Underground excavation construction technology for hard rock stratum large-gradient channel

Abstract

The invention provides a hard rock stratum steep-slope channel underground excavation construction technology, and relates to the technical field of steep-slope channel underground excavation construction.The hard rock stratum steep-slope channel underground excavation construction technology comprises the following steps that S1, early-stage preparation work is conducted, blast hole site surveying and lofting are conducted on a tunnel face, and a core soil area is designed; s2, slope section hard rock reserved stone core soil blasting operation is implemented and comprises the following steps that S21, blasting holes are formed, and a plurality of groups of straight cut grooves, a group of auxiliary holes and a plurality of peripheral holes which are sequentially distributed outwards along the periphery of a core soil area are formed in a tunnel face; the construction method has the beneficial effects that the problems that at present, due to the fact that the gradient of a station entering channel is large, an operation platform is prone to being unstable in construction, and time and labor are wasted when a support is erected and a profile steel platform is moved are solved.

Description

Technical Field

[0001] The invention relates to the technical field of steep-slope tunnel dark excavation construction, and in particular to a steep-slope tunnel dark excavation construction process in a hard rock stratum. Background Art

[0002] Hard rock formations usually refer to those with high rock hardness and dense structure. The formation of these formations is often related to tectonic movements in geological history, such as magma intrusion, regional metamorphism, etc. The characteristics of hard rock formations include high rock strength, strong compressive resistance, good wear resistance, etc. These characteristics make the mining and utilization of hard rock formations have certain technical difficulties and economic costs.

[0003] In the construction of urban subways and rail transit, due to the limitations of terrain conditions, some entrance passages need to be constructed by dark excavation. An operating platform will be used in the construction, but due to the large slope of some entrance passages, the operating platform is prone to unstable construction. In addition, the operating platform includes a bracket and a steel platform, which is time-consuming and laborious to set up the bracket and move the steel platform. Therefore, a dark excavation construction process for a large-slope channel in hard rock formations is urgently needed to solve the above problems. Summary of the invention

[0004] In view of the above-mentioned technical problems existing in the prior art, a dark excavation construction technology for a steep slope channel in hard rock strata is provided, which solves the current problem that the operating platform is easily unstable due to the steep slope of the access channel, as well as the time-consuming and labor-intensive problem in setting up the support and moving the steel platform.

[0005] The purpose and effect of the present invention are achieved by the following specific technical means:

[0006] A dark excavation construction process for a steep-slope channel in a hard rock formation comprises the following steps:

[0007] S1. Preliminary preparation work: measuring and setting out the blasting holes on the tunnel face and designing the core soil area;

[0008] S2. Implement the blasting operation of the reserved stone core soil in the hard rock of the slope section, including the following steps:

[0009] S21, blasting hole drilling, a plurality of groups of straight-eye cutouts, a group of auxiliary holes and a plurality of peripheral holes are opened on the tunnel face and distributed outward in sequence along the periphery of the core soil area; a plurality of groups of shock-absorbing expansion slot holes are opened on the tunnel face, and a plurality of groups of the shock-absorbing expansion slot holes are respectively distributed near a plurality of groups of the straight-eye cutouts; and a plurality of bottom plate holes are opened on the tunnel face, and a plurality of the bottom plate holes are respectively located on both sides of the core soil area and flush with its bottom; the spacing between two adjacent holes is 20-100 cm, the diameter of each hole is 2-5 cm, and the depth of each hole is 1.5-2.5 m;

[0010] S12, blasting holes are charged and detonated after inspection. Explosives and digital electronic detonators are loaded into straight-eye cutouts, auxiliary holes, peripheral holes, and bottom plate holes, and detonated in sequence after inspection. The detonation interval is 10-100ms. The free surface of the straight-eye cutouts and shock-absorbing expansion holes is peeled off layer by layer to the surrounding rock layers, and the stone core soil is reserved;

[0011] S3. Use the reserved stone core soil as an operating platform to carry out support operations on the upper steps.

