Reached Pattern Of Ground Surface Settlement Caused By Construction Of Underground Works In Urban Areas And Establishment Of Database

Due to the rapid development of China's economy and urbanization, the construction of urban underground works in China has entered a rapid development stage. It is expected that large-scale Metros and other underground works will be constructed during the period from the beginning to the middle of the 21st century. Therefore, numerous geotechnical problems will come into being that must be resolved properly. Especially, the ground surface settlement caused by the construction of urban underground works may jeopardize the safety of the surrounding buildings, structures and underground utilities, resulting in huge economic losses and severe adverse social influences. Therefore, how to avoid the collapses during construction and how to effectively predict and control the surface settlement caused by construction have already become one of the most important topics that must be addressed during the construction of Metros and other urban underground works. Furthermore, the geological conditions, structures and surrounding environments of the Metros and other urban underground works become more and more complex, therefore, there exist great difficulties and risks in the construction of the works and the mechanisms and distribution patterns of the surface settlement caused by the construction become very complex.Many scholars in China and foreign countries have made extensive researches on the pattern of the surface settlement resulted from the construction of underground works by means of monitoring data, theoretical calculations or model tests. Due to the complexity of underground works, however, there are many factors that have impact on the surface settlement, therefore it is difficult to achieve research results with common significance by means of theoretical calculations and model tests and most of the empirical formulas achieved by means of monitoring data do not have common significance either, due to their local features.If the surface settlement data of numerous project cases are collected, settlement database is set up and the relations with the corresponding project parameters, such as engineering geology conditions, hydrogeology conditions, construction methods and construction technologies are established, deep analysis and summary can be made on the pattern of the surface settlement of many project cases by means of the database. Furthermore, the database can be used for information reference. In the study, a surface settlement database is established for the first time in China, by means of which deep analysis is made on the monitoring data of the surface settlement of different project cases under the condition of different cities, different geologies and different construction methods. The database has great significance for the evaluation, analysis and prediction of the impacts on the surrounding environments imposed by the construction of underground works. Furthermore, the database can be used as basis for the establishment of the expert system in the future.