Drilling site arrangement method for advance pre-grouting directional drilling construction of working face in tunnel

Abstract

The invention discloses a drill site arrangement method for advance pre-grouting directional drilling construction of a working face in a tunnel, which comprises the following steps of: firstly, evaluating geology and structure: detecting and analyzing geological conditions of tunnel surrounding rock, evaluating stability, arranging multiple stages of construction platforms in the tunnel, arranging a drilling machine on each stage of construction platform, and performing directional drilling construction by using the drilling machine; and after drilling is completed, grouting is conducted through grouting equipment. By means of the method of excavating the working platform in a layered mode, the opening angle of each drill hole around the tunnel can be taken into consideration, construction can be conveniently carried out, the horizontal drilling precision is improved, meanwhile, the target front distance needed by horizontal directional drilling in the tunnel can be shortened, and the construction occupied space is reduced; drilling operation can be synchronously carried out at different positions around the tunnel, the construction efficiency is greatly improved, a plurality of drill holes are drilled at the same time in unit time, synchronous grouting can be carried out on the plurality of drill holes at the same time during grouting, a preliminary strengthening ring can be formed around the tunnel, and the mutual combination effect is improved after grout is diffused.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction engineering, and more particularly to a method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel. Background Art

[0002] In the field of tunnel construction engineering, advanced pre-grouting technology is a key process for dealing with complex geological conditions such as water-rich strata, fault fracture zones and soft surrounding rocks. Its core work is to evenly arrange a certain number of horizontal directional boreholes around the tunnel. The horizontal section of the borehole is the pre-grouting treatment section around the tunnel. Through high-pressure grouting of horizontal directional boreholes, a continuous and uniform grouting reinforcement ring is formed along the direction of the tunnel in the planned treatment section in front of the working face to solve problems such as surrounding rock crushing, water gushing, and soft rock deformation.

[0003] In the prior art, when drilling holes, the drilling site is either arranged on the ground for directional drilling or arranged on the working face for straight hole drilling. If the drilling site is arranged on the ground, although directional drilling can be achieved, it occupies a large area, and the drilling work is large. The drilling exposes more strata, and it is very easy to encounter unfavorable strata such as weak zones and broken zones; the limitations of grouting on the working face are even greater. The application of this method is limited by the narrow space in the cave. Large equipment has low feasibility due to the difficulty of operation. In addition, the scheduling of personnel, materials and equipment during construction is poor, resulting in a significant increase in auxiliary costs. The overall cross-operation directly squeezes the main line construction period, further delaying the progress of the project. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, which can improve construction efficiency and drilling accuracy.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, comprising the following steps: Step A: Geological and structural assessment: Detect and analyze the geological conditions of the tunnel surrounding rock and assess its stability; Step B: Arrange the construction platform: Arrange the first platform, the second platform and the third platform in sequence from the working surface to the tunnel entrance in the tunnel, and the heights of the first platform, the second platform and the third platform are successively reduced; Step C: Drilling rig arrangement: Horizontal directional drilling rigs are arranged on the first platform, the second platform and the third platform respectively; the horizontal directional drilling rig on the first platform is responsible for constructing horizontal directional drilling holes at the top of the tunnel, the horizontal directional drilling rig on the second platform is responsible for constructing horizontal directional drilling holes at the two sides of the tunnel, and the horizontal directional drilling rig on the third platform is responsible for constructing horizontal directional drilling holes at the bottom of the tunnel; the drilling rig adopts a crawler-type horizontal directional drilling rig; Step D: Drilling: The horizontal directional drilling machines on the first platform, the second platform and the third platform perform directional drilling at the same time to form a circle of horizontal directional drill holes around the tunnel; Step E: Grouting: Grouting is carried out into the horizontal directional borehole through grouting equipment to form a grouting reinforcement ring in the pre-treatment section of the tunnel.

[0006] In the above-mentioned method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel, in step B, the allowable load and the bearing capacity of the excavation area are calculated according to the existing structure of the tunnel to ensure that the construction platform will not damage the tunnel structure.

[0007] In the above-mentioned method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, in step B, the height, width and spacing of each construction platform are determined according to the size of the drilling equipment, the operating space requirement and the range of personnel activities.

[0008] In the above-mentioned method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, in step B, the heights of the first platform, the second platform and the third platform evenly divide the height of the tunnel.

[0009] In the above-mentioned method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, the lengths of the first platform, the second platform and the third platform are all 10m; the heights of the first platform, the second platform and the third platform are all 3m.

[0010] In the above-mentioned method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, a ramp connected to the first platform is arranged on the second platform, and a ramp connected to the second platform is arranged on the third platform.

[0011] In the above-mentioned method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel, a first drilling face is formed between the first platform and the top of the tunnel, a second drilling face and a third drilling face are respectively formed between the second platform and the first platform at positions close to the waists on both sides of the tunnel, and a fourth drilling face is formed between the second platform and the third platform. The second drilling face and the third drilling face have the same axial depth in the tunnel, the axial depth of the first drilling face is greater than the axial depth of the second drilling face, and the axial depth of the third drilling face is less than the axial depth of the second drilling face.

