Water-rich large-section soil tunnel excavation construction method

Abstract

The application discloses a water-rich large-section soil tunnel excavation construction method, which comprises the following steps: 1, constructing rotary jet grouting piles for reinforcement in the water-rich soil area to be constructed; 2, excavating and initially supporting a left upper pilot tunnel; 3, excavating and initially supporting a left middle pilot tunnel; 4, excavating and initially supporting an inverted arch of a left lower pilot tunnel; 5, excavating and initially supporting a right upper pilot tunnel; 6, excavating and initially supporting a right middle pilot tunnel; and 7, excavating and initially supporting an inverted arch of a right lower pilot tunnel. The method is simple in steps and reasonable in design, three rows of rotary jet grouting piles are constructed in the water-rich soil area to be constructed before excavation, left, middle and right locking foot anchor rods are anchored to the three rows of rotary jet grouting piles respectively, and system anchor rods in initial support are also anchored to the rotary jet grouting piles, so that the initial support of the tunnel is reinforced, the excavation construction of the tunnel body is ensured to be safe and reliable, the tunnel can safely pass through the water-rich soil layer, and the stability of the tunnel structure is ensured.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, and in particular relates to a method for excavating and constructing water-rich, large-section soil tunnels. Background Technology

[0002] With the continuous expansion of my country's highway network, tunnel construction through water-rich soil is inevitable. To improve traffic flow efficiency and reduce construction costs, the number of lanes in highway tunnels is gradually increasing, leading to larger cross-sectional spans. Although safe and mature methods such as the CD method and CRD method exist for segmented excavation and support of soft soil tunnels, reducing the rise-span ratio and large-scale excavation disturbance during soft rock support, and ensuring the safety and stability of the surrounding rock and support structure during tunnel construction, the rock's grip on the anchor bolts (i.e., the pull-out resistance) is insufficient due to liquefaction during the construction of anchor bolts in water-rich soil in the sidewall steel frame anchor-sprayed structure. This leads to anchor bolt system failure, manifesting in the initial support structure as initial support convergence deformation and initial support settlement caused by insufficient overall bearing capacity of the surrounding rock, posing quality and safety hazards.

[0003] Therefore, there is currently a lack of a well-designed method for excavating and constructing large-section soil tunnels in water-rich soil, so as to enable tunnels to safely and quickly traverse water-rich soil strata and ensure the stability of the tunnel structure. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for excavating and constructing a large-section soil tunnel in water-rich soil. The method is simple in steps and reasonable in design. First, three rows of interlocking jet grouting piles are constructed before excavation in the water-rich soil area. The left, middle, and right locking anchors are then anchored to the three rows of interlocking jet grouting piles. The system anchors in the initial support are also anchored to the interlocking jet grouting piles, which strengthens the initial support of the tunnel and ensures safe and reliable excavation of the tunnel body. This allows the tunnel to safely pass through water-rich soil strata and ensures the stability of the tunnel structure.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for excavating and constructing a water-rich, large-section soil tunnel, wherein the tunnel is excavated along its longitudinal extension direction, and before excavation, interlocking jet grouting piles are used to reinforce the water-rich soil area. The method includes the following steps:

[0006] Step 1: Construct jet grouting piles for reinforcement in the water-rich soil area:

[0007] Step 101: Determine the center points of the first row of interlocking jet grouting piles, the second row of interlocking jet grouting piles, and the third row of interlocking jet grouting piles in the water-rich soil area to be constructed; wherein, the horizontal distance between the line connecting the center points of the first row of interlocking jet grouting piles and the left outer wall of the tunnel to be constructed is 2m to 3m, the horizontal distance between the center points of the second row of interlocking jet grouting piles and the outer wall of the central partition wall is 2m to 3m, and the horizontal distance between the center points of the third row of interlocking jet grouting piles and the right outer wall of the tunnel to be constructed is 2m to 3m;

[0008] Step 102: Vertically construct the first row of interlocking jet grouting piles at the center points of each of the first row of interlocking jet grouting piles; wherein, the first row of interlocking jet grouting piles includes multiple first jet grouting piles interlocking in sequence, and the bottom of the first jet grouting piles extends into the bearing layer of the water-rich soil area being constructed.

[0009] Step 103: Vertically construct the second row of interlocking jet grouting piles at each center point of the second row of interlocking jet grouting piles; wherein, the second row of interlocking jet grouting piles includes multiple second jet grouting piles interlocking in sequence, and the bottom of the second jet grouting piles extends into the bearing layer of the water-rich soil area being constructed.

[0010] Step 104: Vertically construct the third row of interlocking jet grouting piles at the center points of each of the third row of interlocking jet grouting piles; wherein, the third row of interlocking jet grouting piles includes multiple third jet grouting piles that interlock sequentially, and the bottom of the third jet grouting piles extends into the bearing layer of the water-rich soil area being constructed.

