Soft rock tunnel grouting combined control excavation system and construction method

Abstract

The invention relates to a soft rock tunnel grouting combined control excavation system and a construction method. The soft rock tunnel grouting combined control excavation system comprises a concrete grouting stopping wall, a tunnel, a grouting stopping rock tray, a primary supporting type steel frame, a small guide pipe shaping support, a guiding construction platform, a temporary inverted arch, a grouting platform and a section steel transverse temporary supporting frame. The construction method has the beneficial effects that after the first round of advanced grouting, excavation is reserved, the assembly type grout stop wall is installed, the grouting pipe is arranged, and advanced grouting is conducted; the influence of gushing water on a tunnel structure, an underground water environment and surface vegetation is effectively controlled; the lower flange of the primary support profile steel is clamped between the inclined I-shaped steel and the cushion block, and the primary support steel frame fixing bolts are installed in a hole forming mode to complete installation of the small guide pipe connecting device, so that the construction precision of small guide pipe installation is greatly improved, and the small guide pipe connecting device can be recycled.

Description

Technical Field

[0001] The invention belongs to the field of tunnel construction with relatively broken rock masses, and in particular relates to a soft rock tunnel grouting combination controlled excavation system and a construction method. Background Art

[0002] In the case of shallow excavation, severe weathering and rock mass fracture zones, it is necessary to adopt advance support methods. The advance grouting small pipe technology has a unique construction technology and has been widely used in the advance support scheme for tunnel engineering fracture zone construction. However, there are still a series of shortcomings in the advance support of water-rich soft rock. At the same time, it is also an urgent task to vigorously promote the application of tunnel mechanization equipment, improve the mechanization level of railway tunnel construction, narrow the gap with foreign tunnel construction technology, and realize the safe, fast and standardized construction of high-speed railway complex geological large-section tunnels.

[0003] Based on the actual requirements of complex construction conditions, high construction quality and tight construction period of engineering projects, an innovative soft rock tunnel grouting combination controlled excavation system and construction method with high construction efficiency, excellent construction quality and low safety risk is developed. This is of great significance for improving the construction quality of advance support for excavation of water-rich soft rock tunnels, ensuring the safety of construction of water-rich soft rock tunnels, and ensuring safe operation after opening to traffic. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a soft rock tunnel grouting combined controlled excavation system and a construction method.

[0005] This soft rock tunnel grouting combined controlled excavation system includes a concrete grouting wall, a tunnel, a grouting rock plate, an initial support steel frame, a small guide tube shaped support, a guide construction platform, a temporary invert, a grouting platform and a steel horizontal temporary support frame;

[0006] The soft rock of the tunnel is provided with a concrete stop wall, a grouting pipe is provided on the concrete stop wall, a drainage pipe is provided at the bottom of the concrete stop wall, and a water collecting bucket is provided at the end of the drainage pipe; an assembled stop wall is provided behind the concrete stop wall, and a water-stopping rubber is provided in the gap between the top of the assembled stop wall and the advanced grouting area;

[0007] The initial support steel frame is provided with a small duct finalization bracket, which is used to install the small duct; the guide construction platform is provided with pipe curtain construction machinery and pipe curtain transfer equipment for setting up the pipe curtain, and the lower part of the guide construction platform is provided with a lifting system and a platform support system in sequence; the grouting platform is arranged in a temporary invert, and grouting holes are arranged in a closed loop formed by the temporary invert and the initial support of the tunnel; the steel transverse temporary support frame is supported in the tunnel.

[0008] Preferably, after the later excavation, an assembled slurry-stop wall is set up for the next stage of grouting, and groundwater sediment is stored at the bottom of the water collecting barrel. An open bottom plate is provided at the bottom of the water collecting barrel, and an anti-filter is provided at the end of the drainage pipe. A water collecting barrel cover is provided on the top of the water collecting barrel, and a centralized drainage pipe is provided on one side of the water collecting barrel for centralized storage of groundwater. A water-stop rubber is provided in the gap between the top of the assembled slurry-stop wall and the advance grouting area, and the water-stop rubber is fixed by an upper fixed anchor rod. An assembled slurry-stop wall base is provided at the bottom of the assembled slurry-stop wall, and the assembled slurry-stop wall base is fixed to the advance grouting area with a locking anchor rod.

