UAV, laser rangefinder and other high-tech equipment help the Great Wall "physical examination"
through UAV, we can not only look down from high altitude and comprehensively grasp its damage status, but also reach some dangerous city walls that cannot be reached by manpower for close observation
the Ming Great Wall in Beijing is mainly concentrated in Pinggu, Miyun, Huairou, Yanqing and Changping areas. Among them, there are not only tourist attractions such as Badaling, Mutianyu, Jujiang 1 and Yongguan to promote the development of environmental protection, but also "dangerous sections" such as Jiankou and Huanghua city that need to be developed. Over the past hundreds of years, these great walls have been eroded by wind and rain. In recent years, with the increasing number of tourists climbing, many walls have been plagued with diseases
Zhongwang also participated in the optimization design of component structures, material experiments, 2D drawings, cross-section improvement, sample vehicle trial production and other work. Last year and this year, the cultural relics department of Huairou District repaired the damaged Great Wall in Jiankou section in two phases. Since last month, the district has taken the lead in launching a comprehensive investigation of the undeveloped and unrepaired Great Wall in the city. The investigators not only used high-tech equipment such as drones and laser rangefinders, but also spared no effort to measure each section of the wall with their feet, climb each enemy platform, check and record the diseases one by one, and discuss the repair methods. So far, they have found 10 enemy platforms and 3 sections of the wall of the Great Wall in urgent need of rescue. The day before yesterday, I followed the investigators and personally participated in a "physical examination" of the Great Wall
operate UAV aerial photography of the Great Wall
UAV laser rangefinders are on the battlefield
in early November, the lowest temperature in Beijing's urban area was about 3 degrees Celsius. In the Bohai town of Huairou, at the foot of the Great Wall, the temperature in the morning has fallen below zero. Gusts of wind poured into the valley, and those who had put on their charge jackets still felt bitter cold. Less than 9 a.m., investigators gathered under the Great Wall. Zhao Peng, the designer of the Jiankou great wall repair project, and Cheng Yongmao, the construction technology director, "they are foreign aid experts we invited to participate in the 'physical examination' throughout the whole process, so that they will have a clearer grasp of the diseases of the great wall and its future repair." Zhang Tong, director of Huairou District Cultural Relics Management Office, told me
when other survey team members discussed the best way to climb the Great Wall, Zhao Peng found a relatively flat land, opened his backpack and took out a four rotor UAV. After some operation, the drone soared up and flew higher and higher along the winding great wall until it was about 400 meters above the ground. Soon, the majestic appearance of the surrounding Great Wall was displayed in the returned picture. Zhao Peng set up a 5-second automatic photo taking program while piloting the drone to fly along the trend of the Great Wall
"through the UAV, we can not only take out the crushed sample and look down from high altitude to comprehensively grasp its damage status, but also reach some dangerous city walls that cannot be reached by manpower for close observation." He said that these will help make this "physical examination" more accurate. In addition, the data accumulated by UAV aerial photography will also help to establish a three-dimensional digital model of the Great Wall in the future and provide information for restoration and academic research
on the ground, investigators took out another "artifact" - laser rangefinder and began to measure the enemy station of the Great Wall. The maximum effective measurement distance of this distance finder can reach 80 meters, and the measurement accuracy can reach three decimal places. It can also measure the longitude, latitude and altitude, which is also conducive to the accurate inspection of the Great Wall
record the cracking and damage of the enemy platform. 2. The gear bar is deformed or the gear bar is not meshed with the gear: straighten the gear bar or clean and repair the damage of transmission parts such as gears and grooved wheels.
the enemy platform at the highest place has turned into ruins.
