Mastercivilengineer

The Great Wall of China, regarded as one of the seven construction wonders of the world is like a gigantic dragon, winding up and down across river valleys, forested ridges, deserts, grasslands, mountains, and plateaus. It is one of the most appealing attractions owing to its architectural grandeur and historical significance. It stands as a witness to Chinese history, culture, and development. Known in Chinese as Wanli Chang Cheng, the 10,000 Li long wall (Li = 1/3 mile), is a wonder of ancient military fortification stretching, 6,320 km (3936 miles). This distance is one-sixth of the way around the equator. It is a fantastic relic from the past that attracts lakhs of visitors from all parts of the world. It has rightly been said, “The man who doesn’t visit the Wall has never been to China”. A popular and fond legend states that the Wall can be seen from the moon, but astronauts Neil Armstrong, Jim Lovell, and Jim Irwin have denied it. On 6th March 1985, a report from China stated that a 5-year long survey proved that the total length had been 9,980 km (6200 miles).

History

No one can tell precisely when the construction of the Great Wall commenced but it is popularly believed that it started in the 3rd century B.C. The vassal states under the Zhou dynasty in the northern parts of China each built their own walls as a line of defense against the fierce Mongol horsemen of the Hsiung – Nu tribes – the Huns. The Qin dynasty unified China from 221 – 207 B.C. Qin Shihuangdi also called Chin Shih Huang Ti, the First Emperor of Qin began conscripting peasants, enemies, and anyone else who was not tied to the land to work on the wall. This tradition lasted for centuries with each dynasty adding to the height, breadth, length, and design of the Wall. The Qin dynasty joined the Walls to hold off the invaders from the Xiongnu tribes in the north and extended them to more than 10,000 Li or 5,000 km. After the Qin dynasty, the Great Wall was renovated from time to time.

A major renovation started in 1368, with the founding of the Ming Dynasty (1368 – 1644), and took 200 years to complete. The construction of the Great Wall continued into the Han & Sui dynasties. For centuries, the Wall not only served as a defense but symbolized the power of the emperor. It was only when a dynasty had weakened from within that invaders from the north were able to advance and conquer. The Mongols (Yuan Dynasty, 1271 – 1368) and the Manchurians (Qing Dynasty 1644 – 1991) were able to take power due to the weakness of the Government but never due to the defectiveness of the Wall.

Location

The Great Wall extends from Shanhaiguan Pass in the east to Jiayuguan Pass in the west traversing the provinces of Liaohing, Hebei, Beijing, Tianjin, Shanxi, Inner Mongolia, Ningxia and Gansu.

Dimensions

Emperor Shihuangdi stated that the Wall should be 6 horses wide at the top, 8 horses wide at the bottom, and 5 men high. The average height of the present Wall is 10 meters (30 ft.). Thickness varies from place to place ranging from about 4.5 meters to 9 meters (15 – 30 feet). The total length is about 6,700 km. (4163 miles). Every 100 yards, square watch towers two stories high were built. If one takes away the Wall from China and rebuilds it on the Indian coastline it will stretch from Kutch around Kanyakumari to Kolkata. This means that it can cover the entire coastline of India. The Great Wall appears as a thin orange band when seen from space by radar.

The Jiayuguan Pass controls the corridor through Gansu province in the northwest, much of its arid loess (clayey yellow soil) and desert. The fortress, built in 1372 to guard the pass, is made of rammed earth and has walls about 9 m (30 ft) high, 6.7 m (22 ft) thick at the base, and just over 1.8 m (6 ft) wide at the top.

The wall’s height and width vary. In the Badaling section north of Beijing, it is about 8 m (26 ft) high, 6.7 m (22 ft) thick at the base, and about 6 m (20 ft) thick at the top -wide enough for five horsemen or ten marching men abreast. At the Jiaoshanguan Pass in the Yan Shan mountains, from where you can see the sea, the wall is only about 400 mm (16 inches) wide in places.

Architecture & Design

The Great Wall is a marvel in the history of construction. Weapons of ancient times comprised swords, spears, lances, halbards, bows, and arrows.