[0009] Preferably, the segments of the drainage pipe are connected by a sleeve flange, a sleeve is slidably provided on the drainage pipe, the sleeve is sleeved on the outside of the sleeve flange, a geotextile is provided at the end of the drainage pipe, and the end of the drainage pipe segment at the end is a bell mouth.

[0010] Preferably, the assembled grout-stopping wall is formed by nine units spliced ​​together by bolts, and a back rib and grouting holes are arranged on the top of each unit.

[0011] Preferably, an I-beam base is provided at the bottom of the small duct finalized bracket, a top limit plate is provided at the end of the upper flange of the I-beam base, a pad is provided on the upper flange of the I-beam base, the initial support steel is provided on the pad, the pad, the lower flange of the initial support steel and the upper flange of the I-beam base are fixed by the initial support steel frame fixing bolts, an inclined I-beam is provided on the pad, a small duct arc drag is provided on the web of the inclined I-beam, an inclined brace is provided at the bottom of the small duct arc drag, the bottom end of the inclined brace is supported on the top limit plate, and a fixing ring with an open lock is provided on the top surface of the inclined I-beam.

[0012] Preferably, the guide construction platform is provided with pipe curtain construction machinery and pipe curtain transfer equipment, platform hydraulic supports are provided on both sides of the guide construction platform, a lifting system is provided at the bottom of the guide construction platform, the lifting system includes a lifting device and telescopic columns, and a platform support system is provided at the bottom of the lifting system, and the platform support system includes reinforced trusses, column horizontal supports, short support columns and columns under the platform.

[0013] Preferably, a platform column is provided at the bottom of the grouting platform, a pre-buried base is provided at the bottom of the temporary invert, the platform column is placed in the pre-buried base in the temporary invert, a guardrail is provided on the grouting platform, and grouting holes are arranged in a closed loop formed by the temporary invert and the initial support of the tunnel.

[0014] Preferably, the steel transverse temporary support frame includes horizontal bars, vertical bars and diagonal bars, the ends of the horizontal bars and vertical bars are provided with support bars with retractable adjustment blocks, the ends of the support bars are provided with arc-shaped drags, and the bottom of the vertical bars at the corners of the tunnel are provided with conical bases.

[0015] The construction method of the soft rock tunnel grouting combined controlled excavation system comprises the following steps:

[0016] Step 1: Construct concrete stop wall and set up grouting pipes and drainage pipes, carry out the first round of advance grouting, install the assembled stop wall after excavation and reservation, set up grouting pipes and carry out advance grouting;

[0017] Step 2: Install the temporary horizontal support frame of steel, which supports the tunnel outline, and then install the primary support steel frame;

[0018] Step 3: Install a small conduit shaping bracket on the primary support steel frame according to the number of small conduits to be driven, and drive the small conduits into the rock mass along the small conduit shaping bracket;

[0019] Step 4: Install the guide construction platform and install the pipe curtain according to the construction sequence;

[0020] Step 5: Construct a temporary invert, then install the grouting platform, and finally drill grouting holes and complete grouting according to the construction sequence.

[0021] Preferably, an I-beam base is provided at the bottom of the small conduit shaping bracket, a top limit plate is provided at the end of the upper flange of the I-beam base, a pad is provided on the upper flange of the I-beam base, the initial support steel is provided on the pad, the pad, the lower flange of the initial support steel and the upper flange of the I-beam base are fixed by the initial support steel frame fixing bolts, an inclined I-beam is provided on the pad, a small conduit arc drag is provided on the web of the inclined I-beam, an inclined brace is provided at the bottom of the small conduit arc drag, the bottom of the inclined brace is supported on the top limit plate, and a fixing ring with an open lock is provided on the top surface of the inclined I-beam. In step three, the lower flange of the initial support steel is clamped between the inclined I-beam and the pad, and the initial support steel frame fixing bolts are installed through holes, then the small conduit is placed on the small conduit arc drag, and the arc plate on the upper part of the fixing ring is rotated to fix the small conduit, and the open lock is locked, then the small conduit is driven into the rock mass along the small conduit shaping bracket, and the small conduit shaping bracket is recovered after grouting is completed.

