Advanced double rows slip casting ductule construction technique

Abstract

The invention relates to an engineering technique for a lead double-row grouting small duct, which has the specific procedures of: first of all, excavate a structure shaft, then install a steel grate and then position double-row small conduct on the steel grate. The arc inclined angle between the small duct and the outline of the steel grate are respectively set as 7 to 10 degrees and 30 to 60 degrees with circular space of 0.3 to 0.4m. Then, grout into the small duct; excavate the soil body as per the requirement on the longitudinal space of steel grate after the grouted soil body reaches required strength; position another steel grate and position the double-row grouting small duct till the last steel grate is installed. The invention has the advantages that: during the engineering on large section hidden excavated tunnel, especially getting through the sand layer and gravel (pebble) layer at with no cohesion and insufficient self-stabilization capacity at the bottom of constructions and the arc of tunnel, this invention, by positioning the two-row grouting small duct on the ground layer, is able to realize comprehensive reinforcement of the ground layer and form a secondary buffering shell body based on the original reinforcement shell body, thus further alleviating or preventing the settlement after the breaking of ground layer and the damages to constructions (architectures).

Description

technical field [0001] The invention refers to a construction technique of an advanced double-row grouting small conduit. As a necessary and effective means of preventing subsidence in construction, it is suitable for large-section underground excavation tunnels, and projects where pipe jacking (manual pipe jacking) construction in inferior soil layers requires pre-reinforcement of the soil. Especially when passing through the bottom of buildings and structures that require strict control of settlement (such as construction under railways, bridges, etc.), the arch of the tunnel is in a sand layer and gravel (pebble) layer with no bonding and poor self-stabilization and loose geological conditions. soil layer. Background technique [0002] Soil pre-reinforcement by advanced small conduit grouting is an existing construction technology in the field of tunnel engineering. Conventional practice: generally use φ32 water and gas pipes to make small grouting conduits, the length ...

AI Technical Summary

Problems solved by technology

Its disadvantage is that when the large-section underground excavation tunnel passes through the bottom of the building (structure) and the corresponding tunnel arch is in the unbonded, poor self-stabilizing sand layer, gravel (pebble) layer and poor-quality soil layer, due to The closed ring of the grouting shell formed by single-layer reinforcement is relatively weak, the reinforcement effect on the ground is poor, and the settlement is difficult to control. If the soil reinforcement shell fails to achieve the design effect, major accidents may occur

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