Shallow-buried large-span rock tunnel portal section weak blasting excavation construction method

Abstract

The invention discloses a shallow-buried large-span rock tunnel portal section weak blasting excavation construction method. A benching tunneling method is adopted for excavating a tunnel portal section of a constructed rock tunnel from the back side to the front side; and during the excavation on the tunnel portal section, the processes comprises 1, upper step excavation and upper part early-stage support construction (during the excavation of an upper part soil body of the tunnel portal section, excavation is performed in a plurality of excavation sections from the back side to the front side, and each excavation section adopts the same excavation method and adopts a mechanical channeling and weak blasting combining method for excavation; during the excavation on any one excavation section, the processes include surveying and setting out, channeling construction by a channeling drilling machine, drilling blasting construction and slag discharge transportation); and 2, lower step excavating and lower part early-stage support construction. The method provided by the invention has the advantages that the steps are simple; the design is reasonable; the investment cost is low; the realization is convenient; the use effect is good; the excavation process of the tunnel port section can be simply, conveniently and fast completed; and the harmful effect of the blasting can be effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of tunnel excavation construction, and in particular relates to a construction method for excavation by weak blasting at the entrance section of a shallow-buried large-span rock tunnel. Background technique [0002] In recent years, due to the needs of urban construction and development, many local governments have invested in the construction of a large number of municipal tunnel projects. Due to the requirements of the special geographical location and environment of the projects, they are often located in the tunnel entrances of cities, scenic spots, and forest reserves. When the drilling and blasting method is used for construction, the public security organs, environmental protection departments and construction authorities have stricter control over the harmful effects of blasting, and even do not approve the use of blasting operations. The harmful effects of blasting mainly include blasting vibration,...

AI Technical Summary

Problems solved by technology

Nowadays, there are no mature blasting protection safety requirements and corresponding blasting protection methods, and low-efficiency, high-cost non-blasting technologies are often used to avoid high-risk operations or methods of repairing damage after risky operations

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