Undrained cyclic response of a silicate-grouted sand for liquefaction mitigation purposes

An experimental comparative study of a silicate-grouted sand is presented. The experimental procedure adopted for preparing high-quality treatedsamples is accurately described together with test procedures. The overall experimental investigation comprises unconfined compressive strength(UCS) tests, undrained monotonic simple shear (SS) tests, undrained cyclic simple shear and triaxial (TX) tests. A gain in strength due to thesodium-silicate grout is apparent from both undrained monotonic and cyclic test results. The influence of loading mode on undrained cyclic stress–strain–strength behaviour of treated sand samples is explored based on a comparison between simple shear and conventional triaxial stress conditions.The simple shear device is properly adopted to allow a reliable assessment of liquefaction resistance improvement in untreated sand samples. Thepaper highlights that, regardless of test conditions, similarities exist between the behaviour of loose-treated samples and that of dense- untreatedsamples, in terms of undrained cyclic shear strength. Time effects are also explored taking into account the variation of curing time and loadingfrequency.