Chaska West Interceptor Soil Grouting Project (pre-excavation grouting prior to tunnelling), Chaska, Minnesota

ECO designed and directed a soil grouting program on behalf of EJM Pipe Services Inc. to consolidate the soil above the planned tunnel trajectory to protect an important road artery and underlying utilities. The fine grained sand formation was injected several times using the same sleeve pipes. A multiple phase grouting program involving regular cement based suspension grout and sodium silicate based grout was used. Horizontal sleeve pipes were used to perform the grouting program. These steel sleeve pipes had been installed using directional drilling techniques. All grouting activities were monitored and evaluated using the CAGES NS instrumentation system. The grouting program allowed for the tunnel to be mined without causing any settlement whatsoever to the overlying structures.