Refined high raise construction method suitable for heterogeneous rock stratum

Abstract

The invention discloses a refined high raise construction method suitable for a non-homogeneous rock stratum, which comprises the following steps of: after blasting each time, measuring a blasting effect after blasting broken rocks in a well are cleaned; readjusting and optimizing construction contents including the drilling quantity of the newly-drilled blast holes, the hole distribution mode of the newly-drilled blast holes and the detonation sequence of the new blast holes based on the site blasting condition; and then blasting is carried out again, and the steps are repeated until well completion is completed. The method achieves the purpose of high-precision construction of the non-homogeneous rock stratum, and has the characteristic of high well completion precision. The method provided by the invention is especially suitable for tunneling of 50-300m shafts or raises of heterogeneous rock stratums.

Description

Technical Field

[0001] The present invention relates to a construction method for a vertical shaft in the mining field, and more particularly to a high raise construction method applicable to heterogeneous rock formations. Technical Background

[0002] In the field of underground mining, it is necessary to construct vertical deep shafts downward. The construction of such deep shafts often adopts the construction method of sectional rock drilling and blasting and multiple shaft formations.

[0003] The common steps of this construction method are as follows: arranging blast holes on the blasting surface, usually arranging cut holes in the center, auxiliary holes and perimeter holes around, and each blast hole is perpendicular to the horizontal plane. Coupled charging is carried out in one of the cut holes using emulsion explosive to form a free face by blasting. Charging is carried out in the blast auxiliary holes and perimeter holes and then blasting. Removing the fragmented blocks generated after blasting. Making preparations for the next stage of work. Repeating the cycle of cutting, charging, and carrying out the next blasting. Finally, mucking and supporting the shaft wall.

[0004] The existing blasting construction plan is relatively continuous, with strong construction coherence, and the blast hole layout forms of each sectional blasting are the same. The project often continues to excavate downward on the basis of the previous design. This construction plan ensures high construction continuity, short construction period, and high efficiency.

[0005] The construction progress of the existing technology is relatively fast and the construction period is short, but the shaft forming accuracy is low. For deep vertical shafts and areas with uneven rock formation distribution, the final shaft forming effect has a greater deviation from the initial design. The reason is that the construction effect of sectional blasting is not grasped in batches during the construction process, and only the same blasting design is used for multiple cyclic operations.

[0006] For example, Chinese Patent Application No. CN109341449A discloses a method for forming a large-section high raise by one-time rock drilling and sectional controlled blasting. This invention has refined constraints on relevant detailed construction procedures such as the type of drilling rig, shaft forming specifications, blasting compensation space, determination of the number of blast holes, charging, millisecond time, initiation, etc., and has strong applicability to specific rock formation areas and construction spaces. During the construction process, the blasting effect is not measured after the previous blasting, and the number and structure of the charged blast holes are not readjusted and optimized based on the on-site blasting situation. Only using the same blasting design for multiple cyclic operations will inevitably lead to the defect that the shaft forming effect has a large deviation from the initial design. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a refined high raise construction method applicable to heterogeneous rock formations, and further improve the shaft forming accuracy by refined control of the construction process.

[0008] The technical solution of the present invention is as follows:

[0009] A refined high raise construction method applicable to heterogeneous rock formations. After each blasting and cleaning of the blasted broken rocks in the well, the blasting effect is measured, and the construction content including the number of newly drilled blast holes, the hole layout method of the newly drilled blast holes, and the initiation sequence of the new blast holes is readjusted and optimized based on the on-site blasting situation; then blasting is carried out again, and the above steps are repeated until the well is completely formed.

[0010] Preferably, the hole layout method for the initial blasting is as follows: Seven cut holes are arranged: The cut holes include one central cut hole and six surrounding cut holes arranged equidistantly in a circular shape around the central hole; Eight auxiliary holes are arranged: A square is set outside the cut holes, and one auxiliary hole is arranged at each vertex of the square and at the midpoint of each side of the square; Twelve perimeter holes are arranged: A square is set outside the auxiliary holes, and one perimeter hole is arranged at each vertex of the square, and two perimeter holes are arranged equidistantly between the two vertices of each side of the square; The charging structure for the initial blasting: After all the blast holes are drilled, the bottom of the blast holes is blocked and sealed with anchoring agent; Rock emulsion explosive is used for charging in the blast holes; The initiation sequence for the initial blasting: Millisecond differential blasting is carried out in the order of cut holes, auxiliary holes, and perimeter holes.

