Architectural energetics for rammed-earth compaction in the context of Neolithic to early Bronze Age urban sites in Middle Yellow River Valley, China

Abstract

Rammed-earth construction techniques (i.e., tamping or pounding loose earth into a solid mass with a rammer) were invented in the Iron Age Mediterranean and the Neolithic Middle Yellow River Valley and adopted across the globe overtime. Rammed-earth techniques were widely employed for building massive structures ranging from large tombs to the Great Wall in late Neolithic and dynastic China; as such, understanding the labor costs involved is fundamental for understanding labor organization for these public works.Ethnographic, historic, and previous experimental accounts provide inconsistent labor estimations for rammed-earth compaction. Our research develops a method for contextually relevant and reliable labor estimations for archaeological rammed-earth structures of varying quality. We built a rammed-earth wall under realistic conditions, quantified the influential factors for rammed-earth quality, and developed the protocol for calibrating experimental results to match the archaeological record.Our calibrated estimations for the rammed-earth walls at the Taosi and Erlitou urban sites reveal rather light labor demands on the inhabitants, implying that monumental architectures at the dawn of China's dynastic history in the Central Plain were less about manifesting power than facilitating social changes. Our method can be applied to estimate labor costs for earthen structures in general and enables reliable comparative studies across and space regarding the relations between massive earthen construction and social-political transformation.