三、发展历程3.1早期:以改善城市环境为目的,形成庞大的下水道网络早在1370年,巴黎就有了第一个用石头砌筑的弧形封闭式下水道。1850年代奥斯曼主持了巴黎改造,建设了宽敞的下水道,长度也从26 km增长到约600 km,而且与地面道路的命名相同,还建了2.6万个下水道井便于检修和维护。同时,铁路和采矿的需求带动了隧道的发展,地下隧道技术 Third, the development process 3.1 Early: to improve the urban environment for the purpose of the formation of a large sewer network As early as 1370, Paris has the first stone-enclosed arc closed sewer. In the 1850s Haussman moderated the renovation in Paris, built a spacious sewer, and increased its length from 26 km to about 600 km, and named the same as the terrestrial road, and built 26,000 sewer wells for easy access and maintenance. At the same time, the demand for railways and mining has led to the development of tunnels and underground tunneling technology