[0011] Further preferably, the distance between the central cut hole and the center hole of the surrounding cut holes is 0.5 - 1.0 m; The side length of the square where the auxiliary holes are located is 1.5 - 2.5 m; The side length of the square where the perimeter holes are located is 3.0 - 4.0 m; The drilling diameter is not less than 100 mm, the discontinuous charging length is not less than 1.6 m, and the stemming length at the hole mouth is not less than 1.2 m.

[0012] Further preferably, the number of newly drilled blast holes and the hole layout method for the second and subsequent blasts: If the measurement after the previous blast shows that there is a remaining bottom after blasting, an additional attached blast hole is added at the bottom, and the initiation sequence is: attached blast hole, cut hole, auxiliary hole, perimeter hole; If the measurement after the previous blast shows that the f value in this area becomes smaller, only four auxiliary holes are arranged: A square is set outside the cut holes, and only one auxiliary hole is arranged at each vertex of the square; If the measurement after the previous blast shows that there are developed structural planes in this area resulting in an increase in the f value, one additional supplementary blast hole is added between the perimeter holes and the auxiliary holes, and between the auxiliary holes and the cut holes, and the initiation sequence is: cut hole, inner supplementary blast hole, auxiliary hole, outer supplementary blast hole, perimeter hole.

[0013] Preferably, during the construction process, if there is an inclined well formed, corrective construction is carried out according to the original engineering drawings.

[0014] Preferably, according to the formula Determine the number of blast holes constructed; in the formula, N represents the number of blast holes; A represents a constant coefficient, taking a value of 2.5 - 3.0; S represents the cross-sectional area; f represents the rock toughness coefficient.

[0015] Preferably, the value-taking rule of the A value in the formula follows that it takes 3.0 at the shallow end of the deep well, 2.5 when the well is formed at the end, and the value during the remaining intermediate blasting stages is between 3.0 and 2.5.

[0016] Preferably, the refined measurement means after blasting include using long-bar detection, UAV-based three-dimensional laser detection, and infrared laser detection.

[0017] Preferably, after a single blast, samples are taken from the blasted rock debris and rock mechanics experiments are carried out to obtain physical properties including strength and hardness, which are used as the basic data for adjusting the layout and charging conditions of subsequent blast holes.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] After the previous blast, the present invention clears the blasted broken rock in the well, then conducts refined measurement on the effect after the previous blast, and optimizes the drilling quantity of newly drilled blast holes, the hole layout method of newly drilled blast holes, and the initiation sequence of new blast holes, etc., achieving the purpose of high-precision construction for heterogeneous rock formations and having the characteristic of high well-forming precision. The present invention is particularly applicable to the tunneling of 50 - 300 m shafts or raises in heterogeneous rock formations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the first blast hole layout method in the embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of the second blast hole layout method in the first embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of the second blast hole layout method in the second embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of the second blast hole layout method in the third embodiment of the present invention;

[0024] In the figure: 1, peripheral hole; 2, auxiliary hole; 3, cut hole; 4, bottom foundation; 5, additional blast hole; 6, supplementary blast hole; 7, developed structural plane. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0026] I. Determination of the number of blast holes.

[0027] Determine the number of blast holes constructed through the following formula:

[0028] In the formula, N represents the number of blast holes, with the unit of piece; A represents a constant coefficient, taking a value of 2.5 - 3.0. The value of A is affected by different blasting depths. Generally speaking, the value of A is smaller in the fragmentation area and larger in the hard area. The value of A is larger in the shallow area and smaller in the deep area. S is the cross-sectional area, with the unit of m 2 ; f is the coefficient of rock hardness (also known as the Protodyakonov coefficient of hardness), which refers to one-tenth of the uniaxial compressive strength limit of the rock or soil. This coefficient is used to evaluate the relative ability of the rock to resist fragmentation and is dimensionless. In actual drilling construction, the rock is not only subjected to pure indentation or pure rotation, but is fragmented under the action of various forces. Therefore, the coefficient of hardness can more truly reflect the fragmentation difficulty of the rock in actual work and is closer to the actual production situation.

[0029] The calculation formula for the coefficient of rock hardness f is: f = R / 10 MPa, where R is the uniaxial compressive strength of the rock, with the unit of megapascal (MPa). This coefficient has no unit and it indicates how many times the hardness of a certain rock is stronger than that of dense clay, because the compressive strength of dense clay is 10 MPa. By calculating the value of f, the ability of the rock to resist fragmentation and its stability after drilling can be predicted.

