High-section high-pressure presplitting pressure relief-grouting advanced treatment method for ultra-deep vertical shaft

Abstract

The invention provides a high-section high-pressure presplitting pressure relief-grouting advanced treatment method for an ultra-deep vertical shaft, and belongs to the field of underground mining of metal mines, the method comprises the following steps: firstly, determining mining technical parameters of a 1500m deep well building area of the ultra-deep vertical shaft, determining a drilling hole arrangement scheme, constructing a fracturing grouting drilling hole and a guide hole, taking a water stopping measure, constructing a pressure relief groove and a pressure relief hole; and the thickness of the shaft wall is increased, then stratum presplitting and grouting construction is conducted, advanced treatment of high-pressure presplitting pressure relief-grouting of the ultra-deep shaft within the height of the fracturing grouting section is completed after grouting is completed and solidification is conducted, and high-section repeated advanced treatment is conducted on the ultra-deep shaft till target depth construction of the ultra-deep shaft is completed. The drilling hole arrangement scheme is matched with the grouting mode, the fracturing process is effectively controlled, the curtain grouting effect is improved, and the defects and defects of a traditional grouting technology are overcome; by arranging the pressure relief grooves and the pressure relief holes, an effective pressure relief ring is formed in a large range around the shaft, and the safety risk of the working face of the ultra-deep shaft is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of underground mining of metal mines, and in particular to a method for high-segment high-pressure pre-cracking pressure relief-grouting advance treatment of ultra-deep vertical shafts. Background Art

[0002] The vertical shaft is the most important infrastructure project for underground mining, with important functions such as transporting personnel and materials, ventilation, and drainage. With the continuous depletion of shallow resources, the mining depth of mines has also been continuously advancing from 1,000 meters to 2,000 meters, and the supporting vertical shaft projects are also constantly breaking the deepest record. At present, the deepest vertical shaft in my country's existing metal mines is 1,551.8 meters deep. The theoretical and technical achievements formed during the construction process have certain guiding significance for the construction of vertical shafts within 1,500 meters, but there is no experience and technology to refer to for the mining of ultra-deep vertical shafts exceeding 1,500 meters. However, with the development of technology and the efficient use of resources, the mining of ultra-deep vertical shafts is imminent.

[0003] The safe construction of ultra-deep shafts, especially shafts deeper than 1,500 meters, mainly involves the following possible problems:

[0004] (1) Strong compression formations, extremely high formation stress (the ratio of the uniaxial compressive strength of rocks at a depth of 1,500 meters to the maximum principal stress of the formation is less than 3), and the risk of inducing rock bursts, large deformations and other ground pressure disasters after excavation is high. However, the conventional borehole drilling pressure relief method has limited pressure relief effect and it is difficult to form an effective pressure relief circle within a large range around the wellbore (generally within a range of more than 10 meters around the wellbore). If the extremely high stress in the deep formation cannot be effectively controlled, it will cause certain damage to the wellbore wall in the future.

[0005] (2) When the water pressure is high and there is a water-rich structure, a large amount of water will flow out, but the grouting pressure of the conventional water exploration grouting method is insufficient. On the other hand, there are a large number of microcracks in the dense granite of hard rock formations, which induce microcrack water flow, but the grouting materials of the conventional grouting method are difficult to press into the microcracks, making it difficult for the conventional grouting method and process to achieve the ideal grouting and water blocking effect. Summary of the invention

[0006] In view of the technical problems existing in the background technology, the present application provides a high-segment high-pressure pre-cracking and pressure relief-grouting advance treatment method for ultra-deep vertical shafts, aiming to solve the technical problems of high formation stress, high water pressure, difficult safe construction or low service safety in ultra-deep vertical shaft mining.

[0007] The present application provides a method for high-segment high-pressure pre-cracking and pressure relief-grouting advance treatment in an ultra-deep vertical shaft, which is characterized by comprising the following steps:

[0008] S1. When the ultra-deep shaft is constructed to a depth of 1500m, the mining technical parameters of the ultra-deep shaft shall be determined according to the rock mass geomechanical parameters of the area where the ultra-deep shaft is constructed at a depth of 1500m or more;

[0009] S2. Determine the drilling arrangement plan according to the cross-sectional dimensions of the wellbore and the expected fracturing effect, so that the height of the fracturing grouting section is 120 to 180 m, construct the fracturing grouting boreholes and guide holes according to the drilling arrangement plan, and take water-stopping measures;

[0010] S3. Construct pressure relief grooves and pressure relief holes between the shaft section and the upper cast well wall, and increase the well wall thickness by a certain height above the upper cast well wall;

