An experimental investigation on the effects of the silicate grouts on the cyclic behavior of the lightly cemented sands

Accurately designed soil improvement projects need sufficient pre-construction knowledge about the behavior of treated soils. Besides, comprehensive investigations applied to study the monotonic behavior of treated sands using silicate grout, a vacancy of information about their cyclic behavior remains. In this paper, silicate grout with a mixture of nano-silicate sodium and calcium chloride is used to improve the cyclic resistance of loose sands against liquefaction. Sand material was extracted from the Enghelab station of metro line ۳ of Tabriz city, where the water table is adjacent to the ground surface and the underlying soil has a high liquefaction potential. As Tabriz is located in one of the most seismically active regions of Iran, extending knowledge about the behavior of improved soils against upcoming earthquakes is mandatory for pre-crisis management projects. In this paper, using fully automatic direct simple shear apparatuses, the cyclic behavior of untreated and treated sand samples is studied, and it is demonstrated that the lightly cemented treated samples show ۴۰%-۶۰% more resistance against liquefaction. Compared to the pure sand samples, the treated samples show a rate-dependent behavior, especially for smaller consolidation stresses. In addition, it is revealed that the treated samples mostly show adhesion strength against the applied cyclic loads compared to particle-to-particle friction.

کلیدواژه ها:

Silicate grout ، liquefaction ، Lightly cemented sand ، Nano-silicate sodium ، Simple shear