Analysis On Covered Top-down Excavation Technique And Deformation Experiment

Takes precautions against natural calamities and reduces natural disasters in thecity is the great event that concerns the national economy and the people’s livelihood,from the current situation of china’s urban construction, urban planning, urban constr--uction level has been improved universally since reform and opening, while the consr--tuction of civil air defense project is lagged behind the urban construction. As a result,more and more cities began to notice the importance of the construction of civil airdefense projects, many large-scale air defense projects have being constructed in theheart of the city with the rapid social and economic development. Most of these airdefense projects are built in heavy traffic, building dense, underground pipelines criss--crossing the city downtown area and traffic areas, and the civil air defense projectsface the stations which ensure that traffic can not schedule and have much impact onthe environment contradictions at the same time. How to reduce the impact of trafficand the surrounding environment,and ensures that the construction schedule andanticipated technical and economic benefits have become the focus of civil air defenseprojects consideration.Because the Covered Top-down Excavation method has the character of shorterconstruction time, convenient building, less interference, low invest,goodenvironmental protection and other advantages, it has become a valid suggestionmethods in the center of large city with heavy traffic around subway station. In thethesis, a systematic research about the construct of the Covered Top-down method andimpact on the surrounding environment are given combined with the practicalexperience of the core area of the Old City underground civil air defense constructionprocess in Guiyang City. Firstly, the situations and characteristics of technologicaldevelopment in the Covered Top-down Excavation method are reviewed according tosome cities which are involved in the engineering practice and information in a foreign country; then the practice techniques for the Covered Top-down Excavation methodwhich include in the building envelope construction techniques, excavations, massconcrete pouring and construction joint construction technology and so on is proposedby combining the actual situation in china and the core area of the old cityunderground civil air defense projects in Guiyan; secondly, the key construction points,construction technology and the measures of quality supervision in the CoveredTop-down Excavation method are proposed during civil air defense projects; a numberof phenomena of ground deformation in construction process is researched andanalyzed by monitoring, and the impact law on the surrounding environment in theCovered Top-down Excavation construction is discovered finally.