CN110940241B

CN110940241B - Tunnel extremely soft rock deep hole cut peripheral hole isolation air column charging buffering blasting method

Info

Publication number: CN110940241B
Application number: CN201911212255.3A
Authority: CN
Inventors: 张馨; 刘飞香
Original assignee: China Railway 18th Bureau Group Co Ltd
Current assignee: China Railway 18th Bureau Group Co Ltd
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2022-03-15
Anticipated expiration: 2039-12-02
Also published as: CN110940241A

Abstract

The invention discloses a tunnel extremely soft rock deep hole undermining peripheral hole-isolating gas column charging buffering blasting method, which relates to the technical field of tunnel blasting excavation, and is constructed in a two-step deep hole undermining and peripheral hole-isolating charging double-plugging vibration-reduction self-stabilizing drilling blasting mode, wherein 60 undermining holes with the depth of 4.5m are formed; 32 inner ring holes with the depth of 4.2 m; 52 peripheral eyes with the depth of 4.2 m; 11 bottom eyes with the depth of 4.2 m; the total drug loading is 230.6 kg; continuously charging explosive into the cut hole, and blocking 1.0m of stemming at the hole opening; filling powder at hard positions of rock in peripheral holes at intervals, plugging a hole opening with 0.3m of water stemming, filling powder at the positions of soft rock at intervals of two holes, continuously filling powder in an auxiliary hole, an inner ring hole and a bottom hole, and plugging 1.0m of stemming at the hole opening; after blasting, the crowbar prizes floating gangue live stones, and the sprayed concrete is 70mm thick. According to the tunnel extremely soft rock deep hole undermining peripheral hole isolation air column charging buffering blasting method, the blasting circulation footage is increased to 4.0m under the condition that the tunnel face is kept stable, and the construction progress is accelerated.

Description

Tunnel extremely soft rock deep hole cut peripheral hole isolation air column charging buffering blasting method

Technical Field

The invention relates to the technical field of tunnel blasting excavation, in particular to a tunnel extremely soft rock deep hole cut peripheral hole isolation air column charging buffering blasting method.

Background

A high-speed railway double-track tunnel is mainly composed of V-class surrounding rock affected by fault, joint crack development, rock mass breaking, and the crack surface filled with calcite film. The prior art adopts a two-step drilling and blasting method for construction. After excavation, the lithology is gray black sandy shale, the thin-medium-thick layers are formed, the arch rock mass is broken, local fracture water is exposed, the self-stability capability of surrounding rock is poor, the cut depth is limited, and the blasting circulation footage is difficult to break through 3.0 m. The rock quality of the face is uneven, the charging amount is not easy to control, the over-excavation and under-excavation conditions occur, the over-excavation spray anchor material is over-consumed, the under-excavation needs to be supplemented, the surrounding rock disturbance is more, the self-stability of the surrounding rock is not facilitated, the safety risk is high, the working procedure time is too long, and the construction speed is slow.

Disclosure of Invention

The invention aims to provide a tunnel extremely soft rock deep hole cut peripheral hole isolation air column charging buffering blasting method, which aims to solve the problems in the prior art, increase the blasting circulation footage to 4.0m under the condition of keeping the tunnel face stable, shorten the working procedure time and accelerate the construction progress.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a tunnel extremely soft rock deep hole cut peripheral hole isolation air column charging buffer blasting method, which comprises the following steps:

step one; the construction is carried out by adopting a double-plugging vibration-reduction self-stabilizing drilling explosion mode of deep hole undermining with two steps and hole isolation and charging of peripheral holes, a double-type wedge undermining is adopted for a tunnel face, the number of undermining holes is 60, and the depth of the eyeground is 4.5 m; 32 inner ring holes with the depth of 4.2 m; the peripheral eyes are 52 and are 4.2m deep; 11 bottom eyes with the depth of 4.2 m; the total number of blast holes is 155, and the total loading capacity is 230.6 kg;

step two; continuously charging explosive into the cut hole, and blocking 1.0m of stemming at the hole opening; filling powder at hard positions of rock in peripheral holes at intervals, plugging a hole opening with 0.3m of water stemming, filling powder at the positions of soft rock at intervals of two holes, continuously filling powder in an auxiliary hole, an inner ring hole and a bottom hole, and plugging 1.0m of stemming at the hole opening;

step three; blasting, prying floating gangue and live rocks by a crowbar after blasting, and spraying C30 concrete with the thickness of 50-70 mm.

Optionally, the explosive charges are explosive rolls which are identical in structure and are connected in series through detonating cords, the explosive roll positioned at the innermost part of the cut hole is connected with a detonator, and the detonator is communicated with the outside through a detonating tube; stemming is plugged at the hole opening at the outer side of the slotted hole.

Compared with the prior art, the invention has the following technical effects:

the invention provides a method for blasting, buffering and blasting through charging of hole-isolating gas columns at the periphery of tunnel ultra-soft rock deep hole cut, which increases blasting circulation footage to 4.0m under the condition of keeping tunnel face stable. Through the adjustment of the powder charge of the peripheral holes, the vibration reduction and the weak vibration are realized, the light explosion effect is improved, the ultra-short excavation is reduced, the spray anchor material is saved, the construction cost is reduced, the working procedure time is shortened, and the construction progress is accelerated.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic view of a blasthole arrangement of the present invention;

FIG. 2 is a schematic view of a drill-blast slotted hole of the present invention;

FIG. 3 is a schematic diagram of a perimeter eye spaced uncoupled charge configuration of the present invention;

wherein, 1 is detonating cord, 2 is cartridge, 3 is detonator, 4 is detonating tube, 5 is stemming.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Example one

The length of a high-speed railway double-track tunnel is 7827.8m, the exit section is 3907.3m, most of surrounding rocks are V-grade surrounding rocks, the surrounding rocks are influenced by a rural ditch fault, a joint crack develops, a rock mass is broken, a crack surface is filled with a calcite film, and the self-stability of the surrounding rocks is poor. The embodiment innovatively adopts a new double-plugging vibration-reduction self-stabilizing drilling and blasting technology of deep hole cutting with two steps and hole-isolation and explosive charging with peripheral holes.