[0022] The beneficial effects of the present invention are:

[0023] 1) The present invention adopts the technology of blocking and draining combined with full-section grouting. After the first round of advance grouting, excavation is reserved and assembled grouting walls are installed, grouting pipes are set up and advance grouting is carried out; the impact of gushing water on the tunnel structure, groundwater environment and surface vegetation is effectively controlled.

[0024] 2) The primary support steel and the small duct connection device are used. The lower flange of the primary support steel is clamped between the inclined I-beam and the pad, and the primary support steel frame fixing bolts are installed through holes to complete the installation of the small duct connection device, which greatly improves the construction accuracy of the small duct installation and can be recycled.

[0025] 3) A guide construction platform is installed with pipe curtain construction machinery and pipe curtain transfer equipment to form a precise guide construction platform for the locking curtain hole, which improves the construction quality and efficiency of the locking pipe curtain installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of plugging and drainage combined with full-section grouting;

[0027] Figure 2 It is a schematic diagram of the drainage pipe structure;

[0028] Figure 3 It is a schematic diagram of the assembled mortar stop wall;

[0029] Figure 4 This is a schematic diagram of a unit of a prefabricated mortar stop wall;

[0030] Figure 5 It is a schematic diagram of the connection between the primary support steel frame and the small conduit;

[0031] Figure 6 It is a schematic diagram of the connection device between the primary support steel and the small conduit;

[0032] Figure 7 This is a schematic diagram of the precise guidance construction platform for the lock-mouth curtain-hanging hole;

[0033] Figure 8 It is a schematic diagram of the temporary invert and grouting platform;

[0034] Fig. 9 This is a schematic diagram of the temporary horizontal support frame of steel sections.

[0035] Explanation of reference numerals: 1. Concrete grouting wall 2. Tunnel 3. Water collecting bucket cover 4. Anti-filter 5. Water collecting bucket 6. Open bottom plate 7. Centralized drainage pipe 8. Sediment 9. Drainage pipe 10. Grouting pipe 11. Locking foot anchor 12. Assembled grouting wall base 13. Assembled grouting wall 14. Grouting rock plate 15. Water-stopping rubber 16. Upper fixed anchor 17. Advance grouting area 18. Sliding sleeve 19. Sleeve flange 20. Geotextile 21. Bell mouth 22. Back rib 23. Initial support steel frame 24. Small conduit stereotyped bracket 25. Small conduit 26. Top limit plate 27. Diagonal brace 28. Small conduit arc drag 29. Open Opening lock 30. Fixing ring 31. Oblique I-beam 32. Fixing bolts of primary support steel frame 33. Pad 34. I-beam base 35. Short support column 36. Platform lower column 37. Lifting device 38. Telescopic column 39. Guide construction platform 40. Pipe curtain construction machinery 41. Pipe curtain transfer equipment 42. Pipe curtain 43. Platform hydraulic support 44. Strengthening truss 45. Column horizontal support 46. Temporary invert 47. Grouting hole 48. Guardrail 49. Grouting platform 50. Platform column 51. Embedded base 52. Conical base 53. Flange 54. Temporary horizontal support frame of steel section 55. Telescopic adjustment block 56. Arc drag. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0037] Embodiment 1

[0038] As an example, Figure 1 As shown, the combined grouting controlled excavation system for soft rock tunnels mainly involves the full-section grouting technology combined with blocking and drainage, the connection device between the primary support steel and the small conduit, the precise guiding construction platform for the lock-mouth hanging curtain hole, the temporary arch closed ring grouting platform, the steel transverse temporary support frame, etc. It mainly includes a concrete grouting wall 1, a tunnel 2, a grouting rock plate 14, a primary support steel frame 23, a small conduit finalized bracket 24, a guiding construction platform 39, a grouting platform 49, etc., and a steel transverse temporary support frame.

