Tunnelling in Hong Kong : McFeat-Smith, I Tunn Tunnlg V18, N6, June 1986, P39–44

Abstract

Hong Kong, a city of 5.4 million, has most of its population concentrated in a 40 sq km area. Its islands, the steep volcanic and granitic terrain, and large areas of reclaimed land have presented infrastructure construction problems. Included are the subways of the Mass Transit Railway and tunnels linking the harbor area and hinterland for supply of power and water and for surface rail and highway routes. Road projects have included immersed cross-harbor tunnels and twin-tube rock tunnels. Subway construction has evolved so as to avoid cut-and-cover construction, even at higher cost, to avoid surface disruptions. Portal sites present special problems in all construction. Rock tunneling is complicated by the variety of geological conditions; special support measures must also often be taken. Much of the subway construction was in soft ground requiring work under compressed air or adoption of soil stabilization. Hong Kong is a city at the limits of development with new civil engineering projects severely encroaching on the environment and incurring excessive construction costs. Such conditions make widespread use of underground space inevitable. The city has had considerable success in its underground construction, often achieved at high cost and by the sheer tenacity of the construction organizations.