Drilling pressure relief method for ultra-deep shafts

Abstract

The present invention provides a drilling pressure relief method suitable for ultra-deep vertical shafts. During the excavation process of the ultra-deep vertical shaft, drilling pre-pressure relief is performed, and stress relief holes and pressure relief holes are arranged in sequence on the working surface in the excavation direction; the stress relief holes are arranged at equal intervals around the working surface, and the pressure relief holes are arranged in the internal area; multiple pressure relief holes form a straight drilling row passing through the center point of the working surface, and the spacing of the pressure relief holes is arranged in equal intervals from the central area of ​​the working surface to the shaft wall of the vertical shaft, and the maximum spacing is located in the central area; two consecutive excavation-slag removal processes are performed according to the unit excavation depth, and then drilling pre-pressure relief is performed again on the new working surface; the excavation-slag removal and drilling pre-pressure relief processes are repeated alternately until the vertical shaft is excavated to the set depth. The method releases stress in the stress concentration area in advance through drilling pre-pressure relief, and maximizes the pressure relief degree through the design of the hole arrangement structure and related parameters, ensuring the safety of ultra-deep vertical shaft construction, and has high practical application value.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-deep vertical shaft pressure relief, and in particular to a drilling pressure relief method suitable for ultra-deep vertical shafts. Background Art

[0002] With the increasing demand for minerals and the increasing depletion of shallow resources, most mines have entered the deep mining stage, which has become the development trend of mining in the future. With the increase in the depth of mining, high stress characteristics appear, and geological disasters such as rock bursts and rock bursts occur frequently, which increases the difficulty of mining deep mineral resources. Pressure relief technology can effectively solve the local high stress concentration in the deep mine and prevent and control mining dynamic geological disasters. At present, the commonly used pressure relief technologies include hydraulic pressure relief, pressure relief troughs or pressure relief tunnels, blasting pressure relief and drilling pressure relief technology; the water injection pressure of hydraulic pressure relief technology is relatively small, and it is only applicable to soft rocks or cracks; when using pressure relief troughs or pressure relief tunnels, it is difficult to determine the distance from the stress concentration area; in blasting pressure relief technology, there is little research on the mechanism of explosion disturbance on rock mass, and it is difficult to determine the impact range of blasting pressure relief.

[0003] Borehole decompression is a decompression method that forms a weak zone by constructing large-diameter boreholes in high-stress concentration areas, so that high stress is transferred to the deep part of the rock mass or the accumulated energy is released. The invention patent (application number is CN201610915369.4) discloses a method for preventing and controlling coal seam impact-type mine earthquakes. Large-diameter intensive drilling decompression is carried out on the coal wall of the working face. By creating a large space in the high-stress medium, the stress distribution is changed; then, the coal wall around the stopped working face is decompressed and the deep hole blasting of the tunnel is carried out to fully release the impact energy, fundamentally reducing and preventing the occurrence of impact-type mine earthquakes. The invention patent (application number is CN 202010352871.5) discloses a full-range decompression method for dangerous tunnels with rock burst in thick coal seam working faces. By constructing large-diameter boreholes on both sides of the tunnel to decompress, a cylindrical decompression zone is formed, the stress state of the tunnel surrounding rock is determined, and the stress peak area is ensured to be located outside the support range.

[0004] It can be seen from the above-mentioned prior art that the drilling pressure relief technology is mostly used for tunnel support in the process of coal seam mining, and horizontal drilling is used to relieve pressure on the working face or tunnel surface; however, this method is difficult to adapt to the problem of stress concentration caused by the continuous superposition of stress during the construction of ultra-deep vertical shafts; and after stress concentration occurs during the construction of ultra-deep vertical shafts, drilling pressure relief is performed, and the rock mass changes from a relatively stable two-way stress state to a unidirectional stress state. The original high stress of the rock mass and the stress concentration around the pressure relief hole are further superimposed, which will cause an instantaneous increase in high stress in the local rock mass around the pressure relief hole, which may cause unstable destruction of the rock mass, induce rock bursts, and threaten the safety of construction. Therefore, there is no consensus on how to perform drilling pressure relief in ultra-deep vertical shafts.