[0039] The soft rock of the tunnel 2 is provided with a concrete stop wall 1, a grouting pipe 10 is provided on the concrete stop wall 1, a drainage pipe 9 is provided at the bottom of the concrete stop wall 1, and a water collecting bucket 5 is provided at the end of the drainage pipe 9; an assembled stop wall 13 is provided behind the concrete stop wall 1, and a water-stopping rubber 15 is provided in the gap between the top of the assembled stop wall 13 and the advanced grouting area 17;

[0040] The primary support steel frame 23 is provided with a small conduit shaping bracket 24, which is used to install a small conduit 25; the guide construction platform 39 is provided with a pipe curtain construction machinery 40 and a pipe curtain transfer equipment for setting up a pipe curtain 42, and the lower part of the guide construction platform 39 is sequentially provided with a lifting system and a platform support system; the grouting platform 49 is arranged in a temporary invert 46, and a grouting hole 47 is arranged in a closed loop formed by the temporary invert 46 and the initial support of the tunnel; the steel transverse temporary support frame is supported in the tunnel 2.

[0041] like Figure 3 As shown, a concrete stop wall 1 is set at the soft rock of the tunnel 2, and an assembled stop wall 13 is set after the later excavation for grouting in the next stage. A grouting pipe 10 is set on the concrete stop wall 1, and a drainage pipe 9 is set at the bottom opening. A water collecting bucket 5 is set at the end of the drainage pipe. The bottom of the water collecting bucket 5 is used to store groundwater sediment 8, and an open bottom plate 6 is provided. An anti-filter screen 4 is set at the end of the drainage pipe, and a water collecting bucket cover 3 is set on the top of the water collecting bucket. A centralized drainage pipe 7 is set on one side to store groundwater in a centralized manner. A water-stop rubber 15 is set in the gap between the top of the assembled stop wall 13 and the advance grouting area 17, and is fixed with an upper fixed anchor rod 16. An assembled stop wall base 12 is set at the bottom and is fixed to the advance grouting area 17 with a locking anchor rod 11.

[0042] like Figure 2 As shown, the segments of the drainage pipe 9 are connected by a sleeve flange 19. After the connection, the sliding sleeve 18 is slid to the middle position of the splicing to protect the sleeve flange 19. A geotextile is set at the end of the drainage pipe 9, and the end is a bell mouth 22.

[0043] Embodiment 2

[0044] As another embodiment, this embodiment 2 proposes a more specific soft rock tunnel grouting combination controlled excavation system based on the embodiment 1.

[0045] The assembled grout-stopping wall 13 is formed by 9 blocks connected by bolts, and a back rib 22 and a grouting hole are arranged on the upper part of each block.

[0046] like Figure 5 and Figure 6 As shown, a small conduit shaping bracket 24 is arranged on the primary support steel frame 29, and the small conduit shaping bracket is used to install a small conduit 25. An I-beam base 34 is arranged at the bottom of the small conduit shaping bracket 24, a top limit plate 26 is arranged at the end of the upper flange of the I-beam base 34, a pad 33 is arranged on the upper flange, and the fixing bolts of the primary support steel frame pass through the pad, the lower flange of the primary support steel, and the upper flange of the I-beam base 34 in sequence, and fix the three, an inclined I-beam 31 is arranged on the pad, a small conduit arc drag 28 is arranged on the web of the inclined I-beam, an inclined brace 27 is arranged at the bottom of the arc drag, and the bottom end of the inclined brace 27 is supported on the top limit plate 26, and a fixing ring 30 with an open lock 29 is arranged on the top surface of the inclined I-beam.