[0012] A further preferred solution: in S1, before the blasting hole position measurement and layout, the tunnel face is first de-risked.

[0013] A further preferred solution: in S21, the straight-eye grooves and shock-absorbing expansion groove holes are each provided with 4 groups, each group of the straight-eye grooves includes 5 straight-eye grooves, with 1 straight-eye groove as the center point, and the remaining 4 straight-eye grooves surround the straight-eye groove at the center point, and each group of the shock-absorbing expansion groove holes includes 4 shock-absorbing expansion groove holes, and the 4 shock-absorbing expansion groove holes are located on the inner side of the remaining 4 straight-eye grooves and surround the straight-eye groove at the center point.

[0014] A further preferred solution: in S21, the auxiliary holes include 2 groups of auxiliary holes 1 and 14 auxiliary holes 2, the 14 auxiliary holes 2 surround the 4 groups of straight-eye grooves, the 2 groups of auxiliary holes 1 respectively surround the outside of the bottom 2 groups of straight-eye grooves, and the 2 groups of auxiliary holes 1 are both located on the inner side of the 26 auxiliary holes 2.

[0015] A further preferred solution is that two of the auxiliary holes 2 are located between the two groups of straight-eye grooves at the top, and the top two straight-eye grooves are on the same arc line as the remaining 14 auxiliary holes 2.

[0016] A further preferred solution is that the explosive is φ32 emulsion explosive, each section of the explosive is 0.3 kg, 4 sections of explosives are placed in each of the straight-eye grooves, auxiliary hole one, auxiliary hole two and bottom plate holes, and 1.5 sections of explosives are placed in each of the peripheral holes.

[0017] A further preferred solution: the blasting cycle footage of the hard rock reserved stone core soil blasting operation in the slope section is 1.5m.

[0018] A further preferred solution: In S2, the blasting operation of the hard rock reserved stone core soil in the slope section is carried out, and the following steps are also included:

[0019] S13, ventilation in the cave;

[0020] S14, the second danger elimination of the face;

[0021] S15. Check blasting effect and dynamically correct blasting parameters.

[0022] A further preferred solution is that the operating platform is 1.5-1.9 m high and 3.5-5.2 m wide, and the operating height of the staff is 1 to 1.74 m.

[0023] A further preferred embodiment further comprises the following steps:

[0024] S4. Excavate and support the middle step;

[0025] S5. Excavate and support the lower steps.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This kind of dark excavation construction technology for steep-slope channels in hard rock strata is designed to arrange the positions of straight-eye slots, shock-absorbing expansion holes, auxiliary holes, peripheral holes and bottom plate holes at the heading face of the upper step, and to carry out blasting operations of the reserved stone core soil in the hard rock of the slope section in the order of straight-eye slots → auxiliary hole one → auxiliary hole two → peripheral holes → bottom plate holes, i.e., a special design of micro-error phase vibration reduction blasting. After blasting, the stone core soil is in the shape of a rectangular parallelepiped, which can be used as an operating platform to support the upper step without setting up a bracket and a steel platform (the existing operating platform) on the upper step. This solves the current problem of unstable construction of the operating platform due to the large slope of the access channel, as well as the time-consuming and labor-intensive problem of setting up the bracket and moving the steel platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The blasting design drawing of the reserved stone core soil of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the stone core soil of the present invention as an operating platform;

[0030] Figure 3 It is a partial side view schematic diagram of the dark excavation construction process of a hard rock formation steep slope channel of the present invention;

[0031] Figure 4 It is a schematic diagram of the main view of the dark excavation construction process of a hard rock formation steep slope channel of the present invention;

[0032] Figure 5 It is a construction flow chart of the present invention.

