Abstract:

DCA, a special dispersible foam agent for clay stratum, is developed to solve the clogging problems of EPB shield induced by small friction angle, high cohesive force and low permeability coefficient in clay stratum; and it is applied in shield section with high liquid limit and strong plastic cohesive soil layer. By analyzing the tunneling parameters of shield during the application of the new foam agent and comparing with other foam agents in the same stratum, the application effect of the foam agent is evaluated. The application results show that: (1) DCA has the same effect with an imported product used in the field, and the performance of DCA is superior to that of similar products in China, and which can meet the soil conditioning requirements of shield tunneling in stronglyweathered mud stone stratum and sandycobble stratum with mud stone. (2) The application of DCA can save 10%-15% of material consumption per ring with good economic benefit, and which is worth popularizing.

Key words: EPB shield, clogging, soil conditioning, dispersible foam agent, clay layer, field application