Determination of engineering properties of organic soils with sodium silicate-boric acid mixture

In this study, the rheological properties of the solutions prepared by mixing sodium silicate and boric acid and the engineering properties of the samples prepared as a result of permeation grouting into organic soil using the selected mixture were investigated. First of all, sodium silicate and boric acid were mixed in different ratios and their rheological properties (gelling time, syneresis, viscosity) were determined. Solutions used in grouting were identified as Ratio A, in which 2,1 g of boric acid was mixed into a solution with a ratio of 28% SS/Sol., Ratio B, in which 2,4 g of boric acid was mixed into a solution with a ratio of 30% SS/Sol., Ratio C, in which 2,4 g boric acid was mixed into a solution with a ratio of 34% SS/Sol., Ratio D, in which 2,4 g of boric acid was mixed into a solution with a ratio of 42% SS/Sol. All grouting tests were successful, and the mixture was performed on the samples in grouting pressure values changing from 1,90 to 2,30 bar. The samples whose grouting processes had been completed were stored under three different curing conditions, namely air dried, stretch wrapped, and water-cured environments. Since the samples stored in water-cured environment could not stay integrated, unconfined compression tests were not performed on them. Unconfined compression tests were performed on the samples stored under air dried and stretch wrapped conditions on the 3rd, 7th, 14th, 28th, 56th, and 90th days. It is ascertained that the strength values of the samples vary between 162,520 kPa and 572,337 kPa. The strength values of the samples increased with the time of their storage. The sample with the maximum strength value is the one prepared with %42 SS/Sol. ratio and stored for 90 days. The sample with the minimum strength value is the one prepared with %28 SS/Sol. ratio and stored for 3 days. Compared to the ones stored in stretch wrapped environment, the samples stored in air dried environment have almost twice the strength value. Permeability test was carried out on the grouted and ingrouted samples. Permeability coefficients of the samples were determined on the 3rd, 28th, 56th, and 90th days. The permeability coefficient of the ingrouted organic soil was 4,79x10-5 cm/sec. The permeability coefficients of the grouted samples vary between 4,34x10-6 cm/sec and 6,83x10-5 cm/sec. The permeability coefficient of the organic soil used in this test was reduced 10 times by performing permeation grouting procured through sodium silicate and boric acid mixture. The permeability coefficient reaches its maximum value when the SS/Sol. ratio is %34. As a result of this study, it is determined that the permeation grouting of sodium silicate-boric acid solutions into organic soil is successful and that the sodium silicate-boric acid solutions grouted into organic soil improve the engineering properties of the soil.