[0011] Step 2: Excavation and initial support of the upper left pilot tunnel:

[0012] In the water-rich soil area under construction, the upper left pilot tunnel is excavated longitudinally from back to front along the tunnel. During the excavation of the upper left pilot tunnel, the upper left initial support is simultaneously carried out on the upper left side of the excavated upper left pilot tunnel, forming the upper left initial support structure and the upper middle partition wall temporary support structure. Among them, the upper left locking anchor rod of the upper left initial support of the upper left tunnel obliquely penetrates the first row of interlocking jet grouting piles, the middle upper locking anchor rod of the upper middle partition wall temporary support structure obliquely penetrates the second row of interlocking jet grouting piles, and the system anchor rod of the upper left initial support penetrates the first row of interlocking jet grouting piles.

[0013] Step 3: Excavation and initial support of the left and middle pilot tunnels:

[0014] In the water-rich soil area under construction, the left central pilot tunnel is excavated longitudinally from back to front along the tunnel. During the excavation of the left central pilot tunnel, the left central pilot tunnel body is simultaneously supported in the middle left side, forming the initial support structure for the middle left tunnel body and the temporary support structure for the central partition wall. Among them, the left central locking anchor rod of the initial support of the middle left tunnel body is inclined to penetrate the first row of interlocking jet grouting piles, the middle central locking anchor rod of the temporary support structure for the central partition wall is inclined to penetrate the second row of interlocking jet grouting piles, and the system anchor rod of the initial support of the middle left tunnel body penetrates the first row of interlocking jet grouting piles.

[0015] Step 4: Excavation and initial support of the left lower pilot tunnel invert:

[0016] In the water-rich soil area under construction, the left lower pilot tunnel and the bottom invert arch are excavated together along the longitudinal direction of the tunnel from back to front. During the excavation of the left lower pilot tunnel and the bottom invert arch, the excavated left lower pilot tunnel and the left bottom invert arch excavation face are simultaneously supported, forming the initial support of the left lower tunnel and the temporary support structure of the lower middle partition wall, as well as the closed ring of the initial support of the left lower invert arch. Among them, the left lower locking anchor rod of the initial support of the left lower tunnel penetrates the first row of interlocking jet grouting piles at an angle, the middle lower locking anchor rod of the temporary support structure of the lower middle partition wall penetrates the second row of interlocking jet grouting piles at an angle, and the system anchor rod of the initial support of the left lower tunnel penetrates the first row of interlocking jet grouting piles.

[0017] Step 5: Excavation and initial support of the upper right pilot tunnel:

[0018] In the water-rich soil area under construction, the upper right pilot tunnel is excavated longitudinally from back to front along the tunnel. During the excavation of the upper right pilot tunnel, the upper right initial support is simultaneously carried out on the upper right tunnel body to form the upper right tunnel body initial support. Among them, the upper right locking anchor rod of the upper right tunnel body initial support penetrates the third row of interlocking jet grouting piles at an angle, and the system anchor rod of the upper right tunnel body initial support penetrates the third row of interlocking jet grouting piles.

[0019] Step Six: Excavation and Initial Support of the Right Middle Pilot Tunnel:

[0020] In the water-rich soil area under construction, the right middle pilot tunnel is excavated longitudinally from back to front along the tunnel. During the excavation of the right middle pilot tunnel, the right middle pilot tunnel body is simultaneously supported in the middle right side to form the initial support of the middle right tunnel body. Among them, the right middle locking anchor rod of the initial support of the middle right tunnel body is inclined to penetrate the third row of interlocking jet grouting piles, and the system anchor rod of the initial support of the middle right tunnel body penetrates the third row of interlocking jet grouting piles.

[0021] Step 7: Excavation and initial support of the right lower pilot tunnel invert:

[0022] In the water-rich soil area under construction, the lower right pilot tunnel and the bottom invert arch are excavated together along the longitudinal direction of the tunnel from back to front. During the excavation of the lower right pilot tunnel and the bottom invert arch, the excavated lower right pilot tunnel and the excavation face of the bottom right invert arch are simultaneously supported, forming the initial support of the lower right tunnel and the initial support of the lower right invert arch that is closed into a ring. Among them, the lower right locking anchor rod of the initial support of the lower right tunnel is inclined to penetrate the third row of interlocking jet grouting piles, and the system anchor rod of the initial support of the lower right tunnel penetrates the third row of interlocking jet grouting piles.

[0023] The above-mentioned method for excavating a large-section soil tunnel in water-rich areas is characterized by the following specific installation process for the upper left anchor bolt, the middle left anchor bolt, and the lower left anchor bolt:

[0024] Step A: Drill a hole at the designed position of the upper left anchor bolt to form the upper left anchor bolt;

[0025] Step B: Insert the bag containing the resin anchoring agent into the bottom of the upper left locking foot anchor hole through the upper left locking foot anchor hole.

