FOAM GENERATOR FOR EARTH PRESSURE SHIELD TUNNEL PROPULSION MACHINE AND METHOD FOR CONDITIONING REMOVED SOIL MATERIAL AS SUPPORT MEDIUM FOR EARTH PRESSURE SHIELD

摘要

FIELD: soil or rock drilling.;SUBSTANCE: group of inventions relates to a foam generator for a shield tunnel boring machine and a method for conditioning a soil material to be removed as a support medium for a tunnel boring machine. Said foam generator includes a mixing chamber having a first inlet port for a foamable liquid and a second inlet port for a gas, and a foam outlet opening connected to the first inlet port. Said mixing chamber has a tubular flow chamber, at one end of which there is an inlet port for the foamable liquid, and the foam comes out of the other end. Further, a portion of the flow chamber is made in the form of a gas supply region with a gas-permeable porous wall, and the section is adjacent to a pressure chamber. Said pressure chamber has an inlet port for gas and is adjacent to the flow chamber made in the form of a gas supply region in such a way that the gas supplied through the inlet port under pressure through the gas-permeable porous wall enters the tubular flow chamber and is mixed there with the foamable fluid to form foam. Above flow chamber is a tubular flow chamber with a gas supply region having a gas-permeable porous wall. Above foam outlet opening at said other end of the tubular flow chamber is located in such a way that there are no fine mesh barriers in the flow path between the inlet port for the foaming liquid and the outlet opening for the foam. In the method for conditioning soil material to be removed as a support medium for the tunnel shield, the soil to be removed is fed into the excavation chamber. Depending on the characteristics of the soil, foam is prepared, and a foam generator is provided, having a gas supply region of a given length, given flow cross-section and with given size and density of pores, and the ratio of the feed gas to the feed fluid is set so that the desired structure and size of the foam bubbles is obtained. Escaping foam is fed into the extraction chamber and mixed with removed soil. Moreover, there are no fine-cell barriers in the flow path between both ends of the tubular flow chamber, and the foam exiting at the other end of the tubular flow chamber if fed into the extraction chamber and mixed with removed soil.;EFFECT: technical result consists in the absence of blockages, due to the absence of barriers in the flow path between the foamable liquid inlet port and the foam outlet opening.;20 cl, 3 dwg