Methods to Increase Effectiveness of Injective Chemical Stabilisation of Loess Soils

The article deals with issues related to the artificial transformation of loess soil by chemical solutions in order to improve their bearing capacity and to eliminate subsidence. One of measures for elimination of subsidence of loess soils, especially in built-up areas, and to strengthen the foundations of structures is the method of silication based on the impregnation of soils with diluted solutions of sodium silicate. Accumulated industrial experience demonstrates that in some cases there is a reduction in the efficiency of silication, due to the peculiarities of the composition and state of ground sediments (low permeability, low or latent physical and chemical activity and high humidity). With artificial transformation of loess soils it is necessary to purposefully regulate the process of cementing on the basis of their natural characteristics (composition, structure and properties) and on the formulations of injection solutions used. Basing on laboratory and field experiments the advantage of using the newly-developed new modifications of injecting solutions is proved in comparison with traditional single-solution silication to secure the loess soils with low physical and chemical activity, including those with high humidity. These results show that the efficiency and durability of grouting depend on the composition and properties of loess soils and chemical solutions. Higher durability and stability of consolidated arrays in time are obtained with the use of coagulating silicate solutions.