[0005] In view of this, it is necessary to design an improved drilling pressure relief method suitable for ultra-deep shafts to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a drilling pressure relief method suitable for ultra-deep vertical shafts. During the excavation process of the ultra-deep vertical shaft, pre-pressure relief is performed by drilling. By sequentially arranging stress relief holes and pressure relief holes on the working surface, stress concentration areas are released in advance. By designing the hole arrangement structure and related parameters, the pressure relief degree is maximized without affecting the normal construction of the vertical shaft, thereby ensuring the safety of the ultra-deep vertical shaft construction.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a drilling pressure relief method suitable for ultra-deep vertical shafts, comprising the following steps:

[0008] S1. Carry out excavation of ultra-deep vertical shafts and monitor the status of the shaft wall, ore, rock and support bodies in real time;

[0009] S2. When construction difficulties or rock burst problems begin to occur, stop excavation and conduct pre-pressure relief by drilling; the pre-pressure relief by drilling is to arrange a number of stress relief holes and pressure relief holes in sequence in the excavation direction on the current working face; the depth of the stress relief holes and the pressure relief holes is 2 to 2.2 times the unit excavation depth of the ultra-deep shaft;

[0010] The stress release holes are arranged at equal intervals around the working surface, and the pressure relief holes are arranged in the inner area of ​​the working surface; a plurality of the pressure relief holes form a straight line drilling row passing through the center point of the working surface, and the spacing of the pressure relief holes is arranged in equal intervals from the center area of ​​the working surface to the shaft wall of the shaft, and the maximum spacing is located in the center area of ​​the working surface;

[0011] S3, excavating once and discharging slag according to the unit excavation depth, continuing to excavate twice and discharging slag; then performing drilling pre-decompression as described in step S2 on the new working surface; and continuously repeating step S3 until the ultra-deep vertical shaft is excavated to the set depth.

[0012] As a further improvement of the present invention, the pressure relief holes are arranged as two rows of straight drill holes that are perpendicular to each other, and the two rows of straight drill holes intersect at the center of the working surface.

[0013] As a further improvement of the present invention, the maximum spacing of the pressure relief holes in the central area of ​​the working face is determined by the diameter of the ultra-deep shaft, and the maximum spacing is 0.15 to 0.3 times the diameter of the ultra-deep shaft; the minimum spacing of the pressure relief holes close to the shaft wall is 0.1 to 0.5 m.

[0014] As a further improvement of the present invention, the distance between each stress release hole and the well wall is equal, and the distance is 0.2 to 0.4 m; the minimum distance between the stress release hole and the pressure relief hole on the working surface is 0.3 to 0.5 m to achieve the best pressure relief effect.

[0015] As a further improvement of the present invention, the unit excavation depth of the ultra-deep vertical shaft is 3 to 5 m; the depths of the stress release holes and the pressure relief holes are preferably twice the unit excavation depth of the ultra-deep vertical shaft.

[0016] As a further improvement of the present invention, the diameters of the stress release holes and the pressure relief holes range from 100 to 600 mm, preferably 500 mm.

[0017] As a further improvement of the present invention, the number of the stress relief holes is determined by the specifications of the ultra-deep shaft and the stress concentration conditions.

[0018] As a further improvement of the present invention, in step S2, when pre-stress relief is performed during drilling, after the stress release holes are arranged, the stress is left to stand for 2 to 3 hours to release the stress; if the stress release holes are intact, the pressure relief holes are arranged; if the stress release holes are filled and compacted by the rock mass, additional stress release holes of the same specifications are arranged between the existing stress release holes, and the stress is left to stand for another 2 to 3 hours.

[0019] As a further improvement of the present invention, the specific method for determining the number of the stress relief holes is to establish a three-dimensional equivalent model of the ultra-deep shaft, simulate according to the specifications and stress concentration of the ultra-deep shaft, and obtain the number of the stress relief holes to be constructed.

