ENVIRONMENTAL MAINTENANCE OF XIDAN STATION PROJECT OF BEIJING SUBWAY
北京地铁西单车站工程的环境维护

In the construction of Xidan Station of Beijing Subway, a station which is located just under the busiest section of the City, the environmental maintenance constitutes both the cultural requirement of a modern city and the controlling factor of the engineering construction. A "binocular" scheme including layer-by-layer control of country rock and surface subsidence was adopted by the units in charge of designing and construction, in combination with the application of five major technological measures, i.e. roof protection by largepipe shed, grouting through small conduits, supporting with latticed railings, shoterete with hanged net, and country rock measurement, which composed a supporting system with strata controlling and surface subsidence, through which the problem of maintenance of environmental stability both surficial and underground in the process of excavation of the great cave of the station was statisfactorily solved. With the reinforcement of engineering management, the problem concerning the gardens and grasslands, environmental sanitation, noise pollution, appearance of city, and trade activity were also well solved, and the environment around the station was fully maintained. The experience about environmental maintenance in the Xidan Station project is thus worth for reference to all urban underground engineering constructions.