Optimized construction method for inclined shaft deep hole smooth blasting method excavation of large-gradient red layer soft rock

Abstract

The invention discloses a large-gradient red layer soft rock inclined shaft deep hole smooth blasting method excavation optimization construction method which comprises the following steps that S1, smooth blasting parameters are determined according to tunnel surrounding rock geological conditions; s2, blast hole design of smooth blasting is carried out according to the parameters calculated and selected in the step S1; s3, smooth blasting construction is carried out; and S34, rock slag in the blasting area is excavated. According to the method, smooth blasting parameters and a construction technology of the large-gradient rail long inclined shaft red layer soft rock tunnel are optimized, the construction method is optimized through a step method, the difficulty of tunnel blasting excavation footage is reduced, a good free face is manufactured in an optimized parallel empty hole linear barrel-shaped slotting mode, and the purposes of facilitating tunnel excavation footage, improving tunnel excavation efficiency and improving tunnel excavation efficiency are achieved. And the construction effect of inclined shaft over-break and under-break is well controlled. The construction method is convenient to operate and easy to construct, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of underground engineering construction, and relates to a smooth blasting construction method, and specifically to an optimized construction method for excavating a deep hole in a steep red layer soft rock inclined shaft by smooth blasting. Background Art

[0002] Smooth blasting is a relatively mature tunnel blasting scheme. It is widely used in surrounding rocks of Class III and above because of its advantages such as smooth blasting surface, small charge amount, and reduced primary support thickness. However, in poor surrounding rocks such as red layer soft rock, due to the development of rock structure surface, smooth blasting effect is poor, over-excavation and under-excavation are serious, which seriously restricts the excavation efficiency. Summary of the invention

[0003] In order to solve the above problems existing in the background technology, the present invention provides an optimized construction method for excavation of deep holes in red layer soft rock inclined shafts with large slopes by smooth blasting. The method optimizes the smooth blasting parameters and construction technology of red layer soft rock tunnels with large slopes and long rail inclined shafts, uses the step method to optimize the construction method to reduce the difficulty of tunnel blasting excavation footage, and uses the optimized parallel empty hole straight barrel-shaped groove cutting method to create a better free surface, which is conducive to tunnel excavation footage and better controls the over-excavation and under-excavation of inclined shafts. The construction method is easy to operate and easy to construct, and has broad application prospects.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] An optimized construction method for excavating a deep hole by smooth blasting in a large-slope red-layer soft rock inclined shaft comprises the following steps:

[0006] Step S1: Determine smooth blasting parameters according to the geological conditions of the tunnel surrounding rock:

[0007] Step S11: According to the geological conditions of the tunnel, the planned depth of the upper and lower steps and the height of the lower step are selected, and the standard Φ32mm No. 2 rock emulsion explosive is selected, and the non-electric millisecond segmented detonation is performed;

[0008] Step S12: Calculate the borehole diameter according to the uncoupled charge coefficient formula:

[0009] D=d k / d i

[0010] Where: D is the uncoupling coefficient; d k is the blasthole diameter; d i is the explosive diameter;

[0011] Step S13: Determine the minimum resistance line of the peripheral holes according to the minimum resistance line formula:

[0012] K=E / V

[0013] Among them: K is the density coefficient; E is the distance between surrounding blastholes; V is the minimum resistance line;

[0014] Step S14: Select appropriate blasthole utilization rate based on experience to calculate blasthole depth:

[0015] L = l / ρ;

[0016] Where: L is the blasthole depth; l is the planned excavation cycle footage depth; ρ is the blasthole utilization rate;

[0017] Step S15: Calculate the number of peripheral eyes according to the design contour line;

[0018] N 周边眼 =L0 / d;

[0019] Where: N 周边眼 is the number of peripheral eyes; L0 is the length of the designed contour line; d is the peripheral eye margin;

[0020] Step S2: Design the blasthole for smooth blasting according to the parameters calculated and selected in step S1:

[0021] For medium or large tunnel sections, in order to adapt to the step method, the slotting eye adopts an optimized parallel empty hole straight barrel slotting method. Compared with the original parallel empty hole straight barrel slotting method, an empty hole is added in the horizontal direction, and three layers of slotting holes are set outside the two empty holes, namely the inner slotting hole, the outer slotting hole and the outermost slotting hole; the inner slotting hole is square, the empty hole is located in the middle of the square, and the slotting holes are arranged at the four corner points of the square; the outer slotting hole is prismatic, the rightmost point of the left prismatic coincides with the leftmost point of the right prismatic, and the slotting holes are arranged at the seven corner points of the square; the outermost slotting holes are arranged in two rows, each row is arranged in two lines, and the slotting hole at the midpoint of each row and the point where the two prismatic shapes of the outer slotting hole coincide are on a straight line; the slotting eye is 15 to 25 cm deeper than other blastholes, and the charge is 10 to 20% more than the auxiliary hole;

[0022] Step S3: Construction of smooth blasting:

[0023] Step S31: measurement and setting out;

[0024] Step S32: After the drilling is completed and the hole is cleaned, the explosives are charged. The slot holes, main blast holes, and bottom plate holes are charged continuously, and the peripheral holes are charged at intervals.

[0025] Step S33: each charge blasthole adopts non-electric millisecond detonator differential detonation technology to control the explosive quantity and detonation time of the single-stage detonator so that the blasting shock waves are not superimposed to reduce the damage to the surrounding rock;

[0026] Step S34: excavating rock debris from the blasting area.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. There are many geological risks in red layer soft rock tunnels, and it is impossible to equip them with large rock drilling trolleys. The present invention uses the step method to divide the medium and large sections into upper and lower steps, reasonably selects the size of the lower step, reduces the difficulty of blasting excavation of the tunnel, and better controls the over-excavation and under-excavation of the inclined shaft.

[0029] 2. As underground engineering construction is often accompanied by pumping and drainage, explosives with better water resistance should be selected for optimization, such as rock emulsion explosives.

[0030] 3. The slotting holes adopt the optimized straight-eye slotting method, which is simple to operate and easy to construct. It can form a good air-facing surface, which is conducive to the tunnel blasting excavation progress. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of blasthole arrangement in the present invention.

[0032] Figure 2 It is a schematic diagram of the arrangement of hollow holes and slotted holes in the present invention.

[0033] Figure 3 It is a schematic diagram of the main blast hole charging structure in the present invention.

[0034] Figure 4 It is a schematic diagram of the peripheral hole charging structure in the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0036] The present invention provides an optimized construction method for excavating a deep hole in a large-slope red-layer soft rock inclined shaft by smooth blasting, the method comprising the following steps:

[0037] Step S1: Determine smooth blasting parameters according to the geological conditions of the tunnel surrounding rock:

[0038] Step S11: According to the geological conditions of the tunnel, select the appropriate planned depth of the upper and lower steps and the height of the lower step, and select the standard Φ32mm No. 2 rock emulsion explosive, non-electric millisecond segmented detonation. Due to the inclined shaft construction, in order to improve the blasting efficiency, the lower step height (1-2m) can be appropriately adjusted for medium-sized tunnel sections, and the lower step height can be appropriately increased for large tunnel sections as required.

[0039] Step S12: Calculate the borehole diameter according to the uncoupled charge coefficient formula:

[0040] D=d k / d i

[0041] Where: D is the uncoupling coefficient; d k is the blasthole diameter, mm; d i is the diameter of explosive, mm; the uncoupling coefficient of red layer soft rock surrounding rock is required to be 1.4~1.6.

[0042] Step S13: Determine the minimum resistance line of the peripheral holes according to the minimum resistance line formula:

[0043] K=E / V

[0044] Among them: K is the density coefficient; E is the spacing between surrounding blastholes, cm; V is the minimum resistance line, cm. For red layer soft rock, the blasthole spacing E is 35-50 cm, the minimum resistance line V is 40-60 cm, the density coefficient K is 0.5-0.8, and the charge concentration is 0.07-0.12 kg / m.

