Construction method for back-wall pea gravel blow-filling of shield type TBM (tunnel boring machine) and supporting structure of shield type TBM

Abstract

The invention provides a construction method for back-wall pea gravel hydraulic reclamation of a shield type TBM and a supporting structure of the shield type TBM, and relates to the technical field of lining supporting structures of tunnel shield construction.The construction method for back-wall pea gravel hydraulic reclamation of the shield type TBM comprises the following steps that a duct piece is prefabricated, and steel rings are symmetrically welded to the two sides of the duct piece in the width direction of the duct piece; preparing a groove roller; the screen is installed in a groove of the groove roller, the vibration machine is installed on the outer side of the groove roller, the groove roller and the fixing support with the telescopic rod are installed on the outer side of the pipe piece, and the output end of the telescopic rod is connected with the outer side of the screen; a plurality of pipe pieces are assembled into an annular assembly; and blow-filling pea gravels. According to the method, the problem of uneven hydraulic reclamation of the pea gravels can be solved, the phenomenon that due to uneven hydraulic reclamation of the pea gravels, the pressure of the pea gravels with insufficient compactness transmitted to surrounding rocks on the duct pieces is too high is avoided, and tunnel water leakage diseases caused by cracks of the duct pieces are prevented.

Description

Technical Field

[0001] The invention relates to the technical field of lining support structures for tunnel shield construction, and in particular to a construction method for pea gravel blowing filling behind a shield-type TBM wall and a support structure thereof. Background Art

[0002] In the shield tunnel boring machine (TBM) construction method, after the segment lining is installed, there is a gap between the segment and the surrounding rock, which needs to be filled and grouted in time. Pea gravel is a special stone aggregate that is screened and cleaned for filling the gap between the segment and the surrounding rock. The main functions of pea gravel filling grouting are to fix the segment, transfer the surrounding rock pressure and prevent seepage. Filling grouting is an important part of ensuring construction safety and quality management during operation.

[0003] However, in actual construction applications, there is an uneven filling problem with pea gravel. The pea gravel with insufficient density transmits too high a surrounding rock pressure to the pipe segments, causing cracks in the pipe segments and triggering tunnel water leakage.

[0004] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0005] In view of this, the present invention provides a construction method for pea gravel filling behind the wall of a shield-type TBM and a support structure thereof to solve the above-mentioned problems.

[0006] In order to solve the above problems, the specific technical solutions adopted by the present invention are as follows:

[0007] According to one aspect of the present invention, a construction method for pea gravel filling behind a wall of a shield-type TBM is provided. The construction method for pea gravel filling behind a wall of a shield-type TBM comprises the following steps:

[0008] S1. Based on the actual filling construction conditions at the project site, prefabricated segments are welded with steel rings symmetrically on both sides of the segments along the width direction of the segments;

[0009] S2. Prepare a groove roller, wherein the diameter of the groove roller is equal to the diameter of the steel ring, and the groove length of the groove roller is equal to the width of the tube segment;

[0010] S3, installing the screen into the groove of the groove roller, installing the vibrator to the outside of the groove roller, installing the groove roller and the fixed bracket with the telescopic rod to the outside of the pipe segment, and connecting the output end of the telescopic rod to the outside of the screen;

[0011] S4, assembling several pipe segments into a ring-shaped package, and opening the screen by using the telescopic rod in the fixed bracket, and vibrating the pipe segments and the screen by turning on the vibrator;

[0012] S5. Based on the calculation model of the pressure drop of pea gravel filling screen cake, pea gravel is blown into the pipe segment. When the pea gravel is half filled, grouting is performed at the bottom of the pipe segment to use the upwelling slurry to slow down the speed of the pea gravel sliding down and evenly merge it with the pea gravel blocked by the screen.

[0013] Preferably, before the pipe segments are assembled, the screen is in contact with the outer surface of the pipe segments.