[0012] The technical solution of the present invention achieves the following beneficial technical effects: Compared with the traditional in-tunnel pre-grouting technology, the use of crawler horizontal directional drilling rigs not only improves the accuracy and efficiency of drilling operations, but also due to its high flexibility, it can quickly move and adjust its position in a small space, further accelerating the construction progress; the method of layered excavation work platform can take into account the opening angles of each borehole around the tunnel, facilitate construction, improve the accuracy of horizontal drilling, and at the same time shorten the target front distance required for horizontal directional drilling in the tunnel and reduce the construction space; drilling operations can be carried out simultaneously at different positions around the tunnel, greatly improving construction efficiency. In a unit of time, multiple boreholes can be drilled at the same time. When grouting, multiple boreholes can be grouted simultaneously, which can form a preliminary reinforcement circle around the tunnel, and the slurry is combined with each other after diffusion. The effect is improved.

[0013] Compared with the short-distance (less than 50m) grouting treatment method in the tunnel, this method greatly increases the one-time treatment length, shortens the number of grouting cycles in the tunnel, speeds up the tunnel excavation efficiency, and ensures the overall treatment effect of the surrounding rock in the fault fracture zone of the tunnel.

[0014] Compared with the ground directional drilling pre-grouting treatment method, this method has the advantages of flexible equipment layout in the tunnel, low investment, strong mobility, no need for ground acquisition, small space occupation and high efficiency. At the same time, it will not have any impact on the surface environment, nor will it be affected by natural and human factors on the surface. The implementation preparation conditions are simple and can be deeply integrated with the production environment in the tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A three-dimensional schematic diagram of the drilling site layout of the present invention; Figure 2 A top plan view of the drilling site arrangement of the present invention; Figure 3 A side view of the drilling site arrangement of the present invention; Figure 4 A plan view of the horizontal directional drilling distribution of the present invention; Figure 5a A schematic top view of the horizontal directional drilling direction at the bottom of the tunnel of the present invention; Figure 5b A schematic top view of the directions of the horizontal directional drilling holes on both sides of the tunnel of the present invention; Figure 5c A schematic top view of the horizontal directional drilling direction at the bottom of the tunnel of the present invention; Figure 6 A side view schematic diagram of the horizontal directional drilling orientation of the present invention.

[0016] The reference numerals in the figure are as follows: 1 - first platform; 2 - second platform; 3 - third platform; 11 - first drilling surface; 21 - second drilling surface; 22 - third drilling surface; 31 - fourth drilling surface. DETAILED DESCRIPTION

[0017] A method for arranging a drilling site for advanced pre-grouting directional drilling construction on a working face in a tunnel in this embodiment includes the following steps.

[0018] Step A: Geological and structural assessment: Through drilling, geophysical exploration and other means, the geological conditions of the tunnel surrounding rock are analyzed in detail to evaluate the stability; based on the existing structure of the tunnel, the allowable load and the bearing capacity of the excavation area are calculated to ensure that the construction platform will not damage the tunnel structure.

[0019] Step B: Arrange the construction platform: according to the size of the drilling equipment, the operating space requirements and the range of personnel activities, determine the height, width and spacing of each construction platform, and arrange the first platform 1, the second platform 2 and the third platform 3 in the tunnel from the working surface to the tunnel entrance in sequence, the heights of the first platform 1, the second platform 2 and the third platform 3 decrease in sequence, and the heights of the first platform 1, the second platform 2 and the third platform 3 evenly divide the height of the tunnel; in this implementation, the lengths of the first platform 1, the second platform 2 and the third platform 3 are all 10m; the heights of the first platform 1, the second platform 2 and the third platform 3 are all 3m; Step C: Drilling rig arrangement: A ramp connected to the first platform 1 is provided on the second platform 2, and a ramp connected to the second platform 2 is provided on the third platform 3, so as to facilitate the movement of the drilling rig, and horizontal directional drilling rigs are arranged on the first platform 1, the second platform 2 and the third platform 3 respectively; the horizontal directional drilling rig on the first platform 1 is responsible for constructing horizontal directional drilling holes at the top of the tunnel, the horizontal directional drilling rig on the second platform 2 is responsible for constructing horizontal directional drilling holes at the two waists of the tunnel, and the horizontal directional drilling rig on the third platform 3 is responsible for constructing horizontal directional drilling holes at the bottom of the tunnel; a first drilling surface 11 is formed between the first platform 1 and the top of the tunnel, a second drilling surface 21 and a third drilling surface 22 are respectively formed between the second platform 2 and the first platform 1 near the waists on both sides of the tunnel, and a fourth drilling surface 31 is formed between the second platform 2 and the third platform 3, the second drilling surface 21 and the third drilling surface 22 have the same axial depth in the tunnel, the axial depth of the first drilling surface 11 is greater than the axial depth of the second drilling surface 21, and the axial depth of the third drilling surface 22 is less than the axial depth of the second drilling surface 21.

