Deep-buried tunnel full-section millisecond blasting method

Abstract

Provided is a deep-buried tunnel full-section millisecond blasting method. According to density distribution positions of elastic strain energy on a tunnel face, a millisecond electric detonator is adopted to divide cutting blast holes into two sections to perform detonation, spallation blast holes, buffer blast holes and light exposure blast holes are respectively divided into four sections to perform detonation, the number of the blast holes of each section is approximate, and blasting is performed from inside to outside and from low strain energy intensity to high strain energy intensity in each circle. The releasing rate and strength of the elastic strain energy are controlled by changing blast hole priming circuits, and surrounding rock power disturbance caused by quick releasing of strain energy is further weakened. By means of the deep-buried tunnel full-section millisecond blasting method, the peak value mass point vibration velocity caused by quick releasing of strain energy on an excavation face is only 40-50% velocity by means of a conventional blasting method. The deep-buried tunnel full-section millisecond blasting method can be widely applied to deep-buried tunnel blasting excavation in the fields of water and electricity, traffic, mines and the like.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering, in particular to a full-section millisecond blasting method of a deeply buried tunnel. Background technique [0002] With the further deepening of hydropower construction in Southwest my country and the increasing depth of mining of mineral resources, blasting excavation of deep tunnels is becoming more and more common in engineering construction. Due to the large buried depth or strong tectonic movement, the in-situ stress level of the tunnel rock mass is often high, accumulating huge elastic strain energy. During blasting and excavation, with the explosion of explosives, the excavated rock mass is instantly broken, the ground stress on the excavation surface is suddenly relieved, and the elastic strain energy stored in the rock mass is quickly released to the air surface, causing The surrounding rock stress can be adjusted rapidly. Due to the fast excavation speed, the sudden...

AI Technical Summary

Problems solved by technology

However, the current blasting excavation technology is often only aimed at the explosion itself, using methods such as weak charges, short footage, and partial excavation to control the dynamic disturbance of the surrounding rock caused by the explosion from the single-shot charge.

Although shortening the footage and subdividing excavation can also reduce the strain energy released by a single blast, which can achieve a certain effect, but this is a control method that simply sacrifices the excavation efficiency.

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