[0026] Step C: Install the upper left locking anchor in the upper left locking anchor hole, and use the drilling rig to rotate the upper left locking anchor to drill into the hole containing the resin anchoring agent bag. The resin anchoring agent is rotated and stirred and filled along the length of the upper left locking anchor hole until the resin anchoring agent extends and fills the section of the upper left locking anchor that penetrates the first row of interlocking jet grouting piles, thus completing the installation of the upper left locking anchor.

[0027] Step D: Following the methods in steps A to C, complete the installation of the left middle locking anchor and the left lower locking anchor.

[0028] The above-mentioned method for excavating and constructing a large-section soil tunnel in water-rich areas is characterized by the following specific installation process for the upper intermediate anchor bolt, the middle intermediate anchor bolt, and the lower intermediate anchor bolt:

[0029] Step A01: Drill holes to form the middle upper anchor bolt at the designed position of the middle upper anchor bolt;

[0030] Step A02: Insert the bag containing the resin anchoring agent into the bottom of the hole drilled through the middle upper locking foot anchor rod.

[0031] Step A03: Install the middle upper locking anchor rod in the middle upper locking anchor rod drill hole, and use the drilling rig to rotate the middle upper locking anchor rod to drill into the drill hole containing the resin anchoring agent bag. The anchoring agent is rotated and stirred and filled along the length of the middle upper locking anchor rod drill hole until the resin anchoring agent extends and fills the drill hole section of the middle upper locking anchor rod that penetrates the second row of interlocking jet grouting piles, thus completing the installation of the middle upper locking anchor rod.

[0032] Step A04: Following the methods in steps A01 to A03, complete the installation of the middle and lower locking anchor rods.

[0033] The above-mentioned method for excavating a large-section soil tunnel in a water-rich area is characterized by the following specific installation process for the upper right anchor bolt, the middle right anchor bolt, and the lower right anchor bolt:

[0034] Step B01: Drill a hole at the designed position of the upper right anchor bolt to form the upper right anchor bolt hole;

[0035] Step B02: Insert the bag containing the resin anchoring agent into the bottom of the upper right locking foot anchor hole through the upper right locking foot anchor hole;

[0036] Step B03: Install the upper right locking anchor in the upper right locking anchor hole, and use the drilling rig to rotate the upper right locking anchor to drill into the hole containing the resin anchoring agent bag. The anchoring agent is rotated and stirred and filled along the length of the upper right locking anchor hole until the resin anchoring agent extends and fills the section of the upper right locking anchor that penetrates the third row of interlocking jet grouting piles, thus completing the installation of the upper right locking anchor.

[0037] Step B04: Following the methods in steps B01 to B03, complete the installation of the right middle anchor bolt and the right lower anchor bolt.

[0038] The above-mentioned method for excavating and constructing a large-section soil tunnel in water-rich areas is characterized by the following: In step two, initial support is formed on the upper left side of the tunnel body. The specific process is as follows:

[0039] Step 201: Excavate the upper part of the left upper pilot tunnel along the longitudinal direction of the tunnel in the water-rich soil area to form the left upper pilot tunnel body.

[0040] Step 202: Apply initial shotcrete to the inner wall of the upper left pilot tunnel to form an initial shotcrete spray layer.

[0041] Step 203: Install multiple steel arch frames along the longitudinal extension direction of the tunnel on the inner side of the initial shotcrete layer; wherein, a steel mesh is hung between the outer side of the steel arch frame and the initial shotcrete layer, and the outer longitudinal connecting bars are welded to the outer side of the multiple steel arch frames, the steel mesh and the outer longitudinal connecting bars are tied together, and the steel mesh is laid in close contact with the initial shotcrete layer.

[0042] Step 204: Weld inner longitudinal connecting bars to the inner side of the multiple steel arch frames; wherein, anchor bolts are installed at the lower part of the steel arch frames to reinforce them;

[0043] Step 205: According to the design spacing of the system anchor bolts, fill the inner part of the outer end of the hollow steel pipe with geotextile, and then install the hollow steel pipe between two adjacent steel arch frames; wherein, the outer end of the hollow steel pipe near the upper left guide tunnel body penetrates the steel mesh and is attached to the initial shotcrete spraying layer, the outer side wall of the outer end of the hollow steel pipe is welded to the outer longitudinal connecting bar, the inner end of the hollow steel pipe extends out of the inner longitudinal connecting bar by 1mm to 2mm, the outer side wall of the inner end of the hollow steel pipe is welded to the inner longitudinal connecting bar, and the length direction of the hollow steel pipe and the length direction of the outer longitudinal connecting bar are perpendicular to the length direction of the inner longitudinal connecting bar;

[0044] Step 206: Fill the inner end of the hollow steel pipe with geotextile, and thread an iron wire through the center of the geotextile.