The architectural design had to resist these weapons. Hence, Walls with passes, watchtowers, signal towers, and moats were constructed. Feudal rulers strove to improve the construction of the Wall after it took shape in the Qin dynasty. During the Ming dynasty, sophisticated designs were added. Garrison posts, block houses, additional wall structures, beacon towers, and watch towers were redesigned. Modern cannons were mounted in strategic areas. These redesigned systems enabled the imperial court to stay in touch with military and administrative agencies at various levels and provide frontier troops with facilities to carry out effective shelter. Shelter towers with large interiors were built to store food and arms. They also served as living quarters for soldiers. A staircase from the interior led up to the towers where small holes served as lookouts. Signal stations were either round or square and solid in the center. Construction of the military fortifications on the Walls reached its peak when double wall sections were built in some military zones with strongholds and passes. The Great Wall extended from peak to peak. The height of the mountains was used to command a better view and for its advantage in defense. In a section of the Wall, a road is paved on the top with square bricks. It is wide enough for 6 horses or 10 soldiers to march side by side. Parapets are built on both sides of the road. The inner parapet wall, 1 meter high was built to prevent horses and riders from overturning and falling from the mountains.

Destruction

Since the 1600s, parts of the Wall in some areas have either been dismantled or buried in silt. Sands drifting from Mao Wu Su Desert to the north, especially in springtime have wrought considerable havoc on the Great Wall. Some 51.5 km (32 miles) of the wall have been destroyed since 1966. Part of the wall was blown up to make way for a dam in July 1979.

The Yulin belt of Wall lies along the path of the Yulin-Shenmu Road. Construction of the highway on the line of the grand old fortification has also led to destruction. In provinces like Ningxia, Shanxi, Gansu, and Inner Mongolia, thousands of miles of tamped earth have been quarried. Rich soil from the ramparts has been used as fertilizer while in some areas, bricks have been taken for road construction as well as reservoir and house building. Some parts have been dynamited and stone sold off. The China Great Wall Academy, on conducting a 45-day long survey of 101 sections of the Wall in different provinces reported on Dec. 12, 2002, that the distance of 10,000 Li or 5,000 km is now merely a historic record. Only less than 30% of the Wall remains in good condition.

Material & Technology

Materials and technology utilized in the construction of the Great Wall varied in each period depending on the terrain, local conditions & engineering techniques. The management of the contract and responsibility system was put into practice. One principle commonly followed by each dynasty was to ensure that the designer utilized maximum of the natural terrain such as steep mountains, and river gorges. Local resources like masonry, rocks, and packed earth were used in construction. The original Qin Wall was made of layers of compacted earth. Scientists have observed from the exposed transverse section, as seen today, that the foundation is comprised of a layer of raw earth over 1.5 meters thick at the bottom with further layers above, some 3 meters thick. The Wall was built on this foundation with layers of tamped earth. The construction of each section was organized from one of 11 fortress towns from Liaodong in the east to Zhangye in Gansu province in the west.

The Mings were the greatest of Wall builders. Their astounding accomplishments dwarfed the earlier achievements of the Qins and Hans. They not only built a bigger, more solid, and imposing Wall but also added advanced fortifications. The Ming Wall was constructed with a tamped-earth interior with kiln-fired bricks and stone slabs forming the outer layers. Workers mixed lime and sticky rice for use as mortar between bricks. The Great Wall in the east winds its’ way along the ridges of mountains and has a facing of brick and stone while the section to the west has tamped earth with no covering.

Where possible bricks and lime for the building were produced in kilns alongside the site. However, they still had to be carried to the high ground using men and donkeys.

48 brick kilns were recently unearthed near Shanhaiguan Pass, the first pass of the Great Wall built during the Ming Dynasty (1368 -1644). Experts believe that they were used to make bricks for the Wall and are the oldest ever to be discovered in China_ Bricks measured 36 cm in length, 17 cm in width, and 9 cm in thickness, each weighing about 10.5 kgs. Huge slabs of stone have also been used some weighing about a ton. How they were hauled to the heights no one knows. Some may have been hoisted with windlasses rope wound around a drum with a cranked handle. Corner stones were sometimes fixed in place with iron tenons, the molten iron being poured into cut-outs in the stones.

Almost every section of the wall has an inscribed tablet naming the engineers and construction chiefs. But for the many men who died on the job, the wall itself is the only monument. The Shanhaiguan Pass is the gateway from northeast China to the central plains. The three-story gate tower of the Great Wall is over 9 m (30 ft) high, and a tablet over the gateway reads ‘First Pass Under Heaven’.

Tamped Earth Process

This process began with a simple wooden frame. The exact methodology of construction was as follows:

• The workers laid a bed of red willow reeds and twigs at the bottom of a wooden frame.

