A kind of porous foam nozzle used in the improvement test of dregs in shield construction

Abstract

The invention discloses a multihole foaming spray head for residue earth improvement tests for shield construction. The multihole foaming spray head comprises a steel pipeline and a spray head body. A top plane and a bottom plane of the spray head body are parallel, and the side faces of the spray head body are six hexagons which are sequentially connected. A circular hole is formed in the middle of the top plane of the spray head body. Six nozzles with different hole diameters and mesh enclosures are arranged on the side faces of the spray head body, and each nozzle communicates with the circular hole. Liquid is sprayed out through the mesh enclosures and makes contact with air to form foam. The circular hole is formed in the upper surface of the hexagon body, and a circular rotary switch is inserted into the circular hole. The multihole foaming spray head is provided with the six nozzles with the different hole diameters and the mesh enclosures with multiple hole diameters, and the performance indexes including the foaming rate and the half-life period of foam are controlled by selecting the appropriate nozzles and the appropriate mesh enclosures; and by means of the rotary switch, the appropriate nozzles and the appropriate mesh enclosures are selected, and it is not required to reduce pressure.

Description

technical field [0001] The invention relates to a porous foaming nozzle used for the improvement test of dregs in shield tunneling construction, and belongs to the technical field of shield tunneling construction. Background technique [0002] At present, the shield construction method used in urban subways and tunnels is more and more widely used. When the flow plasticity of the soil is poor, the shield construction will be very difficult. In order to ensure the normal progress of the shield construction, the soil must have good Excellent flow plasticity, while having low water permeability to prevent groundwater. To this end, soil improvement technology must be adopted, that is, to inject modified materials such as mud, foam, polymer, etc. into the excavation surface, screw conveyor and soil ballast chamber, here mainly foam, to ensure the stability of the excavation surface and realize the shield machine Earth pressure balance excavation. At the same time, injecting foa...

AI Technical Summary

Problems solved by technology

[0003] Foam performance indicators such as foam expansion rate and half-life have a great influence on the soil improvement effect, and greatly affect the test results

[0004] Although there are many kinds of test foam generators, it is not easy to control the performance indicators of foam expansion rate and half-life with traditional test foam generators.

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