[0011] S4, performing stratum pre-splitting and grouting construction, wherein the grouting construction adopts stepped deep-buried orifice pipe fixed-point grouting, and controls the grouting amount and grouting speed;

[0012] S5. After the grouting is completed and solidified, the high-pressure pre-fracture and pressure relief-grouting advance treatment of the ultra-deep vertical shaft within the height of the fracturing grouting section is completed, and the normal construction and mining of the ultra-deep vertical shaft within the height of the fracturing grouting section is carried out. After the construction within the height of the fracturing grouting section is completed, steps S1 to S5 are repeated to continue to perform high-segment high-pressure pre-fracture and pressure relief-grouting advance treatment in the depth direction until the target depth construction of the ultra-deep vertical shaft is completed.

[0013] In the technical solution of the embodiment of the present application, a technical method for high-segmented high-pressure pre-cracking-grouting pre-treatment of ultra-deep vertical shaft formations in metal mines is provided, which is suitable for ultra-deep vertical shafts with a shaft depth of more than 1500m. The uniaxial compressive strength of the formation rock in the well construction area is generally greater than 150MPa, and the rock strength-stress ratio is less than 3 in the extremely high stress zone, and the formation fracture pressure is greater than 40MPa. The present application adopts a suitable drilling arrangement scheme in conjunction with the grouting method to effectively control the fracturing process and improve the curtain grouting effect. The stepped deep-buried orifice pipe fixed-point grouting technology is adopted, and the grouting and water blocking are more accurate, which can achieve accurate treatment of water-bearing formations and achieve one-time treatment of multi-layer aquifers, that is, the purpose of large-section high-pressure treatment of water-bearing formations. The grouting pressure is large, and micro-cracks below 1mm can be blocked. The number of grouting holes is small, the grouting volume is large, and the grouting cycle is shortened, avoiding the shortcomings and defects of traditional grouting technology.

[0014] In some embodiments, in step S2, the drilling arrangement is that the fracturing grouting drilling is arranged at the center of the wellbore section, the guide hole is arranged along the inner wall of the shaft and gradually extends outward, and the bottom position of the guide hole exceeds the shaft diameter of the shaft by 5 to 8 meters, and the fracturing grouting drilling and the guide hole are both arranged radially. The construction of the fracturing grouting drilling and the guide hole is carried out in stages according to the drilling arrangement, with the hole depth of the first stage being 50 to 60 meters, and the hole depth of the second stage being 110 to 120 meters. In step S4, the process of the stepped deep-buried orifice pipe fixed-point grouting is as follows: in conjunction with the fracturing grouting drilling holes and guide holes constructed in stages, firstly, water-stop casings are buried for the fracturing grouting drilling holes and guide holes constructed in the first stage, and fracturing grouting curtain water blocking is implemented in the aquifer at an altitude of 60-120m; then, based on the fracturing grouting drilling holes and guide holes constructed in the first stage, the fracturing grouting drilling holes and guide holes are constructed in the second stage, water-stop casings are buried for the fracturing grouting drilling holes and guide holes, and fracturing grouting curtain water blocking is implemented in the aquifer at an altitude of 120-180m.

[0015] In this embodiment, by arranging the fracturing grouting hole in the center and gradually extending the guide hole outward along the inner wall of the shaft, it is beneficial to increase the grouting diffusion range, effectively control the fracturing process, and improve the effect of curtain grouting. The centrally arranged fracturing grouting hole is used to repeat the fracturing grouting and water plugging, which shortens the grouting period, reduces the cost increase and risk control difficulty caused by the hole-making engineering volume and the conversion of complex processes. This application realizes the treatment of deep well hard rock water-bearing strata and improves the water plugging rate of the strata by constructing fracturing grouting drilling holes and guide holes in stages, and cooperates with the stepped deep buried orifice pipe fixed-point grouting process.

[0016] In some embodiments, in step S3, the construction surface of the pressure relief groove is the uncast well wall surrounding rock section between the wellbore section and the upper cast well wall, and the construction height is 1.5 to 2.5 m. The pressure relief holes are evenly arranged with the pressure relief groove as the construction surface and horizontally extended into the well wall surrounding rock. The pressure relief holes are arranged in two rows, upper and lower, with a row spacing of 0.5 to 0.8 m, a hole spacing of 2 to 3 m, and a depth of not less than 3.6 m. In step S3, the well wall thickness is increased to 2 to 3 times the original well wall thickness, and the height is 15 to 20 m. In step S2, the water-stopping measures include one or more of burying orifice pipes, reserving rock caps or grouting pads, and the grouting pads adopt a composite grouting pad, that is, a combination of grouting pads + grouting rock caps.

