Large-section tunnel blasting construction method

Abstract

The invention discloses a large-section tunnel blasting construction method. The method comprises the following steps that ring-like blasting is carried out at the middle position of a blasting surface of a large-section tunnel, tunnel face central surrounding rock and large-section tunnel peripheral surrounding rock are formed by blasting surface surrounding rock of the blasted large-section tunnel, a pre-crack is formed at the blasting position, the pre-crack separates the most tunnel face central surrounding rock from the large-section tunnel peripheral surrounding rock, the tunnel face central surrounding rock and the large-section tunnel peripheral surrounding rock are not stressed by each other, then the tunnel face central surrounding rock and the large-section tunnel peripheral surrounding rock are sequentially blasted, and finally back break control is conducted to achieve large-section tunnel blasting construction. According to the large-section tunnel blasting construction method, the minimum distance d1 from a wedge-shaped slotting hole to a tunnel design contour line is determined, the tunnel face central surrounding rock and tunnel peripheral holes are arranged in a wide hole pitch manner, the number of drilled holes is greatly reduced, the construction efficiency is improved, the blast hole utilization rate of all blast holes is increased, and the construction cost is greatly saved.

Description

technical field [0001] The invention relates to the technical field of excavation of large-section tunnels, in particular to a blasting construction method for large-section tunnels. Background technique [0002] With the rapid development of economy and society, traditional small-section tunnels can no longer meet the needs of road transportation, and large-section tunnels such as three-lane and four-lane tunnels have widely appeared in roads built in recent years. The drill and blast method has the advantages of high efficiency and economy, and is the main method of tunnel excavation in my country. However, if the traditional method is used to lay out the hole network of large-section tunnels, it will increase the number of holes drilled, increase the cost of drilling holes, and affect the progress of the project. [0003] The layout of the hole network has always been a research hotspot in tunnel blasting, and a large number of experts and scholars have conducted a lot of...

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Problems solved by technology

[0004] The above research has solved many problems in the tunnel blasting operation site, and the results are quite fruitful. However, with the increase of the tunnel section, how to reduce the layout of blast holes is an urgent scientific problem to be solved. There are few reports on the research on the layout of reduced holes.

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