The behavior of secant pile wall embedded within soil by numerical analysis

Hussein, Ayad K.; Mahmood, Mahmood R.; Aswad, Mohammed F.

doi:10.30684/etj.2024.153503.1818

	The behavior of secant pile wall embedded within soil by numerical analysis
Engineering and Technology Journal
Volume 43, Issue 5, May 2025, Pages 297-307 PDF (870.79 K)
Document Type: Research Paper
DOI: 10.30684/etj.2024.153503.1818
Authors
Ayad K. Hussein^* ; Mahmood R. Mahmood; Mohammed F. Aswad
Civil Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.
Abstract
Deep excavation projects in areas with high groundwater levels, such as industrial zones with large, heavy structures, present significant challenges. Secant piling techniques offer an effective solution for these conditions. These retaining walls are constructed by overlapping reinforced concrete and plain concrete piles to form a continuous barrier against soil and water ingress. This research investigates the effectiveness of secant pile walls as a deep excavation support system, focusing on the impact of various parameters on ground movement, analyzed using the DeepEX program. The case study centers on the Al Dawoodi/Al Mansur District in Baghdad, Iraq. Key factors examined include excavation depth, water level fluctuations, pile diameter, wall stiffness, soil properties, and the bonding between piles. The results revealed that lowering the groundwater level decreases the total lateral earth pressure while enhancing lateral resistance. For a constant excavation depth of 12.85 m, the total active stress at a depth of 9 m decreases as the water table level drops. When the water table is at -1.8 m, the total active stress is 92.952 kN/m²; at -3.5 m, it decreases to 87.837 kN/m²; and at -5.5 m, it further reduces to 82.016 kN/m². Additionally, deeper excavations result in greater horizontal displacement at the top of the wall. Increasing the pile diameter from 0.6 m to 1.2 m reduces lateral displacement from 0.503 m to 0.467 m but increases the bending moments from 832.56 kN.m/m to 1430.22 kN.m/m within the secant pile wall. Furthermore, the interlock ratio between the piles significantly influences wall performance. As this ratio increases, the bending moment also rises, with moment resistance increasing from 1134.72 kN.m/m to 1209.94 kN.m/m when the overlap distance grows from 5% to 30% of the pile diameter. The analysis also demonstrates that enhancing the strength of the secondary piles within the wall leads to higher bending moments, improving the wall's stability against excavation-induced stresses.
Highlights
Lowering water level on the load side reduces wall lateral displacement with constant excavation depth on both sides Lowering the water level causes an initial vertical displacement at the ground surface Lateral displacement decreases and bending moment increases as pile diameter grows from 0.6 m to 1.1 m in secant walls The bending moment in secant pile wall rises as the overlap ratio between the piles increases Raising secondary pile strength in secant pile walls results in higher bending moment values
Keywords
Deep excavation; Secant pile wall; Dewatering; lateral stress; Displacement

References
N. Liu, N. Duan, F. Yu, Deformation characteristics of retaining structures and nearby buildings for different propped retaining walls in soft soil, J. Test. Eval., 47 (2018) 1829-1847. https://doi.org/10.1520/JTE20170763 A. Zahmatkesh, A. J. Choobbasti, Evaluation of wall deflections and ground surface settlements in deep excavations, Arab. J. Geosci., 8 (2015) 3055-3063. https://doi.org/10.1007/s12517-014-1419-6 X. Ji, P. Ni, W. Zhao, H. Yu, Top-down excavation of an underpass linking two large-scale basements in sandy soil, Arab. J. Geosci., 12 (2019) 314. https://doi.org/10.1007/s12517-019-4493-y C. Moormann, Analysis of wall and ground movements due to deep excavations in soft soil based on a new worldwide database, Soils Found., 44 (2004) 87-98. https://doi.org/10.3208/sandf.44.87 I. W. Farmer, and P. B. Attewell, Ground Movements Caused by a Bentonite Supported Excavation in London Clay, Geotechnique, 23 (1973) 576-581. https://doi.org/10.1680/GEOT.1973.23.4.576 Ng C. W., and Yan R. W., Stress Transfer and DeformationMechanisms around a Diaphragm Wall Panel, J. Geotech. Geoenviron., 124 (1998) 638-648. https://doi.org/10.1061/(ASCE)1090-0241(1998)124:7(638) H. Shangyu, Y. Kun, W. Xingxing, Y. Lei, C. Cong, Analysis of the influence of inside and outside water level changes of foundation pit on stability of foundation, Proceedings of the 2016 2nd International Conference on Architectural, Civil and Hydraulics Engineering, Advances in Engineering Research, 2016, 280-284. https://doi.org/10.2991/icache-16.2016.53 M. I. Ramadan, M. Meguid, Behavior of cantilever secant pile wall supporting excavation in sandy soil considering pile-pile interaction, Arab. J. Geosci., 13 (2020) 466. https://doi.org/10.1007/s12517-020-05483-8 A. Mahesh, B. S. Kumar, Effect of Diameter of Secant Pile Wall in Deep Excavation Analysis, Int. J. Recent Technol. Eng., 7 (2019) 2277-3878. M. I. Ramadan, E. H. Ramadan, M. M. Khashila, Analysis of Piles Supporting Excavation Adjacent to Existing Buildings, The 18th International Conference on Soil Mechanics and Geotechnical engineering, Paris, 2013. C. Meng, F. Xiao, H. Linna, L. Hailin, Application of secant piles for Excavation Pit in Complicated Environment, The 7th International Conference on Environmental Science and Civil Engineering, IOP Conf. Series: Earth and Environmental Science, 719, 2021, 032017. https://doi.org/10.1088/1755-1315/719/3/032017 J. Gannon, Primary firm secant pile concrete specification, Geotech. Eng., 169 (2016) 110-120. https://doi.org/10.1680/jgeen.15.00038 Chang-Yu Ou, Pio-Go Hsieh, and Dar-Chang Chiou, (1993) Characteristics of ground surface settlement during excavation, Can. Geotech. J., 30 (1993) 758-767. https://doi.org/10.1139/t93-068 Hashash Y. Analysis of deep excavations in clay. Ph.D. Thesis, Massachusetts Institute of Technology. Department of Civil and Environmental Engineering, United States America, 1992.
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