[0017] In this embodiment, by setting pressure relief grooves and pressure relief holes in the surrounding rock of the working face, the effect of pre-pressure relief is achieved, and an effective pressure relief circle is formed in a large range around the wellbore, which is beneficial to the transmission of strong geocompressive stress into the surrounding rock. At the same time, through water-stopping measures, such as the use of composite grouting pads (caps) and thickening and protecting the upper well wall, the pressure fluctuations generated during hydraulic fracturing and the expansion of cracks to the upper well wall are effectively controlled, thereby reducing the safety risk of the ultra-deep vertical shaft working face and ensuring the effect of curtain grouting and water blocking.

[0018] In some embodiments, in step S4, the water blocking material for the grouting construction uses P.O42.5 silicate cement as a single-liquid cement slurry, and 0.5% of salt and 0.05% of triethanolamine are added as admixtures accounting for 0.5% of the weight of the cement; the process of formation pre-cracking and grouting construction is to perform hole sweeping and grouting operations in five times, and the slurry injection volume each time is 300-400m 3 After each grouting, the cement slurry should be allowed to set for at least 24 hours.

[0019] In this embodiment, according to the geological conditions, rock properties, and water-conducting fissure development conditions of the well construction area obtained in the early stage, suitable grouting and water-blocking materials, i.e., the materials in the scheme of this embodiment, are selected; in practice, the slurry can be selected according to the geological parameters, such as ultrafine cement or other slurries can be selected if ordinary cement slurry is difficult to press in. The main reason for repeated fracturing and grouting is to form a more complex and rich fracture network to better block possible water passages.

[0020] In some embodiments, in step S1, the mining technical parameters include grouting diffusion range, rock fracture pressure, and grouting pumping pressure, and high-pressure grouting equipment and pipelines of appropriate specifications are selected according to the mining technical parameters.

[0021] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 It is a flow chart of a method for high-segment high-pressure pre-cracking and pressure relief-grouting advance treatment of an ultra-deep vertical shaft in an embodiment of the present application;

[0024] Figure 2 Schematic diagram of the drilling arrangement scheme in the embodiment of the present application, wherein (a) is a three-dimensional schematic diagram, and (b) is a cross-sectional schematic diagram;

[0025] Figure 3 A three-dimensional schematic diagram of the arrangement of the pressure relief grooves and the pressure relief holes in the embodiment of the present application;

[0026] Figure 4 It is a cross-sectional schematic diagram of the arrangement of the pressure relief groove and the pressure relief hole in the embodiment of the present application;

[0027] Figure 5 This is a schematic diagram of the grouting construction process in the embodiment of the present application. DETAILED DESCRIPTION

[0028] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0030] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0033] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0034] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0035] As shallow resources continue to be depleted, the mining depth of mines has also been continuously moving from 1,000 meters to 2,000 meters, so the mining of ultra-deep vertical shafts has become imminent. However, the safe construction of ultra-deep vertical shafts, especially shafts deeper than 1,500 meters, mainly has the following possible problems: (1) Strong compression strata, extremely high strata stress (the ratio of the uniaxial compressive strength of rocks deeper than 1,500 meters to the maximum principal stress of the strata is less than 3), and the risk of inducing rock bursts, large deformations and other ground pressure disasters after excavation is high. The conventional wellbore drilling pressure relief method has limited pressure relief effect and it is difficult to form an effective pressure relief circle within a large range around the wellbore (generally within a range of more than 10 meters around the wellbore). If the extremely high stress in the deep strata cannot be effectively controlled, it will cause certain damage to the wellbore in the future. (2) High water pressure. When there is a water-rich structure, large water gushing occurs, and the conventional water exploration grouting method does not have sufficient grouting pressure. On the other hand, there are a large number of microcracks in the dense granite of hard rock formations, which induce microcrack water gushing, and the grouting materials of conventional grouting methods are difficult to press into the microcracks, making it difficult for conventional grouting methods and processes to achieve the ideal grouting and water blocking effect.

[0036] In order to solve the technical problems of high stratum stress, high water pressure, difficult safe construction or low service safety in ultra-deep vertical shaft mining, the present application provides a high-segment high-pressure pre-fracture unloading-grouting advance treatment method for ultra-deep vertical shafts. By adopting a suitable drilling arrangement scheme in combination with the grouting method, the fracturing process is effectively controlled and the curtain grouting effect is improved. The stepped deep-buried orifice pipe fixed-point grouting technology is adopted, and the grouting and water blocking are more precise, which can achieve precise treatment of water-bearing strata and achieve the purpose of one-time treatment of multi-layer aquifers, that is, large-section high-pressure treatment of water-bearing strata. The grouting pressure is high, which can seal micro-cracks below 1 mm. The number of grouting holes is small, the grouting volume is large, the grouting cycle is shortened, and the shortcomings and defects of traditional grouting technology are avoided.