[0014] Preferably, the screen forms an angle of 90 degrees with the outer surface of the tube segment when expanded.

[0015] Preferably, the vibration amplitude of the screen is 88 degrees to 92 degrees with the outer surface of the tube segment.

[0016] Preferably, the pea gravel filling pressure is controlled at 0.25-0.35 MPa.

[0017] Preferably, the mesh sizes of the screen include 14 mm, 12 mm, 10 mm and 8 mm from top to bottom.

[0018] Preferably, the expression of the pea gravel blown fill screen cake pressure drop calculation model is:

[0019]

[0020] In the formula, Δp c Indicates voltage drop, μ g Indicates the viscosity of cement slurry; v g represents the cement slurry flow rate; t represents the thickness of the sieve cake layer; ε represents the porosity of the sieve cake layer; S represents the specific surface area of ​​the sieve; d p represents the average diameter of pea gravel; F(ε) represents the porosity function; σ represents the geometric standard error of pea gravel, and λ represents the shape factor of pea gravel.

[0021] Preferably, ordinary silicate 42.5 cement is used for the injection slurry, and the grouting pressure is controlled at 0.2-0.3 MPa.

[0022] According to another aspect of the present invention, a support structure for pea gravel filling behind a wall of a shield-type TBM is provided, the support structure for pea gravel filling behind a wall of the shield-type TBM comprising a plurality of segments arranged inside the surrounding rock, a groove roller is arranged outside the segment, a groove is opened outside the groove roller, and a screen is arranged inside the groove, a fixed bracket is arranged outside the segment and at one end of the groove roller, and a telescopic rod connected to the screen is arranged inside the fixed bracket;

[0023] Steel rings connected to grooved rollers are provided on both sides of the outer side of the segment;

[0024] A vibrator is arranged on the outer side of the groove roller.

[0025] Preferably, the screen material is ordinary steel bars with a diameter of 10 mm, the screen is a rectangular curved surface, and the length of the rectangular curved surface is equal to the width of the segment, and the width of the rectangular curved surface is equal to the thickness of the gap from the surrounding rock to the segment.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention can solve the problem of uneven filling of pea gravel, avoid the phenomenon that the surrounding rock pressure on the pipe segment is too high due to the uneven filling of pea gravel with insufficient density, and prevent the occurrence of tunnel water leakage caused by cracks in the pipe segment.

[0028] 2. The present invention has a simple structure, reasonable design, mature construction technology, and the lining structure of the present invention adopts a prefabricated mode, which can effectively speed up the construction progress.

[0029] 3. The structural dimensions of the present invention are relatively flexible, and the reinforcement of the pipe segments, the screen steel, the groove roller material, the vibrator power, the distribution of the steel ring and the fixed bracket of the built-in telescopic rod, etc. can all be determined according to the actual project conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0031] Figure 1 is a flow chart of a construction method for pea gravel filling behind a wall of a shield TBM according to an embodiment of the present invention;

[0032] Figure 2 2 is a schematic structural diagram of a supporting structure of pea gravel filling behind a shield TBM according to an embodiment of the present invention;

[0033] Figure 3 1 is a schematic diagram of the structure of a pipe segment in a supporting structure of pea gravel filling behind a shield TBM according to an embodiment of the present invention;

[0034] Figure 4 2 is a schematic structural diagram of a screen in a supporting structure of pea gravel filling behind a shield-type TBM according to an embodiment of the present invention;

[0035] Figure 5 It is a structural schematic diagram of a grooved roller and a vibrator in a supporting structure of pea gravel blowing filling behind a wall of a shield-type TBM according to an embodiment of the present invention;

[0036] Figure 6It is a schematic diagram of the fitting of the screen and the outer surface of the segment in the support structure of the pea gravel filling behind the wall of the shield type TBM according to an embodiment of the present invention;

[0037] Figure 7 It is a schematic diagram of a screen being propped up to 90 degrees by a fixed bracket in a supporting structure of pea gravel filling behind a wall of a shield-type TBM according to an embodiment of the present invention.