[0045] Step S14: Select appropriate blasthole utilization rate based on experience to calculate blasthole depth:

[0046] L = l / ρ;

[0047] Where: L is the blasthole depth, m; l is the planned excavation cycle footage depth, m; ρ is the blasthole utilization rate. To avoid under-excavation, the blasthole depth of the slot hole and the bottom plate hole is 15 to 25 cm deeper than the blasthole depth of the surrounding holes.

[0048] Step S15: Calculate the number of peripheral eyes according to the design contour line;

[0049] N 周边眼 =L0 / d;

[0050] Where: N 周边眼 is the number of peripheral holes; L0 is the length of the design contour line, m; d is the peripheral hole margin. The peripheral hole openings are theoretically arranged on the design contour line. Due to the complex and changeable geological conditions of the long inclined shaft with a large dip angle and the drilling equipment, they are slightly thrown outward from the design contour line by 3° to 5° and 0.1m from the excavation contour line to ensure that the actual longitudinal contour is in a gently connected step shape.

[0051] Step S2: Design the blasthole for smooth blasting according to the parameters calculated and selected in step S1:

[0052] After calculating the blasthole parameters, the blasthole arrangement of the slot holes, main blast holes, bottom plate holes, and peripheral holes is designed. For medium or large tunnel sections, in order to adapt to the step method, the slot holes can adopt the optimized parallel empty hole straight barrel slotting method, such as Figure 2As shown: Compared with the original parallel empty hole straight barrel groove method, an empty hole is added in the horizontal direction with a hole spacing of 120cm. Three layers of groove holes are set outside the two empty holes, namely the inner groove hole, the outer groove hole and the outermost groove hole; the inner groove hole is square with a side length of 20cm, the empty hole is located in the middle of the square, and the inner groove hole is arranged at the four corner points of the square; the outer groove hole is prismatic, the rightmost point of the left prismatic coincides with the leftmost point of the right prismatic, the groove holes are arranged at the seven corner points of the square, and the distance between the groove holes and the empty holes is 60cm; the outermost groove holes are arranged in two rows with a row spacing of 180cm, and each row is arranged with two rows with a row spacing of 150cm. The groove hole at the midpoint of each row and the point where the two prismatic shapes of the outer groove hole coincide with each other are on a straight line, and the distance is 90cm; the groove hole is 15-25cm deeper than other blastholes, and the charge is 10-20% more than the auxiliary hole.

[0053] Step S3: Construction of smooth blasting:

[0054] Step S31: measurement and layout.

[0055] Step S32: After the drilling is completed and the hole is cleaned, charge is loaded. Continuous charging is used for the slot holes, main blast holes, and bottom plate holes, and intermittent charging is used for the peripheral holes. Rock emulsion explosives can be used for the test, and non-electric millisecond differential detonators are used for detonation.

[0056] Step S33: Each charge hole adopts non-electric millisecond detonator micro-difference detonation technology to control the detonation amount and detonation time of the single-stage detonator, so that the blasting shock wave does not overlap, so as to reduce the damage to the surrounding rock, and adopts the micro-difference detonation network in the hole to ensure that the network detonated later is not broken by the network detonated earlier. Detonation is detonated in sequence from the inside to the outside in the order of the slot hole, the main blast hole, the bottom plate hole, and the peripheral hole.

[0057] Step S34: excavating rock debris from the blasting area.

[0058] Example:

[0059] This embodiment takes a long inclined shaft tunnel with a large slope and red soft rock track with a cross-section size of 8.4×7.7m as an example, and the specific implementation process is as follows:

[0060] Step S1: Determine smooth blasting parameters according to the geological conditions of the tunnel surrounding rock.

