Ingenieur Vol 80 ingenieur 2019 octoberfinal | Page 77

Ancient Jiaohe city layout model. The layout of the ancient city is roughly divided into three parts. At the north end of the main road, you will see a large-scale monastery and magnificent towers in the north of the city, which may be pagodas used for burial or worship in ancient times. Jiaohe ruins cover a large area, which can be divided into monasteries, residential buildings, and Government offices to name just a few. Furthermore, the buildings in ancient cities are rammed with loess or clayey materials which are very distinctive. The archaeological finds revealed that the Jushi people had already been able to make iron tools for agriculture and livestock farming activities during the second century BC. The numerous historical articles unearthed at Jiaohe provided rich data for the study of the social economic conditions, politics, ethnic groups and the evolution of the ancient civilisation. Ancient Wells One of the questions posed by most visitors is how the residents obtained their water since the river is 10m below the cliff top plateau. Their main source of water was wells – there are traces of about 300 wells in the city. Most wells have a diameter of 1m and grove lines on the walls of the wells, formed by the cord’s friction. In 1993, archaeologists excavated a buried ancient well and they obtained water at a depth of 27m. The other means of access to water was likely via the 4.1m-wide East Gate which is 8m above the river bed. Archaeologists opined that this gate served mainly as a passage for obtaining water from the river for the residents who lived within the city walls. There is a pit filled with stone lumps at the right side of this East Gate which were used as weapons against invading enemies. Jiaohe was designated as a China State Council’s national major art and science protection area in 1961. With funding from the Government, the preservation and conservation works started in 1993 to 1995 which consisted of the following: a) testing the methods and materials for the protection and conservation 75