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Feng Y.,Tongji University | Feng C.,Tongji University | Liang F.-Y.,Shanghai Lujiazui Finance and Trade Zone Development Co.
Geotechnical Special Publication | Year: 2010

Based on the flexural differential equations of elastic piles and Winkler's spring model, the equation of axially loaded piles subjected to lateral soil movement is solved first. In the solution, the flexural differential equations are established using two-stage method and solved by the finite difference method, which makes the equation solving more easily when dealing with the pile foundation in layered soils. Numerical method using commercial software "LPile" was conducted to verify the effectiveness of the presented solution. The results of parametric study show that the situation of retaining wall and the distribution pattern of soil elastic modulus along the pile depth can affect the behavior of axially loaded piles subjected to lateral soil movement significantly. The analyzing conclusion in this paper should be useful for the design in practice. Source


Liu Y.,Tongji University | Li J.-P.,Tongji University | Chen W.,Shanghai Lujiazui Finance and Trade Zone Development Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

By selecting different parameters of reinforced soil and adopting hardening-soil finite element model based on unloading, the influence of bottom soil on deformation of excavations is studied. The results show that the reinforcing influence on lateral deformation increases with the increase of the excavation depth, and the final lateral deformation can be reduced by 27%. This effect is prominent for controlling the uplift in bottom soil around retaining structures, and the utmost inhibition of uplift may exceed 50%. The influence of reinforcement on soil settlement behind the retaining structures is conspicuous, about 60% in local zone. Therefore, selecting a rational reinforcing form based on different geological conditions and deformation requirements is needed to make the reinforced soil intensity reach the design demand, which can guarantee the excavation safety and environment impact and save the engineering cost. Source


Chu F.,Tongji University | Chu F.,Shanghai Lujiazui Finance and Trade Zone Development Co. | Li Y.,Tongji University | Liang F.,Tongji University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2010

Based on a case of deep excavation adjacent to metro station in Shanghai City, a two-dimensional finite element model to analyze this typical problem is proposed. Small-strain stiffness of soil is considered to investigate the deformation characteristics of deep pit excavation adjacent to metro station. The calculation data show that the deflection of retaining wall is obviously reduced when the small-strain stiffness of soil is considered in numerical analysis. And it is much close to the observed results. As for the deep pit excavation adjacent to metro station, the excavation sequences have obvious influences on the deformations of retaining wall. Numerical results also show that excavating big parts of the pit foundations firstly can reduce the deformation of retaining wall effectively than that of excavating small parts in advance. The results are consistent with the practical experiences in Shanghai area. The conclusions have some instructions for the designs and constructions of similar engineering. Source


Liu Y.,Tongji University | Liu Y.,Shanghai Municipal Engineering Design Institute Group Co. | Li J.-P.,Tongji University | Chen W.,Shanghai Lujiazui Finance and Trade Zone Development Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013

The deep foundation pit of the headquarter base of Tangdong central block in Lujiazui of Shanghai is constructed by use of the top-down method. It is a very distinctive engineering case in this area. Some key design and construction techniques are introduced. They include rational planning of soil excavation, treatment of critical construction nodes and control of uneven settlement, etc. The success of this case may provide engineering experience for similar projects. Source


Liu X.-Q.,Tongji University | Liang F.-Y.,Tongji University | Zhang H.,Tongji University | Chu F.,Shanghai Lujiazui Finance and Trade Zone Development Co.
Yantu Lixue/Rock and Soil Mechanics | Year: 2014

Ground movement induced by tunneling may cause excessive deformation or breakage accident of buried pipelines. Therefore, these problems arouse great concerns of engineers. Based on assumed distribution form of the vertical displacement of buried pipeline, the governing variational equations are established based on the energy method. The energy variational solutions of the vertical displacement of buried pipeline causes by tunneling are obtained accordingly. Using the principle of superposition, further results are extended to solve the twin-track tunnels. The validation of the proposed method is demonstrated through comparison with the centrifuge tests and cases studies. Meanwhile, factors that affect the vertical displacement of buried pipeline are also analyzed. The conclusions can be applied to practical engineering. ©, 2014, Academia Sinica. All right reserved. Source

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