[0033] Markings in the figure: straight eye groove T, shock-absorbing expansion hole J, auxiliary hole F 1 、Auxiliary hole 2F 2 , peripheral holes Z, bottom plate holes D, core soil area H, upper step a, stone core soil a1, middle step b, right middle step b1, left middle step b2, lower step c, unexcavated section d, steel frame e. DETAILED DESCRIPTION

[0034] See also Figure 1-5 , further illustrate the embodiments of the present invention;

[0035] A dark excavation construction process for a steep-slope channel in a hard rock formation comprises the following steps:

[0036] S1. Preliminary preparation work: blasting hole position measurement and layout on the tunnel face and design of core soil area H (located at the tunnel face of upper step a, in a rectangular shape);

[0037] In S1, before measuring and staking out the blasting hole positions, the face was cleared for the first time to ensure safe construction for the workers.

[0038] S2. Implement the blasting operation of the hard rock reserved stone core soil a1 in the slope section, including the following steps:

[0039] S21. Blasting holes are set up. Several groups of straight cuts T are opened on the tunnel face and distributed outwards along the periphery of the core soil area H (evenly distributed along the periphery of the core soil area H, Figure 1 Each group of straight cuts T is similar to the diamond 5 distribution), and a group of auxiliary holes (located on the contour line of the upper step a except the bottom plate, such as Figure 1 The holes connected by the arc line 2 and the bending line 3) and several peripheral holes Z (located on the contour line of the upper step a face and connected to the bottom plate, such as Figure 1 The tunnel face is provided with a plurality of groups of shock-absorbing expansion slot holes J, which are respectively distributed near a plurality of groups of straight-eye cutouts T; and the tunnel face is provided with a plurality of bottom plate holes D, which are respectively located on both sides of the core soil area H and flush with its bottom (located on the contour line of the tunnel face bottom plate of the upper step a, such as Figure 1 The holes are connected by the solid line 4); the spacing between two adjacent holes is 20-100 cm, the diameter of each hole is 2-5 cm, and the depth of each hole is 1.5-2.5 m;

[0040] In S21, if Figure 1 As shown, there are 4 groups of straight-eye cutouts T and shock-absorbing expansion slots J, each group of straight-eye cutouts T includes 5 straight-eye cutouts T, with 1 straight-eye cutout T as the center point and the other 4 straight-eye cutouts T ( Figure 1The straight cut T at the center is surrounded by the shock-absorbing expansion slot holes J (similar to the diamond 5 distribution in the middle), each group of shock-absorbing expansion slot holes J includes 4 shock-absorbing expansion slot holes J, and the 4 shock-absorbing expansion slot holes J are located inside the other 4 straight cut slots T and surround the straight cut T at the center. After the straight cut T is loaded with explosives and detonated, the shock-absorbing expansion slot holes J play a role in stress concentration and guidance for the straight cut T (the stress wave generated during the blasting of the straight cut T will propagate to the surroundings, and reflection and diffraction will occur after encountering the shock-absorbing expansion slot holes J, so that the energy of the stress wave is more concentrated in the predetermined rupture direction, thereby guiding the crack to develop in a favorable direction and improving the cut effect), providing movement guidance and expansion movement space, enhancing rock destruction and shock absorption, and improving the effect and safety of the straight cut T blasting;

[0041] In addition, the auxiliary holes include 2 sets of auxiliary holes - F 1 and 14 auxiliary holes II F 2 , 14 auxiliary holes II F 2 Surrounded by 4 groups of straight hole cuts T, 2 groups of auxiliary holes F 1 Around the outside of the two sets of straight cutouts T at the bottom ( Figure 1 The holes connected by the middle bending line 3) and two sets of auxiliary holes - F 1 All located in 26 auxiliary holes F 2 Inside, 2 auxiliary holes F 2 Located between the two groups of straight-eye cutouts T at the top, the top two straight-eye cutouts T and the remaining 14 auxiliary holes are 2 On the same arc 2; when the auxiliary holes are detonated, the auxiliary hole F is detonated first 1 , then detonate auxiliary hole 2F 2 Auxiliary holes play an important role in straight-eye slot T blasting. They can expand the slot cavity, improve the rock crushing effect, control blasting vibration, improve blasting efficiency and enhance the smooth blasting effect.

