hydro fracturing

[Groutboy]

Currently "Contact Grouting" around and existing tunnel 60-100 ft deep at pressures equal to 1 psi per vertical foot with a high mobility grout. Grout is surfacing with little indication that grout is around the tunnel. Tunnel was installed in the 60's.Soils range from medium to stiff clays and silt. We are installing six packers every 10 feet-packers are at the 1,3,5,7,9 and 11 clock positions. Are we experienceing "hydro fracturing" of soils?

 

[miningman]

If you are hydrofraccing , you have a major problem. Your grouting records need to be meticulous .... you cannot rely on records provided by the grouting crew. Suggest you get knowledgeable personnel involved asap.