[0020] As a further improvement of the present invention, in step S2, after stopping excavation, a ground stress test is immediately carried out, and when the value of the ground stress test exceeds a preset critical value, the borehole pre-depressurization is carried out; the preset critical value is determined based on the simulation results of the three-dimensional equivalent model of the ultra-deep shaft.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention is a drilling pressure relief method suitable for ultra-deep vertical shafts. During the excavation of ultra-deep vertical shafts, drilling pre-pressure relief is performed, and a number of stress release holes and pressure relief holes are arranged in sequence on the working surface in the excavation direction; the stress release holes are arranged at equal intervals around the working surface, and the pressure relief holes are arranged in the inner area of ​​the working surface; multiple pressure relief holes form a straight drilling row passing through the center point of the working surface, and the spacing of the pressure relief holes is arranged in equal intervals from the center area of ​​the working surface to the shaft wall of the vertical shaft; two excavation-slag removal processes are performed according to the unit excavation depth, and then drilling pre-pressure relief is performed again on the new working surface; the excavation-slag removal and drilling pre-pressure relief processes are repeated until the ultra-deep vertical shaft is excavated to the set depth. During the excavation of the ultra-deep vertical shaft, the method releases stress in the stress concentration area below the working surface in advance by means of drilling pre-pressure relief, so as to achieve the effect of early pressure relief. It has the advantages of not affecting the normal construction of the ultra-deep vertical shaft, simple method, reasonable process, economical and practical, and good pressure relief effect.

[0023] 2. The depth of the stress release hole and the pressure relief hole of the present invention is 2 to 2.2 times the unit excavation depth of the ultra-deep shaft, preferably 2 times the unit excavation depth; by setting the relationship between the drilling hole and the unit excavation depth, it is ensured that the pre-pressure relief effect exists in the whole process of the unit excavation depth, the pressure relief effect of the drilling hole is maximized, and the waste of construction volume is avoided. The hole arrangement structure of the pressure relief hole is a straight line drilling row passing through the center point of the working surface, preferably two rows of straight line drilling rows passing through the center position and perpendicular to each other; this hole arrangement structure reduces the number of holes, saves engineering volume, and can also connect the pressure relief areas of each pressure relief hole to form a larger pressure relief area, the integrity of the weak zone is good, and the pressure relief effect on the rock mass is the best. The spacing of the pressure relief holes is arranged in an equidistant manner from the center area of ​​the working surface to the shaft wall of the shaft. When the holes are drilled densely near the shaft wall, the stress concentration in the edge area can be reduced, the range of the low stress area can be expanded, and the number of pressure relief holes can be reduced at the same time, and the working efficiency of the ultra-deep shaft can be improved.

[0024] 3. When construction difficulties or slight rock burst problems begin to occur, the present invention sequentially constructs stress release holes and pressure relief holes on the working surface, and the stress release holes are evenly distributed around, and the pressure relief holes are distributed in a straight line in the middle; by constructing stress release holes, stress is preferentially released on the rock mass of the well wall to avoid aggravation of rock burst problems during construction of pressure relief holes. In addition, by setting the spacing between all the holes on the working surface, a good pressure relief effect is achieved on the basis of saving construction costs.

[0025] 4. The present invention performs pre-pressure relief when the shaft working face is not affected by stress. The distribution range of the pressure relief area in the current pressure relief state of the pressure relief hole is small. As the working face advances forward, the pressure relief area is closer and closer to the working face. The weak zone formed by the drilling and the advanced stress of the working face simultaneously pre-adjust the rock stress, which is beneficial to the stable excavation of the shaft and improves the safety of construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram of the working face hole arrangement structure of the drilling pressure relief method applicable to ultra-deep vertical shafts in Example 1 of the present invention.

[0027] Figure 2 A three-dimensional equivalent model diagram established for Example 1 of the present invention.

[0028] Figure 3 This is a stress distribution diagram of the unconstructed longitudinal section of the vertical shaft of the three-dimensional equivalent model of Example 1 of the present invention.

[0029] Figure 4 This is a stress distribution diagram of the longitudinal section of the shaft construction of the three-dimensional equivalent model of Example 1 of the present invention.

[0030] Figure 5 This is a stress distribution diagram of the shaft construction working surface of the three-dimensional equivalent model of Example 1 of the present invention.

[0031] Figure 6 This is a stress distribution diagram of the vertical section of the shaft after pre-pressure relief by drilling for the three-dimensional equivalent model of Example 1 of the present invention.

[0032] Figure 7 This is a stress distribution diagram of the vertical shaft working surface after pre-pressure relief of the drilling for the three-dimensional equivalent model of Example 1 of the present invention.