[0045] Step 208: Forming a sprayed concrete layer;

[0046] Step 209: Before the final setting of the sprayed concrete layer, chisel a square groove at the protruding part of the wire until the bottom of the square groove is flush with the inner end of the hollow steel pipe.

[0047] Step 20A: Use the wire to pull and remove the geotextile filling inside the hollow steel pipe.

[0048] Step 20B: Drill along the hollow steel pipe to form a system anchor bolt borehole, and install the system anchor bolt in the system anchor bolt borehole; wherein, the system anchor bolt extends into the surrounding rock of the upper left pilot tunnel, and cement mortar is poured between the system anchor bolt and the borehole;

[0049] Step 20C: Install anchor plates at the extended ends of the system anchor bolts; wherein the anchor plates are located in square grooves;

[0050] Step 20D: Spray concrete into the square groove until it is flush with the sprayed concrete layer, and complete the initial support of the upper left tunnel.

[0051] Step 20E: Following the methods described in steps 201 to 20D, the left middle pilot tunnel is excavated along the longitudinal direction of the tunnel from back to front in the water-rich soil area to form the left middle pilot tunnel body, and the initial support of the left middle tunnel body is completed.

[0052] Step 20F: Following the methods described in steps 201 to 20D, the lower left pilot tunnel is excavated along the longitudinal direction of the tunnel in the water-rich soil area to form the lower left pilot tunnel body, and the initial support of the lower left tunnel body is completed.

[0053] The above-mentioned method for excavating and constructing a large-section soil tunnel in water-rich areas is characterized by the following specific process for the system anchor bolts to penetrate the first row of interlocking jet grouting piles, the second row of interlocking jet grouting piles, and the third row of interlocking jet grouting piles in steps two to four:

[0054] Step C01: Insert the bag containing the resin anchoring agent into the bottom of the system anchor drill hole through the system anchor drill hole in step 20B.

[0055] Step C02: Install the system anchor bolts in the system anchor bolt boreholes. After the system anchor bolts are drilled into the boreholes containing resin anchoring agent bags by rotating the drilling rig, the anchoring agent is stirred by rotation and fills the boreholes along the length of the system anchor bolt boreholes until the resin anchoring agent extends and fills the boreholes of the system anchor bolt boreholes, penetrating the borehole sections of the first row of interlocking jet grouting piles, the second row of interlocking jet grouting piles, and the third row of interlocking jet grouting piles, thus completing the installation of the system anchor bolts.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] 1. The method of the present invention has simple steps, reasonable design and easy construction, so as to enable the tunnel to safely pass through water-rich soil strata and ensure the stability of the tunnel structure.

[0058] 2. This invention involves excavating the tunnel along its longitudinal extension direction. Before excavation, jet grouting piles are used to reinforce the water-rich soil areas. This significantly isolates the lateral seepage of groundwater, reduces the soil moisture content, and facilitates excavation of the water-rich soil areas. It also facilitates the subsequent anchoring system with the high-bearing-capacity and high-strength jet grouting piles, improving the stability of the initial support and greatly enhancing the overall bearing capacity around the tunnel structure. This ensures the stability of the tunnel structure. Compared to the traditional method of reinforcing the surrounding rock of the tunnel with bouquet-shaped jet grouting piles throughout the tunnel width, this invention saves on engineering work and cost.

[0059] 3. After the construction of jet grouting piles to reinforce the water-rich soil area, the present invention sequentially carries out the excavation and initial support of the upper left pilot tunnel, the excavation and initial support of the middle left pilot tunnel, the excavation and initial support of the lower left pilot tunnel invert, the excavation and initial support of the upper right pilot tunnel, the excavation and initial support of the middle right pilot tunnel, and the excavation and initial support of the lower right pilot tunnel invert, making the construction convenient and safe.

[0060] 4. In this invention, the upper left locking anchor, the middle left locking anchor, and the lower left locking anchor obliquely penetrate the first row of interlocking jet grouting piles, while the upper middle locking anchor, the middle middle locking anchor, and the lower middle locking anchor obliquely penetrate the second row of interlocking jet grouting piles. The left locking anchor is anchored to the first row of interlocking jet grouting piles, and the middle locking anchor is anchored to the second row of interlocking jet grouting piles, thereby improving the stability of the left-side support and facilitating the stability of the structure during the next excavation.

[0061] 5. The upper right, middle right, and lower right locking anchor bolts of this invention penetrate the third row of interlocking jet grouting piles at an angle, and are anchored by the right-side locking anchor bolts and the third row of interlocking jet grouting piles, thereby improving the stability of the right-side support and facilitating the stability of the structure during the next excavation.