[0042] S12, blast hole charging, inspection and detonation, straight hole cut T, auxiliary hole F 1 、Auxiliary hole 2F 2 Explosives and digital electronic detonators are loaded into the peripheral holes Z and bottom plate holes D and detonated in sequence after inspection. The detonation time interval is 10-100ms. The free surface at the straight-eye cutout T and the shock-absorbing expansion slot hole J peels off the rock layer around layer by layer. The blasting cycle footage is 1.5m. The explosive is φ32 emulsion explosive, 0.3kg per section of explosives, and each straight-eye cutout T, auxiliary hole F 1 、Auxiliary hole 2F 2 And 4 sections of explosives are placed in the bottom plate hole D, and 1.5 sections of explosives are placed in each peripheral hole Z, leaving a rectangular stone core soil a1;

[0043] S13. Ventilation in the tunnel. Ventilation in the tunnel after blasting can remove harmful gases (such as carbon monoxide, nitrogen oxides, and sulfides). Blasting will generate a lot of dust. Ventilation can reduce dust concentration and restore oxygen content, so that workers can continue construction and inspectors can enter the working surface for inspection. It is of great significance to ensure the safety of workers, improve construction efficiency and project quality.

[0044] S14, the second danger elimination of the face, reserve the stone core soil a1. After the blasting operation is completed, use an excavator to eliminate the loose stones and top dangerous rocks to ensure construction safety and eliminate potential dangers;

[0045] S15. Blasting effect inspection and dynamic correction of blasting parameters can improve project quality, construction efficiency, reduce losses caused by safety accidents, and avoid unnecessary rework.

[0046] S3, using the reserved stone core soil a1 as the operating platform to support the upper step a, that is, to make the initial support arch cover e (combined with Figure 2-4 ), the initial support arch cover 11 is composed of a shotcrete layer, a steel frame, a steel mesh, a system anchor rod and a locking anchor rod; the operating platform is 1.5-1.9m high and 3.5-5.2m wide, and the staff's operating height is 1-1.74m; when supporting the upper step a, the staff installs the steel frame and the steel mesh, drives the system anchor rod and the locking anchor rod, and sprays concrete on the operating platform. The thickness of the initial support arch cover 11 is gradually thickened from the arch top to the arch foot, and large arch feet are formed at the ends on both sides, and the upper load is transferred to the relatively stable surrounding rock on both sides through the large arch feet, ensuring the convenience and safety of the dark excavation construction of the large slope channel in the hard rock stratum.

[0047] S4, excavate and support the middle step b. First, blast and excavate the stone core soil a1 at the upper step a and the left middle step b2. The left middle step b2 is about 3m high and 3-5m long in the longitudinal direction. Each excavation is 1.5m deep. Support is immediately carried out after excavation. The right middle step b1 lags behind the left middle step b2 by 3-5m to prevent arch excavation on both sides from causing safety hazards. The right middle step b1 is about 3m high and 3-5m long in the longitudinal direction. Each excavation is 1.5m deep. Initial support f of the side wall is immediately made after excavation (combined with Figure 4 ).

[0048] S5. Excavate and support the lower step c. After the upper step a and the middle step b are connected, the lower step c2 on the left is blasted and excavated. Immediately after excavation, the initial support f of the side wall is made. Finally, the lower step c1 on the right is blasted and excavated. Immediately after excavation, the initial support f of the side wall is made. It should be noted that the excavation on both sides of the lower step c is staggered by 3 to 5 meters to prevent arch excavation and cause safety hazards. The height of the lower step c is about 3 meters, the longitudinal length is 3 to 5 meters, and the excavation depth is 1.5 meters each time. Immediately after excavation, the initial support f of the side wall is made (combined with Figure 4 );

[0049] Compared with the prior art, the advantages of this application are:

