Ground directional drilling grouting control method

Abstract

The invention relates to the technical field of coal mines, in particular to a ground directional drilling grouting control method which comprises the steps that S1, a ground vertical drilling hole and a ground directional drilling hole are constructed, and the ground directional drilling hole and the ground vertical drilling hole are communicated in a target area; s2, a water pressure test is conducted on the ground directional drilling hole, the unit water absorption rate q water of a target grouting area of the stratum is calculated, and the initial grouting slurry specific gravity rho slurry and the grouting mode are determined; and S3, grouting construction is conducted through ground directional drilling, the pressure P2 of a ground vertical drilling hole opening and the pressure P1 of a ground directional drilling hole opening are observed and compared, the specific gravity and the grouting mode of grouting slurry are adjusted accordingly till the pressure P2 of the ground vertical drilling hole opening is larger than or equal to the sum of the designed final pressure P0 of the grouting area and the pressure rho water gH2 of a water column above the grouting area, and grouting is conducted. And grouting of the target area is completed. Through the arrangement, the pressure intensity of the target area can be directly observed, the grouting condition of the target area is accurately mastered, and the grouting effect is improved.

Description

Technical Field

[0001] The present application relates to the field of coal mine technology, and in particular to a ground directional drilling grouting control method. Background Art

[0002] In order to solve the problems of water hazards in coal mines and roof support of tunnels, ground directional holes are often used for advance grouting treatment. At present, the termination pressure of directional hole grouting is mostly judged by experience. The change of grouting pressure at the bottom of the ground directional drilling hole during the grouting process cannot be grasped. In addition, since the three-opening section of the ground directional drilling hole is generally long, the grouting diffusion position cannot be grasped, and it is difficult to judge the grouting effect on the target stratum.

[0003] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0004] The purpose of the present application is to provide a ground directional drilling grouting control method to solve or alleviate the problems existing in the above-mentioned prior art.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A ground directional drilling grouting control method, wherein the ground directional drilling is used to grout a target area, and the control method comprises:

[0007] Step S1: constructing a ground vertical drilling hole and a ground directional drilling hole, wherein the ground directional drilling hole and the ground vertical drilling hole are connected in the target area;

[0008] Step S2: Perform a water pressure test on the ground directional drilling hole to calculate the unit water absorption rate q of the target grouting area of ​​the formation 水 , determine the initial grouting slurry specific gravity ρ 浆 , grouting method;

[0009] Step S3: Perform grouting construction through ground directional drilling, observe and compare the ground vertical drilling hole pressure P2 and the ground directional drilling hole pressure P1, and adjust the grouting slurry specific gravity and grouting method accordingly until

[0010] P2≥P′2=P0+ρ 水 H2

[0011] Grouting of the target area is completed;

[0012] Where: P2 is the surface vertical drilling hole pressure, MPa; P ′ 2 is the design final pressure of the vertical drilling hole on the ground, MPa; P0 is the design final pressure of the grouting area, MPa; ρ 水 is the density of water, g / cm 3; H2 is the vertical depth of the connecting point between the ground vertical drilling and the ground directional drilling, m; g is the gravitational acceleration, N / g.

[0013] In the above-mentioned ground directional drilling grouting control method, preferably, in step S2,

[0014]

[0015] Where: q 水 is the average unit water absorption rate, Lu; P1 is the surface directional drilling hole mouth pressure, MPa; H1 is the vertical depth of the second opening of the surface directional drilling casing bottom, m; Q 水 is the water injection flow rate, L / min; L is the length from the bottom of the second-section casing of the ground directional drilling to the connecting point, m.

[0016] In the above-mentioned ground directional drilling grouting control method, preferably, in step S3, the observation and comparison of the ground vertical drilling hole pressure P2 and the ground directional drilling hole pressure P1 is specifically to calculate the average unit grouting rate q of the target area during the grouting process 浆 ,

[0017]

[0018] Where: q 浆 is the average unit grouting rate, Lu; ρ 浆 is the specific gravity of grouting slurry, g / cm 3 ;Q 浆 is the grouting flow rate, L / min.