[0062] 6. In this invention, hollow steel pipes are installed between two adjacent steel arch frames. The outer wall of the outer end of the hollow steel pipe is welded to the outer longitudinal connecting bar, and the outer wall of the inner end of the hollow steel pipe is welded to the inner longitudinal connecting bar. The hollow steel pipes are embedded so that after the sprayed concrete layer is formed, holes are drilled through the hollow steel pipes, and the system is installed after the sprayed concrete layer is formed. This avoids the problem that when drilling the system anchor bolts, it is very easy to drill into the mesh and steel frame connecting bars, which can damage the drill bit and equipment, and make drilling difficult, further hindering tunnel construction. In addition, it can also avoid the problem that the protruding part of the system anchor bolts will be exposed to the sprayed concrete layer after installation, resulting in an uneven initial support surface that requires a lot of spraying or manual cutting of a lot of anchor bolt rebar heads.

[0063] In summary, the method of this invention is simple in steps and reasonable in design. First, three rows of interlocking jet grouting piles are constructed before excavation in the water-rich soil area to be constructed. The left locking anchor, the middle locking anchor, and the right locking anchor are then anchored to the three rows of interlocking jet grouting piles, and the system anchors in the initial support are also anchored to the interlocking jet grouting piles. This strengthens the initial support of the tunnel, ensures safe and reliable excavation of the tunnel body, enables the tunnel to safely pass through the water-rich soil strata, and ensures the stability of the tunnel structure.

[0064] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the structure of the present invention.

[0066] Figure 2 This is a schematic diagram of the hollow steel pipe structure in this invention.

[0067] Figure 3 This is a flowchart of the present invention.

[0068] Explanation of reference numerals in the attached figures:

[0069] 1-1—Left upper pilot tunnel body; 1-2—Left middle pilot tunnel body;

[0070] 1-3—Lower left pilot tunnel; 1-4—Upper right pilot tunnel;

[0071] 1-5—Right middle pilot tunnel body; 1-6—Right lower pilot tunnel body;

[0072] 1-11—Initial support for the upper left tunnel; 1-12—Temporary support structure for the upper central partition wall;

[0073] 1-13—Upper left anchor bolt; 1-14—Upper middle anchor bolt;

[0074] 1-21—Initial support for the middle section of the left tunnel; 1-22—Temporary support structure for the central partition wall;

[0075] 1-23—Left middle anchor bolt; 1-24—Middle middle anchor bolt;

[0076] 1-31—Initial support for the lower left section of the tunnel; 1-32—Temporary support structure for the lower central partition wall;

[0077] 1-33—Lower left anchor bolt; 1-34—Lower middle anchor bolt;

[0078] 1-41—Initial support for the upper right section of the tunnel; 1-43—Rock bolts for the upper right section;

[0079] 1-51—Initial support for the middle section of the tunnel on the right side; 1-53—Right middle section anchor bolt;

[0080] 1-61—Initial support for the lower right section of the tunnel; 1-63—Lower right section anchor bolt;

[0081] 1-71—Excavation face of the left bottom invert arch; 1-72—Initial support of the lower part of the left tunnel invert arch;

[0082] 1-73—Excavation face of the right bottom invert arch; 1-74—Initial support of the lower part of the right tunnel invert arch;

[0083] 4—Steel arch frame; 4-1—Initial shotcrete layer; 4-2—Inner longitudinal connecting bars;

[0084] 4-3—Outer longitudinal connecting bars; 4-4—Re-sprayed concrete spray layer;

[0085] 4-5—Reinforcing mesh; 5—Hollow steel pipe;

[0086] 5-1—Geotextile; 5-2—Wire; 6—Square groove;

[0087] 7—System anchor bolt; 8—Anchor bolt pad; 10—First row of jet grouting piles;

[0088] 20—Second row of jet grouting piles; 30—Third row of jet grouting piles. Detailed Implementation

[0089] like Figures 1 to 3 The method for excavating a large-section soil tunnel in water-rich soil, as shown, involves excavating the tunnel along its longitudinal extension direction. Before excavation, interlocking jet grouting piles are used to reinforce the water-rich soil area. The method includes the following steps:

[0090] Step 1: Construct jet grouting piles for reinforcement in the water-rich soil area:

[0091] Step 101: Determine the center points of the first row of interlocking jet grouting piles, the second row of interlocking jet grouting piles, and the third row of interlocking jet grouting piles in the water-rich soil area to be constructed; wherein, the horizontal distance between the line connecting the center points of the first row of interlocking jet grouting piles and the left outer wall of the tunnel to be constructed is 2m to 3m, the horizontal distance between the center points of the second row of interlocking jet grouting piles and the outer wall of the central partition wall is 2m to 3m, and the horizontal distance between the center points of the third row of interlocking jet grouting piles and the right outer wall of the tunnel to be constructed is 2m to 3m;

[0092] Step 102: Vertically construct the first row of interlocking jet grouting piles 10 at each center point of the first row of interlocking jet grouting piles; wherein, the first row of interlocking jet grouting piles 10 includes a plurality of first jet grouting piles interlocking in sequence, and the bottom of the first jet grouting piles extends into the bearing layer of the water-rich soil area being constructed.