[0030] According to the coefficient of rock hardness f, rocks can be divided into 10 grades (see Table 1). The higher the grade of the rock, the easier it is to fragment. For the convenience of use, a half-grade is added between adjacent grades of III, IV, V, VI, and VII. Considering that rocks with a compressive strength greater than 200 MPa will not be encountered in large quantities in production, all rocks with a compressive strength greater than 200 MPa are classified into Grade I.

[0031] Table 1 Table of Rock Hardness Coefficient f

[0032]

[0033]

[0034] II. Primary Blasting.

[0035] (1) Number of Blast Hole Drills:

[0036] The cross-sectional area excavated in this embodiment is 9 m 2 , and after measuring that the coefficient of rock hardness is 10, the number of blast holes calculated according to the determination formula of the number of blast holes is twenty-four to twenty-nine. Considering comprehensively, the number of blast holes is taken as twenty-seven.

[0037] (2) Hole Layout Method:

[0038] Such as Figure 1, Seven cut holes 3 are arranged: The cut holes 3 include a central cut hole and six surrounding cut holes arranged equidistantly in a circular shape around the central hole. Eight auxiliary holes 2 are arranged: A square is set outside the cut holes 3, and one auxiliary hole 2 is arranged at each vertex of the square and at the midpoint of each side of the square. Twelve perimeter holes 1 are arranged: A square is set outside the auxiliary holes 2, and one perimeter hole 1 is arranged at each vertex of the square, and two perimeter holes 1 are arranged equidistantly between the two vertices of each side of the square.

[0039] (3) Charge structure: After all the blast holes are drilled, the bottom of the blast holes is blocked and sealed with anchoring agent; Rock emulsion explosive is used for charging in the blast holes.

[0040] (4) Initiation sequence: Millisecond differential blasting is carried out in the order of cut holes 3, auxiliary holes 2, and perimeter holes 1.

[0041] III. Second and subsequent blasts.

[0042] After the previous blast including the first one is completed, the broken rocks in the well are cleared, and then the effect after the previous blast is measured in detail, and the number of newly drilled blast holes, the hole layout method of the newly drilled blast holes, the initiation sequence of the new blast holes, etc. are optimized.

[0043] This embodiment takes the optimization of relevant indicators after the first blast and before the second blast as an example.

[0044] (1) Number of newly drilled blast holes and hole layout method:

[0045] In the first embodiment, the measurement after the first blast shows that there is a remaining bottom 4 after the first blast, then an additional blast hole 5 needs to be added at the bottom 4. As Figure 2 shown.

[0046] In the second embodiment, the measurement after the first blast shows that the f value in this area becomes smaller after the first blast. According to the formula, the number of blast holes is recalculated to be twenty-three, then only four auxiliary holes 2 are arranged: A square is set outside the cut holes 3, and only one auxiliary hole 2 is arranged at each vertex of the square. As Figure 3 shown.

[0047] In the third embodiment, the measurement after the first blast shows that there is a developed structural plane 7 in this area after the first blast and the f value becomes larger. Then, according to the formula, the number of blast holes is recalculated to be twenty-nine, and one additional supplementary blast hole 6 is added between the perimeter holes 1 and the auxiliary holes 2, and between the auxiliary holes 2 and the cut holes 3. As Figure 4 shown.

[0048] (2) Charge structure: After all the blast holes are drilled, the bottom of the blast holes is blocked and sealed with anchoring agent; Rock emulsion explosive is used for charging in the blast holes.

[0049] (3) Initiation sequence of new blast holes:

[0050] For the first above-mentioned embodiment, the initiation sequence is: millisecond differential blasting in the order of attached blast hole 5, cut hole 3, auxiliary hole 2, and perimeter hole 1.

[0051] For the second above-mentioned embodiment, the initiation sequence is: millisecond differential blasting in the order of cut hole 3, auxiliary hole 2, and perimeter hole 1.

[0052] For the third above-mentioned embodiment, the initiation sequence is: millisecond differential blasting in the order of cut hole 3, inner supplementary blast hole 6, auxiliary hole 2, outer supplementary blast hole 6, and perimeter hole 1.

[0053] (3) Correct the inclined shaft that has been formed: Adjust the construction according to the original engineering drawings.

