阅读说明：本技术 一种小断面水利凝灰岩隧洞超欠挖控制方法 (Small-section water conservancy tuff tunnel overbreak control method ) 是由 张海波 张凤海 白涛 传兴风 伍洋 于 2021-01-26 设计创作，主要内容包括：本发明公开了一种小断面水利凝灰岩隧洞超欠挖控制方法,包括如下步骤：1)掏槽角度和开口范围的确定；2)辅助孔布置及角度控制；3)钻孔质量控制；4)炮孔封堵质量控制。本发明具有操作简单快速、安全可靠的优点,采用它有效降低隧洞平均线性超挖,提高了循环进尺,减少了炸药单耗量,节约了施工成本,提升了经济效益,同时,还保障了隧道的安全和质量。(The invention discloses a small-section water conservancy tuff tunnel overbreak control method, which comprises the following steps: 1) determining a cut angle and an opening range; 2) auxiliary hole arrangement and angle control; 3) controlling the drilling quality; 4) and controlling the plugging quality of the blast hole. The method has the advantages of simple and quick operation, safety and reliability, effectively reduces the average linear overexcavation of the tunnel, improves the cyclic footage, reduces the unit consumption of explosive, saves the construction cost, improves the economic benefit, and simultaneously ensures the safety and the quality of the tunnel.)

1. A small-section water conservancy tuff tunnel overbreak control method is characterized by comprising the following steps: 1) determining a cut angle and an opening range; 2) auxiliary hole arrangement and angle control; 3) controlling the drilling quality; 4) and controlling the plugging quality of the blast hole.

2. The method for controlling the overbreak and the underexcavation of the small-section water conservancy tuff tunnel according to claim 1, wherein in the step 1), the determination of the cut angle and the opening range is performed by the following calculation formula:

b slot =2 (L + Δl) span α + B

Wherein, the B groove is a horizontal distance of the opening of the wedge-shaped cut hole; l is the vertical distance from the bottom of the cut hole to the face; the delta L is the ultra-deep cut hole; b is the distance between the bottoms of the cut holes; alpha is 70-75 ℃.

3. The method for controlling the overbreak and the underexcavation of the small-section water conservancy tuff tunnel according to claim 2, wherein in the step 2), the arrangement and the angle control of the auxiliary holes adopt the following steps:

firstly, arranging auxiliary holes in a layered and sequential manner from a cut hole to a peripheral hole, and at least ensuring 2-3 layers of auxiliary holes;

secondly, gradually adjusting the blast hole angle of each layer (circle) from the wedge-shaped cut hole to the peripheral light blasting holes from inside to outside, and keeping a certain external insertion angle of the peripheral light blasting holes on the outermost side according to design requirements;

the distance between the peripheral holes is 350-plus 400 mm;

and fourthly, controlling the thickness of the optical explosion layer from the inner ring hole to the peripheral hole to be 400-450 mm, and keeping the thickness of the same circulating optical explosion layer consistent.

4. The small-section water conservancy tuff tunnel overbreak control method of claim 3, which is characterized in that: in the step 3), all hole sites need to be measured and positioned before drilling; wherein, the spacing error of the cut hole and the auxiliary hole is controlled within the range of +/-50 mm, and the spacing error of the hole bottom is controlled within the range of +/-50 mm; the distance error of the peripheral holes is ensured to be within the range of +/-50 mm, and the bottoms of the peripheral holes fall on the same plane as much as possible.

5. The method for controlling the overbreak and underexcavation of a small section tuff tunnel according to claim 4, wherein: in the step 4), the blast hole is plugged by adopting a cement gun or a polyurethane material;

when blasting is carried out, the holes and the auxiliary holes are cut, a cartridge with a larger diameter or a No. 2 emulsion explosive is adopted, the cartridge is pressed to the middle lower part of a blast hole when charging, and the peripheral holes are charged at intervals;

when the cut hole and the auxiliary hole are plugged, the plugging material contacts the explosive cartridge, and when water stemming is used for plugging, the plugging length is ensured to be not less than 20% of the length of the cut hole and the auxiliary hole; when the polyurethane material is adopted for plugging, the plugging length is at least ensured to be 400 mm; when the peripheral holes are plugged, the plugging material is placed in the orifice, and the plugging length is not greater than the hole spacing of the peripheral holes.