[0093] Step 103: Vertically construct the second row of interlocking jet grouting piles 20 at each center point of the second row of interlocking jet grouting piles; wherein, the second row of interlocking jet grouting piles 20 includes multiple second jet grouting piles interlocking in sequence, and the bottom of the second jet grouting piles extends into the bearing layer of the water-rich soil area being constructed.

[0094] Step 104: Vertically construct the third row of interlocking jet grouting piles 30 at each center point of the third row of interlocking jet grouting piles; wherein, the third row of interlocking jet grouting piles 30 includes multiple interlocking third jet grouting piles, and the bottom of the third jet grouting piles extends into the bearing layer of the water-rich soil area being constructed.

[0095] Step 2: Excavation and initial support of the upper left pilot tunnel:

[0096] In the water-rich soil area under construction, the left upper pilot tunnel is excavated longitudinally from back to front along the tunnel. During the excavation of the left upper pilot tunnel, the left upper pilot tunnel body 1-1, which is formed by the excavation of the left upper pilot tunnel, is simultaneously supported on the upper left side, forming the left upper tunnel body initial support 1-11 and the upper middle partition wall temporary support structure 1-12. Among them, the left upper locking anchor 1-13 of the left upper tunnel body initial support 1-11 penetrates the first row of interlocking jet grouting piles 10 at an angle, the middle upper locking anchor 1-14 of the upper middle partition wall temporary support structure 1-12 penetrates the second row of interlocking jet grouting piles 20 at an angle, and the system anchor 7 of the left upper tunnel body initial support 1-11 penetrates the first row of interlocking jet grouting piles 10.

[0097] Step 3: Excavation and initial support of the left and middle pilot tunnels:

[0098] In the water-rich soil area under construction, the left central pilot tunnel is excavated longitudinally from back to front. During the excavation of the left central pilot tunnel, the left central pilot tunnel body 1-2 is simultaneously supported in the middle left side, forming the left central tunnel body initial support 1-21 and the middle partition wall temporary support structure 1-22. Among them, the left central locking anchor 1-23 of the left central tunnel body initial support 1-21 penetrates the first row of interlocking jet grouting piles 10 at an angle, the middle central locking anchor 1-24 of the middle partition wall temporary support structure 1-22 penetrates the second row of interlocking jet grouting piles 20 at an angle, and the system anchor of the left central tunnel body initial support 1-21 penetrates the first row of interlocking jet grouting piles 10.

[0099] Step 4: Excavation and initial support of the left lower pilot tunnel invert:

[0100] In the water-rich soil area under construction, the left lower pilot tunnel and the bottom invert arch are excavated together along the longitudinal direction of the tunnel from back to front. During the excavation of the left lower pilot tunnel and the bottom invert arch, the excavated left lower pilot tunnel body 1-3 and the left bottom invert arch excavation face 1-71 are simultaneously supported, forming the left lower tunnel initial support 1-31, the lower middle partition wall temporary support structure 1-32, and the closed ring left tunnel lower invert arch initial support 1-72. Among them, the left lower locking anchor 1-33 of the left lower tunnel initial support 1-31 penetrates the first row of interlocking jet grouting piles 10 at an angle, the middle lower locking anchor 1-34 of the lower middle partition wall temporary support structure 1-32 penetrates the second row of interlocking jet grouting piles 20 at an angle, and the system anchor of the left lower tunnel initial support 1-31 penetrates the first row of interlocking jet grouting piles 10.

[0101] Step 5: Excavation and initial support of the upper right pilot tunnel:

[0102] In the water-rich soil area under construction, the upper right pilot tunnel is excavated longitudinally from back to front along the tunnel. During the excavation of the upper right pilot tunnel, the upper right initial support of the upper right pilot tunnel body 1-4 is simultaneously carried out to form the upper right initial support 1-41. Among them, the upper right locking anchor 1-43 of the upper right initial support 1-41 penetrates the third row of interlocking jet grouting piles 30 at an angle, and the system anchor of the upper right initial support 1-41 penetrates the third row of interlocking jet grouting piles 30.

[0103] Step Six: Excavation and Initial Support of the Right Middle Pilot Tunnel:

[0104] In the water-rich soil area under construction, the right central pilot tunnel is excavated longitudinally from back to front. During the excavation of the right central pilot tunnel, the right central pilot tunnel body 1-5 is simultaneously supported in the middle right side to form the right central pilot tunnel body initial support 1-51. Among them, the right central locking anchor 1-53 of the right central pilot tunnel body initial support 1-51 penetrates the third row of interlocking jet grouting piles 30 at an angle, and the system anchor of the right central pilot tunnel body initial support 1-51 penetrates the third row of interlocking jet grouting piles 30.