[0038] In the figure:

[0039] 1. Surrounding rock; 2. Segment; 3. Screen; 4. Grooved roller; 5. Vibrator; 6. Steel ring; 7. Fixed bracket. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0041] According to an embodiment of the present invention, a construction method for pea gravel filling behind a wall of a shield-type TBM and a supporting structure thereof are provided.

[0042] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to one embodiment of the present invention, a construction method for pea gravel filling behind the wall of a shield type TBM is provided, and the construction method for pea gravel filling behind the wall of the shield type TBM includes the following steps:

[0043] S1. Based on the actual filling construction conditions at the engineering site, prefabricate the pipe segment 2, and weld steel rings 6 symmetrically on both sides of the pipe segment 2 along the width direction of the pipe segment 2;

[0044] Specifically, the reinforcement and size of the pipe segment 2 are determined according to the actual situation at the engineering site. Along the width direction of the pipe segment 2, 8 groups of steel rings 6 are symmetrically welded on both sides, with 2 in each group.

[0045] S2, preparing a groove roller 4, wherein the diameter of the groove roller 4 is equal to the diameter of the steel ring 6, and the groove length of the groove roller 4 is equal to the width of the tube segment 2;

[0046] Specifically, eight groove rollers 4 are manufactured, the diameter of the groove roller 4 is equal to the diameter of the steel ring 6, the length of the groove is equal to the width of the pipe segment 2, and the screen 3 is welded at the groove.

[0047] S3, install the screen 3 into the groove of the groove roller 4, install the vibrator 5 to the outside of the groove roller 4, install the groove roller 4 and the fixed bracket 7 with the telescopic rod to the outside of the pipe segment 2, and the output end of the telescopic rod is connected to the outside of the screen 3;

[0048] S4, assembling several segments 2 into a ring-shaped package, and opening the screen 3 by the telescopic rod in the fixed bracket 7, and vibrating the segments 2 and the screen 3 by turning on the vibrator 5;

[0049] Specifically, before the segments 2 are assembled, the screen 3 is in contact with the outer surface of the segments 2 to facilitate transportation of the segments 2 .

[0050] After the pipe segment 2 is assembled, the telescopic rod provided inside the fixed bracket 7 is opened by controlling the switch, and the telescopic rod opens the screen 3 to 90 degrees with the outer surface of the pipe segment 2 .

[0051] The vibrator 5 is turned on by the remote control switch, the groove roller 4 swings at a fast frequency and a small amplitude, and the linked screen 3 vibrates, and the vibration amplitude of the screen 3 is 88 degrees to 92 degrees with the outer surface of the pipe segment 2.

[0052] S5. Based on the pea gravel filling screen cake pressure drop calculation model, pea gravel is blown into the pipe segment 2, and when the pea gravel is half filled, grouting is performed at the bottom of the pipe segment 2 to use the upwelling slurry to slow down the speed of the pea gravel sliding down and evenly merge it with the pea gravel blocked by the screen 3.

[0053] Specifically, when blowing pea gravel, the particle size of the pea gravel is generally 5-15 mm. Figure 1 As shown, the mesh sizes of the screen 3 are 14 mm, 12 mm, 10 mm and 8 mm from top to bottom.

[0054] Pea gravel with a particle size of less than 12 mm slides to the gap outside the lower half of the pipe segment 2. The present invention considers the influence of pea gravel pores, pea gravel diameter, pea gravel shape, and pea gravel distribution on the pressure drop of the screen cake based on the Carman-Kozeny equation, and proposes a calculation model for the pressure drop of the pea gravel blown fill screen cake, wherein:

[0055]

[0056] According to the above formula, the pressure drop calculation model of pea gravel blown fill screen cake can be obtained;

[0057] The expression of the calculation model for the pressure drop of pea gravel blown fill screen cake is:

[0058]