[0061] Step S11: According to the geological conditions of the tunnel, the upper and lower steps are planned to have a cycle footage of 2m and a lower step height of 2m. The standard No. 2 rock emulsion explosive with a diameter of Φ32mm is selected, and non-electric millisecond segmented detonation is used.

[0062] Step S12: Use standard No. 2 rock emulsion explosive with a diameter of Φ32 mm and a decoupling coefficient of D=d k / d i=50 / 32=1.56, which meets the coupling coefficient requirement of Class IV surrounding rock of 1.4 to 1.6.

[0063] Step S13: Based on experience and the special geological conditions of the branch tunnel, the peripheral eye margin is d=55cm, V=60cm, then K=55 / 60=0.92<1, which meets the requirements.

[0064] Step S14: The blasthole utilization rate is proposed to be ρ=0.91, and the planned excavation cycle footage is l=2m, then the blasthole depth is L=2.2m.

[0065] Step S15: To avoid under-digging, the trench hole is slightly deepened by 15-25 cm. 掏槽眼、底板眼 =2.4m, L 周边眼 =2.2m; To ensure that the actual longitudinal profile is in a step-like shape,

[0066]

[0067] Step S2: Design the blasthole for smooth blasting according to the calculated and selected parameters.

[0068] The slotting holes adopt the optimized parallel hole straight barrel slotting method. Compared with the original parallel hole straight barrel slotting method, one more hole is added, and the outer slotting holes become rectangular, with two rows in total, and 3 slotting holes in each row. The specific slotting hole arrangement is as follows: Figure 2 shown.

[0069] After fine-tuning the calculated blasting parameters based on engineering construction experience, a blasthole layout diagram and blasting parameter table are formed. Figure 1 As shown in Table 1. The designed cycle excavation footage is 2m, and there are 132 blastholes per cycle. Among them: upper step: 2 empty holes, 50cm in diameter; 8 inner slot holes, 7 outer slot holes, 50cm in diameter, 6 auxiliary slot holes, 50cm in diameter; 33 main blast holes in three layers, all with a diameter of 50mm. The hole spacing of the peripheral holes is 0.55m, the row spacing of the collapse holes is 0.8m, and the hole spacing of the bottom plate holes is 55cm. There are 132 drill holes in total, with a total charge of 164.4kg.

[0070] Table 1 Blasting parameters

[0071]

[0072] Step S3: Construction of smooth blasting.

[0073] Step S31: measurement and layout.

[0074] Step S32: After the drilling is completed and the hole is cleaned, the explosives are charged. Continuous charging is used for the slot holes, main blast holes, and bottom plate holes, and intermittent charging is used for the peripheral holes. The standard Φ32mm No. 2 rock emulsion explosive is selected for the test, and non-electric millisecond differential detonators are used for detonation; the depths of the slot holes on the upper step are 240cm (MS1), 240cm (MS3), and 220cmM (MS5), respectively, and Φ32mm explosive rolls are loaded, and the filling lengths are 60cm (MS1), 60cm (MS3), and 50cm (MS5), respectively. The lengths of the charges for the slot holes (MS1, MS3, MS5) are 180cm (MS1), 180cm (MS3), and 150cm (MS5), respectively. The main blast holes (MS7, MS9, MS11) and bottom holes (MS13) are 220cm deep, with a plugging length of 50cm and a charge length of 150cm. The main blast holes (MS1 and MS3) on the lower steps are 220cm deep and filled with Φ32mm explosive rolls. The charge lengths are 120cm and 150cm, respectively, and the plugging lengths are 50cm and 40cm, respectively. Figure 3 , use interval charging for peripheral holes, charging instructions Figure 4 .

[0075] Step S33: Each charge borehole adopts non-electric millisecond detonator differential initiation technology and a differential initiation network in the borehole. The initiation is carried out in the order of MS1, MS3, MS5, MS7, MS9, MS11, MS13, and surrounding holes from inside to outside.

[0076] Step S34: excavating rock debris from the blasting area.

