THE SYSTEM STIFFNESS AND WALL DISPLACEMENT OF A DEEP EXCAVATION STRENGTHENED WITH CROSS WALLS IN SOFT CLAY

Hsii-Sheng Hsieh ； Zih-Yun Wang ； Ting-Mei Lin ； Louis Ge

《Journal of GeoEngineering》 14卷4期 (2019/12) Pp. 203-217

https://doi.org/10.6310/jog.201912_14(4).1

摘要

System stiffness is an index to estimate the lateral displacement of retaining wall for deep excavations in soft clay. The original system stiffness considers two key parameters, the flexural rigidity of retaining wall and the average vertical spacing of lateral supports. However, these two parameters are unable to incorporate the effect of cross walls which are extensively used in modern day excavation projects. It is obvious that the overall stiffness of retaining system is dramatically increased with the presence of cross walls, though its amount of increment is difficult to assess. This paper devises a systematic approach to estimate the strengthening effect of cross walls on both system stiffness and the factor of safety against basal heave. The original design curves are also extended by extrapolation technique into low displacement zone that had rarely been addressed before. A deep excavation case history in soft clay is presented to demonstrate the development of these schemes. A three-dimensional numerical analysis is then used to further examine the applicability of the proposed schemes.

關鍵字

System stiffness ； deep excavation ； cross wall ； wall displacement ； three-dimensional effect