[0059] In the formula, Δp c Indicates voltage drop, μ g Indicates the viscosity of cement slurry, in kg / ms; vg represents the cement slurry flow rate, in m / s; t represents the thickness of the sieve cake layer, in m; ε represents the porosity of the sieve cake layer; S represents the specific surface area of ​​the sieve, in m 2 / m 3 ;d p represents the average diameter of pea gravel, in m; F(ε) represents the porosity function, which represents the drag force between adjacent pea gravel on cement paste; σ represents the geometric standard error of pea gravel, λ represents the shape factor of pea gravel, when the pea gravel is approximately spherical, λ=1, K c represents the Kjeldahl constant, and K represents the modified permeability coefficient.

[0060] In addition, when the pea gravel is half filled, grouting is started at the bottom of the pipe segment 2. Ordinary silicate 42.5 cement is used for grouting, and the grouting pressure is controlled at 0.2-0.3Mpa. The upwelling slurry can slow down the speed of the pea gravel sliding down and evenly merge with the pea gravel blocked by the screen 3.

[0061] like Figure 2-7 As shown, according to another embodiment of the embodiment of the present invention, a support structure for bean gravel blowing filling behind the wall of a shield-type TBM is provided, and the support structure for bean gravel blowing filling behind the wall of the shield-type TBM includes a plurality of segments 2 arranged on the inner side of the surrounding rock 1, and the gap thickness between the surrounding rock 1 and the segment 2 is 160 mm. A groove roller 4 is arranged on the outer side of the segment 2, a groove is opened on the outer side of the groove roller 4, and a screen 3 is arranged inside the groove, a fixed bracket 7 is arranged on the outer side of the segment 2 and at one end of the groove roller 4, and a telescopic rod connected to the screen 3 is arranged inside the fixed bracket 7; steel rings 6 connected to the groove roller 4 are arranged on both sides of the outer side of the segment 2; a vibrator 5 is arranged on the outer side of the groove roller 4.

[0062] Among them, the material of screen 3 is ordinary steel bar with a diameter of 10mm, the mesh sizes of screen 3 are 14mm, 12mm, 10mm and 8mm, screen 3 is a rectangular curved surface, and the length of the rectangular curved surface is equal to the width of the segment 2, the width of the rectangular curved surface is equal to the thickness of the gap from the surrounding rock 1 to the segment 2, and the curvature of screen 3 is the same as that of segment 2, ensuring that the outer surface of screen 3 and the outermost surface of segment 2 are on the same curved surface.

[0063] In addition, the screen 3 and the groove roller 4 are tightly connected to form a whole by welding, the steel ring 6 is welded to the outer surface of the pipe segment 2, the steel ring 2 fixes the two ends of the groove roller 4, and when the fixed bracket 7 is closed, the screen 3 fits the outer surface of the pipe segment 2, and the screen 3 is stretched open by the telescopic rod set on the inner side of the fixed bracket 7. When the fixed bracket 7 is opened, it is 90 degrees to the outer surface of the pipe segment 2.

[0064] It should be noted that the segment 2 is a reinforced concrete structure. The segment 2 is located on the inner side of the surrounding rock 1 and plays the role of supporting the surrounding rock. The reinforcement conditions, structural dimensions and hole size of the segment 2 are calculated based on the actual size of the tunnel on site and the deformation of the surrounding rock. The support force that the segment 2 needs to provide is then determined.

[0065] The groove roller 4 is made of ordinary steel with a diameter of 25 mm. The length of the groove is equal to the length of the curved surface of the screen 3, and the depth of the groove is 12.5 mm.