Claims

1. An optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft, characterized in that The method comprises the following steps: Step S1: Determine smooth blasting parameters according to the geological conditions of the tunnel surrounding rock: Step S11: According to the geological conditions of the tunnel, the planned depth of the upper and lower steps and the height of the lower step are selected, and the standard Φ32mm No. 2 rock emulsion explosive is selected, and the non-electric millisecond segmented detonation is performed; Step S12: Calculate the borehole diameter according to the uncoupled charge coefficient formula: D=d k / d i Where: D is the uncoupling coefficient; d k is the diameter of the blasthole; d i is the explosive diameter; Step S13: Determine the minimum resistance line of the peripheral holes according to the minimum resistance line formula: K=E / V Among them: K is the density coefficient; E is the distance between surrounding blastholes; V is the minimum resistance line; Step S14: Select appropriate blasthole utilization rate based on experience to calculate blasthole depth: L = l / ρ; Where: L is the blasthole depth; l is the planned excavation cycle footage depth; ρ is the blasthole utilization rate; Step S15: Calculate the number of peripheral eyes according to the design contour line; N 周边眼 =L0 / d; Where: N 周边眼 is the number of peripheral eyes; L0 is the length of the designed contour line; d is the peripheral eye margin; Step S2: Design the blasthole for smooth blasting according to the parameters calculated and selected in step S1: For medium or large tunnel sections, in order to adapt to the step method, the slotting eye adopts an optimized parallel empty hole straight barrel slotting method. Compared with the original parallel empty hole straight barrel slotting method, an empty hole is added in the horizontal direction, and three layers of slotting holes are set outside the two empty holes, namely the inner slotting hole, the outer slotting hole and the outermost slotting hole; the inner slotting hole is square, the empty hole is located in the middle of the square, and the slotting holes are arranged at the four corner points of the square; the outer slotting hole is prismatic, the rightmost point of the left prismatic coincides with the leftmost point of the right prismatic, and the slotting holes are arranged at the seven corner points of the square; the outermost slotting holes are arranged in two rows, each row is arranged in two lines, and the slotting hole at the midpoint of each row and the points where the two prismatic shapes of the outer slotting hole coincide with each other are on a straight line; Step S3: Construction of smooth blasting: Step S31: measurement and setting out; Step S32: After the drilling is completed and the hole is cleaned, the explosives are charged. The slot holes, main blast holes, and bottom plate holes are charged continuously, and the peripheral holes are charged at intervals. Step S33: each charge blasthole adopts non-electric millisecond detonator differential detonation technology to control the explosive quantity and detonation time of the single-stage detonator so that the blasting shock waves are not superimposed to reduce the damage to the surrounding rock; Step S34: excavating rock debris from the blasting area.

2. The optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft according to claim 1 is characterized in that In step S11, in order to improve the blasting efficiency, for medium-sized tunnel sections, the lower step height is adjusted by 1 to 2 m, and for large-sized tunnel sections, the lower step height is appropriately increased as required.

3. The optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft according to claim 1 is characterized in that In step S12, the uncoupling coefficient of the red layer soft rock surrounding rock is required to be 1.4 to 1.

6.

4. The optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft according to claim 1 is characterized in that In step S13, for red layer soft rock, the blasthole spacing E is 35-50 cm, the minimum resistance line V is 40-60 cm, the density coefficient K is 0.5-0.8, and the charge concentration is 0.07-0.12 kg / m.

5. The optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft according to claim 1 is characterized in that In step S14, in order to avoid under-digging, the blasthole depths of the cutout holes and the bottom plate holes are 15 to 25 cm deeper than the blasthole depths of the peripheral holes.

6. The optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft according to claim 1 is characterized in that In step S15, 7. The optimized construction method for deep hole smooth blasting excavation in a steep red layer soft rock inclined shaft according to claim 1 is characterized in that In step S2, the charge amount of the cutout hole is 10-20% more than that of the auxiliary hole.

Images