Three-Dimensional Analysis of Jet Grouting Piles and Deep Excavation

• Main Authors: LO,WEN-KUNG, 羅文恭
• Other Authors: CHEN,SHONG-LOONG
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/459nb8

碩士 === 國立臺北科技大學 === 土木工程系土木與防災碩士班 === 107 === This study was intended to investigate the use of jet grouting piles below the foundation surface of deep excavation to increase the shear strength of soil on the excavation side and, thus, reduce the lateral displacement in the raining walls. To determine the influence of jet grouting piles on retaining walls in deep excavation, the FE program, PLAXIS 3D was used for numeric analysis and the building project of excavation on Zhongshan North Road, Taipei City selected for simulation. The excavation was performed using the bottom-up procedure were the construction steps were configured accordingly. For the numeric analysis model, plate element was used to simulate diaphragm walls, composite soil, solid pile element and embedded beam for soil improvement piles, and anchor element for the I-beam members of the strutting system. Prestressing was added at each construction step to create the excavating strutting system for the deep excavation. Area load was added to the analysis to simulate the surface load acting on surrounding roads, whereas neighboring buildings were converted into an elastic volume material with equivalent load. The Mohr-Coulomb model was introduced to this study. The “soil improvement piles” below the excavation surface were grouped into 3 models, namely Model (I) for composite soil simulation, Model (II) for solid pile elements for soil strengthening and Model (III) for embedded beam simulation, for analysis and comparison to in-situ monitoring data. The comparison between the curve plotted from the Plaxis 3D analysis and that from monitoring data indicated that the displacement of diaphragm walls was underestimated regardless the Mohr-Coulomb undrained (A) model or undrained (C) model. However, when it comes to the analysis with the three soil improvement simulation models, the curves from the simulation with solid piles or that with embedded beam were closer to the in-situ monitoring curves than those from the simulation with composite soil in terms of diaphragm wall displacement.