The most popular repair of Jiankou Great Wall was

2022-07-28
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Repair Jiankou Great Wall: the design scheme is improved for the first time with the help of UAV and other high-tech means. As the weather warms up, the Jiankou great wall restoration project is about to start again

the Jiankou Great Wall, 30 kilometers away from Huairou City, is named for its shape of bows and arrows. It reaches Shanhaiguan in the East, Jiayuguan in the west, and Badaling and Juyong Pass in the southwest. Its military status is dangerous. Nearly 8000 meters of the city wall twists and turns on the Yanshan cliff, known as the most dangerous section of the Great Wall

in 2016, the Jiankou Great Wall started to be repaired. At present, the most famous TIANTI and Yingfei inverted sections with a total length of 1003 meters have been completed. In February this year, the State Administration of cultural relics officially approved the repair plan for the eastern and southern sections of the Jiankou Great Wall. In the next three years, a total of 2772 meters of the great wall and 17 enemy towers will be repaired

it is worth mentioning that the arrow buckle repair follows the new concept of minimum intervention, improves the design scheme with the help of UAV and other high-tech means for the first time, and includes the archaeological link. In the previous great wall renovation projects, these ideas and technical attempts have been groundbreaking

the most dangerous section of the Great Wall. The Great Wall is scattered in 15 cities across the country. It is a majestic military defense line in ancient China. It also integrates thousands of years of history and symbolizes the national spirit

according to the census data of cultural relics, the Beijing section of the Great Wall is 629 kilometers long, most of which are the Ming Great Wall. There are more than 800 beacon towers and 71 checkpoints along the line. In the new Beijing urban master plan, it is clearly proposed to promote the protection and utilization of the Great Wall Cultural belt and build four clusters from west to East: Badaling Juyongguan section, Jiankou section, Gubeikou section and hongshimen section

Badaling, Juyong Pass, Simatai and Mutianyu have been repaired and opened to visitors for many years. At present, Huairou Jiankou and Pinggu hongshimen are still undeveloped wild great wall

arrow buckle is known as the most famous dangerous section of the Great Wall. The southern foot of Yanshan mountain is circuitous and overlapped, and the Jiankou Great Wall is winding along the mountain. There are many classification methods for fatigue experiment, sometimes piercing the peak, sometimes falling into the valley. The place names along the line, such as ox horn, Sabal tower, Beijing knot, general guarding the pass, eagle flying down to Yangon, are so cold that people can't help taking a breath

126 years ago, liuqingtang, a poet of the late Qing Dynasty, described the difficulty of climbing Jiankou, almost crossing the Shu Road, and left a poem: "when you travel here, you will look forward to people coming from the bird path.". Today, the precipitous Xiong 2.0 Qi Jian Kou has become the first choice for travelers to visit and photograph the wild great wall

in addition to its precipitousness, Jiankou Great Wall also has a decisive military position. Under the military pattern of the emperor guarding the border in the Ming Dynasty, nine important border defense towns were set up from the Yalu River in the east to the Jiayuguan pass in the West. Among them, the great wall of Ji Town, Xuanfu town and Chang town meets just north of the capital. This intersection is the Beijing knot of Jiankou Great Wall

when you climb the 958m node in Shanghai, you can clearly see three great walls from different directions, such as three ribbons, forming a big flower knot. Because of its military position, the Great Wall has dense enemy towers and tall walls. More and more rubble are used to fill the wall with bricks and cars

the vicissitudes of time. Floods, earthquakes, lightning strikes, plant roots and so on have all caused damage to the Great Wall, which is as solid as gold. Public data show that only about one tenth of the Beijing section of the Great Wall is well preserved. Before this repair, the weathering and collapse of the Jiankou section had been serious: trees were growing on the top of the wall, many side walls were collapsed and damaged, bricks and stones fell into the deep valley, and the ground was scattered and broken, endangering the safety of the structure

the cultural relics of the great wall are the geographical support and cultural carrier of the cultural belt. Zhangtong, director of Huairou District Institute of cultural relics, said that the Great Wall Cultural belt has rich connotations, including heritage protection, ecological restoration, infrastructure construction, cultural tourism and cultural communication. However, just as the skin does not exist, Mao will not be attached. All the excavation of the historical and cultural connotation of the Great Wall should be based on the remains of the Great Wall

it is urgent to repair the arrow buckle to slow down its natural weathering and damage

people carry mules and carry stones up the mountain

in April this year, the repair project temporarily suspended due to the cold weather is about to resume. As a technical consultant, chengyongmao, 62, has recently made several trips up the mountain to prepare for the repair of the arrow buckle. He was not tall and gray. He picked up a hickory tree as a walking stick in the mountains and set out from xizhazi village at the foot of the mountain

walk along a tractor road, bypass the puddles, and then enter the rugged trail. Before he reached the foot of the Great Wall, he was tired and breathless, but chengyongmao walked with ease. In August, 2016, the first phase of Jiankou great wall renovation project was launched to rescue the most famous ladder and Yingfei inverted section with a total length of 1003m. After 355 days, he ran to the Great Wall twoorthree times a week

when you climb on a bushy mountain road for more than an hour, a blue sky suddenly appears overhead. Here is the most famous dangerous peak of Jiankou: eagle flying upside down. After the repair, the rubble from the collapse of the enemy building and the enemy platform has been cleaned up, showing the broken walls. The cracked parts have been reinforced with cow legs, and the drainage system has been combed again