Explosive: using No. 2 rock emulsion explosive with diameter of 32mm multiplied by 200 mm; detonator: adopting a non-electric millisecond detonator; a detonation network: the detonating tubes are connected in series and in parallel, and the differential detonation is adopted.

Drilling: an excavation rack and a pneumatic rock drill are adopted, the length of a drill rod is 5.0m, the diameter of a drill bit is 38mm, and the diameter of a drill hole is 40 mm.

The blasthole arrangement is shown in figures 1-3: the compound wedge-shaped underholing is adopted, 60 underholing holes are formed, and the fundus depth is 4.5 m; 32 inner ring holes with the depth of 4.2 m; the number of the peripheral holes is 52, the depth is 4.2m, and the peripheral holes are filled with powder at intervals of holes or at intervals of two holes; 11 bottom eyes, 4.2m deep. The total number of blast holes is 155, and the total loading is 230.6 kg. According to the setting position of the blast holes on the face, the blast holes are finely divided, the blast holes are positioned at the bottom and are bottom holes, the round arc blast holes positioned at the outer side are peripheral holes, and the inner side of the round arc blast holes is provided with two circles of holes, three circles of holes, four circles of holes, small holes, large holes and center holes in sequence, wherein the specific setting quantity refers to a circular footage blasting parameter table in the scheme of the embodiment shown in table 1.

Table 1 cyclic footage blasting parameter table of the invention

The peripheral holes are charged with 1 blasthole in a spacing mode when the rock is slightly hard, and are charged with 2 blastholes in a spacing mode when the rock is slightly soft. And the peripheral holes are filled with powder at intervals through reverse air columns, the water stemming is blocked at the hole opening by 0.8m, and the detonating cord is detonated. The explosive amount is reduced by detonating the detonators at the same section of the peripheral holes, so that the purposes of reducing vibration, regularly forming by light explosion, controlling a rock loose ring and prolonging the self-stabilization time of surrounding rock are achieved.

The charge structure: the cut hole is filled with powder continuously, and the hole opening is plugged with 1.0m of stemming. The peripheral hole rock is filled at a slightly hard position by adopting a separation hole and a spacing mode, the hole opening is blocked by 0.3m of water stemming, and the soft rock is filled at a spacing mode by adopting two holes. The explosive is filled with explosive sticks 2 which have the same structure and are connected in series through detonating cords 1, the explosive stick 2 positioned at the innermost part of the slotted hole is connected with a detonator 3, and the detonator 3 is communicated with the outside through a detonating tube 4; stemming 5 is plugged at the hole outside the cut hole, and a non-coupling explosive loading structure is arranged at the interval of peripheral holes in the figure 3. The auxiliary hole, the inner ring hole and the bottom hole are charged continuously, and 1.0m of stemming is plugged by adopting an orifice. The residual blast hole length after the continuous charging is used for completely plugging the stemming, the action time of high-temperature and high-pressure explosive gas in the blast hole is prolonged, the hole bottom explosive force is increased, the explosive energy loss is reduced, and the explosive effect of the undercut hole and the bottom hole is fully ensured. After blasting, the tunnel face is sprayed with concrete for the first time, the blasting footage is 4.0m, the smooth face effect is better, and the details are shown in a blasting effect statistical table in a table 2.

Table 2 statistical table of blasting effect of the present invention

After blasting, a crowbar is used for prying off floating gangue live rocks, concrete is primarily sprayed on the exposed surfaces of the tunnel face, the vault and the side walls, C30 concrete is sprayed for 50-70 mm thick, the self-stabilization time of the surrounding rock is prolonged, blocks are prevented from falling, collapse is avoided, the construction safety risk is reduced, the strength of the surrounding rock during self-stabilization is increased, and the safety risk is reduced.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims

1. A tunnel extremely soft rock deep hole cut peripheral hole isolation gas column powder charge buffering blasting method is characterized in that: the method comprises the following steps:

step one; the construction is carried out by adopting a double-plugging vibration-reduction self-stabilizing drilling explosion mode of deep hole undermining with two steps and hole isolation and charging with peripheral holes, and the tunnel face adopts compound wedge undermining with 60 undermining holes; 32 inner ring holes are formed; 52 peripheral eyes; 11 bottom eyes; the fundus depth of the cutting eye is 4.5 m; the depth of the inner ring hole is 4.2 m; the peripheral eye depth is 4.2 m; the bottom eye depth is 4.2 m; the total number of blast holes is 155, and the total loading capacity is 230.6 kg;

step two; continuously charging explosive into the cut hole, and blocking 1.0m of stemming at the hole opening; the hard rock parts of the peripheral holes are filled with powder in a spaced mode through spaced holes, the powder is filled with explosive rolls which are identical in structure and are connected in series through detonating cords, the explosive roll positioned at the innermost part of the cut hole is connected with a detonator, and the detonator is communicated with the outside through a detonating tube; stemming is plugged at the hole opening at the outer side of the cut hole, the hole opening is plugged with 0.3m of water stemming, the soft rock is filled at intervals of two holes, the auxiliary hole, the inner ring hole and the bottom hole are filled continuously, and the hole opening is used for plugging 1.0m of stemming;