Abstract:The excavation of the north square underground shopping center of Shanghai South Railway Station is a complex deep excavation using the top-down construction method. The excavation has a considerable size and is close to the operating Metro Lines. In order to predict the performance of the excavation more accurately, 3D finite-element analyses are conducted to simulate the construction of this complex excavation. The effects of the anisotropic soil stiffness, the adjacent excavation, and zone excavation on the… Show more
“…Published case studies of monitored excavations in Shanghai include Wang et al (2005), Tan & Li (2011) and Ng et al (2012). Numerical studies back-analyzing excavations in Shanghai include Hou et al (2009). This paper offers an extension and refinement of some of the ideas presented by Bolton et al (2010) at a keynote lecture to the DFI conference in London in 2010.…”
General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms Abstract: Recent research has clarified the sequence of ground deformation mechanisms that manifest themselves when excavations are made in soft ground. Furthermore, a new framework to describe the deformability of clays in the working stress range has been devised using a large database of previously published soil tests. This paper aims to capitalize on these advances, by analyzing an expanded database of ground movements associated with braced excavations in Shanghai. It is shown that conventional design charts fail to take account either of the characteristics of soil deformability or the relevant deformation mechanisms, and therefore introduce significant scatter. A new method of presentation is found which provides a set of design charts that clarify the influence of soil deformability, wall stiffness, and the geometry of the excavation in relation to the depth of soft ground.
“…Published case studies of monitored excavations in Shanghai include Wang et al (2005), Tan & Li (2011) and Ng et al (2012). Numerical studies back-analyzing excavations in Shanghai include Hou et al (2009). This paper offers an extension and refinement of some of the ideas presented by Bolton et al (2010) at a keynote lecture to the DFI conference in London in 2010.…”
General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms Abstract: Recent research has clarified the sequence of ground deformation mechanisms that manifest themselves when excavations are made in soft ground. Furthermore, a new framework to describe the deformability of clays in the working stress range has been devised using a large database of previously published soil tests. This paper aims to capitalize on these advances, by analyzing an expanded database of ground movements associated with braced excavations in Shanghai. It is shown that conventional design charts fail to take account either of the characteristics of soil deformability or the relevant deformation mechanisms, and therefore introduce significant scatter. A new method of presentation is found which provides a set of design charts that clarify the influence of soil deformability, wall stiffness, and the geometry of the excavation in relation to the depth of soft ground.
“…It can analyze complex solid mechanics and structural mechanics, especially to control very large and complex problems and simulate highly nonlinear problems. It is widely used in the accurate modeling and analysis of various practical projects such as subways, tunnels, slopes, foundation pits, pile foundations, hydraulics, and mines, the field monitoring values fit well with the numerical results [34, 35, 36, 37, 38, 39]. Fig.…”
In this study, a three-dimensional (3D) response of anchored sheet pile walls was investigated on double-anchored sheet pile system during soils excavation and tunnel construction sequence. This construction procedure is executed in areas front and adjacent the sheet pile walls. This paper focused on both areas of construction effects on the sheet piles. This numerical study aimed at the evaluation of the variation of bottom wall bending moment, top wall lateral and vertical displacements and anchor reactions forces exerted in the sheet piles. This paper also described the variation of the total anchor's reactions forces from the upper and lower anchors rows. A parametric effect such as upper and lower anchors rows distance was also performed to evaluate the variation of the wall bending moment, displacement and anchors total forces. The analysis results indicated that the reactions forces developed in the lower anchor rods are always higher than those developed in the upper anchor rods. The higher the distance between the upper and the bottom anchors the lower the displacement of the top wall in any stage of the construction. The minimum bottom walls bending moment is developed in the case where the distance between the anchor's rows divided by the wall height is 0.51. Positioning the upper anchors at 0.15 and the lower at 0.39 the wall height from the top wall will induce minimum top wall vertical displacement during soil excavation. This paper presents the results and findings of the parametric study performed.
“…Design of anchored sheet pile wall depends on many factors like the height of excavation, surcharge loads, the kind of structure (temporary or permanent), and the level of groundwater table [3].The analysis and design of cantilever sheet pile walls and anchored sheet pile walls can be carried out utilizing a numerical model or traditional methods that depend on the limit equilibrium approach. Many researchers studied the safety conditions, soil deformation, lateral earth pressure distribution and stress-strain analysis for cantilever sheet pile walls and anchored sheet pile walls using the finite element method [4,5,6,7,8,9,10,11,12,13]. Tang et al [14] used a finite element model based on field data to investigate the lateral earth pressure distribution on sheet pile walls and provide the guidelines recommendations to design the sheet pile walls.…”
Section: Figure (1) Influence Of Ground Anchors On Wall Stability (After Sabatini Etal 1999)mentioning
Anchored sheet pile walls are used to restrain excavation when the depth of the excavation exceeds about 6 m. In this paper, the influence of some parameters on anchored sheet pile walls was studied. The parameters are: anchor inclination with the horizontal ground, the number of anchors (one -row, or more), the cohesion of soil, and angle of internal friction of the backfill soil. The previous parameters affect soil behavior, wall bending moments, and wall displacement. Numerical analysis of the anchored sheet pile walls was implemented using a finite element program GEO5. The results of the analysis indicated that the optimum angle of anchor inclination is 25 degrees to reduce the horizontal displacement at the top of the wall and maximum bending moment. Variation of the angle of internal friction has a significant effect on the wall. As the friction angle increases, the maximum displacement and the internal forces decrease. As the cohesion of soil increases, the maximum bending moment, shear force, and wall displacement decreases. Increasing the number of anchors decreases the maximum bending moment, wall displacement, and increases the maximum shear force.
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