[0047] like Figure 7 As shown, the guide construction platform 39 is provided with pipe curtain construction machinery 40 and pipe curtain transfer equipment, platform hydraulic supports 43 are provided on both sides of the platform, and a lifting system is provided at the bottom, which is composed of a lifting device 37 and a telescopic column 38. A platform support system is provided at the bottom of the lifting system, including a reinforced truss 44, a column horizontal support 45, a short support column 35, a platform lower column 36, etc.

[0048] like Figure 8 As shown, the platform column 50 of the grouting platform 49 is placed in the embedded base 51 in the temporary invert 46, a guardrail 48 is set on the grouting platform, and the grouting holes 47 are arranged in the closed loop formed by the temporary invert and the initial support of the tunnel.

[0049] like Fig. 9 As shown, the temporary transverse support frame of the steel section mainly includes a horizontal bar, a vertical bar and an inclined bar. The ends of the horizontal bar and the vertical bar are provided with a support bar with a telescopic adjustment block 55, and an arc-shaped drag 56 is provided at the end of the support bar. A conical base 52 is provided at the vertical bar at the corner position of the tunnel 2.

[0050] It should be noted that the parts in this embodiment that are the same or similar to those in the first embodiment can be referenced to each other and will not be described in detail in this application.

[0051] Embodiment 3

[0052] As another embodiment, this embodiment 3 proposes, based on the embodiments 1 and 2, a construction method of the soft rock tunnel grouting combined controlled excavation system, comprising the following steps:

[0053] The construction of blocking and drainage combined with full-section grouting: First, construct the concrete grouting wall 1, and pre-embed the through holes of the grouting pipe and the through holes of the drainage pipe in the grouting wall, then drill the grouting pipe 10, and perform pre-grouting, then splice the drainage pipe 9 through the sleeve flange segment, adjust the sliding sleeve 10, then install the drainage pipe in place, install the water collecting bucket 5 and the centralized drainage pipe 7 at the end of the drainage pipe, and regularly open the water collecting bucket cover 3 to check the amount of sediment 8. If there is too much, open the open bottom plate 6 to discharge it. After the first round of grouting excavation reservation, the second round is to install the assembled grouting wall 13 before grouting. The assembled grouting wall base 12 is fixed with locking anchor rods, and then spliced ​​in sequence. After the overall assembly is completed, the water-stopping rubber is inserted into the gap with the rock mass, and finally the fixed anchor rod is installed. Finally, the grouting pipe is drilled in the reserved hole of the assembled grouting wall and pre-grouting is performed.

[0054] Construction of temporary transverse support frame of steel: If the surrounding rock is more broken, first install the temporary transverse support frame of steel, and then construct the small guide tube 25. First install the conical base 52, then install the steel rods in sequence, and fix them to each other, and install the retractable adjustment block with arc drag 56 at the end, and adjust the arc drag 56 to press against the tunnel contour line, and then install the primary support steel.

[0055] Construction of small conduits: After the installation of the primary support steel is completed, a small conduit shaping bracket 24 is installed on the primary support steel according to the number of small conduits 25. The small conduit shaping bracket 24 is made in advance. During installation, only the lower flange of the primary support steel needs to be inserted into the bracket, and holes need to be made to install the primary support steel frame fixing bolts 32. Then, the small conduit 25 is placed on the small conduit arc drag 28, and the arc plate on the upper part of the fixing ring is rotated to fix the small conduit 25, and the open lock is locked. Then, the small conduit 25 is driven into the rock mass along the small conduit shaping bracket 24. After grouting is completed, the bracket is removed for reuse.

[0056] Locking curtain construction: install the platform lower column 36, short column support 35, column horizontal support 45 reinforcement truss 44, lifting device 37, telescopic column in sequence, then install the guide construction platform 39, and install the platform hydraulic support 43 at both ends, then install the pipe curtain transfer equipment 41 and pipe curtain construction machinery on the construction platform, and install the pipe curtain according to the construction sequence.

[0057] Temporary invert closed ring grouting construction: during the construction of the temporary invert, a pre-buried base 51 is set, followed by the installation of platform columns 50, grouting platform 49 and guardrails, and finally, grouting holes 47 are drilled according to the construction sequence and grouting is completed.