[0019] In the above-mentioned ground directional drilling grouting control method, preferably, the target area adopts a segmented grouting method;

[0020] Step S1: constructing a ground vertical drilling hole and a ground directional drilling hole, wherein the ground directional drilling hole reaches a first section, and the ground directional drilling hole is connected with the ground vertical drilling hole in the first section;

[0021] In step S3, the target area is specifically the first segment.

[0022] The above-mentioned ground directional drilling grouting control method, preferably, the control method further comprises:

[0023] Step S4b: Calculate the pressure loss w along the grouting process,

[0024]

[0025] Where: w is the pressure loss along the grouting process, MPa / m; P1 is the orifice pressure of the ground directional drilling, MPa; H1 is the vertical depth of the bottom of the second opening of the ground directional drilling casing, m; ρ浆 is the specific gravity of grouting slurry, g / cm 3 ; L is the length from the bottom of the second-section casing of the ground directional drilling to the connecting point, m;

[0026] Step S5b: Continue to perform ground directional drilling to the next target segment;

[0027] Step S6b: Grouting is performed by directional drilling on the ground until

[0028] P1≥P ′ 1=P0+w

[0029] The target segmented grouting is completed;

[0030] Where: P ′ 1 is the designed final pressure of the ground directional drilling hole, MPa;

[0031] Step S7b, looping steps S5b-S6b until the grouting of the target area is completed.

[0032] The above-mentioned ground directional drilling grouting control method, preferably, the control method further comprises:

[0033] Step S4a: Continue to construct the ground directional drilling to the next target segment, and construct a new ground vertical drilling hole, wherein the ground directional drilling hole is connected to the new ground vertical drilling hole in the target segment;

[0034] Step S5a: Grouting is performed by directional drilling on the ground until

[0035] P3≥P′3=P0+ρ 水 H3

[0036] The target segmented grouting is completed;

[0037] Where: P ′ is the mouth pressure of the new vertical borehole on the ground, MPa; P ′ 3 is the designed final pressure of the new ground vertical borehole, MPa; H3 is the vertical depth of the connection point between the new ground vertical borehole and the ground directional borehole, m;

[0038] Step S6a, looping steps S4a-S5a until the grouting of the target area is completed.

[0039] In the above-mentioned ground directional drilling grouting control method, preferably, the connection point is set at 1 / 2-2 / 3 of the ground directional drilling three-opening section, and the distance from the bottom of the casing of the ground directional drilling two-opening section to the connection point is ≤400m.

[0040] The above-mentioned ground directional drilling grouting control method is preferably:

[0041] When the grouting area is a fault, the designed final pressure P0 of the grouting area is the hydrostatic pressure P 静 More than twice;

[0042] When the grouting area is a limestone aquifer or a collapse column, the designed final pressure P0 of the grouting area is the hydrostatic pressure P 静 More than 1.5 times of.

[0043] The above-mentioned ground directional drilling grouting control method is characterized in that, preferably, the initial grouting pressure P 初 Set it to 0.4-0.6 times the design final pressure P0 of the grouting area.

[0044] In the above-mentioned ground directional drilling and grouting control method, preferably, in step S1, the ground vertical drilling is first constructed, and then the ground directional drilling is constructed.

[0045] Compared with the closest prior art, the technical solution of the embodiment of the present application has the following beneficial effects:

[0046] In step S3, the ground directional drilling hole is used as the grouting hole, and the ground vertical drilling hole is set above the target area as an observation hole for the pressure of the target area at the bottom of the well. On the one hand, the conversion relationship between the ground vertical drilling hole mouth pressure P2 and the target area grouting pressure can be established to achieve direct observation of the target area pressure, so as to accurately grasp the grouting situation of the target area and improve the judgment accuracy of the grouting effect of the target area; on the other hand, by comparing the ground vertical drilling hole mouth pressure P2 with the ground directional drilling hole mouth pressure P1 in real time, the grouting slurry diffusion position information can also be obtained to adjust the grouting slurry specific gravity ρ accordingly. 浆 , grouting methods and other grouting parameters to improve the grouting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. Among them:

[0048] Figure 1 A schematic diagram of the arrangement of ground vertical drilling and ground directional drilling provided according to some embodiments of the present application.

