Analysis Study On Deformation And Stability Of Excavation With Pile-Anchor Supporting Under Complex Geological Conditions

In recent years, with the continuous development of city construction, our country built many underground facilities, such as subway, underground shopping malls and so on, in such construction of the underground engineering we will often involve excavation supporting problems. Although pile-anchor supporting of excavation design theory in our country has been very mature, but in some binary structure soil rock areas, because of the dramatic differences in the physical and mechanical properties between soil and rock, making our pile-anchor support design theory and experience very scarce in some binary structure soil rock areas, and the relevant literature also rarely, so the research and analysis of the deformation and stability about the pile-anchor supporting structure in some binary structure soil rock areas have very important practical significance.Firstly, this paper introduces the research background and significance of the excavation engineering, forms and features of the excavation engineering, the domestic research status and foreign research present situation of pile-anchor supporting structure and characteristics. Secondly, this paper introduces the system structure, working principle, deformation characteristics, mechanics analysis and calculation method. about the pile-anchor supporting structure. Then Shuiquangou Zhangjiakou national security housing excavation project to be as the research background, using Lizheng deep excavation supporting software for the engineering design and calculation analysis, through the monitoring network layout and the selection of monitoring point monitor foundation pit excavation in real-time monitoring. Finally, according to the actual situation of excavation engineering and engineering geological exploration report, establish numerical model by using FLAC3 D software, and analysis the maximum unbalanced force and the initial stress, anchor axial force, horizontal displacement and vertical displacement of the excavation, analysis the simulation results and the measured value, design value, also analysis the different prestressed anchor cable force influence on the deformation of supporting pile body.After the analysis and research, we found that the maximum deformation of pile occurs on the side of boundary between soil and rock, the deformation of rock and soil mass part mainly occurs at miscellaneous fill, and in the region of rock mass deformation of rock mass is small; Relative to Lizheng software, FLAC3 D software has a better simulation result; Increasing anchor cable prestress mainly will reduce the deformation of the pile body central, have almost no effect on the deformation of the pile ends, and with the increasing of anchor cable prestress, the deformation of the pile body is reduced more and more slowly, finally, the deformation of pile body basically has no change with the increasing of prestress.