An Improved Thick Mud Excavation Method of Shield Machine

Abstract

The invention relates to an improved thick mud type tunneling construction method for a shield tunneling machine. According to the method, by generating high-fluidity and high-expansibility uniform liquid high-purity mud in an excavation chamber and doubling mixing power within a short period of time, tunneling speed is increased by three times compared with that of a single cutter adopted in the prior art; soil discharge inside and outside the machine is conducted intermittently through two soil discharge ports at different positions, overall soil discharge amount on the ground is reduced, propelling force is reduced, and the earth pressure of gap soil can be stabilized; the rate of accidents occurring often before during dredging is reduced to be zero by means of an automatic sucking device and a vacuum conveying device, and 2000 m ultra-long distance conveyance can be achieved without a relay pump; the automatic sucking device and the vacuum conveyance mud discharge mode are low in workload and high in safety performance and can help with forced ventilation inside a tunnel, and then damages caused by harmful gas such as gas in the tunnel are avoided.

Description

technical field [0001] The invention relates to a tunnel construction method, in particular to an improved mud-thick excavation method of a shield machine (including a pipe jacking machine). Background technique [0002] At present, most urban tunnel construction in my country adopts earth pressure balance shield tunnel construction. This method is more suitable for strata dominated by fine particles, with low water permeability and easy to form plastic flow state after disturbance. It can also be about 30% cheaper than the cost. However, when most sections of the shield section are fine-grained soil strata and there are local coarse sand and gravel strata with high permeability, the section with high permeability of the earth pressure balance shield cannot well maintain the stability of the excavation surface , It is easy to cause accidents such as the instability and collapse of the excavation surface and surface subsidence. If the muddy water pressurized shield is used i...

AI Technical Summary

Problems solved by technology

However, when most sections of the shield section are fine-grained soil strata and there are local coarse sand and gravel strata with high permeability, the section with high permeability of the earth pressure balance shield cannot well maintain the stability of the excavation surface , it is easy to cause accidents such as the instability and collapse of the excavation surface and the ground subsidence

If the muddy water pressurized shield is used in the whole section because of the highly permeable stratum in some sections, the project cost will increase significantly

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