Technical Field

The invention relates to a tunnel overbreak and underbreak method, in particular to a small-section water conservancy tuff tunnel overbreak and underbreak control method.

Background

At present, when a small-section hydraulic tuff tunnel (the shape of an urban gate is 4500 x 4950 mm) is constructed by drilling and blasting, due to the frequent problems of cut angles, opening ranges, the number and angles of auxiliary hole layers and blast hole plugging quality, the quality of tunnel over-excavation and under-excavation control is poor, and the over-consumption of sprayed concrete is serious. The phenomenon not only causes the construction cost to be increased and the benefit to be lost, but also causes a series of problems of increased cycle time, prominent construction safety problem and the like.

Disclosure of Invention

The invention aims to provide a small-section water conservancy tuff tunnel overbreak control method capable of effectively controlling the overbreak quality of the tunnel.

The invention aims to realize the technical scheme that a small-section water conservancy tuff tunnel overbreak control method comprises the following steps: 1) determining a cut angle and an opening range; 2) auxiliary hole arrangement and angle control; 3) controlling the drilling quality; 4) and controlling the plugging quality of the blast hole.

Wherein, in the step 1), the determination of the cut angle and the opening range is performed by the following calculation formula:

b slot =2 (L + Δl) span α + B

Wherein, the B groove is a horizontal distance of the opening of the wedge-shaped cut hole; l is the vertical distance from the bottom of the cut hole to the face; the delta L is the ultra-deep cut hole; b is the distance between the bottoms of the cut holes; alpha is 70-75 ℃.

Further, in the step 2), the auxiliary hole arrangement and angle control adopt the following steps:

firstly, arranging auxiliary holes in a layered and sequential manner between a cut hole and a peripheral hole, and at least arranging 2-3 layers of auxiliary holes;

secondly, gradually adjusting the blast hole angle of each layer (circle) from the wedge-shaped cut hole to the peripheral light blasting holes from inside to outside, and keeping a certain external insertion angle of the peripheral light blasting holes on the outermost side according to design requirements;

thirdly, the distance between the peripheral holes is 350-400 mm, wherein holes are properly drilled and encrypted or holes are added at the individual weak surrounding rock;

and fourthly, controlling the thickness of the optical explosion layer from the inner ring hole to the peripheral hole to be 400-450 mm, and keeping the thickness of the same circulating optical explosion layer consistent.

In the step 3), all hole sites need to be measured and positioned before drilling; wherein, the spacing error of the cut hole and the auxiliary hole is controlled within the range of +/-50 mm, and the spacing error of the hole bottom is controlled within the range of +/-50 mm; the distance error of the peripheral holes is ensured to be within the range of +/-50 mm, and the bottoms of the peripheral holes fall on the same plane as much as possible.

Wherein, in the step 4), the blast hole is plugged by adopting a cement gun or a polyurethane material;

when blasting is carried out, the holes and the auxiliary holes are cut, a cartridge with a larger diameter or a No. 2 emulsion explosive is adopted, the cartridge is pressed to the middle lower part of a blast hole when charging, and the peripheral holes are charged at intervals;

when the cut hole and the auxiliary hole are plugged, the plugging material contacts the explosive cartridge, and when water stemming is used for plugging, the plugging length is ensured to be not less than 20% of the length of the cut hole and the auxiliary hole; when the polyurethane material is adopted for plugging, the plugging length is at least ensured to be 400 mm; when the peripheral holes are plugged, the plugging material is placed in the orifice, and the plugging length is not greater than the hole spacing of the peripheral holes.

By adopting the technical scheme, the method has the advantages of simple and quick operation, safety and reliability, effectively reduces the average linear overexcavation of the tunnel, improves the circulating footage, reduces the unit consumption of explosive, saves the construction cost, improves the economic benefit, and simultaneously ensures the safety and the quality of the tunnel.

