Liquefaction mitigation using sodium polyacrylate: Large-scale in-situ applications with a unique grouting apparatus

• Published in: Soil dynamics and earthquake engineering (1984) 2024-04, Vol.179, p.108540, Article 108540
• Main Authors: Evirgen, Burak, Özbakan, Nesil, Gültekin, Asker Alp, Tos, Mert, Tuncan, Mustafa
• Format: Article
• Language: English
• Subjects: Chemical grouting; Ground improvement; Liquefaction; Plate load test; Pore pressure; Settlement; Shaking table
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2024.108540

Soil liquefaction is an important problem that threatens the safety of buildings during earthquakes due to its destructive effects caused by a serious decrease in soil strength. In addition to the existing soil improvement methods, a reasonable approach to tackle this problem could be a superabsorbent polymer called sodium polyacrylate (SPA), which has a 125 ml/gr water absorption capacity as well as an extraordinary swelling pressure, used as grouting inside the liquefiable soil. This mitigates the effects associated with liquefaction-induced damage by changing the phase of excess water into a gel formation within the ground without changing the soil skeleton. In this study, the use of SPA is evaluated against post-liquefaction problems of saturated liquefiable soil, such as pore pressure generation, surface settlement and bearing capacity both in shaking table tests in a laboratory and full-scale in-situ tests thanks to its viscous gel structure and swelling potential. Firstly, an optimum SPA column spacing was determined to be four times the drilling diameter according to the shaking table tests in terms of pore water pressure generation and surface settlement. After this, an original chemical grouting device was designed, produced, and mounted on a drilling machine with two different mechanisms that provides multiple injections in a dry state and multiple boring at the same time. Finally, the results of the full-size liquefaction tests within an 8 m3 test pit demonstrate that generation of excess pore pressure is dissipated at up to 150%, settlements are reduced, and liquefaction resistance is increased due to the maximum 0.4 pore water pressure ratio value, after improvement through single, double, and triple SPA column application. •A sodium polyacrylate has a significant impact on pore pressure and settlement.•Optimum arrangement of columns is obtained in pre-evaluation shaking table tests.•Real sized liquefaction tests and plate load tests are conducted.•Field responses of treated and non-treated soil are compared after dynamic effect.•The effectiveness of SPA columns is verified at approximately 150% dissipation.