Monitoring Data Analysis And FLAC Numerical Simulation Of Deep Excavation Applying The Pile-Anchor System

As society advances quickly, the underground space is gradually paid more attention along with the floor space is gradually reducing, so there are more and more foundation engineering. The emergence of tall buildings and the urgent need for underground space will inevitably lead to the emergence of deep foundation pit. Since 1990, there was a rapid development of high-rise buildings in China, while the construction of large underground shopping malls, subway stations, underground municipal facilities.To ensure the deep excavation system is safe in the process of structure construction, soil excavation stage and the system is safe itself, the monitoring job is an integral part of the deep foundation. At the present time, most of the deep foundations use the pile-anchor system, so we also need to monitor the pile-anchor system while monitoring the displacement of slope. With the extensive application of computer technology, numerical simulation technology has been tremendous progress in the field of geotechnical engineering, and successfully solved many engineering problems. The numerical simulation technology provides a strong visual mean for the analysis of excavation, slope's displacement and the force of the retaining structure. Combining the E-05 deep foundation of the China Life Insurance' R & D center, the monitoring scheme was constituted based on the analyzing of the project and the supporting scheme. This project uses the way of pile-anchor system to protect the slope, so the main monitoring projects are the horizontal displacement on the top of the system, the displacement of the pile and the force of the anchor. Monitoring the horizontal displacement of supporting structure uses the quasi-line method. Monitoring the displacement of the pile uses the inclinometer method, and using the anchor dynamometer monitor the force of the anchor. Through analyzing the monitoring data, we have a result about the action of the support structure and the stability of the slope.Numerical simulation methods expand the field of engineering geology, and solve lots of major engineering problems successfully. This paper has introduced the theory of the finite difference software FLAC3D, and made the numerical simulation according to the actual situation. The soil nails and anchors have been simulated by applying the cable structural unit, while the piles by applying the pile structural unit. There are eight steps to excavate according to the eight working conditions. After getting the horizontal displacement of supporting structure, the displacement of the piles and the force of anchors, the values were compared with monitoring data to get the differences between them. They will verify whether the foundation is safe or not, and will provide some experience for the future monitoring system.