[0037] The ultra-deep vertical shaft high-segment high-pressure pre-cracking and pressure relief-grouting advance treatment method provided in the embodiment of the present application is suitable for large-scale high-segment high-pressure pre-cracking and grouting advance treatment of ultra-deep vertical shaft strata in hard rock of metal mines. It is suitable for ultra-deep vertical shafts with a shaft burial depth of more than 1500m. The uniaxial compressive strength of the stratum rock in the well construction area is generally greater than 150MPa, and the rock strength-stress ratio is less than 3 in the extremely high stress zone, and the formation fracture pressure is greater than 40MPa.

[0038] For the convenience of explanation, the following embodiments are described by taking an ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to one embodiment of the present application as an example.

[0039] See also Figure 1 As shown, the embodiment of the present application provides a method for high-segment high-pressure pre-cracking and pressure relief-grouting advance treatment in an ultra-deep vertical shaft, comprising the following steps:

[0040] S1. When the ultra-deep shaft is constructed to a depth of 1500m, the mining technical parameters of the ultra-deep shaft shall be determined according to the rock mass geomechanical parameters of the area where the ultra-deep shaft is constructed at a depth of 1500m or more;

[0041] S2. Determine the drilling arrangement plan according to the wellbore cross-sectional dimensions and the expected fracturing effect, so that the height of the fracturing grouting section is 120 to 180 meters, construct the fracturing grouting boreholes and guide holes according to the drilling arrangement plan, and take water-stopping measures;

[0042] S3. Construct pressure relief grooves and pressure relief holes between the shaft section and the upper cast well wall, and increase the well wall thickness by a certain height above the upper cast well wall;

[0043] S4, perform stratum pre-cracking and grouting construction, the grouting construction adopts stepped deep-buried orifice pipe fixed-point grouting, and controls the grouting amount and grouting speed;

[0044] S5, after the grouting is completed, the high-pressure pre-fracture and pressure relief-grouting advance treatment of the ultra-deep vertical shaft within the height of the fracturing and grouting section is completed, and the normal construction and mining of the ultra-deep vertical shaft within the height of the fracturing and grouting section is carried out. After the construction within the height of the fracturing and grouting section is completed, steps S1 to S5 are repeated until the target depth construction of the ultra-deep vertical shaft is completed.

[0045] The technical solution of the embodiment of the present application is applicable to large-scale high-segment high-pressure pre-fracture-grouting advance treatment of ultra-deep vertical shaft formations of hard rocks in metal mines, and is applicable to ultra-deep vertical shafts with a shaft depth of more than 1500m. The present application adopts a suitable drilling arrangement scheme in conjunction with the grouting method to effectively control the fracturing process and improve the curtain grouting effect. The stepped deep-buried orifice pipe fixed-point grouting technology is adopted, and the grouting and water blocking are more accurate, which can achieve accurate treatment of water-bearing formations and achieve the purpose of one-time treatment of multi-layer aquifers, that is, large-section high-pressure treatment of water-bearing formations. The grouting pressure is high, and micro-cracks below 1mm can be blocked. The number of grouting holes is small, and the grouting volume is large, which shortens the grouting cycle and avoids the shortcomings and defects of traditional grouting technology.

[0046] For further information, see Figure 2 As shown, in some embodiments, in step S2, the drilling arrangement is that the fracturing grouting drilling is arranged at the center of the wellbore section, and the guide hole is arranged along the inner wall of the shaft and gradually extends outward, and the bottom position of the guide hole exceeds the shaft diameter of the shaft by 5 to 8 meters, and the fracturing grouting drilling and the guide hole are both arranged radially. The construction of the fracturing grouting drilling and the guide hole is carried out in stages according to the drilling arrangement plan. The hole depth of the first stage is 50 to 60 meters, and the hole depth of the second stage is 110 to 120 meters. Please refer to Figure 5 As shown, in step S4, the process of stepped deep-buried orifice pipe fixed-point grouting is: in conjunction with the fracturing grouting drilling and guide holes constructed in stages, first, water-stop casings are buried for the fracturing grouting drilling and guide holes constructed in the first stage, and fracturing grouting curtain water blocking is implemented in the aquifer with a hole depth of 60-120m; then, on the basis of the fracturing grouting drilling and guide holes constructed in the first stage, the fracturing grouting drilling and guide holes are constructed in the second stage, water-stop casings are buried for the fracturing grouting drilling and guide holes, and fracturing grouting curtain water blocking is implemented in the aquifer with a height of 120-180m, so that the height of the fracturing grouting section is 120~180m.