[0033] Figure 8 This is a working face hole arrangement structure diagram of the ultra-deep vertical shaft drilling pressure relief method of comparative example 1 of the present invention.

[0034] Fig. 9 The stress distribution diagram of the vertical section of the shaft after pre-pressure relief by drilling is performed on the three-dimensional equivalent model of Example 1 of the present invention.

[0035] Fig.10 The stress distribution diagram of the vertical shaft working surface after pre-pressure relief by drilling of the three-dimensional equivalent model of Example 1 of the present invention.

[0036] Reference numerals

[0037] 1-stress release hole; 2-pressure relief hole. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0040] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0041] A drilling pressure relief method applicable to ultra-deep vertical shafts comprises the following steps:

[0042] S1. Carry out excavation of ultra-deep vertical shafts and monitor the status of the shaft wall, ore, rock and support bodies in real time;

[0043] S2. When construction difficulties or rock burst problems begin to occur, stop excavation and perform pre-pressure relief of drilling holes; pre-pressure relief of drilling holes is to arrange a number of stress relief holes 1 and pressure relief holes 2 in sequence on the current working face in the excavation direction; the depth of the stress relief holes 1 and the pressure relief holes 2 is 2 to 2.2 times the unit excavation depth of the ultra-deep shaft; preferably 2 times the unit excavation depth; by setting the relationship between the drilling hole and the unit excavation depth, it is ensured that the pre-pressure relief effect exists in the whole process of the unit excavation depth, so as to maximize the pressure relief effect of the drilling hole and avoid waste of construction volume;

[0044] The stress release holes 1 are arranged at equal intervals around the working face, and the pressure relief holes 2 are arranged in the inner area of ​​the working face; the stress of the well wall is preferentially released through the stress release holes 1 to avoid aggravation of the rock burst problem during the construction of the pressure relief holes 2; multiple pressure relief holes 2 form a straight drilling row passing through the center point of the working face, and the spacing of the pressure relief holes 2 is arranged in equal intervals from the center area of ​​the working face to the well wall of the shaft, and the maximum spacing is located in the center area of ​​the working face; the spacing of the pressure relief holes 2 is arranged in equal intervals, that is, the spacing between adjacent pressure relief holes 2 gradually decreases from the center area of ​​the working face to the well wall of the shaft, and the reduction value is the same; Figure 1 The arrangement of the pressure relief holes 2 shown;

[0045] Preferably, the pressure relief holes 2 are arranged as two rows of straight boreholes that are perpendicular to each other, and the two rows of straight boreholes intersect at the center of the working surface; the hole arrangement structure of the pressure relief holes 2 reduces the number of boreholes, saves engineering work, and can also connect the pressure relief areas of each pressure relief hole 2 to form a larger pressure relief area, with good integrity of the weak zone and the best pressure relief effect on the rock mass. The spacing of the pressure relief holes 2 is arranged in equal steps from the center area of ​​the working surface to the shaft wall of the shaft. The holes are drilled densely when approaching the shaft wall, which can reduce stress concentration in the edge area and expand the range of the low stress area. At the same time, the number of pressure relief holes 2 can be reduced, and the working efficiency of the ultra-deep shaft can be improved;

[0046] S3, excavate once and discharge slag according to the unit excavation depth, continue to excavate twice and discharge slag; then perform drilling pre-unloading as in step S2 on the new working surface; and repeat step S3 continuously until the ultra-deep vertical shaft is excavated to the set depth.

[0047] In particular, the maximum spacing of the pressure relief holes 2 in the central area of ​​the working face is determined by the diameter of the ultra-deep shaft, and the maximum spacing is 0.15 to 0.3 times the diameter of the ultra-deep shaft; the minimum spacing of the pressure relief holes 2 close to the well wall is 0.1 to 0.5 m. The distance between each stress relief hole 1 and the well wall is equal, and the distance is 0.2 to 0.4 m; the minimum distance between the stress relief hole 1 and the pressure relief hole 2 on the working face is 0.3 to 0.5 m. In actual application, when the spacing between the boreholes is too large, a continuous weak pressure relief zone cannot be formed, and a good pressure relief effect cannot be achieved; when the spacing between the boreholes is too small, the number of boreholes to be constructed will increase greatly, and the construction cost and time will also increase. In this way, by setting the spacing between all the boreholes on the working face surface, a good pressure relief effect can be achieved on the basis of saving construction costs.

