Investigation on the performance of walls reinforced by helical nails under strip footing loading using physical model test

Document Type : Research Article

Authors

1 Department of Civil Engineering, University of Qom, Qom, Iran

2 Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

Abstract

In the current study, the performance of helical soil-nailed walls (HSNWs) was evaluated under footing loading using reduced-scale model tests. For this purpose, sixteen soil-nailed wall models were constructed with different lengths, patterns, and inclinations of the helical nails and then were loaded to failure using the strip footing. The quantitative and qualitative responses of the models to footing loading were identified in terms of the wall displacements, the deformation modes, and the bearing capacity of footing. Particle Image Velocimetry (PIV) technique was also used to trace shear bands and identify the failure mechanism. PIV results showed that increasing the nail length, as well as using a square pattern and a 15° angle to install the nails, could be three effective solutions to reduce the penetration depth of the slip surface and, consequently, to limit wedge failure dimensions. Findings also indicated that 15° can be introduced as the optimal inclination for installing helical nails in walls under strip footings to achieve the maximum bearing capacity and minimum lateral wall displacements.

Keywords

Main Subjects


[1] A. Ghaly, A. Hanna, and M. Hanna. “Uplift behavior of screw anchors in sand. I: Dry sand.” Journal of Geotechnical Engineering 117(5) (1991) 773-793.
[2] C.D.H.C Tsuha, N. Aoki, G. Rault, L. Thorel, and J. Garnier. “Evaluation of the efficiencies of helical anchor plates in sand by centrifuge model tests.” Canadian Geotechnical Journal 49(9) (2012): 1102-1114.
[3] D. Wang, R.S. Merifield, and C. Gaudin. “Uplift behaviour of helical anchors in clay.” Canadian Geotechnical Journal 50(6) (2013) 575-584.
[4] S. Mittal, and S. Mukherjee. “Vertical Pullout Capacity of a Group of Helical Screw Anchors in Sand: An Empirical Approach.” Indian Geotechnical Journal 44(4) (2014) 480-488.
[5] H. Tokhi, G. Ren, and J. Li. “Laboratory study of a new screw nail and its interaction in sand.” Computers and Geotechnics 78 (2016) 144-154.
[6] S.  Rawat, and A.K. Gupta. “Numerical modelling of pullout of helical soil nail.” Journal of Rock Mechanics and Geotechnical Engineering 9(4) (2017) 648-658.
[7] S. Rawat, A. K. Gupta, and A. Kumar. “Pullout of soil nail with circular discs: A three-dimensional finite element analysis.” Journal of Rock Mechanics and Geotechnical Engineering 9(5) (2017) 967-980.
[8] M. E. Mahmoudi-Mehrizi, A. Ghanbari, M. Sabermahani. “Investigating the Effect of Grout on Improving the Performance of Helical Anchors Used in Wall Stabilization.” Transportation Infrastructure Geotechnology 7 (2020) 332-353. ‏
[9] D. Deardorff, M., Moeller, and E. Walt. “Results of an instrumented helical soil nail wall.” In Earth Retention Conference 3 (2010) 262-269.
[10] M. Sharma, D. Choudhury, M. Samanta, S. Sarkar, V.R. Annapareddy. “Analysis of helical soil-nailed walls under static and seismic conditions.” Canadian Geotechnical Journal 57(6) (2020) 815-827.
[11] R. Mollaei, M. Yazdandoust, F. Askari. “Seismic evaluation of helical soil-nailed walls using shaking table testing.” Soil Dynamics and Earthquake Engineering 163 (2022) 107331. ‏
[12] P. Zahedi, A. Rezaei-Farei, H. Soltani-Jigheh. “Performance Evaluation of the Screw Nailed Walls in Tabriz Marl.” International Journal of Geosynthetics and Ground Engineering 7(1) (2021) 1-15.
[13] M.-E. Mahmoudi-Mehrizi, A. Ghanbari, M. Sabermahani. “The study of configuration effect of helical anchor group on retaining wall displacement.” Geomechanics and Geoengineering 17(2) (2022) 598-612.
[14], H.A. Perko. “Helical piles: a practical guide to design and installation.” John Wiley & Sons (2009).
[15] FSI. “Technical manual: helical piles and anchors, hydraulically driven push piers, polyurethane injection & supplemental support systems.” second ed. Omaha: Foundation Support Works (2014).
[16] D.M. Wood. “Geotechnical Modeling.” Version (2.2) (2014).
[17] M. Yazdandoust. “Investigation on the seismic performance of steel-strip reinforced-soil retaining walls using shaking table test.” Soil Dynamics and Earthquake Engineering 97 (2017) 216-232.
[18] N-J. Yoo, K-S. Yoo, J. .Kim. “Model Tests of Soil Nailing System under Surcharges.” Journal of Industrial Technology 14 (1994) 77-87.
[19] G. Zhang, J. Cao, and L. Wang. “Centrifuge model tests of deformation and failure of nailing-reinforced slope under vertical surface loading conditions.” Soils and foundations 53(1) (2013) 117-129.
[20] S. Plumey, A. Muttoni, L. Vulliet, V. Labiouse. “Analytical and numerical analyses of the load-bearing capacity of retaining walls laterally supported at both ends.” Int J Numer Anal Methods Geomech 35(9) (2011) 1019–1033.
[21] G. Zhang, J. Cao, and L. Wang. “Failure behavior and mechanism of slopes reinforced using soil nail wall under various loading conditions.” Soils and Foundations 54(6) (2014) 1175–1187.
[22] J.B. Hansen. “Earth pressure calculation.” Copenhagen: Danish Technical Press (1953).
[23] M.R. Tufenkjian, and M.Vucetic. “Dynamic failure mechanism of soil-nailed excavation models in centrifuge.” J Geotech Geoenviron Eng. 126(3) (2000) 227–35.
[24] J. Salençon. “The influence of confinement on the bearing capacity of strip footings.” Comptes Rendus Mécanique 330(5) (2002) 319–26.
[25] L. Zhao, F. Yang, and H.Dan. “The influence of horizontal confinement on the bearing capacity factor Nγ of smooth strip footing.” Computers and Geotechnics 61 (2014) 127–131.