[0047] In the technical solution of the embodiment of the present application, by arranging the fracturing grouting hole in the center and gradually extending the guide hole outward along the inner wall of the shaft, it is beneficial to increase the grouting diffusion range, effectively control the fracturing process, and improve the effect of curtain grouting. The centrally arranged fracturing grouting hole is used to repeat the fracturing grouting and water plugging, which shortens the grouting period, reduces the cost increase and risk control difficulty caused by the hole-making engineering volume and the conversion of complex processes. The present application realizes the treatment of deep well hard rock water-bearing strata and improves the water plugging rate of the strata by constructing fracturing grouting drilling holes and guide holes in stages, and cooperates with the stepped deep buried orifice pipe fixed-point grouting process.

[0048] For further information, see Figure 3-4As shown, in some embodiments, in step S3, the construction surface of the pressure relief groove is the uncast well wall surrounding rock section between the wellbore section and the upper cast well wall, and the construction height is 1.5 to 2.5 m. The pressure relief holes are evenly arranged with the pressure relief groove as the construction surface and horizontally extended into the well wall surrounding rock. The pressure relief holes are arranged in two rows, upper and lower, with a row spacing of 0.5 to 0.8 m, a hole spacing of 2 to 3 m, and a depth of not less than 3.6 m. In step S3, the well wall thickness is increased to 2 to 3 times the original well wall thickness, and the height is 15 to 20 m. In step S2, the water stopping measures include one or more of burying the orifice pipe, reserving the rock cap or the grouting pad. The grouting pad adopts a composite grouting pad, that is, a combination of the grouting pad + the grouting rock cap.

[0049] In this embodiment, by setting pressure relief grooves and pressure relief holes in the surrounding rock of the working face, the effect of pre-pressure relief is achieved, and an effective pressure relief circle is formed in a large range around the wellbore, which is beneficial to the transmission of strong geocompressive stress into the surrounding rock. At the same time, through water-stopping measures, such as the use of composite grouting pads (caps) and thickening and protecting the upper well wall, the pressure fluctuations generated during hydraulic fracturing and the expansion of cracks to the upper well wall are effectively controlled, thereby reducing the safety risk of the ultra-deep vertical shaft working face and ensuring the effect of curtain grouting and water blocking.

[0050] Furthermore, in some embodiments, in step S4, the water blocking material for grouting construction uses P.O42.5 silicate cement as a single-liquid cement slurry, and 0.5% of salt and 0.05% of triethanolamine are added as admixtures accounting for 0.5% of the weight of the cement; the process of formation pre-cracking and grouting construction is to perform hole sweeping and grouting operations in five times, and the slurry injection volume each time is 300-400m 3 After each grouting, the cement slurry should be allowed to set for at least 24 hours.

[0051] In this embodiment, according to the geological conditions of the well construction area, rock properties, and the development of water-conducting fissures obtained in the early stage, suitable grouting and water-blocking materials, i.e., the materials in the scheme of this embodiment, are selected; in practice, the slurry can be selected according to the geological parameters, such as if ordinary cement slurry is difficult to press in, ultrafine cement or other slurries can be selected. The main reason for repeated fracturing and grouting is to form a more complex and rich fracture network to better block possible water passages. In addition, in step S4, high-pressure grouting equipment and processes are used to carry out formation pre-cracking and grouting construction according to the relevant parameters calculated in the early stage, and a pressure test should be carried out before grouting; before fracturing, the fracturing pipeline needs to be strictly pressure-resistant tested; the test pressure should be 1.2 to 1.5 times higher than the final pressure, and it can be considered qualified only if there is no puncture or leakage for 5 minutes.

[0052] Furthermore, in some embodiments, in step S1, the mining technical parameters include grouting diffusion range, rock fracture pressure, and grouting pumping pressure, and high-pressure grouting equipment and pipelines of appropriate specifications are selected according to the mining technical parameters.