the most difficult thing to build the great wall between the cliffs is to transport materials such as stone and lime. More than 200000 bar stones, each weighing hundreds of kilograms, were carried by more than 30 mules to the centralized stacking site at the root of the Great Wall, and then transferred to the construction site. The mule was too tired to stand up because of the extremely hard work. It always fell to the ground to take a nap near noon. The stones that collapsed in the deep valley were also recovered one by one and transported to the cliff with a slope of nearly 80 degrees. A distance of more than 200 meters is nothing on the flat ground. However, on the steep cliffs, it has to be transported seven times by means of graders, winches, and people. It is as difficult as it was when Jiankou was built 480 years ago

it is difficult to transport stones up the mountain, and the technical difficulty of repair is also very high. Chengyongmao said that the city wall was built according to the mountain potential, without vertical lines and horizontal lines. The size and angle of city bricks and stones have their own characteristics. During the repair, he summarized the principle of following the layer, slope, bend, old and residual. Not only are each city brick customized by hand, but also tung oil mixed with lime should be used for jointing to form buckwheat edge joint or loach back joint

the repair process follows the ancient method, but the scheme design uses high-tech means. In May last year, Zhaopeng, the designer of the Jiankou repair project, used a UAV for the first time during the survey. On the steep cliffs, the cracks of the city wall, which are difficult to view from a close distance, are presented in high-definition images one by one to help Zhao Peng improve his scheme

explore the limit of minimum intervention

on the Yanshan Dragon Ridge, the Jiankou Great Wall fell sharply along the 80 degree slope, like an eagle spreading its wings and turning over. The outermost stone steps on the city wall have been stripped away, exposing the core of the wall filled with rubble. During the repair, the steps were not restored, but the crushed stones falling from the surrounding areas were put back to their original positions for fixation, and the broken stubbles were retained

the repair of the great wall can be divided into several types, including rescue, restoration and installation of protective facilities for welcoming guests. Among them, the amount of emergency repair intervention is the smallest, and the historical information is retained most fully. Zhang Tong said that when Jiankou Great Wall was repaired, the concept of rescue and reinforcement was adopted. In the eyes of tourists, the purpose of the minimum intervention is to preserve the ancient and unsophisticated nature of the Great Wall, while Zhang Tong said its deeper meaning: rescue measures are reversible

take the North Building of the largest and most complete enemy building along Jiankou as an example. After years of wind and rain erosion, the wall was split by a palm thick crack, which was in danger of collapse at any time. During emergency rescue, 26 channel steels were used to hold corners and hoop the four corners of the coupon hole. Generally speaking, it is to tie up the Zhengbei building with a steel frame to eliminate potential safety hazards. Zhang Tong said: this method will not permanently change cultural relics. In the future, if we continue to repair and develop, we can directly remove the steel frame and restore its original appearance

the setting sun of the old fortress is more delicious than the neat new brick wall. Such an advanced repair concept started more than half a century ago

In 1952, Luo Zhewen, who presided over the repair of the Great Wall at Badaling, recalled his teacher Liang Sicheng's view that the old should be kept as the old, not replaced with new bricks and stones, and not used foreign ashes; Where there is no danger or danger to the safety of tourists, there is no need to repair all the broken places

up to now, the minimum intervention has long been the golden rule for the repair of the Great Wall. However, there are different opinions on how to do the minimum intervention, and there is no unified standard

in the first phase of the Jiankou great wall renovation project, the scheme requires no intervention during the renovation, and the addition rate of new bricks is only about 40%. In the second phase of the project started in August 2018, Zhaopeng, the designer of Jiankou renovation, became more conservative and even proposed not to add a new brick. At present, he is working out the repair plan for the eastern and southern sections of Jiankou, which will be more conservative than the second phase

we are constantly exploring the limits of minimum intervention. Zhao Peng thought for a while and described it with a metaphor: how many tablets can a patient take to recover? If two tablets can be cured, take only one next time. Next time, try half a tablet

leave nine wild trees for the Great Wall in early spring, there is still residual snow under the crenels of the city wall, but the mountains and weeds have quietly turned green

as long as the weather warms up and there is a rain, the flowers here will bloom everywhere. Chengyongmao said that the wild peach and apricot blossoms are the most beautiful scenery in spring

the trees on the mountain are jing'er, but the miscellaneous trees growing in the cracks in the bricks of the Great Wall make chengyongmao worried

the plant root system may be deeply embedded into the brick joint, resulting in wall loosening. Even if the root system is not deep, silt will gather around it to block the drainage of rainwater. Water, the greatest enemy of the Great Wall, causes freezing and thawing in winter and cracks the indestructible wall

should these trees be left when repairing the Great Wall? In terms of the project itself, this is not a difficult choice. However, the tenacious growth of wild trees has brought a different kind of beauty to the Great Wall: under the summer sun, the top of the wall is verdant, just like a mall; In winter, clusters of withered trees make the city wall more desolate and vigorous. Such a scene moved many travelers, calling for the preservation of wild trees as far as possible

one side is the safety of the wall, and the other side is the public aesthetic. Chengyongmao, who has been dealing with bricks and ashes for half his life, is in a dilemma. Since 2002, he has successively presided over the repair of 11 sections of the Great Wall, but such problems are unprecedented

Zhao Peng is also embarrassed. The Great Wall is not an ordinary cultural relic or site. It is rooted in the hearts of every Chinese. Therefore, under the premise of ensuring safety, we should also take into account the public aesthetic. Zhao Peng said that in the second phase of the project, he surveyed and analyzed every tree and shrub on the wall. Those threatening the safety of the wall will be cut off, and the trees that do not cause much damage to the wall will be preserved

the remaining trees are nine mountain peaches and apricots, about the thickness of the wrist, which grow in front of and behind the barracks 152 and 153. They grow on slopes and do not affect drainage. Moreover, the tree age is relatively long, and it has been closely hugged with bricks and stones. Zhao Peng explained that, just like a doctor, he would follow up these trees regularly. Once he found a threat to the wall structure, he would further develop a solution

build an open mode in sections

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