[0048] Specifically, the aperture range of the stress release hole 1 and the pressure relief hole 2 is 100 to 600 mm, preferably 500 mm; when the aperture of the borehole increases to a certain value, on the basis of controlling the borehole spacing, it is beneficial to connect the pressure relief areas of each borehole to each other, forming a larger pressure relief area and improving the integrity of the pressure relief area; however, if the borehole spacing is too large, the construction cost will be greatly increased, and the pressure relief effect of the borehole may not be fully applied, resulting in a waste of construction work.

[0049] It should be noted that in step S2, when pre-stress relief is performed during drilling, after the stress release hole 1 is arranged, it is left to stand for 2 to 3 hours to release the stress; if the stress release hole 1 is intact, the pressure relief hole 2 is arranged; if the stress release hole 1 is filled and compacted by the rock mass, additional stress release holes 1 of the same specification are set between the existing stress release holes 1, and the stress is left to stand for 2 to 3 hours to achieve stress release.

[0050] The number of stress relief holes 1 is determined by the specifications of the ultra-deep shaft and the stress concentration. The specific method for determining the number of stress relief holes 1 is to establish a three-dimensional equivalent model of the ultra-deep shaft, simulate it according to the specifications and stress concentration of the ultra-deep shaft, and obtain the number of stress relief holes 1 to be constructed.

[0051] In some specific embodiments, when construction difficulties or rock burst problems begin to occur during the excavation of the ultra-deep shaft, excavation is stopped and a ground stress test is immediately performed. When the value of the ground stress test exceeds a preset critical value, pre-drilling pressure relief is performed. The preset critical value is determined based on the simulation results of the three-dimensional equivalent model of the ultra-deep shaft.

[0052] In some specific embodiments, the unit excavation depth of the ultra-deep shaft is 3 to 5 meters.

[0053] Example 1

[0054] This embodiment provides a drilling pressure relief method applicable to ultra-deep vertical shafts, comprising the following steps:

[0055] S1. Excavate a super-deep shaft with a diameter of 6.7m and a unit excavation depth of 4m. At the same time, monitor the status of the shaft wall, ore, rock and support in real time;

[0056] S2. When construction difficulties or minor rock burst problems begin to occur, stop excavation and conduct pre-drilling pressure relief. Pre-drilling pressure relief is to arrange 4 stress release holes 1 and 17 pressure relief holes 2 in sequence on the current working face in the excavation direction. The hole arrangement structure is as follows: Figure 1 As shown; the depth of stress relief hole 1 and pressure relief hole 2 are both 8m, and the hole diameter is 150mm;

[0057] S3, excavate once and discharge slag according to the unit excavation depth, continue to excavate twice and discharge slag; then perform drilling pre-unloading as in step S2 on the new working surface; and repeat step S3 continuously until the ultra-deep vertical shaft is excavated to the set depth of 1700m.

[0058] See also Figure 1 As shown, the arrangement of holes for pre-pressure relief in the drilling of this embodiment is as follows: the four stress release holes 1 are distributed around the working surface, the pressure relief holes 2 are arranged in a straight line row perpendicular to each other, and the spacing of the pressure relief holes 2 is arranged in equal intervals from the central area of ​​the working surface to the wall of the shaft, and the maximum spacing is located in the central area of ​​the working surface. This arrangement reduces the number of holes, saves engineering work, and connects the pressure relief areas of each pressure relief hole to form a larger pressure relief area with good integrity and the best pressure relief effect on the rock mass; drilling more densely when close to the wall of the shaft can reduce stress concentration in the edge area and expand the range of the low stress area.

[0059] See also Figure 2 As shown in the figure, according to the actual situation of this ultra-deep shaft, a three-dimensional equivalent model is established. The dimensions of the three-dimensional model of the shaft are: length × width × height = 100m × 100m × 600m. The representative depth of the model is 1100m ~ 1700m. In order to consider the influence of the upper rock mass on the simulation results, the corresponding surface load is applied to the upper surface of the model, and according to Figure 1 The hole layout structure of drilling pressure relief is simulated.

