| This paper makes Weinan city Xinzhou estate F region deep foundation pit engineering as an example.In the deformation monitoring tasks, data processing, monitoring data feedback work, and in the process of data processing, found the layout of monitoring points is high in practical engineering, monitoring tasks, it tries to from the existing monitoring data of deep foundation pit engineering deformation characteristics and laws, and guide the determination of the important content of the layout of monitoring points and the monitoring work.Papers selected from a large number of monitoring data for the project F region on the west side of the horizontal displacement of pile and the surface subsidence as the research object, the side points more and gradation, can provide a more favorable for the analysis of the data.On scientific, rigorous processing of measured data, on the basis of the thesis analyze the west side of deep foundation pit horizontal displacement of each hole pile along the depth direction, along with the excavation of the foundation pit supporting curve characteristics under different working conditions and at different times, think the displacement of pile body above the foundation surface for the excavation of the location of the accumulation for the maximum. At the same time, at the top of the hole in the horizontal plane considering multiple survey, the 3 m above the foundation surface and the foundation of the horizontal position of the horizontal displacement, believe in the central position of foundation pit side CX9 displacement in different depth are larger, more Angle to the foundation pit, the smaller the deformation, and thus is deduced, and the center point to estimate the displacement of foundation pit lateral displacement formula of other points, and compared with the measured values, and more. Also, analysis of the rule of surface subsidence and the estimate formula of comparison, the result is more reasonable. Finally, using FLAC 3D numerical simulation, and analysis of the numerical results and estimates the results and the measured values, the numerical simulation can reflect the deformation law of foundation pit excavation, but estimates more close to measured values than the results of numerical calculation, estimate method is simple and accurate.In this paper the main results were as follows:(1) For single pile horizontal displacement deformation, At the beginning of the excavation, horizontal displacement of pile top is the largest. With the increase of excavation depth and construction of soil nailing and prestressed anchor cable support, the maximum horizontal displacement of retaining pile gradually moved towards the deep foundation pit. Ultimate displacement deformation presents a bow, the largest deformation in the vicinity of the middle lower part of the depth of excavation. The one side horizontal displacement of foundation pit shows a "big belly" shape, that is, small in the two head, big in the middle.(2) The one side horizontal displacement of foundation pit shows a "big belly" shape, that is, small in the two head, big in the middle. The more near to foundation pit corner, the smaller displacement it is. In contrast, the more near to foundation pit center, the greater displacement it is.(3) According to the research and analysis of multiple root pile in foundation pit side one point total displacement envelope diagram area characteristic, and the foundation pit side known about the maximum horizontal displacement of the 1/2 pile, the actual distance “l†between piles and the actual long distance “l side length†what can predict a side other pile horizontal displacement of foundation pit and fully reflect the characteristics of the foundation pit side horizontal displacement change somewhere.(4) According to the characters of surface subsidence displacement envelope area of research and analysis, the known displacement of 1/2 foundation pit side about maximum ground settlement and the actual distance between the monitoring points, can estimate the other monitoring displacement of the settlement of foundation pit side, and fully reflect the characteristics of the foundation pit side displacement of ground surface settlement changes.(5) Using FLAC 3D software to simulate the excavation process of the deep foundation pit. The whole to complete simulation of excavation points five steps,each step is first after excavation support,for each step of retaining pile horizontal displacement and the changes of surface displacement. Through analyzed the results to compare the monitored and calculated results. Through field monitoring results and the analysis of simulation results, it is concluded that the general rule of deformation of deep foundation pit excavation, at the same time for verification of monitoring solution reasonably, guarantee the construction safety and optimization design for retaining structure provide reference value. |