[0053] Specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0054] Example 1

[0055] This embodiment takes the construction of a 2005m ultra-deep vertical shaft in Shandong as an example. The cross-sectional diameter of the shaft is 11.5m, the net cross-section after lining is 10.5m, and the designed depth of the shaft is 2005m. According to the on-site construction conditions, strain-type rock bursts and structural surface sliding-type rock bursts have occurred when the construction reached 1500m. At the same time, according to the previous ground stress test results and rock mass geomechanical parameters, the maximum horizontal principal stress at a depth of 1500m is greater than 50MPa, and the maximum horizontal principal stress at a depth of 2000m is greater than 70MPa. The measured uniaxial compressive strength of the surrounding rock revealed by the shaft construction is greater than 150MPa, which is a dense altered granite formation. At the same time, there are high-angle cracks in the surrounding rock. The use of traditional grouting technology has resulted in insufficient grouting pressure and poor grouting effect. This embodiment adopts a high-segmented high-pressure pre-cracking and pressure relief-grouting advance treatment method for ultra-deep vertical shafts, including the following steps:

[0056] S1. When the ultra-deep shaft is constructed to a depth of 1500m, the mining technical parameters of the ultra-deep shaft are determined according to the rock mass geomechanical parameters of the ultra-deep shaft construction area of ​​1500m or more; according to the parameters such as grouting diffusion range, rock fracture pressure, grouting pumping pressure, etc., high-pressure grouting equipment and pipelines of different powers and specifications are selected; theoretical calculations and RFPA numerical simulation calculations show that the rock fracture pressure at this depth is 40MPa, the grouting pumping pressure is 45.54MPa, the fracturing grouting diffusion height can reach 56.7m, the diffusion length can reach 15.75m, and the fracturing grouting displacement is not less than 2m 3 / min; According to the above parameters, a mixing skid with a speed of 120m 3 , using 3 JR1000Q plunger pumps, each with a 1000kW motor, single parameter: 0.73m 3 / min@70MPa, the three parameters meet: 2.19m 3 / min@70MPa, i.e. construction displacement 2.19m 3 / min, pressure level is 70MPa;

[0057] S2. Determine the drilling arrangement plan based on the wellbore cross-sectional dimensions and the expected fracturing effect, so that the height of the fracturing grouting section is 180m, that is, carry out fracturing grouting control work in the 1500m-1680m section, construct fracturing grouting boreholes and guide holes according to the drilling arrangement plan, and take water-stopping measures;

[0058] Among them, the drilling arrangement plan is that the fracturing grouting drilling holes are arranged at the center of the shaft section, and 6 guide holes are arranged gradually extending outward from 0.5m along the inner wall of the shaft, and the bottom position of the guide hole exceeds the shaft diameter of the shaft by 5m. The fracturing grouting drilling holes and the guide holes are both arranged radially, with a hole diameter of 90mm; the construction of the fracturing grouting drilling holes and the guide holes is carried out in stages according to the drilling arrangement plan, with a hole depth of 55m in the first stage and a hole depth of 115m in the second stage; in this embodiment, the W70 type hydrodynamic submerged hole is selected Hammer, using water-powered down-the-hole hammer rapid drilling and construction technology to construct fracturing grouting drilling holes and guide holes. The water-powered down-the-hole hammer adopts high-power output, high-frequency impact, frequency 3600 blows / min (60Hz), and has better drilling performance. The water hammer is always surrounded by water, and the slag and water are discharged normally without additional power consumption. The water-stopping measures include burying the orifice pipe, reserving the rock cap or grout-stopping pad. The grout-stopping pad adopts a composite grout-stopping pad, that is, a combination of a grout-stopping pad + a grout-stopping rock cap. The grout-stopping pad is 1m, and the grout-stopping rock cap is selected to be 60m after calculation.

[0059] S3. Construct pressure relief grooves and pressure relief holes between the shaft section and the upper cast shaft wall, and increase the thickness of the upper cast shaft wall to a certain height upward; the construction surface of the pressure relief groove is the uncast shaft wall surrounding rock section between the shaft section and the upper cast shaft wall, with a construction height of 1.5m. The pressure relief holes are evenly arranged with the pressure relief groove as the construction surface and horizontally extended into the shaft wall surrounding rock; the pressure relief holes are arranged in two rows, with a row spacing of 0.5m, a hole spacing of 2m, a diameter of Ф32mm, and a depth of not less than 3 .6m; 15 pressure relief holes are evenly distributed in each row of surrounding rock along the well wall, totaling 30 pressure relief holes, the buried length of the mouth section orifice pipe is 1.2m, and a high-pressure ball valve is installed to ensure construction safety; to ensure the safety of the well wall structure, the well wall thickness is increased from the original design well wall thickness of 0.5m to 1.2m, the height is 16m upward from the fracturing working surface, and the well wall label is increased from the original C40 to C60. At the same time, 3 groups of pressure sensing systems are installed on the well wall, and each group has 6 evenly distributed along the well wall;