[0105] Step 7: Excavation and initial support of the right lower pilot tunnel invert:

[0106] In the water-rich soil area under construction, the lower right pilot tunnel and the bottom invert arch are excavated together along the longitudinal direction of the tunnel from back to front. During the excavation of the lower right pilot tunnel and the bottom invert arch, the excavated lower right pilot tunnel body 1-6 and the excavation face 1-73 of the right bottom invert arch are simultaneously supported, forming the lower right tunnel body initial support 1-61 and the closed ring lower right invert arch initial support 1-74. Among them, the lower right locking anchor 1-63 of the lower right tunnel body initial support 1-61 penetrates the third row of interlocking jet grouting piles 30 at an angle, and the system anchor of the lower right tunnel body initial support 1-61 penetrates the third row of interlocking jet grouting piles 30.

[0107] In this embodiment, the specific installation process of the upper left locking anchor rod 1-13, the middle left locking anchor rod 1-23, and the lower left locking anchor rod 1-33 is as follows:

[0108] Step A: Drill holes to form the upper left anchor bolts at the designed positions 1-13;

[0109] Step B: Insert the bag containing the resin anchoring agent into the bottom of the upper left locking foot anchor hole through the upper left locking foot anchor hole.

[0110] Step C: Install the upper left locking anchor 1-13 in the upper left locking anchor hole, and use the drilling rig to rotate the upper left locking anchor 1-13 to drill into the hole containing the resin anchoring agent bag. The resin anchoring agent is rotated and stirred and filled along the length of the upper left locking anchor hole until the resin anchoring agent extends and fills the upper left locking anchor through the drilled section of the first row of interlocking jet grouting piles 10, thus completing the installation of the upper left locking anchor 1-13.

[0111] Step D: Following the methods in steps A to C, complete the installation of the left middle locking anchor rod 1-23 and the left lower locking anchor rod 1-33.

[0112] In this embodiment, the specific installation process of the upper middle locking anchor 1-14, the middle middle locking anchor 1-24, and the lower middle locking anchor 1-34 is as follows:

[0113] Step A01: Drill holes to form the middle upper anchor bolt at the designed position of the middle upper anchor bolt;

[0114] Step A02: Insert the bag containing the resin anchoring agent into the bottom of the hole drilled through the middle upper locking foot anchor rod.

[0115] Step A03: Install the middle upper locking anchor 1-14 in the middle upper locking anchor hole, and use the drilling rig to rotate the middle upper locking anchor 1-14 to drill into the hole containing the resin anchoring agent bag. The anchoring agent is rotated and stirred and filled along the length of the middle upper locking anchor hole until the resin anchoring agent extends and fills the middle upper locking anchor through the drilled section of the second row of interlocking jet grouting piles 20, thus completing the installation of the middle upper locking anchor 1-14.

[0116] Step A04: Following the methods in steps A01 to A03, complete the installation of the middle locking anchor rods 1-24 and the lower middle locking anchor rods 1-34.

[0117] In this embodiment, the specific installation process of the upper right locking anchor rod 1-43, the middle right locking anchor rod 1-53, and the lower right locking anchor rod 1-63 is as follows:

[0118] Step B01: Drill a hole at the designed position of the upper right anchor bolt to form the upper right anchor bolt hole;

[0119] Step B02: Insert the bag containing the resin anchoring agent into the bottom of the upper right locking foot anchor hole through the upper right locking foot anchor hole;

[0120] Step B03: Install the upper right anchor bolt 1-43 in the upper right anchor bolt hole, and use the drilling rig to rotate the upper right anchor bolt 1-43 to drill into the hole containing the resin anchoring agent bag. The anchoring agent is rotated and stirred and filled along the length of the upper right anchor bolt hole until the resin anchoring agent extends and fills the upper right anchor bolt through the drilled section of the third row of interlocking jet grouting piles 30, thus completing the installation of the upper right anchor bolt 1-43.

[0121] Step B04: Following the methods in steps B01 to B03, complete the installation of the right middle locking anchor rod 1-53 and the right lower locking anchor rod 1-63.

[0122] In this embodiment, the initial support 1-11 for the upper left cavern is formed in step two, and the specific process is as follows:

[0123] Step 201: Excavate the upper part of the left upper pilot tunnel along the longitudinal direction of the tunnel from back to front in the water-rich soil area to form the left upper pilot tunnel body 1-1;

[0124] Step 202: Apply initial shotcrete to the inner wall of the upper left pilot tunnel 1-1 to form the initial shotcrete spray layer 4-1;

[0125] Step 203: Install multiple steel arch frames 4 along the longitudinal extension direction of the tunnel on the inner side of the initial shotcrete layer 4-1; wherein, a steel mesh 4-5 is hung between the outer side of the steel arch frame 4 and the initial shotcrete layer 4-1, and the outer longitudinal connecting bars 4-3 are welded to the outer side of the multiple steel arch frames 4, the steel mesh 4-5 and the outer longitudinal connecting bars 4-3 are tied together, and the steel mesh 4-5 is arranged to fit the initial shotcrete layer 4-1.