Huairou District numbered every enemy platform in the Great Wall, from 001 to 284. The Great Wall in the hazel valley section is mainly from enemy station 205 to enemy station 199. Among them, No. 205 and No. 204 enemy stations jointly formed the hazel Valley pass. In those days, this was an important channel connecting the inside and outside of the Great Wall, guarded by soldiers, and also the starting point of this "physical examination" of the Great Wall
inspectors soon found the problem. The bottom of the east side of enemy station 204 at the hazel Valley pass had collapsed, and dozens of stones were missing. The gateway arch on the outside should have a higher specification of five tickets and five volts, but now there are only four tickets and four volts left, and the rest of the bricks and stones are either damaged or simply gone. "We learned from the investigation with the villagers nearby that it should have been taken away by the local people to build water conservancy facilities many years ago." Wang Yu of Huairou district cultural relics administration explained that at present, the enemy tower at this pass has been seriously damaged. If left unchecked, the whole enemy tower will collapse soon
climbing eastward along the wall from enemy tower 204, the inspectors found that the wall of this section of the great wall also suffered from diseases to varying degrees: from the wall to the length of hickory and some other unknown vegetation, the root system has been embedded into the wall. "That is, in early spring and late autumn every year, we can climb the Great Wall to check the disease. In summer, lush vegetation can almost wrap the Great Wall, and it is almost impossible to walk." Cheng Yongmao introduced
climb countless steep slopes and climb to No. 200 enemy platform, the highest part of the Great Wall. Everyone is already panting. The enemy platform here is almost in ruins. "This place has become a ruins, and there is no way to repair it. It is also false to repair it to its original appearance, losing the original significance of cultural relics protection." Cheng Yongmao said
check the "condition" and "prescribe"
everyone began to climb the Great Wall at 9 a.m., and eating some bread with mineral water at noon was lunch. By the time they went down the mountain, it was close to 4 p.m. Passing by several steep walls with serious landslides in the middle, everyone helped each other, and even squatted forward and moved slowly. "Since last month, every 'physical examination' has been like this." Wang Yu said to him
it is noted that the "physical examination" of great wall is not only to check the "condition", but also to "prescribe a prescription". For example, in No. 202 enemy station, the inspectors found that the foundation of the enemy station had sunk and the external wall had bulged and flashed, and the maximum extent of wall cracking had reached about 10 cm, "it must be repaired as soon as possible". Everyone immediately began to discuss repair measures on the wall. According to the basic principle of the great wall repair, the repair must be minimal intervention, eliminate hidden dangers, do not change the original state of the cultural relics, and maintain their original shape, structure, materials and technology. Cheng Yongmao, who has rich experience in repair, told that the maintenance of this enemy station needs to be reinforced with channel steel to "pull" the wall on the north side, which has a tendency to collapse
as for the 204 enemy platform with the collapse of stones, Cheng Yongmao believed that it could be repaired by the collapse and masonry of the crenel wall, the collapse and masonry of stones, and the collapse and masonry of rubble. In addition, trees and weeds on the city wall can also be cleaned as appropriate to facilitate drainage and eradicate the hidden danger of wall frost heave caused by water storage
Cheng Yongmao bluntly said that repairing this section of the Great Wall is even more difficult than repairing arrow buckles. This is also a water shortage area, which needs to draw water from the foot of the mountain, and the pipeline needs to be re laid. Unlike Jiankou, a set of safeguard facilities have been established at the foot of the mountain and halfway up the mountain. "There are many collapsed places here, and there is also a certain danger." He said
call on tourists not to climb the wild great wall
Zhang Tong, director of Huairou District Cultural Relics Management Office, told that the Ming Great Wall in Huairou is the most essence of the Great Wall, and there is a saying that "the great wall of China looks at Beijing, and the great wall of Beijing looks at Huairou". Huairou Great Wall is an important part of Beijing's construction of the Great Wall Cultural belt. She revealed that in the third National Great Wall resource survey in 2006, Huairou District conducted a resource survey of 65.4 kilometers of the Great Wall in the territory and established the archives and basic data of the Great Wall. This time, the main thing is to find out the "cause" of the great wall and carry out "treatment" after it is convenient
she said that except for a small part of the great wall that has been reinforced and repaired, the vast majority of the Great Wall has not been repaired. In recent years, due to the large number of tourists climbing the wild great wall and the long history, there is a trend of increasing damage, which is in urgent need of further investigation. Based on this, the Huairou District Cultural Relics Management Office took the lead in carrying out a detailed survey of the Great Wall in the city. This survey is mainly aimed at the undeveloped, unrepaired and the great wall where tourists climb more. Ancient architecture experts and repair and design experts were invited to complete the investigation, find out the diseases of the Great Wall on site, conduct preliminary design on site, and put forward the rescue and reinforcement method of minimum intervention and not changing the current situation of cultural relics, so that the Great Wall will no longer be damaged
it was learned that the "physical examination" of the Great Wall began in mid October, and the "physical examination" of the great wall section was mainly concentrated in Jiuduhe Town, Bohai town and Yanqi Town, Huairou District, with a total length of about 35 kilometers. As of press time, all the Great Wall in Jiuduhe town and some of the Great Wall in Bohai town have completed the "physical examination", and a total of 10 enemy platforms and 3 sections of the Great Wall have been found in urgent need of rescue. "After the completion of this work, we will report the design scheme to the Beijing Municipal Bureau of cultural relics in accordance with our priorities, and strive for the fastest time for rescue and reinforcement." Zhang Tong said. In addition, the Department of cultural relics specifically appealed to tourists not to climb the wild great wall; Disorderly climbing is not only very dangerous, but also easy to damage the historical and cultural heritage left by our ancestors