Great Wall construction

Construction of the Great Wall

Why to build up the Great Wall?
The construction of the Great Wall started during the Warring States Period on 7th century B.C, more than 2,500 years ago.At that time, it was the Warring States Period in ancient China, Many dukedoms built walls in Central China to protect themselves from each other and from the "barbarians" in mongolia, the walls were built in the states of Qi, Chu, Yan, Han, Zhao, Wei and Qin. The Great Wall was only a regional project to ward off enemies from the north then. However, the separate walls were joined together and consequently stretched from east to west for about 5000 thousand kilometers in Qin Dynasty. The Wall had been further extended and strengthened the succeeding dynasties. Especially in Ming dynasty, the northern nomadic ethnic groups became very powerful, the emperor ordered to renovate the Wall many times to a full length of 6,700 kilometers (more than ten thousand Li, Li is a measure unit in ancient China).

What was the Great Wall made of?

The material to build up the Great Wall is different in different areas.
At the beginning, the Great Wall was mainly made of earth, stones and wood. Due to the large quantity of materials required constructing the Great Wall, the builders tried to use local resources. When they built over the mountain ranges, the stones of the mountain were exploited and used;In the plains, earth was rammed to construct;In the desert, even the sanded reeds and juniper tamarisks were used to build the Great Wall.
In Qin Dynasty (221BC-206BC) or earlier and later, the Great Wall was basically built by stamping earth because of the weapons like swords and spears at a low technology. Neither fortresses were constructed along the wall, nor bricks were used in the construction of gates at the passes. In this period, the wall was made of layers of rammed earth. The section remaining in GansuProvince today is a typical example. Scientists have found that the foundation comprises a layer of raw earth, over 1.5 meters thick at the bottom, with further loess above, some three meters thick. The wall was built on this foundation from layers of tamped-earth. The tamped-earth process began with a simple wooden frame. Workers filled the frame with loose earth, which was then tamped into a compact layer 4 inches thick. The process was repeated layer upon layer, and the wall slowly rose four inches at a time. So you can imagine how long it will take to build a seven-meter high wall. Detritus was mixed into the wall to make it more solid.
The period of Han Dynasty (202BC-220AD), earth or crude stones were still popular. The construction material did not reach a new level until the middle of the Ming Dynasty (1368-1644); however the principle of using local material was maintained.However, three hundred million cubic meters (393 million yards) of earthwork were used in the construction of the Great Wall, and with the appearance of large brick and lime workshops, some parts were also built with these new materials.
In a construction team there was Material Supply Department. For example, in JuyongguanPass names of supply departments such as kiln workshops, stone ponds and material supply departments were recorded. But the timbers for constructing the passes did have to be transported from outside areas when there were none available locally.
Bricks were material more convenient than earth and stone as their small size and light weight and convenient to carry, so that the speed of construction was improved obviously. Stone material was found to better resist efflorescence. So that in Ming dynasty,the great progress made is that the wall was built with a tamped-earth interior between kiln-fired bricks and stone slabs forming the outer layers. The popularly tourist section, Badaling section in Beijing is in this type. The workers mixed lime and sticky rice as a mortar filled between the bricks. This form of cement made the wall more solid. The Ming Wall is divided into the eastern part and the western part. The wall in the east winds its way along the ridges of mountains and here the wall has a facing of brick and stone while the section to the west of Shanxi, was built from tamped earth with no covering.

Who to build up the Great Wall?
Emperor Qin Shihuang sent General Meng Tian with an army of 300,000 forced laborers for the mission and built part of the new wall. That was the QinGreatWall-FromGansuProvince in the west to Liaodong in the east. When the Great Wall was firstly joined together under the direction of General Meng Tian for 10 years long during the Qin Dynasty, 300,000 troops were used. In addition to the frontier soldiers, the builders included conscripted laborers and convicts in exile. Later in 555 A.D. under the Northern Qi Dynasty, a 450-kilometre section of the wall was built ranging from Nankou, Beijing, to Datong, Shanxi. 1.8 million people were forced to join the ranks of the laborers. Owing to the arduous work and poor conditions both for living and construction, a lot of people died in the course of this project. Some of their remains were even buried under the wall.

How to transfer construction materials in ancient times?
On the Great Wall, big blocks of stone are each about two to three meters (6.6-9.8 feet) long and weighing 1,000 kilograms (close to a ton). But there was only primitive moving equipment in old ages. How ancient Chinese people moved massive materials up to the mountains in the Great Wall Construction? As historical records, people in ancient China adopted several ways to solve the problem:
It is the most primitive method in the construction of the Great Wall by labor force. Many people(They are soldiers, peasants and prisoners)died from the harsh work. People burdened the weight on their shoulders, and backs, passing the materials from the foot of the mountain right to the very top. The advantage of this method was that it could save a great of time. In addition, they were in a narrow path, and it can avoid workers running down each other. It also can raise efficiency of the construction.
Use wheelbarrows to roll timbers and crowbars. People made ingenious use of simple tools and took advantage of the natural setting to accomplishing their goals. The wheelbarrows were often used in the construction of passes and fortresses, which were built on the flat ground. Rolling timbers were used to carry huge stones onto the mountain. People also set up capstan on the top of the mountain to carry huge stones. Sometimes, they strung ropes across ravines to ferry the materials in baskets.
Put harnesses on beasts of burden to carry the most heavy goods and materials. Some of the domesticated animals helped greatly in building the Great Wall in the mountain range. Anyway, people tried all kinds of methods to transport the material for the construction of the Great Wall.
Thousands of years ago, these methods worked. It reveals the creativity and hard working of Chinese ancient working people.

Construction formation

In Qin Dynasty, neither fortresses were constructed along the wall, nor bricks were used in the construction of gates at the passes, Unlike the construction during the Qin Dynasty, the Han Great Wall is on the plain and in the Gobi region moats formed the main fortification. Along these moats at intervals of 1.25 kilometers, a beacon tower was built. Solders lit straw and wolf dung on beacon tower for signal fires because wolf dung was easily available, and it gave good upright smoke. Columns of smoke were used to warn defenders of an attack. One column smoke lit on beacon tower meant an outpost was being threatened by a force of fewer than 500 troops and two columns meant an attacking force of fewer than 3,000. Today in Dunhuang, you can also see the remains of these towers and even the firewood used to light the smoke.
In 1468, the Ming standardized the warning signals with cannon shots in addition to the smokes. In some regions, the mountains and rivers also served as barriers so no wall or moat was necessary but towers and castles were built in key points to ensure the continuity of the defenses. The important beacon towers were built in the following way: First, the workers laid a bed of red willow reeds and twigs at the bottom of a wooden frame. Then, they filled the frame with a mixture of water and fine gravel, which was tamped solid. When the mixture had thoroughly dried, the wooden frame was removed, leaving behind a solid slab of tamped earth, strengthened by the willow reeds just as steel rods reinforce modern concrete. Besides, fortresses, and shelters or simply as a signal station along the wall. For example, the shelter towers were built with large interiors to store food, arms and served as the living quarters for soldiers. A staircase from the interior led up to the top of the tower. On each side of the wall were small holes for lookouts. The structure of a signal station was either round or square shaped and solid in the center. The overall defenses were enhanced with a variety of features that included the use of artillery. To this day rusting iron canons can be seen at various locations along the wall.