Small-radius curve large-slope shield construction method in coastal soft soil stratum

Abstract

The invention discloses a small-radius curve large-slope shield construction method in a coastal soft soil stratum. The construction method comprises the two following major steps of an axial line control measure and a duct piece displacement control measure, wherein in an axial line control measure, the precorrection regulation on a shield machine needs to be firstly carried out; an overbreaking cutter is set; a proper duct piece is selected; the duct piece deviation correction is carried out; the shield posture precorrection is needed in a duct piece displacement control measure; the total thrust is reduced; a grouting hole position is set; and finally, a duct piece screw bolt is tightened again in time in the tunneling process. The construction method has the advantages that the shield axial line control and dust piece control measures and methods in the coastal special soft soil stratum are comprehensively stated from all aspects, so that the goal of fine construction is achieved, and the shield tunnel construction quality is improved; and meanwhile, the method provides the guidance opinion and reference for the shield construction in similar strata under similar conditions.

Description

technical field [0001] The invention relates to the technical field of subway construction, in particular to a construction method for small-radius curved and large-slope shield tunneling in coastal soft soil stratum. Background technique [0002] The second phase project of Ningbo Metro Line 1 has 1 station and 2 sections: Qiuai Station, the section from Qiuai Station to Donghuan South Road Station, and the section from Qiuai Station to U-shaped trough. For the Qiu U shield section under construction, the crossing stratum is mainly the coastal soft soil strata in the east of Ningbo, and the excavation route is a small radius curve (R=350M) and a large slope (28‰). Difficulties in shield construction: (1) Since the Ningbo coastal soft soil strata are mainly: silty clay, silty silty clay, and silt interbedded with silt; the soil has high water content, high sensitivity, low strength, high flow plasticity, The soil engineering performance is poor, and the consolidation time i...

AI Technical Summary

Problems solved by technology

Difficulties in shield construction: (1) Since the Ningbo coastal soft soil strata are mainly: silty clay, silty silty clay, and silt interbedded with silt; the soil has high water content, high sensitivity, low strength, high flow plasticity, Poor soil engineering performance, long consolidation time after construction disturbance

Shield construction in soft soil areas is like "punching holes in tofu", which brings difficulties to the quality of shield construction, and segments are prone to breakage and water leakage; And the segment floats up, the posture is difficult to control, and the construction is more difficult

(2) The shield machine itself is a straight-line rigid body, while the tunnel design is a curve. It is difficult for the broken line to closely match the small-radius curve, and the fitting is difficult. The construction of a large-slope tunnel is unfavorable for the control of the segment axis

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