[0049] Description of reference numerals:

[0050] 1. Section 1 of ground vertical drilling; 2. Section 2 of ground vertical drilling; 3. Section 3 of ground vertical drilling; 4. Section 1 of ground directional drilling; 5. Section 2 of ground directional drilling; 6. Section 3 of ground directional drilling; 7. Connecting point. DETAILED DESCRIPTION

[0051] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as a part of an embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desired that the present application includes such modifications and variations within the scope of the appended claims and their equivalents.

[0052] In the following description, the terms "first / second / third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first / second / third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0054] In the description of the present application, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present application and do not require that the present application must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present application. The terms "connected", "connected", and "set" used in the present application should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component; it can be a wired electrical connection, a radio connection, or a wireless communication signal connection. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0055] The following is combined with Figure 1 A ground directional drilling grouting control method of the present application is further described in detail.

[0056] A ground directional drilling grouting control method, the ground directional drilling is used to grout a target area, the control method comprises:

[0057] Step S1: constructing ground vertical drilling and ground directional drilling, wherein the ground directional drilling and the ground vertical drilling are connected in the target area;

[0058] Step S2: Perform a water pressure test on the ground directional drilling hole to calculate the average unit water absorption rate q of the formation 水 , determine the initial grouting slurry specific gravity and grouting method;

[0059] Step S3: Perform grouting construction through ground directional drilling, observe and compare the ground vertical drilling hole pressure P2 and the ground directional drilling hole pressure P1, and adjust the grouting slurry specific gravity and grouting method accordingly until

[0060] P2≥P′2=P0+ρ 水 H2

[0061] Grouting in the target area is completed;

[0062] Where: P2 is the surface vertical drilling hole pressure, MPa; P ′ 2 is the design final pressure of the vertical drilling hole on the ground, MPa; P0 is the design final pressure of the grouting area, MPa; ρ 水 is the density of water, g / cm 3 ; H2 is the vertical depth of the connecting point between the ground vertical drilling and the ground directional drilling, m; g is the gravitational acceleration, N / g.

[0063] Both the ground vertical drilling and the ground directional drilling adopt a three-opening hole structure, wherein the first opening section 1 of the ground vertical drilling is a loose layer cementing section, a solid casing is lowered for cementing to isolate the loose layer, and the casing enters the bedrock 5 to 10 m. The bottom of the second opening section 2 of the ground vertical drilling is a distance away from the third opening section 6 of the ground directional drilling, a solid casing is lowered, and cement is used for cementing to provide support for the later grouting pressure conduction. The third opening section 3 of the ground vertical drilling is an open hole section, and a connecting instrument is lowered to connect with the open hole of the third opening section 6 of the ground directional drilling; the first opening section 4 of the ground directional drilling is a loose layer cementing section, and the grouting solid casing of the first opening section 4 of the ground directional drilling is installed, and the casing enters the bedrock 5 to 10 m. The bottom of the second opening section 5 of the ground directional drilling is located below the top interface of the formation in the grouting target area, and the grouting solid casing of the second opening section 5 of the ground directional drilling is installed. The third opening section 6 of the ground directional drilling is an open hole section, which is drilled along the formation in the target area and connected with the ground vertical drilling;

[0064] In a specific embodiment of the present application, the first section 4 of the ground directional drilling has a hole depth of 314m, and a φ244.5×8.94mm seamless steel pipe is inserted to 10m below the bedrock surface, and cement is used for well cementing. The second section 5 of the ground directional drilling has a hole depth of 720m and a vertical depth of 712m, and a φ177.8×8.05mm seamless steel pipe is inserted, and cement is used for well cementing. The third section 6 of the ground directional drilling has a hole depth of 1190m and a vertical depth of 774m. The third section 6 of the ground directional drilling is 470m long, and the connecting point 7 has a hole depth of 910m. The first section 1 of the ground vertical drilling has a hole depth of 314m, and a φ244.5×8.94mm seamless steel pipe is lowered to 10m below the bedrock surface and cemented. The second section 2 of the ground vertical drilling has a hole depth of 760m, and a φ177.8×8.05mm seamless steel pipe is lowered and cemented. The third section 3 of the ground vertical drilling has a hole depth of 791m and a length of 31m. The connecting point 7 has a hole depth of 774m and a hole diameter of 400mm.

