Selection method for earth pressure balance shield muck improvement parameters of viscous formation adopting foam as additive

Abstract

The invention relates to a selection method for earth pressure balance shield muck improvement parameters of viscous formation adopting foam as an additive and belongs to the technical field of earth pressure balance shield construction. According to the method, the function relation of liquid-plastic limit and the foam injection ratio, the function relation of the slumps and the foam injection ratio and the function relation of the slumps and the water content are obtained through fitting of curve mathematical relationships. In order to facilitate establishment of effective earth pressure balance in the shield tunneling process, based on the requirement that the viscosity index is 0.4-0.75, the relation of the water content and the foam injection ratio is established, and a relation curve is drawn. On coordinate axes of the relation curve, the optimum foam injection ratio range is determined through the optimum slump range, and then the optimum water content range of muck is determined according to the relation of the water content and the foam injection ratio. In the process of field application, the influences of soil warehouse pressure on the volume of the foam, the bulk factor of the muck and the moisture of undisturbed soil are taken into account, and finally the use amount of foaming agents and the water injection ratio needed for muck improvement of each ring duct piece footage of the earth pressure balance shield are obtained. Experiments needed by the method are simple in operation, low in experiment cost and can be effectively applied to field construction.

Description

technical field [0001] The invention relates to a method for selecting dreg improvement parameters of an earth pressure balance shield in a cohesive formation with foam as an additive, and belongs to the technical field of earth pressure balance shield construction. Background technique [0002] The construction of earth pressure balance shield has the advantages of high safety, fast excavation speed, and little impact on the surrounding environment. The mass of particles smaller than 0.06mm accounts for more than 30% of the total amount of muck in the stratum. In the process of earth pressure balance shield tunneling in cohesive strata, in order to facilitate the establishment of earth pressure balance in the soil bin, prevent cohesive muck from forming mud cakes, reduce the thrust of excavation, reduce the torque of cutter head and screw conveyor, and reduce energy consumption, it is required Improve the flow plasticity of the strata in front of the cutter head and the mu...

AI Technical Summary

Problems solved by technology

However, so far, there is still a lack of strong theoretical guidance for the selection of parameters for muck improvement. Most of them rely on on-site trials, select muck improvement methods and parameters based on experience, and modify them when problems arise

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