[0050] By designing the hole arrangement of straight-eye cutout T, shock-absorbing expansion hole J, auxiliary hole, peripheral hole Z and bottom plate hole D at the upper step a face, and 1 →Auxiliary hole 2F 2 →The detonation sequence of peripheral hole Z→bottom plate hole D, that is, the special design of micro-error phase reduction vibration blasting, is used to carry out the blasting operation of the reserved stone core soil a1 in the hard rock of the slope section. The detonation time interval is 10-100ms. After the blasting, the stone core soil a1 is in the shape of a rectangular parallelepiped. As an operating platform, the upper step a can be supported. There is no need to set up a bracket and a steel platform (the existing operating platform) on the upper step a, which solves the current problem that the operating platform is prone to unstable construction due to the large slope of the station access channel, as well as the time-consuming and labor-intensive problem of setting up the bracket and moving the steel platform.

[0051] Specific examples are as follows:

[0052] This construction technology is used in Chongqing Station of Chongqing Metro Line 18. In the 450*7.5*8 (unit: m) dark excavation tunnel, before measuring and setting out the blasting hole positions, the tunnel face is first cleared of danger to ensure the safety of the workers. According to the design drawings, the blasting hole positions are measured and set out on the tunnel face and the core soil area H is designed;

[0053] Then carry out the blasting operation of the hard rock reserved stone core soil a1 in the slope section, such as Figure 1 As shown in FIG. 1 , 4 groups of straight cuts T, 1 group of auxiliary holes and 26 peripheral holes Z are opened on the tunnel face and distributed outward along the periphery of the core soil area H. Each group of straight cuts T includes 5 straight cuts T, with 1 straight cut T as the center point and the other 4 straight cuts T ( Figure 1 The straight hole T at the center point is surrounded by a diamond-shaped distribution (5), wherein the auxiliary holes include two groups of auxiliary holes: 1 and 14 auxiliary holes II F 2 , 2 sets of auxiliary holes - F 1 They are respectively around the outside of the two sets of straight eye cutouts T at the bottom, and the two sets of auxiliary holes F 1All located in 26 auxiliary holes F 2 Inside, 2 auxiliary holes F 2 Located between the two groups of straight-eye cutouts T at the top, the top two straight-eye cutouts T and the remaining 14 auxiliary holes are 2 On the same arc 2; 4 groups of shock-absorbing expansion slot holes J are opened on the tunnel face, each group of shock-absorbing expansion slot holes J includes 4 shock-absorbing expansion slot holes J, and the 4 shock-absorbing expansion slot holes J are located inside the other 4 straight-eye cutouts T and surround the straight-eye cutout T at the center point; and 8 bottom plate holes D are opened on the tunnel face, and the 8 bottom plate holes D are respectively located on both sides of the core soil area H and flush with its bottom (such as Figure 1 The arc 4 and the solid line 4 form a tunnel shape); wherein, the straight-eye cutout T, the auxiliary hole and the peripheral hole Z are of the same size, with a hole depth of 1.7m and a hole diameter of 3cm; the bottom plate hole D has a hole depth of 2.1m and a hole diameter of 3.7cm; the distance between two adjacent bottom plate holes D on the same side is 80-100cm, the distance between the outermost bottom plate hole D and the adjacent peripheral hole Z is 60-70cm, the distance between the shortest bottom plate hole D and the straight-eye cutout T is 50-60cm, the distance between the shortest bottom plate hole D and the auxiliary hole is 63-75cm, the distance between two adjacent peripheral holes Z and two adjacent auxiliary holes is 50-80cm, the distance between the shortest peripheral hole Z and the auxiliary hole, and the distance between the peripheral hole Z and the straight-eye cutout T is 62-73cm, the distance between the shock-absorbing expansion slot hole J and the central straight-eye cutout T is 20-25cm, and the distance between two adjacent straight-eye cutouts T is 65-90cm;

