Influences Of Excavation And Dewatering On Settlement And Safety Of Adjacent Buildings

With the large-scale development of urban underground space, the excavation engineering has become one of the important geotechnical engineering topics in urban construction. Nowadays, most of the excavation projects located in city center, and buildings are always influenced by the adjacent excavation construction. Therefore, the excavation engineering should not only to ensure the safety of the excavation itself, but also need to ensure the safety and normal use of adjacent buildings. Actual excavation engineering usually have matters with geological environment of the site, adjacent buildings and many other factors, so the results of theoretical studies should include different kinds of complex engineering problems. This research based on typical soft soil engineering geology in Nanjing He xi district, practical and deeply researches are carried on to study the influences of excavation and dewatering on adjacent buildings. The main research work includes the following aspects:(1) Seepage consolidation theory, influence factors of soil displacement during the excavation process, influence mechanism and influence type of excavation and dewatering on adjacent buildings are summarized.(2) According to the engineering geological characteristics in Nanjing He xi district, three-dimensional numerical analysis model considering the whole processes of the excavation are constructed. And this model is used to analysis the soil displacement change regulation close to the foundation pit and deform regulation of retaining structures. During the analysis, the influences of dewatering and excavation methods are considered, and different calculation results are compared. The calculation results indicate that the dewatering effects have significant influences on soil displacement close to the foundation pit, and different construction methods have different results.(3) The whole three-dimensional numerical model considering the foundation pit and adjacent building(frame structure, frame-sheer wall structure) are constructed to analysis the settlement influence regulation of adjacent building under different factors, these factors included the distance between the building and the foundation pit, excavation depth, dewatering, the thickness and depth of the retaining structure, construction method, foundation type and so on. The calculation results indicate that the settlement change regulations of buildings close to the foundation pit are almost the same, but the settlement value and differential settlement have certain difference.(4) The influence of excavation and dewatering on inter force change regulation of adjacent building are studied, and the safety and applicability of structure members are checked. The calculation results indicate that the bottom floor of the adjacent building will appear larger additional inter force, and when the foundation deformation of the adjacent building excess the allowable value of "Code for design of building foundation", part of the structure members may occur bearing capacity failure.