[0065] In step S2, the borehole water pressure test refers to a test in which clean water is pressed into the test section of the borehole to measure the water permeability of the rock mass by observing the relationship between the amount of water pressed in and the amount of pressure applied within a certain period of time. The borehole water pressure test can be used to measure the unit water absorption and water permeability of the rock mass, providing basic data for evaluating the permeability and seepage control design of the rock mass; at the same time, it can also provide information on the integrity of the rock mass, cracks, and the degree of karst development, so as to facilitate a comprehensive analysis of the injectability of the target area and provide information on the specific gravity of the grouting slurry ρ 浆 On the one hand, it can provide guidance for the selection of grouting parameters such as grouting method; on the other hand, it can also be used to verify whether the ground vertical drilling and ground directional drilling are connected and remove the mud material on the well wall in the hole;

[0066] In the specific embodiment of the present application, according to the classification of rock and soil permeability in the "Specification for Geological Survey of Water Conservancy and Hydropower Engineering GB50487-2008", the grouting method and the specific gravity of the grouting slurry are established. 浆 The corresponding relationship between the average unit water absorption / slurry rate. 水 After that, the initial grouting slurry specific gravity ρ 浆 , grouting method according to Table 1 and the average unit water absorption rate q 水 Select the corresponding relationship.

[0067] Table 1 Grouting parameter selection table

[0068]

[0069]

[0070] In step S3, the ground directional drilling hole is used as the grouting hole, and the ground vertical drilling hole is set above the target area as an observation hole for the pressure of the target area at the bottom of the well. On the one hand, the conversion relationship between the ground vertical drilling hole mouth pressure P2 and the target area grouting pressure can be established to achieve direct observation of the target area pressure, so as to accurately grasp the grouting situation of the target area and improve the judgment accuracy of the grouting effect of the target area; on the other hand, by comparing the ground vertical drilling hole mouth pressure P2 with the ground directional drilling hole mouth pressure P1 in real time, the grouting slurry diffusion position information can also be obtained to adjust the grouting slurry specific gravity ρ accordingly. 浆 , grouting method and other grouting parameters to improve the grouting effect. Specifically, when adjusting the grouting flow rate Q 浆 , when the surface directional drilling hole pressure P1 changes significantly, while the surface vertical drilling hole pressure P2 does not change significantly, it can be known that the grouting slurry diffuses along the way and does not reach the target area, and then the grouting slurry specific gravity ρ needs to be gradually increased 浆 , change the grouting method from continuous grouting to intermittent grouting;

[0071] In the specific embodiment of the present application, the grouting flow rate Q 浆 The options are 52L / min, 90L / min, 160L / min, 250L / min, and 390L / min.

[0072] In step S2,

[0073]

[0074] Where: q 水 is the average unit water absorption rate, Lu; P1 is the surface directional drilling hole mouth pressure, MPa; H1 is the vertical depth of the bottom of the second opening section 5 casing of the surface directional drilling hole, m; Q 水 is the water injection flow rate, L / min; L is the length from the bottom of the casing of the second opening section 5 of the ground directional drilling to the connecting point 7, m.