[0020] Step D: Drilling: The horizontal directional drilling rigs on the first platform 1, the second platform 2 and the third platform 3 perform directional drilling at the same time to form a circle of horizontal directional boreholes around the tunnel; after the drilling is completed, since the lengths of the platforms at each level increase successively, during the actual grouting, the slurry can be diffused on the platforms at each level. After the grouting is completed, a reinforced protection circle with a larger bottom size is formed, which disperses the pressure on the bottom of the tunnel to a certain extent, improves the stability of the grouting protection circle, and strengthens the support effect on the broken zone; Step E: Grouting: Grouting is performed into the horizontal directional borehole by grouting equipment to form a grouting reinforcement ring in the pre-treatment section of the tunnel. Conventional grouting is to drill a hole and then perform grouting. Since the number of holes drilled at one time is limited, when the next hole is completed and grouting is performed, the previously injected slurry may have begun to solidify, and the combination of the two is not effective. In this embodiment, multiple drilling rigs are used for synchronous construction, and multiple horizontal holes can be drilled at different positions around the tunnel at one time. After the drilling is completed, the multiple boreholes are synchronously grouted. As the slurry diffuses, the slurry in multiple horizontal holes is injected into the treatment area at the same time, the grouting effect is improved, and a grouting protection zone is formed around the tunnel. In addition, since the slurry is injected into the formation at the same time, the combination effect is better after the slurry diffuses and contacts.

[0021] In actual construction, the first platform 1, the second platform 2 and the third platform 3 can be formed by excavation. The third platform 3 is the tunnel bottom plate. On the basis of the existing face, the second platform 2 is excavated inwards. After the second platform 2 is lifted to a certain height, it is excavated inwards again to form the first platform 1. It is also possible to adopt a combination of excavation and construction. For example, on the basis of the existing face, the first platform 1 is formed by excavating inwards at a height of three meters from the tunnel top plate. On the basis of the existing face, the second platform 2 is built backwards, and then the third platform 3 is built to realize a three-level platform. The third platform 3 can be directly the tunnel bottom plate, so that the construction cost and excavation cost are balanced and the construction efficiency is high.

[0022] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel, characterized in that: The following steps are involved: Step A: Geological and structural assessment: Detect and analyze the geological conditions of the tunnel surrounding rock and assess its stability; Step B: Arranging construction platforms: Arranging a first platform (1), a second platform (2) and a third platform (3) in sequence from the working surface to the tunnel entrance in the tunnel, wherein the heights of the first platform (1), the second platform (2) and the third platform (3) are successively reduced; Step C: Drilling rig arrangement: horizontal directional drilling rigs are arranged on the first platform (1), the second platform (2) and the third platform (3) respectively; the horizontal directional drilling rig on the first platform (1) is responsible for constructing horizontal directional drilling holes at the top of the tunnel, the horizontal directional drilling rig on the second platform (2) is responsible for constructing horizontal directional drilling holes at both sides of the tunnel, and the horizontal directional drilling rig on the third platform (3) is responsible for constructing horizontal directional drilling holes at the bottom of the tunnel; Step D: Drilling: The horizontal directional drilling machines on the first platform (1), the second platform (2) and the third platform (3) perform directional drilling at the same time to form a circle of horizontal directional drill holes around the tunnel; Step E: Grouting: Grouting is carried out into the horizontal directional borehole through grouting equipment to form a grouting reinforcement ring in the pre-treatment section of the tunnel.

2. The method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel according to claim 1, characterized in that: In step B, the allowable load and the bearing capacity of the excavation area are calculated based on the existing structure of the tunnel to ensure that the construction platform will not damage the tunnel structure.

3. The method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel according to claim 1, characterized in that: In step B, the height, width and spacing of each construction platform are determined according to the size of the drilling equipment, the operating space requirements and the range of personnel activities.

4. The method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel according to claim 1, characterized in that: In step B, the heights of the first platform (1), the second platform (2) and the third platform (3) evenly divide the height of the tunnel.

5. A method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel according to claim 4, characterized in that: The lengths of the first platform (1), the second platform (2) and the third platform (3) are all 10 meters; the heights of the first platform (1), the second platform (2) and the third platform (3) are all 3 meters.

6. The method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel according to claim 1, characterized in that: The second platform (2) is provided with a ramp connected to the first platform (1), and the third platform (3) is provided with a ramp connected to the second platform (2).

7. The method for arranging a drilling site for advanced pre-grouting directional drilling of a working face in a tunnel according to claim 1, characterized in that: A first drilling surface (11) is formed between the first platform (1) and the top of the tunnel, a second drilling surface (21) and a third drilling surface (22) are respectively formed between the second platform (2) and the first platform (1) near the waist of both sides of the tunnel, and a fourth drilling surface (31) is formed between the second platform (2) and the third platform (3), the second drilling surface (21) and the third drilling surface (22) have the same axial depth in the tunnel, the axial depth of the first drilling surface (11) is greater than the axial depth of the second drilling surface (21), and the axial depth of the third drilling surface (22) is less than the axial depth of the second drilling surface (21).

Images