[0058] It should be noted that the parts in this embodiment that are the same or similar to those in Embodiments 1 and 2 can be referenced to each other and will not be described in detail in this application.

[0059] Embodiment 4

[0060] As another embodiment, this embodiment 4 proposes, on the basis of embodiments 1 to 3, a construction method of a soft rock tunnel grouting combined controlled excavation system, and specific steps of small pipe construction are as follows:

[0061] An I-beam base 34 is provided at the bottom of the small duct finalization bracket 24, a top limit plate 26 is provided at the upper flange end of the I-beam base 34, a cushion block 33 is provided on the upper flange of the I-beam base 34, the primary support steel is provided on the cushion block 33, the cushion block 33, the lower flange of the primary support steel and the upper flange of the I-beam base 34 are fixed by the primary support steel frame fixing bolts 32, an inclined I-beam 31 is provided on the cushion plate, a small duct arc drag 28 is provided on the web of the inclined I-beam 31, an inclined brace 27 is provided at the bottom of the small duct arc drag 28, and the bottom end of the inclined brace 27 is supported on the top On the limiting plate 26, a fixing ring 30 with an open lock 29 is provided on the top surface of the inclined I-beam 31. In step three, the lower flange of the primary support steel is clamped between the inclined I-beam 31 and the pad 33, and the primary support steel frame fixing bolts 32 are installed through holes. Then, the small conduit 25 is placed on the small conduit arc drag 28, and the arc plate on the upper part of the fixing ring 30 is rotated to fix the small conduit, and the open lock 29 is locked. Then, the small conduit 25 is driven into the rock mass along the small conduit shaping bracket 24, and the small conduit shaping bracket 24 is recovered after grouting is completed.

[0062] It should be noted that the parts in this embodiment that are the same or similar to those in Embodiment 3 can be referenced to each other and will not be described in detail in this application.

[0063] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A soft rock tunnel grouting combined controlled excavation system, characterized in that: It includes concrete grouting wall, tunnel, grouting rock plate, initial support steel frame, small duct finalized support, guide construction platform, temporary invert, grouting platform and steel horizontal temporary support frame; The soft rock of the tunnel is provided with a concrete stop wall, a grouting pipe is provided on the concrete stop wall, a drainage pipe is provided at the bottom of the concrete stop wall, and a water collecting bucket is provided at the end of the drainage pipe; an assembled stop wall is provided behind the concrete stop wall, and a water-stopping rubber is provided in the gap between the top of the assembled stop wall and the advanced grouting area; The initial support steel frame is provided with a small duct finalization bracket, which is used to install the small duct; the guide construction platform is provided with pipe curtain construction machinery and pipe curtain transfer equipment for setting up the pipe curtain, and the lower part of the guide construction platform is provided with a lifting system and a platform support system in sequence; the grouting platform is arranged in a temporary invert, and grouting holes are arranged in a closed loop formed by the temporary invert and the initial support of the tunnel; the steel transverse temporary support frame is supported in the tunnel.

2. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: After the later excavation, an assembled slurry-stop wall is set up for the next stage of grouting. Groundwater sediment is stored at the bottom of the water collecting barrel. An open bottom plate is provided at the bottom of the water collecting barrel, an anti-filter is provided at the end of the drainage pipe, a water collecting barrel cover is provided on the top of the water collecting barrel, and a centralized drainage pipe is provided on one side of the water collecting barrel for centralized storage of groundwater. A water-stop rubber is provided in the gap between the top of the assembled slurry-stop wall and the advance grouting area. The water-stop rubber is fixed by an upper fixed anchor rod. An assembled slurry-stop wall base is provided at the bottom of the assembled slurry-stop wall. The assembled slurry-stop wall base is fixed to the advance grouting area with a locking anchor rod.

3. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: The segments of the drainage pipe are connected by sleeve flanges. A sleeve is slidably provided on the drainage pipe, and the sleeve is sleeved on the outside of the sleeve flange. A geotextile is provided at the end of the drainage pipe, and the end of the drainage pipe segment at the end is a bell mouth.

4. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: The assembled grout-stopping wall is formed by splicing nine units by bolts, and a back rib and a grouting hole are arranged on the upper part of each unit.

5. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: An I-beam base is arranged at the bottom of the small duct standardized bracket, a top limit plate is arranged at the end of the upper flange of the I-beam base, a pad is arranged on the upper flange of the I-beam base, the initial support steel is arranged on the pad, the pad, the lower flange of the initial support steel and the upper flange of the I-beam base are fixed by the initial support steel frame fixing bolts, an inclined I-beam is arranged on the pad, a small duct arc drag is arranged on the web of the inclined I-beam, an inclined brace is arranged at the bottom of the small duct arc drag, the bottom end of the inclined brace is supported on the top limit plate, and a fixing ring with an open lock is arranged on the top surface of the inclined I-beam.

6. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: The guide construction platform is provided with pipe curtain construction machinery and pipe curtain transfer equipment, platform hydraulic supports are provided on both sides of the guide construction platform, a lifting system is provided at the bottom of the guide construction platform, the lifting system includes a lifting device and telescopic columns, a platform support system is provided at the bottom of the lifting system, and the platform support system includes reinforced trusses, column horizontal supports, short support columns and columns under the platform.

7. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: A platform column is provided at the bottom of the grouting platform, a pre-buried base is provided at the bottom of the temporary invert, the platform column is placed in the pre-buried base in the temporary invert, a guardrail is provided on the grouting platform, and grouting holes are arranged in the closed loop formed by the temporary invert and the initial support of the tunnel.

8. The soft rock tunnel grouting combined controlled excavation system according to claim 1 is characterized in that: The steel transverse temporary support frame includes a horizontal bar, a vertical bar and an oblique bar. The ends of the horizontal bar and the vertical bar are provided with a support bar with a telescopic adjustment block. The ends of the support bar are provided with an arc drag. The bottom of the vertical bar at the corner position of the tunnel is provided with a conical base.

9. The construction method of the soft rock tunnel grouting combined controlled excavation system according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Construct concrete stop wall and set up grouting pipes and drainage pipes, carry out the first round of advance grouting, install the assembled stop wall after excavation and reservation, set up grouting pipes and carry out advance grouting; Step 2: Install the temporary horizontal support frame of steel, which supports the tunnel outline, and then install the primary support steel frame; Step 3: Install a small conduit shaping bracket on the primary support steel frame according to the number of small conduits to be driven, and drive the small conduits into the rock mass along the small conduit shaping bracket; Step 4: Install the guide construction platform and install the pipe curtain according to the construction sequence; Step 5: Construct a temporary invert, then install the grouting platform, and finally drill grouting holes and complete grouting according to the construction sequence.

10. The construction method of the soft rock tunnel grouting combined controlled excavation system according to claim 9, characterized in that: An I-beam base is arranged at the bottom of the small conduit finalizing bracket, a top limit plate is arranged at the end of the upper flange of the I-beam base, a pad is arranged on the upper flange of the I-beam base, the initial support steel is arranged on the pad, the pad, the lower flange of the initial support steel and the upper flange of the I-beam base are fixed by the initial support steel frame fixing bolts, an inclined I-beam is arranged on the pad, a small conduit arc drag is arranged on the web of the inclined I-beam, an inclined brace is arranged at the bottom of the small conduit arc drag, the bottom end of the inclined brace is supported on the top limit plate, and a fixing ring with an open lock is arranged on the top surface of the inclined I-beam. In step three, the lower flange of the initial support steel is clamped between the inclined I-beam and the pad, and the initial support steel frame fixing bolts are installed through holes, then the small conduit is placed on the small conduit arc drag, and the arc plate on the upper part of the fixing ring is rotated to fix the small conduit, and the open lock is locked, then the small conduit is driven into the rock mass along the small conduit finalizing bracket, and the small conduit finalizing bracket is recovered after grouting is completed.

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