Mixed detonation method for tunnel slotting holes

Abstract

The invention discloses a mixed detonation method for tunnel slotting holes, comprising the following steps: S1, determining the slotting form and logarithm of the tunnel slotting holes according to the size of a tunnel face and surrounding rock conditions; S2, according to the blasting design requirement, drilling the tunnel slotting holes in the tunnel face; S3, checking the hole forming quality, and ensuring that the bottoms of all the blast holes are at the same design depth by adopting a drilling rock debris filling method; and S4, each pair of tunnel slotting holes being filled with explosives in sequence, mounting a forward detonator in one hole of each pair of tunnel slotting holes and arranging at the position 1 / 4-1 / 3 away from the top of the charging section, mounting a reverse detonator in the other hole of the same pair of tunnel slotting holes and arranging at the position 1 / 4-1 / 3 away from the bottom of the charging section, and after charging is completed, using drilling rock debris to complete blocking; and S5, connecting leg wires of the primer detonators in all the holes into a detonating network to complete detonation. Compared with traditional one-way detonation, the energy utilization rate and the tunneling efficiency are improved by arranging an adjacent hole reverse detonation propagation mode.

Description

technical field [0001] The invention relates to the technical field of tunnel drilling and blasting excavation, in particular to a mixed blasting method for tunnel cutting holes. Background technique [0002] In tunnel construction, there are two common construction methods: mechanical excavation and drill-and-blast method. However, mechanical excavation has many problems for tunnels with a rock Platinum coefficient greater than 7, so the drill-and-blast method still plays a dominant role in tunnel construction. During the drilling and blasting construction of tunnels, the tunneling rate is mainly affected by the cutting effect. Existing methods to improve tunnel cutting efficiency mainly focus on the improvement of tunnel cutting methods and hole layout methods, optimization of tunnel cutting parameters, etc. The method of increasing the rock breaking and expansion space of the groove cavity improves the cutting efficiency; under the condition that the width of the face fa...

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Problems solved by technology

[0013] Although the mid-point initiation can reduce the large block rate of the rock at the hole and eliminate the root of the blasting at the bottom of the hole, it does not fully break the rock mass in the middle. Figure 7 As shown, if the detonator is placed in the middle of the charging section of the cut hole (that is, the midpoint detonates), the detonation wave will be excited from the midpoint, and will be transmitted to the face of the hole and the bottom of the hole at the same time. Figure 8 , the explosion energy is also preferentially distributed to the face of the hole and the bottom of the hole. At this time, the shape of the cutout contour is close to a hyperbola, which is beneficial to the rock mass breaking at the hole and the bottom of the hole, but the rock mass in the middle of the blast hole will be broken. There are obvious deficiencies

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