[0075] The water pressure test was carried out through ground directional drilling. The ground vertical borehole was used as an observation hole to observe the pressure of the target area at the bottom of the well. Based on the pressure change under the connection relationship between the ground directional drilling hole and the ground vertical drilling hole, the average unit water absorption rate q of the formation section from the bottom of the second opening section 5 to the connection point 7 of the ground directional drilling hole was established without considering the internal friction of the water flow in the casing. 水 The calculation formula of

[0076] In the specific embodiment of the present application, during the water pressure test, the water pressure pump adopts the 390 mud pump in the fourth gear, Q 水 Set to 250L / min, the surface directional drilling hole pressure P1 is 6MPa, the surface vertical drilling hole pressure P2 is 2.2MPa, and the average unit water absorption rate q 水 It is 11.4Lu.

[0077] In step S3, the surface vertical borehole pressure P2 and the surface directional borehole pressure P1 are observed and compared to calculate the average unit grouting rate q of the target area during the grouting process. 浆 ,

[0078]

[0079] Where: q 浆 is the average unit grouting rate, Lu; ρ 浆 is the specific gravity of grouting slurry, g / cm 3 ;Q 浆 is the grouting flow rate, L / min;

[0080] Since the surface vertical drilling hole pressure P2 and the surface directional drilling hole pressure P1 can be monitored in real time during the grouting process, the average unit grouting rate q can be calculated in real time according to the pressure changes of the two through the above formula: 浆 , and also adjust the grouting slurry specific gravity ρ in real time according to the corresponding relationship in Table 1 浆 The grouting method is used to improve the grouting effect of ground directional drilling in real time. After the grouting starts, the ground directional drilling changes to grouting slurry, and the ground vertical drilling is still clear water. 浆 When calculating, the weight of the clean water above the bottom of the second opening 5 of the ground directional drilling hole needs to be adjusted to the weight of the grouting slurry.

[0081] In the specific embodiment of the present application, when grouting starts, Q 浆 Set to 250L / min, the average unit water absorption rate q measured by water pressure test 水 , the specific gravity of the grouting slurry is determined to be 1.4, and the grouting method is continuous grouting; after the grouting starts, the ground vertical drilling hole pressure P2 and the ground directional drilling hole pressure P1 gradually increase, and the difference between the two gradually decreases; at the end of grouting, the ground directional drilling hole pressure P1 is 15MPa, and the ground vertical drilling hole pressure P2 is 14.4MPa.

[0082] The target area is grouted in sections;

[0083] Step S1: constructing ground vertical drilling and ground directional drilling, the ground directional drilling reaches the first section, and the ground directional drilling is connected with the ground vertical drilling in the first section;

[0084] In step S3, the target area is specifically the first segment.

[0085] Segmented grouting can adopt appropriate grouting materials and grouting pressure according to the different depths and geological conditions of ground directional drilling, thereby improving the density and uniformity of grouting. Especially under complex geological conditions, segmented grouting can ensure that the grouting material is fully filled into the cracks and pores, improving the strength and stability of the grouting body.

[0086] The control method also includes:

[0087] Step S4b: Calculate the pressure loss w along the grouting process,

[0088]

[0089] Where: w is the pressure loss along the grouting process, MPa / m; P1 is the orifice pressure of the ground directional drilling, MPa; H1 is the vertical depth of the bottom of the casing of the second opening section 5 of the ground directional drilling, m; ρ 浆 is the specific gravity of grouting slurry, g / cm 3 ; L is the length from the bottom of the casing of the second opening section 5 of the ground directional drilling to the connecting point 7, m;

[0090] Step S5b: Continue to perform ground directional drilling to the next target segment;

[0091] Step S6b: Grouting is performed by directional drilling on the ground until

[0092] P1≥P ′ 1=P0+w

[0093] Target segmented grouting completed;

[0094] Where: P ′ 1 is the designed final pressure of the ground directional drilling hole, MPa;

[0095] Step S7b, looping steps S5b-S6b until the grouting of the target area is completed.

[0096] To save costs, only one ground vertical borehole is set in the first segment. To improve the grouting effect of the subsequent target segments, the pressure loss of the grouting slurry along the way before reaching the target segment is considered, and the conversion relationship between the ground directional drilling hole mouth pressure P1 and the target segment grouting pressure is established to achieve direct observation of the target segment grouting pressure through the ground directional drilling.