[0054] (4) After single blasting, samples of the blasted rock debris can be taken and rock mechanics experiments can be carried out on them to obtain their strength, hardness and other related physical properties, and based on this, the layout and charging conditions of subsequent blast holes can be adjusted.

[0055] IV. Value selection of A in the formula for determining the number of blast holes.

[0056] The value selection rule of A in the formula follows that 3.0 is taken at the shallow end of the deep well, and 2.5 is taken when the final shaft is formed. The values in the remaining intermediate blasting stages are between 3.0 and 2.5. Due to the influence of blasting vibration when the final shaft is formed, the lithology is weaker than the strength at the initial blasting, so the upper limit value of the number of blast holes can be taken at the shallow end of the initial deep well, and the lower limit value can be taken at the last shaft formation.

[0057] In the above-mentioned embodiments, the measurement method can be long rod type or UAV type three-dimensional laser detection, infrared laser detection, ground penetrating radar and other detection means to determine the blasting effect. When necessary, physical and mechanical experiments are carried out on the blasting rock samples at different depths to re-determine their strength.

[0058] In the above-mentioned embodiments, the distance between the central cut hole and the circular hole around the center of the cut hole is 0.5 m, the side length of the square where the auxiliary hole is located is 2 m, and the side length of the square where the perimeter hole 1 is located is 3.5 m. The drilling diameter is not less than 100 mm, the discontinuous charging length is not less than 1.6 m, and the stemming length at the hole mouth is not less than 1.2 m.

[0059] In the above-mentioned embodiments, each hole is initiated by a single detonator + full-length detonating cord method, and in order to make the rock after the previous blasting completely break away from the original rock and fall freely, half-second delay detonators are selected, and the same-position holes are connected by detonating cords; all the detonating tubes in the holes are collected and initiated to form a sectional shaft with a height of 20 m.

[0060] In the above-mentioned embodiments, a QZJ-100B type drill is used to drill the charging holes.

[0061] The above embodiments further include the following steps: post-grouting the shaft wall through the grouting pipe to completely fill the collapsed section of the broken zone and fit it with the original rock. That is, after all filling is completed and the well is completed, grouting is carried out on the well to solve the engineering problem of shaft water gushing and ensure the stability of the shaft formation.

[0062] Precautions:

[0063] First, before drilling, each construction worker should be familiar with the drilling orientation, depth, and geological conditions. The initial rock drilling and blasting must be carried out in accordance with the design requirements. The drill rig should be erected vertically, the vertical angle of the drill hole should be adjusted properly, and the upper and lower supports should be fixed firmly to prevent the deviation of the blast hole. The hole-drilling operators should strictly follow the design drawings and drill holes according to the blast holes surveyed by the surveyors.

[0064] Second, before drilling, the drill rig must be verified with a spirit level, and the verticality of the sliding frame and drill pipe should be checked from four directions: front, back, left, and right. If deviation is found, it should be corrected in time. After construction, the dip angle, hole depth, and dip direction of the blast hole should meet the design requirements. The error of the hole position at the hole mouth of the drill hole and the error of the dip angle of the drill hole should be strictly controlled.

[0065] Third, taking the central empty hole of the raise as the free surface, each cut hole blasts towards the central empty hole to form a cavity, and columnar continuous charging is adopted.

[0066] Fourth, due to factors such as misloading of explosives, uneven distribution of lithology, influence of joints and fissures in the rock stratum, misconnection of the initiation network, measurement and actual drilling operation errors, etc., there is often a certain difference between the effect of the initial blasting and the design effect.

[0067] Fifth, after the previous blasting is completed, clean the loose materials in the well after blasting. Refined measurement of the well-forming effect of the initial blasting, and the main measurement contents are: the flatness of the blasting section, the inclination and deviation of the blasted well, the depth of the well formed by blasting, and the forming situation of the blasting bottom.

[0068] Sixth, after sectional blasting is completed, check the height of the wellhead and the slag surface. When the height of the slag surface in the well reaches the preset value from the height of the blasted rock mass in the previous section, after sufficient ventilation, personnel enter the working space to pick and pry loose stones and level the site to prepare for the rock drilling and blasting work of the next section.

[0069] Seventh, during the period of wall brushing, mucking, and shaft lining, if the raise passes through a complex water-bearing broken zone, construction needs to be suspended, and holes are opened on the circular shaft wall, and a number of grouting pipes are fixedly connected radially around through the openings.