[0060] See also Figure 3 to Figure 5 As shown, from Figure 3 It can be seen that when the shaft is not excavated, the stress distribution of the rock formation is positively correlated with the depth, that is, the deeper the depth, the greater the stress. Figure 4 and Figure 5It can be seen that when the shaft is constructed to a certain depth, stress concentration begins to occur; from the stress distribution diagram of the shaft working face, it can be seen that the stress value in the center of the working face is small, and the closer to the shaft surrounding rock, the greater the stress; and the low stress area in the stress distribution diagram is a relatively regular circle; the stress area below 7MPa is a circular area with the center of the shaft as the center and a radius of about 1.4m.

[0061] See also Figure 6-7 As shown in the figure, after pre-pressure relief of drilling, the area of ​​low stress zone increases significantly, and the stress variation amplitude of the front of the working face becomes smaller, and the pressure relief hole 2 plays a significant role in pressure relief. And due to the construction of pressure relief hole 2, the low stress zone changes from a relatively regular circle to a more irregular shape, and the range of the low stress zone increases. In this scheme, the range of the stress zone below 7MPa is a circular area with the center of the shaft as the center and a radius of about 1.9m.

[0062] Comparative Example 1

[0063] Comparative Example 1 provides a drilling pressure relief method for an ultra-deep vertical shaft. Compared with Example 1, the difference is that the spacing of the pressure relief holes 2 in Comparative Example 1 is arranged at equal intervals. The specific hole arrangement structure and related parameters are as follows: Figure 8 As shown, the rest is roughly the same as Example 1 and will not be described again.

[0064] The same model as in Example 1 was established, and the corresponding surface load was applied to the upper surface of the model. Figure 8 The hole layout structure of drilling pressure relief is simulated.

[0065] See also Figure 9-10 As shown in the figure, it can be seen that after the drilling pressure relief is carried out in Example 1, the low stress area in the center changes from a relatively regular circle to an X shape, and the stress area below 7MPa is a circular area with the center of the shaft as the center and a radius of about 1.6m; the high stress area is still in the shape of a ring surrounding the ground stress area; it can be seen that the pressure relief effect of this scheme is not as good as the pressure relief effect of Example 1.

[0066] Comparative Example 2

[0067] Comparative Example 2 provides a drilling pressure relief method for an ultra-deep vertical shaft. Compared with Example 1, the difference is that Comparative Example 2 does not construct the stress release hole 1, but directly constructs the pressure relief hole 2. The rest is roughly the same as Example 1 and will not be repeated here.

[0068] By adopting the scheme of comparative example 2 for actual construction operation, it is found that if the stress release hole 1 is not constructed in advance and the pressure relief hole 2 is directly constructed, a slight rock burst will occur during the construction; this shows that only constructing the pressure relief hole 2 for the ultra-deep shaft cannot achieve the best pressure relief effect.

[0069] Comparative Example 3

[0070] Comparative Example 3 provides a drilling pressure relief method for an ultra-deep vertical shaft. Compared with Example 1, the difference is that in Comparative Example 3, only stress release hole 1 is constructed, and pressure relief hole 2 is not constructed. The rest is roughly the same as Example 1 and will not be repeated here.

[0071] By adopting the solution of comparative example 3 to conduct actual construction attempts, it is found that if only the stress relief hole 1 is constructed, a good pressure relief effect cannot be achieved.

[0072] In summary, the present invention provides a drilling pressure relief method suitable for an ultra-deep vertical shaft, wherein drilling pre-pressure relief is performed during the excavation process of the ultra-deep vertical shaft, and a plurality of stress relief holes and pressure relief holes are sequentially arranged on the working face in the excavation direction; the stress relief holes are arranged at equal intervals around the working face, and the pressure relief holes are arranged in the inner area of ​​the working face; a plurality of pressure relief holes form a straight line drilling row passing through the center point of the working face, and the spacing of the pressure relief holes is arranged equidistantly from the center area of ​​the working face to the shaft wall of the vertical shaft; two excavation-slag discharge processes are performed according to a unit excavation depth, and then drilling pre-pressure relief is performed again on the new working face; the excavation-slag discharge and drilling pre-pressure relief processes are repeated until the ultra-deep vertical shaft is excavated to a set depth. During the excavation of the ultra-deep shaft, this method releases stress in the stress concentration area below the working face in advance by pre-unloading the pressure through drilling, thereby achieving the effect of early pressure relief. By designing the hole layout structure and related parameters, the pressure relief degree is maximized without affecting the normal construction of the shaft and saving construction volume, thereby ensuring the safety of the ultra-deep shaft construction. This method has the advantages of simple method, reasonable process, economy and practicality, good pressure relief effect, and has high practical application value.