Drawings

The drawings of the invention are illustrated as follows:

fig. 1 is a schematic view of the cut hole structure of the present invention.

Detailed Description

The following detailed description of the embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments will still fall within the scope of the present invention claimed in the claims.

Example 1: as shown in fig. 1, a method for controlling the overbreak and the underexcavation of a small-section water conservancy tuff tunnel comprises the following steps: 1) determining a cut angle and an opening range; 2) auxiliary hole arrangement and angle control; 3) controlling the drilling quality; 4) and controlling the plugging quality of the blast hole.

Wherein, in the step 1), the determination of the cut angle and the opening range is performed by the following calculation formula:

b slot =2 (L + Δl) span α + B

Wherein, the B groove is a horizontal distance of the opening of the wedge-shaped cut hole; l is the vertical distance from the bottom of the cut hole to the face; the delta L is the ultra-deep cut hole; b is the distance between the bottoms of the cut holes; alpha is 70-75 ℃;

through repeated tests, the opening range is 1800mm, and the value of the hard rock is 250 mm-300 mm.

Wherein, in the step 2), the auxiliary hole arrangement and angle control adopt the following steps:

firstly, arranging auxiliary holes in a layered and sequential manner between a cut hole and a peripheral hole, and at least arranging 2 layers of auxiliary holes;

secondly, gradually adjusting the blast hole angle of each layer (circle) from the wedge-shaped cut hole to the peripheral light blasting holes from inside to outside, and keeping a certain external insertion angle of the peripheral light blasting holes on the outermost side according to design requirements;

thirdly, the distance between the peripheral holes is 350-plus 400mm (the individual weak surrounding rock is properly drilled and encrypted);

and fourthly, controlling the thickness of the optical explosion layer from the inner ring hole to the peripheral hole to be 400-450 mm, and keeping the thickness of the same circulating optical explosion layer consistent.

The device comprises a first layer of auxiliary holes, a second layer of auxiliary holes and an inner ring of inner rings, wherein the angle of each cut hole is 70-75 degrees, the angle of each first layer of auxiliary holes is 80-85 degrees, and the angle of each inner ring of inner rings is close to 90 degrees;

through repeated tests, the distance between the peripheral holes is adjusted from original 450 mm to 400 mm.

Further, in the step 3), all hole sites need to be measured and positioned before drilling; wherein, the spacing error of the cut hole and the auxiliary hole is controlled within the range of +/-50 mm, and the spacing error of the hole bottom is controlled within the range of +/-50 mm; the distance error of the peripheral holes is ensured to be within the range of +/-50 mm, and the bottoms of the peripheral holes fall on the same plane as much as possible.

Wherein, in the step 4), the blast hole is plugged by adopting a cement gun or a polyurethane material;

when blasting is carried out, the holes and the auxiliary holes are cut, a cartridge with a larger diameter or a No. 2 emulsion explosive is adopted, the cartridge is pressed to the middle lower part of a blast hole when charging, and the peripheral holes are charged at intervals;

when the cut hole and the auxiliary hole are plugged, the plugging material contacts the explosive cartridge, and when water stemming is used for plugging, the plugging length is ensured to be not less than 20% of the length of the cut hole and the auxiliary hole; when the polyurethane material is adopted for plugging, the plugging length is at least ensured to be 400 mm; when the peripheral holes are plugged, the plugging material is placed in the orifice, and the plugging length is not greater than the hole spacing of the peripheral holes.

By the method, the average linear over-excavation of the tunnel is reduced to 70 mm from the original 110 mm; the excess consumption of sprayed concrete is reduced to about 50-70% from the original 80-110%. The tunnel circulating advancing rule is originally 2100-graded and 2300-graded mm, and is improved to be 2300-graded and 2600-graded each circulating advancing rule. Before the tunnel overbreak and underbreak control, the explosive consumption of each cycle is 78 kilograms, and after the tunnel overbreak control, the single-consumption of each cycle is 66 kilograms, and the single-consumption of the explosive saves the cost by 15 percent.