[0060] S4. According to the relevant parameters calculated in the early stage, high-pressure grouting equipment and technology are used to carry out the pre-fracture and grouting construction of the formation. A pressure test should be carried out before grouting. By gradually adjusting the grouting pump pressure and construction displacement, it is stabilized at a specific value. After waiting for 5 minutes, the pump is suddenly stopped. The pump pressure and the surface pressure of the working surface are recorded to determine the actual fracture pressure of the formation; this pressure is compared with the design pressure to determine the fracture pressure gradient. The injection volume of the slurry basically meets the design requirements, and the number of boreholes is checked to be no less than 2, and the water inflow of the boreholes should be less than 1m 3 / h is the standard for the end of grouting; the formation pre-fracture and grouting construction are carried out. The grouting construction adopts the step-type deep-buried hole pipe fixed-point grouting to control the grouting volume and grouting speed; in the process of fracturing grouting and water blocking, the hole sweeping and grouting operations are carried out five times, and the slurry injection volume of each grouting is 336m 3 , and after each grouting, the cement slurry should wait for at least 24 hours to set; the main motor of the plunger pump used for grouting is a variable frequency motor, which can adjust the speed as needed to control the pressure and flow parameters of the pumping; the plunger pump is equipped with a safety valve, which can automatically unload the pressure when the set pressure is exceeded, and the electronic control program sets overpressure protection, and automatically shuts down when the set pressure is exceeded; the system can set emergency stop buttons at multiple locations as needed for emergency handling;

[0061] Among them, according to the geological conditions, rock properties, and water-conducting fissure development of the well construction area obtained in the early stage, suitable grouting and water plugging materials are selected. This scheme uses single-liquid cement slurry materials. The single-liquid cement slurry uses P.O42.5 ordinary Portland cement, and 0.5% of salt and 0.05% of triethanolamine are added as admixtures by weight of cement. The admixtures play the role of rapid setting and early strength.

[0062] The stepped deep-buried orifice pipe fixed-point grouting technology cooperates with the process of constructing fracturing grouting drilling holes and guide holes in two stages in step S2. After the fracturing grouting drilling holes and guide holes are constructed in the first stage and the water-stop casing is buried, the fracturing grouting curtain water blocking is implemented in the aquifer at a height of 60-120m; then, the fracturing grouting drilling holes and guide holes are constructed in the second stage, and after the water-stop casing is buried in the fracturing grouting drilling holes and guide holes, the fracturing grouting curtain water blocking is implemented in the aquifer at a height of 120-180m, so as to complete the grouting within the height (1500m-1680m) of the fracturing grouting section;

[0063] There are two types of water-stop casing models and specifications, one is API oil pipe steel grade C-90, with a specification of Φ114.3×6.88mm; the other is seamless steel pipe, with a specification of Φ108×6mm. The two orifice pipes are connected by welding. The upper part is API oil pipe, with a length of 2m; the lower part is seamless steel pipe. The orifice pipe is buried by first constructing a Φ168mm drill hole, then inserting the orifice pipe, and using a high-pressure grouting pump to press the mortar into the hole, and the orifice pipe and the drill hole annular space flow out, so as to achieve the fixed pipe.

[0064] S5. After the grouting is completed, the high-pressure pre-fracture and pressure relief-grouting advance treatment of the ultra-deep vertical shaft within the height of the fracturing and grouting section (1500m to 1680m section) is completed, and the normal construction and mining of the ultra-deep vertical shaft within the height of the fracturing and grouting section is carried out. After the construction within the height of the fracturing and grouting section is completed, steps S1 to S5 are repeated to continue to perform high-segment high-pressure pre-fracture and pressure relief-grouting advance treatment in the depth direction until the construction of the 2005m ultra-deep vertical shaft is completed.

[0065] This embodiment can effectively solve the problems of the current conventional vertical shaft grouting process, such as small grouting section height, large number of grouting holes, low grouting pressure (<20MPa), difficulty in injecting granular materials (cement slurry), small grouting volume, use of new grouting materials (such as ultra-fine cement, chemical slurry, etc.), long grouting cycle, poor grouting effect, and large amount of residual water in the wellbore grouting section construction. In addition, the use of water-powered down-the-hole hammers or high-pressure down-the-hole drilling rigs and construction technology can achieve fast drilling of hard rock deep holes in limited spaces, improve drilling efficiency, reduce costs and reduce environmental impact. Grouting automation control ensures the safety and quality of construction. Through the research of remote control and automatic monitoring and control system technology, the quality and safety of the fracturing process are ensured.

