By Simatai Great Wall
Dong Yaohui
Defensive walls
The architectural styles, types of structures and materials used in defensive walls were determined by differences in the geography, construction conditions and engineering technologies of the area. Walls can be categorized into earth walls, stone walls, brick walls, walls built into cliff faces, wooden barrier walls, trenches and other forms.
Jiayu Pass Great Wall by Xue Taibai / TuchongSimatai Great Wall
Rammed earth walls
Two main kinds of walls were used in the Great Wall of the pre-Qin period: walls packed with rammed earth, and dry stone walls. In the flat plains of northwest China where rainfall is low, rammed earth was often used to build walls. A layered packing method was generally used to build rammed-earth walls.
Zhangjiakou section of Great Wall by Chunlei Photography / TuchongSimatai Great Wall
Stone walls
Walls in mountainous areas and stone production areas were built with stone. Before the Ming Dynasty, stone walls were built with rubble; no neatly processed rectangular stones were used.
Huangya Pass Great Wall by David Parker / TuchongSimatai Great Wall
Brick walls and stone walls
By the Ming Dynasty, various types of walls had appeared along the Great Wall, and they were reaching perfection. Depending on the characteristics of various areas, there were packed-earth walls, rubble walls, brick walls, and rectangular-stone walls during the Ming Dynasty.
General Qi Jiguang mainly built the brick walls and stone walls. According to the Chronicle of Qi Shaobao, Qi Jiguang said in his memorial to the imperial court that “the old walls at the border are all crumbling, and cannot serve as defenses." He suggested building the Great Wall starting from Shanhai Pass measuring over 1,000km.
Ming Great Wall at Sanguankou in Helan Mountain by Tian Zhimin / TuchongSimatai Great Wall
Packed-earth walls were widely used to the west of the Garrison of Yulin, and they had very good defensive properties. Due to its rigorous construction, the Great Wall was very strong, and the invaders could only breach it by drilling holes underneath the wall.
The wall at the Garrison of Shanxi was built with packed earth on the inner side and bricks on the outer side. In some places, the core of the wall is packed with triad (a mixture of lime, soil and sand) and covered with bricks and stones on both sides.
Zhangjiakou section of the Great Wall by Ningfu Tingrui / TuchongSimatai Great Wall
The wall at the Garrison of Ji is mostly packed with lime soil or rubble in the center and then sandwiched between blue bricks, stone strips, or blocks on both sides. The walls that are covered in blue bricks were all built during the Ming Dynasty (1368-1644 A.D.). Lime paste was often used in brick walls to bond and fill the joints.
Special types of walls
In addition to the above, there were some special types of walls. Walls in mountainous areas were built on mountainsides. When a cliff face was extremely steep, the cliff itself would be used as the wall, and crenels would be built directly on top of the cliff.
In some places the Great Wall is made of oak. Its structure is different in various places. The walls built on plains or on important passes are tall and strong, while those built on steep mountains are low and narrow.
Great Wall at Niangzi Pass (Lady's Pass) by Laotan664 / TuchongSimatai Great Wall
The ground
The top of the Great Wall was paved with square bricks to make it convenient for troops to transport grain and weapons in times of war or peace.
Parapets
At the top of the wall, the side facing the inner lands was equipped with a parapet, which was about a meter high and helped to protect troops. This parapet allowed troops to avoid slipping and falling from the top of the wall.
Juyong Pass by Ma Jun Shark / TuchongSimatai Great Wall
Crenellated walls
On the side facing enemy territories, at the top of the wall, there was a battlement that lent itself to observation and shooting. It was about 2 meters high and was used for protection, and for attacking the enemy. On top of the Great Wall, crenellated walls were built on the inside and outside of some sections. This construction plan was adopted to prevent the enemy from bypassing the Great Wall and attacking from the inside.
Drainage system
The top of the battlement walls and parapet walls were paved with a layer of ridged bricks, which were high in the middle and low on either side to facilitate drainage. Rainwater flowed along the trough to the drainage hole and poured the water out of the wall through a spout. The spout was a stone trough more than a meter long, which was usually built into the inner wall of the Great Wall.
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During the Qi Jiguang period of the Ming Dynasty, along the outer sides of the walls, rugged slopes were carved into mountain sides, and trenches were dug on plains.
