Construction method for entering shallow-buried multi-arch tunnel under water-rich geological conditions

Abstract

A construction method for a shallow-buried multi-arch tunnel under water-rich geological conditions includes the following steps: cleaning a grouting ground surface; marking a grouting reinforcement scope; performing survey setting-out; drawing a cross-section diagram to scale; calculating out coordinates and angles of anchor points that need to be set; marking drilling positions; nailing small wooden piles at the drilling positions for identifying; determining a setting depth of the anchor rods according to ground elevation; drilling holes, cleaning bottom of hole, grouting, performing construction preparation, performing long pipe shed construction at the entrance after an earth-rock of a tunnel entrance and an open cut tunnel is excavated to flush with a springing line of the tunnel. A down-the-hole drill is used for drilling in construction. Long pipe shed grouting is designed based on solidifying a soil mass in limited scope around a consolidation pipe shed.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This patent application claims the benefit and priority of Chinese Patent Application No. 202010465066.3, entitled “Construction Method for Multi-arch Tunnel Entrance under Shallow-buried and Water-rich Geological Conditions” filed on May 28, 2020, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.BACKGROUND OF THE INVENTIONField of the Invention[0002]The present disclosure relates to the technical field of tunnel engineering, in particular, to a construction method for a multi-arch tunnel entrance under shallow-buried and water-rich geological conditions.Description of the Related Art[0003]Shallow-buried tunnel is a tunnel engineering under specific conditions. The buried depth is less than twice the diameter of the tunnel. Its construction is not only restricted by geological factors of overburden, but also affected by ground environment. The shallow-buried tunnel does not sim...

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Benefits of technology

[0022]The present disclosure is novel in concept, ingenious in structure, and high in practicability. The present disclosure solves the problems that it is very difficult to control the ground surface settlement and the stability of the surrounding r...

Problems solved by technology

Its construction is not only restricted by geological factors of overburden, but also affected by ground environment.

The structural trace is mainly manifested by the development of joints and fissures, so the geological conditions are poor.

The surrounding rocks of fully weathered mixed granites at the entrance and the exit of the tunnel are at Grade V. The fully weathered mixed granites at the entrance of the tunnel is thick and loose in structure, and easily collapses, so that the stability of a rock-soil mass of an face upward slope at the entrance of the tunnel is extremely poor, which is extremely easy to cause shallow engineering landslide or large collapse during construction and excavation, and the quaternary eluvial slope layer at the up...

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