[0066] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for high-segment high-pressure pre-cracking and pressure relief-grouting advance treatment of ultra-deep vertical shafts, characterized in that: The following steps are involved: S1. When the ultra-deep shaft is constructed to a depth of 1500m, the mining technical parameters of the ultra-deep shaft shall be determined according to the rock mass geomechanical parameters of the area where the ultra-deep shaft is constructed at a depth of 1500m or more; S2. Determine the drilling arrangement plan according to the cross-sectional dimensions of the wellbore and the expected fracturing effect, so that the height of the fracturing grouting section is 120 to 180 m, construct the fracturing grouting boreholes and guide holes according to the drilling arrangement plan, and take water-stopping measures; S3. Construct pressure relief grooves and pressure relief holes between the shaft section and the upper cast well wall, and increase the well wall thickness by a certain height above the upper cast well wall; S4, performing stratum pre-splitting and grouting construction, wherein the grouting construction adopts stepped deep-buried orifice pipe fixed-point grouting, and controls the grouting amount and grouting speed; S5. After the grouting is completed and solidified, the high-pressure pre-fracture and pressure relief-grouting advance treatment of the ultra-deep vertical shaft within the height of the fracturing grouting section is completed, and the normal construction and mining of the ultra-deep vertical shaft within the height of the fracturing grouting section is carried out. After the construction within the height of the fracturing grouting section is completed, steps S1 to S5 are repeated to continue to perform high-segment high-pressure pre-fracture and pressure relief-grouting advance treatment in the depth direction until the target depth construction of the ultra-deep vertical shaft is completed.

2. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 1 is characterized in that: In step S2, the drilling arrangement is that the fracturing grouting drilling holes are arranged at the center of the wellbore section, the guide holes are arranged along the inner wall of the shaft and gradually extend outward, and the bottom position of the guide holes exceeds the rough diameter of the shaft by 5 to 8 meters, and the fracturing grouting drilling holes and the guide holes are both arranged radially.

3. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 2 is characterized in that: The construction of the fracturing grouting drilling holes and the guide holes is carried out in stages according to the drilling arrangement plan. The hole depth of the first stage construction is 50-60m, and the hole depth of the second stage construction is 110-120m.

4. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 1 is characterized in that: In step S3, the construction surface of the pressure relief groove is the uncast well wall surrounding rock section between the wellbore section and the upper cast well wall, and the construction height is 1.5 to 2.5 m. The pressure relief holes are evenly arranged with the pressure relief groove as the construction surface and extending horizontally into the well wall surrounding rock.

5. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 4 is characterized in that: The pressure relief holes are arranged in two rows, upper and lower, with a row spacing of 0.5 to 0.8 m, a hole opening spacing of 2 to 3 m, and a depth of not less than 3.6 m.

6. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 3 is characterized in that: In step S4, the process of the stepped deep-buried orifice pipe fixed-point grouting is as follows: in conjunction with the fracturing grouting drilling holes and guide holes constructed in stages, firstly, water-stop casings are buried in the fracturing grouting drilling holes and guide holes constructed in the first stage, and fracturing grouting curtain water blocking is implemented in the aquifer at an altitude of 60-120m; and then, after the fracturing grouting drilling holes and guide holes are constructed in the second stage, water-stop casings are buried in the fracturing grouting drilling holes and guide holes, and fracturing grouting curtain water blocking is implemented in the aquifer at an altitude of 120-180m.

7. The method for high-segment high-pressure pre-cracking and pressure-relieving-grouting advance treatment of ultra-deep vertical shaft according to claim 1 is characterized in that: In step S4, the water blocking material of the grouting construction adopts P.O42.5 silicate cement as a single-liquid cement slurry, and 0.5% of salt and 0.05% of triethanolamine are added as admixtures accounting for 0.5% of the weight of the cement; the process of formation pre-cracking and grouting construction is to perform hole sweeping and grouting operations in five times, and the slurry injection volume each time is 300-400m 3 After each grouting, the cement slurry should be allowed to set for at least 24 hours.

8. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 1 is characterized in that: In step S2, the water-stopping measures include one or more of burying an orifice pipe, reserving a rock cap or a grout-stopping pad, and the grout-stopping pad is a composite grout-stopping pad, that is, a combination of a grout-stopping pad and a grout-stopping rock cap.

9. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 1 is characterized in that: In step S3, the thickness of the well wall is increased to 2 to 3 times of the original well wall thickness, and the height is 15 to 20 m.

10. The ultra-deep vertical shaft high-segment high-pressure pre-cracking pressure relief-grouting advance treatment method according to claim 1 is characterized in that: In step S1, the mining technical parameters include grouting diffusion range, rock fracture pressure, and grouting pumping pressure. High-pressure grouting equipment and pipelines of appropriate specifications are selected according to the mining technical parameters.

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