Description

Shield foaming agent has high foaming rate, bubble uniform and high stability, which are guarantees that the earth pressure balance shield machine and take necessary for the smooth construction of the shield products. The products applicable to rock and soil tunnel engineering of soil, its performance is better than the other similar products. 1. Application of foaming agent in shield tunneling construction It is composed of numerous small bubbles mixed into the muck, Often referred to as the injection is injected into the bubble. The bubble is a typical gas *- liquid two-phase system, is more than *0%, less than *0% of the foaming solution. And foaming solution *2%**8.5% water. The rest of the foaming agent and the raw liquor. Foam injection of excavation face, support or screw conveyor, the excavation soil is plastic flow through the use of fruit surface paste Micro Foam lubrication. When it is subjected to strong mixing, fine bubbles and excavation soil mixing, and subsequently replacement of soil particles in pore water, foam generated from andimprove the sealing property. From in head chamber of shield machine after discharge encountered decompression will break itself, without adding foaming agent. 2. The product uses and Applications 1、Shield foam is suitable for rock and soil, gravel soil, silty soil, with fine foam, has the following properties: 1. To reduce mechanical wear of the shield machine. Earth pressure balance is shield machine in the friction of the larger soil excavation, and the soil occurred in the role of cutting tool wear easily. Therefore, the injection foam on the cutter can reduce soil friction, reduces the cutting tool, cutter and shield abrasion. 2. Adjustment values of soil plastic flow. Earth pressure balanced shield tunneling process, soil nature, will directly affect the smooth excavation of shield machine, if after cutting the muck has good plasticity and fluidity, not only can the excavation face maintain good support pressure and guarantee the smooth implementation of soil drainage. Furthermore, in shield tunneling, due to changes in the formation, not after processing into the soil of the earth are usually easy to within the chamber occurs "cake", "blocked" and problems, seriously affect the tunneling efficiency. Foam occupancy can effectively solve the problem. 3. Reduce the permeability of the sediment, soil pressure balance type purchase in the gravel layer through the layer of foundation construction, excavation face high water 
pressure will cause of purchase screw conveyor export groundwater occurrence loss of a large number of, severe will spew. Driving effect smoothly into foam can effectively reduce the permeability of the muck, effectively prevent occurrence of tunneling spewing. 4. Reduce cutting muck of internal friction force and reduce cutter, screw conveyor wear and reduce knife wheel torque to prevent the machine energy consumption high fever and failure. 5. In the rock tunnel and mine in the dust inhibitor. 6. Improve the safety of construction work on the surrounding ecological environment pollution.