A case study on behaviors of composite soil nailed wall with bored piles in a deep excavation

ZHU Feng-bin(朱逢斌)^{1, 2}, MIAO Lin-chang(缪林昌)¹, GU Huan-da(顾欢达)², CHENG Yue-hong(程月红)³

(1. Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China;
2. School of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215011, China;
3. Suzhou Erjian Construction Group Co., Ltd, Suzhou 215131, China)

Abstract:A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.

Key words:deep excavation; 3D non-linear finite element; bored pile; composite soil nailed wall; corner effect; deformation; internal force