[0054] Then the blast hole is charged, checked and detonated, and the straight hole T and auxiliary hole F are cut. 1 、Auxiliary hole 2F 2 Explosives and digital electronic detonators are loaded into the peripheral holes Z and bottom plate holes D and detonated in sequence after inspection. The detonation time interval is 10-100ms. The free surface at the straight-eye cutout T and the shock-absorbing expansion slot hole J peels off the rock layer around layer by layer. The blasting cycle footage is 1.5m. The explosive is φ32 emulsion explosive, 0.3kg per section of explosives, and each straight-eye cutout T, auxiliary hole F 1 、Auxiliary hole 2F 2 And 4 sections of explosives are placed in the bottom plate hole D, and 1.5 sections of explosives are placed in each peripheral hole Z, leaving a rectangular stone core soil a1;

[0055] After that, the cave is ventilated. Ventilating the cave after the blasting hole can remove harmful gases;

[0056] After the blasting operation of the reserved rock core soil a1 is completed, the tunnel face is cleared for the second time, and loose stones and top dangerous rocks are removed by excavator to ensure construction safety and eliminate potential dangers;

[0057] Checking blasting effects and dynamically correcting blasting parameters can improve project quality and construction efficiency, reduce losses from safety accidents, and avoid unnecessary rework;

[0058] Afterwards, the reserved stone core soil a1 is used as an operating platform to support the upper step a, i.e., to make the initial support arch cover e; wherein, the operating platform (stone core soil a1) is 1.76m high and 4.29m wide, and the operating height of the staff is 1 to 1.74m;

[0059] like Figure 4 As shown, the middle step b is excavated and supported. First, the stone core soil a1 at the upper step a and the left middle step b2 are blasted and excavated. The left middle step b2 is about 3m high and 3-5m long in the longitudinal direction. Each excavation is 1.5m deep. Support is immediately carried out after excavation. The right middle step b1 lags behind the left middle step b2 by 3-5m to prevent arch excavation on both sides from causing safety hazards. The right middle step b1 is about 3m high and 3-5m long in the longitudinal direction. Each excavation is 1.5m deep. Initial support f for the side wall is immediately made after excavation.

[0060] like Figure 4 As shown, the lower step c is excavated and supported. After the upper step a and the middle step b are connected, the lower step c2 on the left is excavated by blasting, and the initial support f of the side wall is made immediately after the excavation; finally, the lower step c1 on the right is excavated by blasting, and the initial support f of the side wall is made immediately after the excavation; it should be noted that the excavation on both sides of the lower step c is staggered by 3 to 5m to prevent arch excavation from causing safety hazards. The height of the lower step c is about 3m, the longitudinal length is 3 to 5m, the excavation advance is 1.5m each time, and the initial support f of the side wall is made immediately after the excavation.

[0061] The average daily footage of this construction technology is 2.25m / day, while the average daily footage of the traditional construction technology is 1.5m / day, and the overall work efficiency is improved by about 50%.

[0062] The original construction period of a 450m-long underground tunnel was 300 days, but this method can save 204 days, saving 96 days in total, as well as large equipment shifts (96 shifts of CAT150 crawler excavators, 96 shifts of tire loaders, and reduced energy consumption of ventilation equipment. The overall cost of normal construction is about 50,000 yuan per day. Therefore, the 450m-long underground tunnel reduces the direct cost by 96*5=4.7 million yuan in total).