[0073] 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 may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A drilling pressure relief method suitable for ultra-deep vertical shafts, characterized in that: The following steps are involved: S1. Carry out excavation of ultra-deep vertical shafts and monitor the status of the shaft wall, ore, rock and support bodies in real time; S2. When construction difficulties or rock burst problems begin to occur, stop excavation and conduct pre-pressure relief by drilling; the pre-pressure relief by drilling is to arrange a number of stress relief holes and pressure relief holes in sequence on the current working face in the excavation direction; the depth of the stress relief holes and the pressure relief holes is 2 to 2.2 times the unit excavation depth of the ultra-deep shaft; The stress release holes are arranged at equal intervals around the working surface, and the pressure relief holes are arranged in the inner area of ​​the working surface; a plurality of the pressure relief holes form a straight line drill hole row passing through the center point of the working surface, and the spacing of the pressure relief holes is arranged in equal intervals from the center area of ​​the working surface to the shaft wall of the shaft, and the maximum spacing is located in the center area of ​​the working surface; the pressure relief holes are arranged as two rows of straight line drill hole rows that are perpendicular to each other, and the two rows of straight line drill hole rows intersect at the center position of the working surface; S3, excavating once and discharging slag according to the unit excavation depth, continuing to excavate twice and discharging slag; then performing drilling pre-decompression as described in step S2 on the new working surface; and continuously repeating step S3 until the ultra-deep vertical shaft is excavated to the set depth.

2. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 1, characterized in that: The maximum spacing of the pressure relief holes in the central area of ​​the working face is determined by the diameter of the ultra-deep shaft, and the maximum spacing is 0.15 to 0.3 times the diameter of the ultra-deep shaft; the minimum spacing of the pressure relief holes close to the shaft wall is 0.1 to 0.5 m.

3. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 1, characterized in that: The distance between each stress release hole and the well wall is equal, and the distance is 0.2~0.4m; the minimum distance between the stress release hole and the pressure relief hole on the working surface is 0.3~0.5m, so as to achieve the best pressure relief effect.

4. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 1, characterized in that: The unit excavation depth of the ultra-deep vertical shaft is 3-5 m; the depths of the stress release holes and the pressure relief holes are twice the unit excavation depth of the ultra-deep vertical shaft.

5. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 1, characterized in that: The diameters of the stress release holes and the pressure relief holes range from 100 to 600 mm.

6. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 5, characterized in that: The diameter range of the stress release hole and the pressure relief hole is 500 mm.

7. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 1, characterized in that: The number of the stress relief holes is determined by the specifications of the ultra-deep shaft and the stress concentration conditions.

8. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 1, characterized in that: In step S2, when pre-stress relief is performed by drilling, after the stress release holes are arranged, the stress is released by standing for 2 to 3 hours; if the stress release holes are intact, the pressure relief holes are arranged; If the stress release holes are filled and compacted by the rock mass, additional stress release holes of the same specification are set between the existing stress release holes, and the system is left to stand for another 2 to 3 hours.

9. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 7, characterized in that: The specific method for determining the number of the stress relief holes is to establish a three-dimensional equivalent model of the ultra-deep shaft, simulate according to the specifications and stress concentration of the ultra-deep shaft, and obtain the number of the stress relief holes to be constructed.

10. The drilling pressure relief method applicable to ultra-deep vertical shafts according to claim 9, characterized in that: In step S2, after stopping the excavation, the ground stress test is immediately carried out, and when the value of the ground stress test exceeds a preset critical value, the borehole pre-decompression is carried out; the preset critical value is determined according to the simulation result of the three-dimensional equivalent model of the ultra-deep shaft.

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