Digital tech to reinforce Great Wall conservation

Digital technologies are increasingly helping researchers move beyond documenting the Great Wall to diagnosing deterioration, assessing future risks and uncovering previously hidden patterns in the ancient structure.

Initially, 3D surveying was largely used to digitally record the Great Wall and reproduce its form on computers. But researchers are now combining such records with environmental and geographical data to answer more complex questions about its conservation, said Li Zhe, a professor at Tianjin University's School of Architecture.

"Taking a scan is only the first step," Li said. "What we really need is the result of a full-body examination, to see what the problems are, where the risks lie and what should be done next."

That shift toward a diagnostic approach is also reflected in a new Beijing technical standard specifically covering surveys for Great Wall conservation projects. The standard, which took effect on Jan 1, establishes a framework covering field investigation, surveying, specialized testing and deterioration assessment.

It calls for quantitative analysis of deterioration and the combined use of technologies including 3D laser scanning, oblique photography and ground-penetrating radar. The standard is intended to address problems including inconsistent survey methods and inaccurate diagnosis of deterioration, according to a statement on the Beijing Municipal Cultural Heritage Bureau's official website.

Li addressed the recently held 8th Badaling Great Wall Cultural Forum in Beijing's Yanqing district. Under its theme of "Preservation, Integration and Continuity", the forum brought together Chinese and international experts to discuss Great Wall conservation, cultural heritage and sustainable development.

For a structure stretching thousands of kilometers across varied terrain, digital data can help researchers map the location and severity of deterioration and identify sections requiring greater attention, Li said. By incorporating factors such as rainfall, terrain and water flow, researchers can move from mapping existing deterioration toward assessing future risks.

The growing role of technology has also been incorporated into Beijing's legal framework for Great Wall conservation.

The Regulations on the Conservation of the Great Wall in Beijing, which took effect on March 1, require the municipal cultural heritage authority to establish an information management platform to collect, organize and analyze data on Great Wall resources, conservation and monitoring.

The regulations also call for meteorological, seismic, geological and hydrological monitoring data to be shared to support risk assessment and preventive measures. They encourage the use of technology and multidisciplinary research to improve research-based restoration, preventive conservation, monitoring and early warning.

Some of those technologies are already being utilized. During a Beijing municipal government news conference in December 2025 on the city's cultural development, Chu Jianhao, deputy director of the heritage bureau, proposed the development of a Great Wall resource information, monitoring and early warning platform, establishing regular drone patrol routes and piloting the use of quadruped robots for inspections.

Projects at Badaling and Dazhuangke sections have also used 3D scanning and digital modeling to build digital archives that allow conservation work to be traced over time, Chu said. The use of drones has already expanded at Badaling. Yanqing has carried out 3D digital modeling of Great Wall resources and expanded the use of drones in conservation, said Li Dan, Party secretary and director of the Yanqing district Great Wall administration, in an interview with China Tourism News.

Drone patrol routes have increased to 30, extending for 43 kilometers and covering the entire Badaling Great Wall heritage area, Li Dan said.

Such digital tools can also challenge judgments based on field observation alone. Li Zhe said that a section of the Great Wall on the Loess Plateau appeared vulnerable because of the steep terrain, but calculations incorporating geological and rainfall conditions indicated relatively low risk. "There are things you simply cannot perceive yourself," he said. "The data can give you a scientific conclusion."

Digital technology is also allowing researchers to answer seemingly simple questions about the Great Wall that were previously difficult to resolve.

Using data collected along the structure, Li Zhe's team identified a section around Jiajiakou in Dazhenyu village of Beijing's Huairou district as the steepest they had measured. Its gradient exceeds 64 degrees when measured over 30 meters and 72 degrees over 10 meters.

The data further showed that particularly steep sections are concentrated along a stretch of less than 16 km from Jiankou through Jiajiakou toward Huanghuacheng. According to Li Zhe, that pattern reflected a combination of the area's sharply cut mountainous terrain and its historical strategic importance northwest of Beijing. "Whether we are studying deterioration or making new discoveries, the key is that data eventually leads us to scientific conclusions," Li Zhe said. "It is about much more than the data itself."

The next step, Li Zhe noted, is to better integrate large-scale digital surveys with long-term monitoring and records of previous restoration projects. Such integration could help researchers determine not only where conservation is needed, but also which restoration approaches are likely to prove more durable under different environmental conditions.

zhengjinran@chinadaily.com.cn