[0063] The shortened construction period can remove the ground enclosures at the station entrances and exits in advance to restore the construction land, reduce the impact of construction on the urban environment, and at the same time reduce the corresponding measures costs. The shortened construction period reduces the management fees of the project department and the enterprise, further reducing the project cost. This construction process has high economic benefits.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A construction process for dark excavation of a steep channel in a hard rock formation, characterized in that: The following steps are involved: S1. Preliminary preparation work: measuring and setting out the blasting holes on the tunnel face and designing the core soil area (H); S2. Implement the blasting operation of the hard rock reserved stone core soil (a1) in the slope section, including the following steps: S21, blasting holes are set up, and a plurality of groups of straight-eye cutouts (T), a group of auxiliary holes and a plurality of peripheral holes (Z) are sequentially distributed outward along the periphery of the core soil area (H) on the tunnel face; a plurality of groups of shock-absorbing expansion slot holes (J) are opened on the tunnel face, and the plurality of groups of shock-absorbing expansion slot holes (J) are respectively distributed near the plurality of groups of straight-eye cutouts (T); and a plurality of bottom plate holes (D) are opened on the tunnel face, and the plurality of bottom plate holes (D) are respectively located on both sides of the core soil area (H) and flush with its bottom; the spacing between two adjacent holes is 20-100 cm, the diameter of each hole is 2-5 cm, and the depth of each hole is 1.5-2.5 m; S12, blasting holes are charged and detonated after inspection. Explosives and digital electronic detonators are loaded into the straight hole (T), auxiliary holes, peripheral holes (Z), and bottom plate holes (D), and detonated in sequence after inspection. The detonation interval is 10-100ms. The free surface of the straight hole (T) and the shock-absorbing expansion slot hole (J) is peeled off layer by layer to the surrounding rock layers, and the stone core soil (a1) is reserved; S3. Use the reserved stone core soil (a1) as an operating platform to support the upper step (a).

2. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 1 is characterized in that: In S1, the tunnel face is first cleared of dangers before the blasting hole positions are measured and laid out.

3. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 1 is characterized in that: In S21, the straight-eye grooves (T) and the shock-absorbing expansion groove holes (J) are each provided with 4 groups, each group of the straight-eye grooves (T) includes 5 straight-eye grooves (T), with 1 straight-eye groove (T) as the center point, and the other 4 straight-eye grooves (T) surround the straight-eye groove (T) at the center point, and each group of the shock-absorbing expansion groove holes (J) includes 4 shock-absorbing expansion groove holes (J), and the 4 shock-absorbing expansion groove holes (J) are located on the inner side of the other 4 straight-eye grooves (T) and surround the straight-eye groove (T) at the center point.

4. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 3 is characterized in that: In S21, the auxiliary holes include 2 groups of auxiliary holes 1 (F1) and 14 auxiliary holes 2 (F2), the 14 auxiliary holes 2 (F2) surround 4 groups of straight-eye grooves (T), the 2 groups of auxiliary holes 1 (F1) respectively surround the outside of the bottom 2 groups of straight-eye grooves (T), and the 2 groups of auxiliary holes 1 (F1) are both located on the inner side of the 26 auxiliary holes 2 (F2).

5. The process for dark excavation of a steep-slope channel in a hard rock formation according to claim 4 is characterized by: Two of the auxiliary holes 2 (F2) are located between the two groups of straight-eye grooves (T) at the top, and the top two straight-eye grooves (T) are on the same arc line as the remaining 14 auxiliary holes 2 (F2).

6. The process for dark excavation of a steep-slope channel in a hard rock formation according to claim 4 is characterized by: The explosive is φ32 emulsion explosive, each section of the explosive is 0.3 kg, 4 sections of explosives are placed in each of the straight-eye cutouts (T), auxiliary hole 1 (F1), auxiliary hole 2 (F2) and bottom plate hole (D), and 1.5 sections of explosives are placed in each of the peripheral holes (Z).

7. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 1 is characterized in that: The blasting cycle footage of the hard rock reserved stone core soil blasting operation in the slope section is 1.5m.

8. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 1 is characterized in that: In S2, the blasting operation of the hard rock reserved stone core soil (a1) in the slope section is carried out, and the following steps are also included: S13, ventilation in the cave; S14, the second danger elimination of the face; S15. Check blasting effect and dynamically correct blasting parameters.

9. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 1 is characterized in that: The operating platform is 1.5-1.9 m high and 3.5-5.2 m wide, and the operating height of the staff is 1-1.74 m.

10. The method for dark excavation of a steep-slope channel in a hard rock formation according to claim 1 is characterized in that: The following steps are also included: S4, excavate and support the middle step (b); S5. Excavate and support the lower step (c).

Images