Claims

1. A refined high raise construction method applicable to heterogeneous rock formations, characterized in that: After each blasting and cleaning of the broken rock in the well, the blasting effect is measured, and the construction content including the number of newly drilled blast holes, the hole layout method of the newly drilled blast holes, and the initiation sequence of the new blast holes is readjusted and optimized based on the on-site blasting situation; then the blasting is carried out again, and the above steps are repeated until the well is completely formed.

2. The refined high raise construction method applicable to heterogeneous rock formations according to claim 1, characterized in that The hole layout method for the initial blasting is as follows: Seven cut holes (3) are arranged: The cut holes (3) include a central cut hole and six surrounding cut holes arranged equidistantly in a circular shape around the central hole; Eight auxiliary holes (2) are arranged: A square is set outside the cut holes (3), and an auxiliary hole (2) is arranged at each vertex of the square and at the midpoint of each side of the square; Twelve perimeter holes (1) are arranged: A square is set outside the auxiliary holes (2), and a perimeter hole (1) is arranged at each vertex of the square, and two perimeter holes (1) are arranged equidistantly between the two vertices of each side of the square. The charging structure for the initial blasting: After all the blast holes are drilled, the bottom of the blast holes is blocked and sealed with an anchor agent; Rock emulsion explosive is used for charging in the blast holes; The initiation sequence for the initial blasting: Millisecond differential blasting is carried out in the order of cut holes (3), auxiliary holes (2), and perimeter holes (1).

3. The refined high raise construction method applicable to heterogeneous rock formations according to claim 2, characterized in that: The distance between the central cut hole and the center hole of the surrounding cut holes is 0.5 - 1.0 m; The side length of the square where the auxiliary holes (2) are located is 1.5 - 2.5 m; The side length of the square where the perimeter holes (1) are located is 3.0 - 4.0 m; The drilling diameter is not less than 100 mm, the discontinuous charging length is not less than 1.6 m, and the stemming length at the hole mouth is not less than 1.2 m.

4. The refined high raise construction method applicable to heterogeneous rock formations according to any one of claims 2, characterized in that The number of newly drilled blast holes and the hole layout method for the second and subsequent blasts: If the measurement after the previous blast shows that there is a remaining bottom (4) after blasting, then an additional attached blast hole (5) is added at the bottom (4), and the initiation sequence is: attached blast hole (5), cut holes (3), auxiliary holes (2), perimeter holes (1); If the measurement after the previous blast shows that the f value in this area becomes smaller, then only four auxiliary holes (3) are arranged: A square is set outside the cut holes (3), and only an auxiliary hole (2) is arranged at each vertex of the square; If the measurement after the previous blast shows that there is a developed structural plane (7) in this area resulting in an increase in the f value, then a supplementary blast hole (6) is added between the perimeter holes (1) and the auxiliary holes (2), and between the auxiliary holes (2) and the cut holes (3), and the initiation sequence is: cut holes (3), inner supplementary blast hole (6), auxiliary holes (2), outer supplementary blast hole (6), perimeter holes (1).

5. A refined high raise construction method applicable to heterogeneous rock formations according to claims 1 to 4, characterized in that: During the construction process, if there is an inclined well formed, corrective construction is carried out according to the original engineering drawings.

6. A refined high raise construction method applicable to heterogeneous rock formations according to claims 1 to 4, characterized in that: Determine the number of blast hole construction according to the formula where N represents the number of blast holes; A represents a constant coefficient, taking 2.5 - 3.0; S represents the cross-sectional area; f represents the rock hardness coefficient.

7. The refined high raise construction method applicable to heterogeneous rock formations according to claim 6, characterized in that: The value-taking rule of the A value in the formula follows that it takes 3.0 at the shallow mouth of the deep well, 2.5 at the end of the well formation, and the value during the remaining intermediate blasting stages is between 3.0 and 2.

5.

8. A refined high raise construction method applicable to heterogeneous rock formations according to claims 1 to 4, characterized in that: The refined measurement means after blasting include using long-bar detection, UAV-based three-dimensional laser detection, and infrared laser detection.

9. A refined high raise construction method applicable to heterogeneous rock formations according to claims 1 to 4, characterized in that: After a single blast, samples of the blasted rock fragments are taken and rock mechanics experiments are conducted to obtain physical properties including strength and hardness, which are used as the basic data for adjusting the layout and charging conditions of subsequent blast holes.

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