[0066] In actual application, in order to solve the problem of uneven filling of pea gravel, an intelligent telescopic screen is installed on the outside of the segment. The screen is made of ordinary steel and has the characteristics of easy installation, high bearing capacity and corrosion resistance. Based on the horizontal line, a screen is installed by rotating 30 degrees counterclockwise. Excluding the horizontal and vertical axis directions, a total of 8 screens are installed. The mesh sizes of the screen are 14mm, 12mm, 10mm and 8mm from top to bottom. The particle size of pea gravel is generally 5-15mm. When filling pea gravel, pea gravel with a particle size less than 12mm slides to the gap outside the lower half of the segment, and pea gravel with a particle size greater than 12mm will be blocked by the screen in the gap outside the upper half of the segment. In order to prevent excessive pea gravel from sliding down and accumulating at the bottom outside the lower half of the segment, when the pea gravel is half filled, grouting begins at the bottom of the segment. The upwelling slurry can slow down the speed of the pea gravel sliding down and evenly merge with the pea gravel blocked by the screen. This method has a significant effect on solving the problem of uneven pea gravel filling in existing lining support structures.

[0067] In addition, the engineering case of the present invention is based on the shield construction project of Shenzhen Airport to Pingshan section in the Guangdong-Hong Kong-Macao Greater Bay Area (Shenzhen-Dalian intercity railway project). The research section is Pingshan to Julong section, the geology is mainly slightly weathered granite, and the rock mass quality grade is II-IV. The TBM method is used for construction, which is divided into left and right lines, the left line shield section is 3409m, the right line shield section is 3530m, and the interval tunnel is buried at a depth of about 20.8-66.0m. The tunnel excavation diameter is 9.13m, the outer radius of the segment ring is 4.4m, the segment thickness is 0.4m, the segment width is 1.8m, the segment concrete strength grade is C50, the elastic modulus is 34.5GPa, and the Poisson's ratio is 0.2. The gap thickness of the surrounding rock-segment is 0.16m, the diameter of the pea gravel is 5-15mm, and the pea gravel filling pressure is controlled at 0.25-0.35MPa. Ordinary silicate 42.5 cement is used for grouting, and the grouting pressure is controlled at 0.2-0.3MPa. The material of the screen is ordinary steel bar with a diameter of 10mm. The screen is a rectangular curved surface with a length of 1.8m and a width of 0.16m. Based on the horizontal line, a screen is installed by rotating 30 degrees counterclockwise. Excluding the horizontal and vertical axis directions, a total of 8 screens are installed. The mesh sizes of the screen are 14mm, 12mm, 10mm and 8mm from top to bottom. The length of the groove roller is 1.8m and the diameter of the groove roller is 25mm.

[0068] In summary, with the help of the above technical solutions of the present invention, the present invention can solve the problem of uneven filling of bean gravel, avoid the phenomenon of excessive surrounding rock pressure on the pipe segment caused by uneven filling of bean gravel with insufficient density, and prevent the occurrence of tunnel water leakage caused by cracks in the pipe segment. The present invention has a simple structure, reasonable design, mature construction technology, and the lining structure of the present invention adopts a prefabricated mode, which can effectively speed up the construction progress. The structural dimensions of the present invention are relatively flexible, and the reinforcement of the pipe segment 2, the steel material of the screen 3, the material of the groove roller 4, the power of the vibrator 5, the distribution of the steel ring 6 and the fixed bracket 7 of the built-in telescopic rod can all be determined according to the actual project situation.

[0069] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, optical storage, etc.) containing computer-usable program code.