[0097] In a specific embodiment of the present application, the pressure loss w along the grouting process is 0.017 MPa / m.

[0098] The control method also includes:

[0099] Step S4a: Continue to construct the ground directional drilling to the next target segment, construct a new ground vertical drilling hole, and the ground directional drilling hole is connected with the new ground vertical drilling hole in the target segment;

[0100] Step S5a: Grouting is performed by directional drilling on the ground until

[0101] P3≥P′3=P0+ρ 水 H3

[0102] Target segmented grouting completed;

[0103] Where: P3 is the new ground vertical borehole pressure, MPa; P ′ 3 is the designed final pressure of the new ground vertical borehole, MPa; H3 is the vertical depth of the connection point between the new ground vertical borehole and the ground directional borehole, m;

[0104] Step S6a, looping steps S4a-S5a until the grouting of the target area is completed.

[0105] In a specific embodiment of the present application, a plurality of ground vertical drill holes are arranged at intervals along the ground directional drilling construction direction, and the plurality of ground vertical drill holes are arranged one by one at the center position of each target segment to realize direct observation of the grouting pressure of each target segment, accurately grasp the grouting situation of each target segment, and further improve the accuracy of judgment on the grouting effect of the target area.

[0106] The connecting point 7 is set at 1 / 2-2 / 3 of the third opening section 6 of the ground directional drilling, and the distance from the bottom of the casing of the second opening section 5 of the ground directional drilling to the connecting point 7 is ≤400m.

[0107] In a specific embodiment of the present application, when a fault fracture zone exists in the target segment, the connection point 7 needs to be located 20-30 m behind the fault; when a collapse column exists in the target segment, the connection point 7 needs to be located directly above the collapse column.

[0108] The final design pressure of the grouting area is selected according to the segmental characteristics of different grouting targets. According to the experience summary in this field and the "Detailed Rules for Water Control in Coal Mines", when the grouting area is a fault, the final design pressure of the grouting area P0 is the hydrostatic pressure P of the grouting area. 静 More than twice;

[0109] When the grouting area is a limestone aquifer or a collapsed column, the final design pressure P0 of the grouting area is the hydrostatic pressure P 静 More than 1.5 times of.

[0110] In order to improve the diffusion effect of the grouting slurry, the ground directional drilling is carried out with pressure grouting at the beginning of grouting, specifically:

[0111] In step S3, the initial grouting pressure P 初 Set it to 0.4-0.6 times the design final pressure P0 of the grouting area.

[0112] In step S1, firstly, vertical drilling is performed on the ground, and then directional drilling is performed on the ground.

[0113] In a specific embodiment of the present application, in step S1, a vertical ground hole is first constructed, and the hole is expanded and a hole is created at the expected connection point 7, with a hole diameter of 400 to 500 mm to increase the possibility of successful connection with the ground directional drilling hole, and then a ground directional drilling hole is constructed.

[0114] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A ground directional drilling grouting control method, characterized in that: The ground directional drilling is used to perform grouting on the target area, and the control method includes: Step S1: constructing a ground vertical drilling hole and a ground directional drilling hole, wherein the ground directional drilling hole and the ground vertical drilling hole are connected in the target area; Step S2: Perform a water pressure test on the ground directional drilling hole to calculate the unit water absorption rate q of the target grouting area of ​​the formation 水 , determine the initial grouting slurry specific gravity ρ 浆 , grouting method; Step S3: Perform grouting construction through ground directional drilling, observe and compare the ground vertical drilling hole pressure P2 and the ground directional drilling hole pressure P1, and adjust the grouting slurry specific gravity and grouting method accordingly until P2≥P′2=P0+ρ 水 gH2 Grouting of the target area is completed; Where: P2 is the orifice pressure of the vertical borehole on the ground, MPa; P′2 is the design final pressure of the orifice of the vertical borehole on the ground, MPa; P0 is the design final pressure of the grouting area, MPa; ρ 水 is the density of water, g / cm 3 ; H2 is the vertical depth of the connecting point between the ground vertical drilling and the ground directional drilling, m; g is the gravitational acceleration, N / g.

