Method for evacuating transfer air from a mixture of pressurized air and binding agent

A method for evacuating transfer air contained in a binding agent from a mixture of pressurized air and binding agent when stabilizing earth masses by adding binding agent, in which method is used an apparatus comprising means for producing pressurized air, a binding agent container, a supply pipe for the mixture of pressurized air and binding agent, the apparatus including a mixing head for mixing the binding agent into the earth mass, and in which method the pressurized air used for transferring the binding agent is evacuated through a separate discharge pipe by the following measures before the pressurized air is conveyed into the earth mass:

• 1) the binding agent is conveyed into a storage space with a binding agent discharge opening into a ground;
• and
• 2) a pressure level in the apparatus is adjusted to be such that the pressure in the storage space exceeds a counter-pressure caused by the ground at the discharge opening, whereupon the binding agent discharges from the storage space via the discharge opening out into the ground and at least a part of the pressurized air discharges controllably from an upper part of the storage space into the discharge pipe, wherein water is sprayed into the supply pipe and a flow rate of the mixture of pressurized air, binding agent and water is accelerated momentarily by a Venturi-type nozzle, a so-called Laval nozzle, to disperse the water into a mist to which a powdery binding agent adheres, thus forming a sludge-like mass which is led to the storage space.