[0070] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The construction method of pea gravel filling behind the wall of shield TBM is characterized by: The construction method of the shield TBM behind-the-wall pea gravel filling includes the following steps: S1. Based on the actual filling construction conditions at the engineering site, prefabricate the pipe segment (2), and symmetrically weld steel rings (6) on both sides of the pipe segment (2) along the width direction of the pipe segment (2); S2, preparing a grooved roller (4), wherein the diameter of the grooved roller (4) is equal to the diameter of the steel ring (6), and the groove length of the grooved roller (4) is equal to the width of the tube segment (2); S3, installing the screen (3) into the groove of the groove roller (4), installing the vibrator (5) to the outside of the groove roller (4), installing the groove roller (4) and the fixed bracket (7) with the telescopic rod to the outside of the pipe segment (2), and connecting the output end of the telescopic rod to the outside of the screen (3); S4, assembling a plurality of pipe segments (2) into a ring-shaped package, and opening the screen (3) by means of a telescopic rod in a fixed bracket (7), and vibrating the pipe segments (2) and the screen (3) by means of a vibrating machine (5); S5. Based on the calculation model of the pressure drop of the pea gravel filling screen cake, pea gravel is blown into the pipe segment (2). When the pea gravel is half filled, grouting is performed at the bottom of the pipe segment (2). The upwelling slurry is used to slow down the speed of the pea gravel sliding down and evenly merge with the pea gravel blocked by the screen (3).

2. The construction method of pea gravel filling behind the wall of shield type TBM according to claim 1, characterized in that: Before the tube segments (2) are assembled, the screen (3) is in contact with the outer surface of the tube segments (2).

3. The construction method of pea gravel filling behind the wall of shield type TBM according to claim 1, characterized in that: When the screen (3) is expanded, the angle between it and the outer surface of the tube sheet (2) is 90 degrees.

4. The construction method of pea gravel filling behind the wall of shield type TBM according to claim 1, characterized in that: The vibration amplitude of the screen (3) is 88-92 degrees with the outer surface of the tube segment (2).

5. The construction method of pea gravel filling behind the wall of shield type TBM according to claim 1, characterized in that: The pea gravel filling pressure is controlled at 0.25-0.35 MPa.

6. The construction method of pea gravel filling behind the wall of shield type TBM according to claim 1, characterized in that: The mesh sizes of the sieve (3) include, from top to bottom, 14 mm, 12 mm, 10 mm and 8 mm respectively.

7. The construction method of pea gravel filling behind the wall of shield type TBM according to claim 1, characterized in that: The expression of the pea gravel blown fill screen cake pressure drop calculation model is: In the formula, Δp c Indicates voltage drop, μ g Indicates the viscosity of cement slurry; v g represents the cement slurry flow rate; t represents the thickness of the sieve cake layer; ε represents the porosity of the sieve cake layer; S represents the specific surface area of ​​the sieve; d p represents the average diameter of pea gravel; F(ε) represents the porosity function; σ represents the geometric standard error of pea gravel, and λ represents the shape factor of pea gravel.

8. The construction method of pea gravel filling behind the wall of shield type TBM and its supporting structure according to claim 1, characterized in that: The injection slurry uses ordinary silicate 42.5 cement, and the grouting pressure is controlled at 0.2-0.3MPa.

9. A supporting structure for pea gravel filling behind the wall of a shield-type TBM, used to implement the construction method for pea gravel filling behind the wall of a shield-type TBM according to any one of claims 1 to 8, characterized in that: The shield-type TBM wall-rear pea gravel blowing support structure comprises a plurality of segments (2) arranged on the inner side of surrounding rocks (1), a groove roller (4) is arranged on the outer side of the segment (2), a groove is formed on the outer side of the groove roller (4), and a screen (3) is arranged inside the groove, a fixed bracket (7) is arranged on the outer side of the segment (2) and at one end of the groove roller (4), and a telescopic rod connected to the screen (3) is arranged inside the fixed bracket (7); Steel rings (6) connected to the grooved rollers (4) are provided on both sides of the outer side of the tube segment (2); A vibrator (5) is arranged on the outer side of the grooved roller (4).

10. The construction method of pea gravel filling behind the wall of shield type TBM and its supporting structure according to claim 9, characterized in that: The material of the screen (3) is ordinary steel bars with a diameter of 10 mm. The screen (3) is a rectangular curved surface, and the length of the rectangular curved surface is equal to the width of the pipe segment (2), and the width of the rectangular curved surface is equal to the thickness of the gap from the surrounding rock (1) to the pipe segment (2).

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