Internal building structure of the Great Wall (2021-08-11) by Wu QiangSimatai Great Wall
Although the external structure of the Great Wall is highly similar, the internal structure of each watchtower is different. There are domes, corridor roof, square roof, hollow roof and so on.
Dome
The dome is rare in the construction of the Great Wall watchtower as it's a complex and extremely difficult construction technology. It is also one of the criteria for judging the building level of the watchtowers.
Corridor roof
The design of a corridor roof inside a four-way watchtower demonstrates exquisite craftsmanship.
Internal building structure of the Great Wall--circular arch (2021-08-11) by Wu QiangSimatai Great Wall
There are four door openings around the dome, corresponding to the four directions of East, West, South, and North respectively. The center of the circle is the center of the watchtower.
Compared with the external structure, the internal structure of the Great Wall has more strict requirements and a higher technology level. It's also one of the reasons that makes the the Great Wall unbreakable and stands strong for a long time.
Multi-layer door openings
Usually, the Great Wall watchtower has three corridors and six door openings extending in all directions. It is convenient for rapid position changes, immediate operations and mobility of the soldiers.
The long and thin exterior passageway and arched roof
The combination of a long and thin interior corridor and multiple door openings enabled soldiers to run, transfer, and set up defense equipment at a sharp speed.
Protective measures for arched roof
Given its long history, the inner arched roof has been penetrated by rain. To protect the internal building structure, we use steel cables and other measures for reinforcement during maintenance.
