Whole-section front pre-grouting construction method

Abstract

The invention discloses a whole-section front pre-grouting construction method. The method comprises the steps that concrete is used for pouring a blocked concrete wall with the thickness being 2.5-5m inside a face, and 2-4 rows of mortar anchors are adopted on the peripheral edge of the blocked concrete wall to be embedded into surrounding rock; a 8-10 m range is reserved behind the blocked concrete wall for leveling and compacting, and then a concrete layer is poured to be adopted as an application platform. A grouting hole is determined outside the counter line within the radial reinforcing range, an outer ring grouting hole final hole is within 4-6 m outside the excavated counter line, and the hole forming position and the final hole position of the grouting hole are distributed in anannular mode; the grouting hole is drilled, the diameter of the grouting hole is set to be 40-70 mm, the hole depth is set to be 5-30 m, multiple seamless steel tubes with the diameter being 35-50 mmcontinue to be ejected into the hole, the length of the seamless steel tubes is 3-5 m, 20-30 cm is exposed outside, the array pitch of the grouting hole is 1-1.5 m, and the grouting hole is formed ina quincunx mode. The single-hole water outlet amount is measured, and whether drill rod retrograding grouting or segmentation advanced grouting is adopted is determined according to the single-hole water outlet amount.

Description

technical field [0001] The invention relates to a tunnel construction method, in particular to a curtain grouting construction method. Background technique [0002] At present, the geology of water and mud inrush sites has the characteristics of multi-phase, secondary structure development, complex lithological composition, loose cementation, and broken rock mass. Saturated water often deteriorates rock and soil properties. Structural fissures are developed, and the water permeability is strong. The central core zone is dominated by soft materials similar to gravel-containing silty clay or gravel, and the water permeability and water conduction capacity is weak. The nature of the project is characterized by low strength and poor stability of the surrounding rock, and it will face disasters such as large-scale landslides and debris flows during the construction and excavation of the tunnel. Most of the rock mass is located near structural belts such as folds and faults, and ...

AI Technical Summary

Problems solved by technology

However, the water-rich quicksand and the full-section grouting hole and the grouting wall of the tunnel in the fault section disclosed in the patent application cannot solve emergencies such as water gushing during the grouting process, and the construction quality is unstable and there are potential safety hazards

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