Chemical Grouting in Soils Permeated by Water

Based on data obtained from seventy‐nine large‐scale one‐dimensional laboratory tests, limiting conditions were established to define the transition zone between retention and elutriation of chemical grout injected into a cohesionless soil permeated by water. Various combinations of four grouts, four sands, and one gravel were included in the experimental program, and the interpretation is presented in terms of seepage velocity versus gel time relationships. The position and extent of the transition zone are strongly dependent on the viscosity and miscibility of the grout and to a lesser extent, on the effective grain size of the soil. These parameters are largely responsible for the dilution that occurs and that, in turn, lengthens the gel time and decreases the viscosity, thereby governing the distribution of the injected grout and the resulting permeability of the soil. Even if a water seal is established, the grout may be dissolved or eroded, or both, after a relatively short time. Measurements from a limited number of tests demonstrate that the strength is substantially higher in the vicinity of the injection point.