2. A ground directional drilling grouting control method as claimed in claim 1, characterized in that: In step S2, Where: q 水 is the average unit water absorption rate, Lu; P1 is the surface directional drilling hole mouth pressure, MPa; H1 is the vertical depth of the second opening of the surface directional drilling casing bottom, m; Q 水 is the water injection flow rate, L / min; L is the length from the bottom of the second-section casing of the ground directional drilling to the connecting point, m.

3. A ground directional drilling grouting control method as claimed in claim 2, characterized in that: In step S3, the observation and comparison of the surface vertical borehole pressure P2 and the surface directional borehole pressure P1 is specifically to calculate the average unit grouting rate q of the target area during the grouting process. 浆 , Where: q 浆 is the average unit grouting rate, Lu; ρ 浆 is the specific gravity of grouting slurry, g / cm 3 ;Q 浆 is the grouting flow rate, L / min.

4. A ground directional drilling grouting control method as claimed in claim 1, characterized in that: The target area adopts a segmented grouting method; Step S1: constructing a ground vertical drilling hole and a ground directional drilling hole, wherein the ground directional drilling hole reaches a first section, and the ground directional drilling hole is connected with the ground vertical drilling hole in the first section; In step S3, the target area is specifically the first segment.

5. A ground directional drilling grouting control method as claimed in claim 4, characterized in that: The control method further comprises: Step S4b: Calculate the pressure loss w along the grouting process, Where: w is the pressure loss along the grouting process, MPa / m; P1 is the orifice pressure of the ground directional drilling, MPa; H1 is the vertical depth of the bottom of the second opening of the ground directional drilling casing, m; ρ 浆 is the specific gravity of grouting slurry, g / cm 3 ; L is the length from the bottom of the second-section casing of the ground directional drilling to the connecting point, m; Step S5b: Continue to perform ground directional drilling to the next target segment; Step S6b: Grouting is performed by directional drilling on the ground until P1≥P′1=P0+w The target segmented grouting is completed; Where: P′1 is the design final pressure of the ground directional drilling hole, MPa; Step S7b, looping steps S5b-S6b until the grouting of the target area is completed.

6. A ground directional drilling grouting control method as claimed in claim 4, characterized in that: The control method further comprises: Step S4a: Continue to construct the ground directional drilling to the next target segment, and construct a new ground vertical drilling hole, wherein the ground directional drilling hole is connected to the new ground vertical drilling hole in the target segment; Step S5a: Grouting is performed by directional drilling on the ground until P3≥P′3=P0+ρ 水 gH3 The target segmented grouting is completed; Where: P3 is the orifice pressure of the new ground vertical borehole, MPa; P′3 is the designed final pressure of the new ground vertical borehole, MPa; H3 is the vertical depth of the connection point between the new ground vertical borehole and the ground directional borehole, m; Step S6a, looping steps S4a-S5a until the grouting of the target area is completed.

7. A ground directional drilling grouting control method according to any one of claims 1 to 5, characterized in that: The connection point is set at 1 / 2-2 / 3 of the third section of the ground directional drilling, and the distance from the bottom of the casing of the second section of the ground directional drilling to the connection point is ≤400m.

8. A ground directional drilling grouting control method according to any one of claims 1 to 6, characterized in that: When the grouting area is a fault, the designed final pressure P0 of the grouting area is the hydrostatic pressure P 静 More than twice; When the grouting area is a limestone aquifer or a collapse column, the designed final pressure P0 of the grouting area is the hydrostatic pressure P 静 More than 1.5 times of.

9. A ground directional drilling grouting control method as claimed in claim 8, characterized in that: In step S3, the initial grouting pressure P 初 Set it to 0.4-0.6 times the design final pressure P0 of the grouting area.

10. A ground directional drilling grouting control method according to any one of claims 1 to 6, characterized in that: In step S1, firstly, vertical drilling is performed on the ground, and then directional drilling is performed on the ground.

Images