworthy areas of subsidence. This study examines the risk factors for the Great Wall in these subsidence areas, using the classification of damage, causes of damage, and existing diseases of the Great Wall specified in the \"Handbook for Great Wall Resource Survey\" released by the National Cultural Heritage Administration in April 2007 [(43)]. Segment D1 is located along the Yulong Bay shoreline in Hequ County, featuring a wall constructed from brick and stone. The topography of this area is defined by loess hills and gullies. Figure 6 illustrates the deformation rates of the D1 wall. Shanxi Province experiences significant annual variations in precipitation, characterized by uneven temporal distribution and frequent episodes of heavy, short-duration rainfall. These heavy rainfall events have the potential to cause damage to the structure of the Great Wall [(44; 45)]. Figure 4: Vertical ground deformation rates. The temporal deformation characteristics are analyzed by focusing on the well-preserved No. 1 Watchtower of Luoquebao in Hequ County, Xinzhou City. Figure 7 presents the surface deformation at Shichengkou and the corresponding precipitation levels during different time intervals, combining historical precipitation data from meteorological bureau statistics. There is a strong consistency between the deformation patterns at Shichengkou and the monthly variations in local precipitation. During the flood season,  
Figure 5: Vertical ground deformation segments. Figure 6: Deformation rate map of Great Wall Segment D1. which lasted from June to September in the years 2017 to 2022, Shanxi Province experiences increased precipitation. Consequently, the Luoquebao No. 1 Watchtower exhibits conspicuous subsidence, with a maximum subsidence rate approaching 10 mm/month. This suggests that erosion induced by intense, short-duration rainfall serves as the primary factor driving the subsidence and deformation of the Great Wall in Segment D1. Segment D2 is located in Shuocheng District, Shuozhou City, where the wall is predominantly constructed with sturdy brick and stone materials. The topography of the Great Wall's location is characterized by mountains and hills, with significant undulations and intense geological activities. The deformation rates of the D2 wall are illustrated in Figure 8. During the construction of Segment D2 of the Great Wall, advantageous topography was utilized along the western side of Shuocheng District, particularly the Daliang Mountains and other ranges, where the wall extended along the ridge lines. Consequently, factors such as unstable slope landslides and earthquakes have emerged as significant causes of deformation in Segment D2. This study investigates areas with significant subsidence rates in Segment D2, based on the distribution of subsidence rates. Figure 9 displays photographs of four locations in Segment D2 with severe deformation, captured by the Shanxi Provincial Cultural Heritage Bureau in 2018. It is evident that all four locations exhibit unstable slope bodies, indicating that deformation and subsidence in Segment D2 are primarily induced by unstable slope landslides and seismic events resulting from crustal movement. Segment D3 is situated in the northern part of Datong City, covering the counties of Huairen and Youyu. The wall primarily comprises yellow clay, which contains a significant amount of sand, gravel, and crushed stone. The topography of the area is characterized by plains and hills. The deformation rates of the D3 wall are depicted in Figure 10. Shanxi Province boasts abundant coal resources, with over fifty coal mines located in Datong City alone as of December 2022.