scholarly journals Single Pile Settlement and Load Transfer Mechanism due to Excavation in Silty Clay

2018 ◽  
Vol 8 (1) ◽  
pp. 2485-2492 ◽  
Author(s):  
M. A. Soomro ◽  
K. F. Memon ◽  
M. A. Soomro ◽  
A. Memon ◽  
M. A. Keerio

In densely built areas, development of underground transportation system often involves excavations for basement construction and cut-and-cover tunnels which are sometimes inevitable to be constructed adjacent to existing piled foundations. In order to gain new insights into single pile responses (i.e. settlement and load transfer mechanism) to an adjacent excavation in saturated silty clay, a three-dimensional coupled- consolidation numerical analysis is conducted in this study. An advanced hypoplasticity (clay) constitutive model with small-strain stiffness was adopted. A linear increase in pile settlement was observed due to excavation-induced stress release. This is because part of the pile is placed within the boundaries of a major influence zone due to excavation-induced ground movement. Based on a settlement criterion, apparent loss of pile‘s capacity is 14%. A maximum bending moment of about 350 kNm is induced in the pile with the maximum deflection of 28 mm. In addition, mobilisation of shear strength at the pile-soil interface was found to be a key factor governing pile-soil-excavation interaction. During excavation, a downward load-transfer mechanism in the piles can be identified.

2018 ◽  
Vol 55 (5) ◽  
pp. 749-757 ◽  
Author(s):  
Yaru Lv ◽  
Dongdong Zhang

This paper investigates geometrical effects on the load transfer mechanism of off-ground capped pile groups subjected to vertical load by four three-dimensional numerical simulations, including a circular single pile, an X-shaped cross-sectional concrete (XCC) single pile, a 4 × 4 circular pile group, and a 4 × 4 XCC pile group. The ultimate bearing capacities of the XCC and circular piles within pile groups are approximately 0.86 and 0.74 times that of the XCC and circular single piles, respectively. The group efficiency of the XCC pile group is mainly improved by its side resistance. Comparing the XCC pile group to the circular pile group, the increment in side resistance is almost larger than the increment in pile perimeter, indicating that the pile geometry alters the load transfer mechanism via stress concentration and lateral stress arching. A nonuniform load distribution on piles within a capped pile group causes a bending moment along the pile shafts. The bending moment of XCC piles is smaller than that of circular piles because the raft stiffness of an XCC pile group is increased by its larger circumscribing pile diameter.


2018 ◽  
Vol 8 (4) ◽  
pp. 3189-3193 ◽  
Author(s):  
D. A. Mangnejo ◽  
M. A. Soomro ◽  
N. Mangi ◽  
I. A. Halepoto ◽  
I. A. Dahri

To gain new insights into single pile responses to adjacent excavations in soft ground, numerical parametric studies are carried out. An advanced hypoplastic (clay) constitutive model which takes account of small-strain stiffness is adopted. The effects of excavation depths (i.e. formation level) relative to pile were investigated by simulating the excavation near the pile shaft (i.e., He/Lp=0.67), next to (He/Lp=1.00) and below the pile toe (He/Lp=1.33). Among the three cases, the excavation in case of He/Lp=1.33 resulted in the largest pile settlement (i.e. 7.6%dp). On the other hand, the largest pile bending moment was induced in case of He/Lp=0.67.


2020 ◽  
Vol 222 ◽  
pp. 111088
Author(s):  
Lili Sui ◽  
Shiyong Fan ◽  
Zhenyu Huang ◽  
Wei Zhang ◽  
Yingwu Zhou ◽  
...  

2021 ◽  
Vol 226 ◽  
pp. 111427
Author(s):  
Zhenyu Huang ◽  
Xiaolong Zhao ◽  
Wei Zhang ◽  
Zhanxia Fu ◽  
Yingwu Zhou ◽  
...  

2020 ◽  
Vol 50 (6) ◽  
pp. 871-879
Author(s):  
Hossein Soltani-Jigheh ◽  
Pouya Zahedi

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