• They filled the frame with a mixture of water and fine gravel and tamped the solid into a compact 100 mm (4 inches) thick layer. In sandy areas of the Gobi Desert, it consisted of 200 mm (8 inches) layers of sand and pebbles alternating with 50 mm (2 inches) layers of desert grass and tamarisk twigs tied in long bundles.

• After the mixture had thoroughly dried, the wooden frame was removed leaving behind a solid slab of tamped earth. The willow reeds reinforced the earth just as steel rods reinforce the modern concrete and the wooden frame worked as a formwork.

• The process was repeated layer upon layer and the Wall slowly rose 4 inches at a time. Detritus (organic and inorganic waste and debris) was mixed into the wall in order to make it solid.

Signaling and Coding Systems

Beacon towers were constructed along the Wall at an interval of 25 to 50 km (15 to 30 miles). Communication signals were sent out from the towers. During daylight, smoke signals were widely used. Many different materials like wolf dung were used to create variations in the color and density of the smoke which results in smoke hanging in the sky for a long time. At night, lanterns and beacon fires, clappers, drums, and bells were used for signaling. The invention of gunpowder proved to be an invaluable asset to the signal system as the firing of cannons could travel over longer distances. Ingenious coding systems were devised. Codes included a combination of cannon fire, smoke signals, and other devices. During the Ming Dynasty, a single shot and a single fire or smoke signal meant that about 100 enemies were attacking. Two shots and two signals warned of 500, three shots and three signals warned of over 1000, and so on. Thus, messages were transmitted over more than 500 km within a few hours. Chinese rulers found that the beacon system relayed messages faster than a rider on horseback.

Hard Labour

A great army of manpower comprising of soldiers, convicts with shaven heads and iron collars, prisoners, and local people built the wall. The emperor’s soldiers grabbed criminals, troublemakers, musicians, teachers, writers (scholars), artists, and humble peasants to help build the Great Wall. Forced labor was mostly used. They were pushed to exhaustion & often left without food. Although Meng Tian construct a road as a supply chain for garrisons & workers, food often did not reach the outlying places. It was either sold or eaten by the carriers themselves. Qin Shi Huang began a policy of growing crops on wasteland located beside the wall. This policy continued through successive dynasties that repaired or rebuilt the wall. Peasant farmers resettled in the area to boost the food requirement for the workers and the militia. The soldiers too were allotted small plots. The farmers not only grew crops but also fruit trees in case the crops failed. Water conservancy schemes were organized to irrigate the crops from the Han Qu canal fed from the yellow river near Yinchuan in the central area of the wall. Labors/workers who tried and complained to run away were buried alive. It is sometimes referred to as the “LONG GRAVEYARD” because so many people died while building the Wall. Chinese legends say that a million died before it was finished. Conditions of living and construction were poor and work was arduous. Laborers had to work in difficult terrain in extreme weather with temperatures plummeting from 35° C in summer to -21° C in winter.

During the Qin Dynasty, under the direction of General Meng Tian, 3,00,000 troops worked over a period of 10 years. Later in 555 A.D., 18,00,000 people were forced to join the ranks of laborers when a 450 km long section was added to the wall from Nemkon, Beijing to Datong, Shanxi.

Culture

The Great Wall has long been incorporated into Chinese mythology and popular symbolism. Many great, soul-stirring campaigns and historical events were inseparable from the ancient walls. A considerable part of Chinese history unfolded around the Great Wall. Beautiful legends are centered on the construction of the Great Wall. The most noted is the story of the collapse of a section of the Wall caused by Meng Jiangnu’s tears over the death of her husband during construction.

In the 20th Century, the Great Wall came to be regarded as a national symbol. Sun Yat-Sen & Mao Zedong utilized the Wall to represent the nation. In 1984 Deng Xiaoping commanded that patriotic Chinese should restore the structure. “Let us love our China, let us restore our Great Wall’, became a popular slogan.

Swarms of tourists from over the world have come to see this ancient Chinese Wonder with the result that it has become trendy to walk along the wall. The current difficulty is to strike a balance between the need to protect China’s cultural heritage & the economic benefit it engenders through the tourism it brings to the nation. Steps have to be followed to maintain the Wall in a manner that doesn’t detract from its cultural importance while keeping it in good condition for the benefit of future eternity.

Conclusion

The Great Wall of China qualifies for the title of the greatest building work attempted by human hands and surviving today. It is a symbol of man’s spirit and the capacity to construct what he needs. It has served as a monument of the Chinese nation throughout history.