Modern thinking about the ground tends to take it as a purely material base for the unfolding of history and ideas emerging on its surface. In this article, I question above-ground visions of city building by drawing on both the history of ground engineering and ethnographic fieldwork carried out in Paris with geotechnicians. I address the difficulties that theorists have faced over past centuries in modelling soils, and the contemporary practice of building piles underneath buildings to anchor them. From this unfolds an understanding of the ground as produced through an equilibrium between forces and materials in which buildings become participants, rather than a solid base upon which they stand. Looking at the activities of foundation builders, we find that the inertia of the urban soil no longer betokens an absence of activity or movement, but is rather a continuous achievement, a slow and dangerous process of balancing tensions.

现代对大地的思考倾向于将大地视为展现历史和浮现于地表的思想的纯粹物质基础。在这篇文章中，我利用地面工程的历史和在巴黎与岩土工程师一起进行的人种学实地考察，质疑城市建设的地上愿景。我解决了过去几个世纪理论家在模拟土壤方面面临的困难，以及在建筑物下方建造桩以固定它们的当代实践。由此展开对地面的理解，它是通过力和材料之间的平衡产生的，建筑成为其中的参与者，而不是它们站立的坚实基础。观察地基建设者的活动，我们发现城市土壤的惯性不再意味着没有活动或运动，