[0126] Step 204: Weld inner longitudinal connecting bars 4-2 to the inner side of the multiple steel arch frames 4; wherein, anchor bolts are installed at the lower part of the steel arch frames 4 to reinforce the steel arch frames 4;

[0127] Step 205: According to the design spacing of the system anchor bolts, fill the inner part of the outer end of the hollow steel pipe 5 with geotextile 5-1, and then install the hollow steel pipe 5 between two adjacent steel arch frames 4; wherein, the outer end of the hollow steel pipe 5 near the upper left guide tunnel body 1-1 penetrates the steel mesh 4-5 and is attached to the initial shotcrete spraying layer 4-1, the outer side wall of the outer end of the hollow steel pipe 5 is welded to the outer longitudinal connecting bar 4-3, the inner end of the hollow steel pipe 5 extends out of the inner longitudinal connecting bar 4-2 by a length of 1mm to 2mm, the outer side wall of the inner end of the hollow steel pipe 5 is welded to the inner longitudinal connecting bar 4-2, and the length direction of the hollow steel pipe 5 and the length direction of the outer longitudinal connecting bar 4-3 and the inner longitudinal connecting bar 4-2 are arranged perpendicularly;

[0128] Step 206: Fill the inner end of the hollow steel pipe 5 with geotextile 5-1, and thread iron wire 5-2 through the center of the geotextile 5-1.

[0129] Step 208: Forming the second sprayed concrete spray layer 4-4;

[0130] Step 209: Before the final setting of the sprayed concrete layer 4-4, chisel out a square groove 6 at the protrusion of the wire 5-2 until the bottom of the square groove 6 is flush with the inner end of the hollow steel pipe 5.

[0131] Step 20A: Use wire 5-2 to pull and remove the geotextile 5-1 filling the inner end of the hollow steel pipe 5;

[0132] Step 20B: Drill along the hollow steel pipe 5 to form a system anchor bolt borehole, and install the system anchor bolt 7 in the system anchor bolt borehole; wherein, the system anchor bolt 7 extends into the surrounding rock of the upper left pilot tunnel 1-1, and cement mortar is poured between the system anchor bolt 7 and the borehole.

[0133] Step 20C: Install anchor plate 8 at the protruding end of system anchor 7; wherein, anchor plate 8 is located in square groove 6;

[0134] Step 20D: Shot concrete at the square groove 6 until it is flush with the sprayed concrete layer 4-4 to complete the initial support of the upper left tunnel.

[0135] Step 20E: Following the method described in steps 201 to 20D, the left middle guide tunnel is excavated along the longitudinal direction of the tunnel from back to front in the water-rich soil area to form the left middle guide tunnel body 1-2, and the initial support 1-21 of the left middle tunnel body is completed.

[0136] Step 20F: Following the methods described in steps 201 to 20D, the lower left pilot tunnel is excavated along the longitudinal direction of the tunnel in the water-rich soil area to form the lower left pilot tunnel body 1-3, and the initial support 1-31 of the lower left tunnel body is completed.

[0137] In this embodiment, the specific process of the system anchor 7 penetrating the first row of interlocking jet grouting piles 10, the second row of interlocking jet grouting piles 20, and the third row of interlocking jet grouting piles 30 in steps two to four is as follows:

[0138] Step C01: Insert the bag containing the resin anchoring agent into the bottom of the system anchor drill hole through the system anchor drill hole in step 20B.

[0139] Step C02: Install the system anchor 7 in the system anchor borehole, and use the drilling rig to rotate the system anchor 7 to drill into the borehole containing the resin anchoring agent bag. The anchoring agent is rotated and stirred and filled along the length of the system anchor borehole until the resin anchoring agent extends and fills the borehole section that penetrates the first row of interlocking jet grouting piles 10, the second row of interlocking jet grouting piles 20 and the third row of interlocking jet grouting piles 30, thus completing the installation of the system anchor 7.

[0140] In this embodiment, before excavating the upper left guide tunnel in step two, the upper left guide tunnel is first reinforced by pre-grouting with small guide pipes.

[0141] Before excavating the right-side pilot tunnel in step three, the right-side pilot tunnel is reinforced with pre-grouting using small guide pipes.

[0142] In this embodiment, when used in practice, the diameter of the first, second, and third jet grouting piles is 600mm. All three jet grouting piles are cement jet grouting piles. The distance between the cores of adjacent first, second, and third jet grouting piles is 400mm. The design strength of the first, second, and third jet grouting piles is 2.0MPa to 8.0MPa.

[0143] In this embodiment, when used in practice, the bearing capacity of the bearing layer in the water-rich soil area being constructed shall not be less than 120 kPa.

[0144] In this embodiment, the outer end of the hollow steel pipe 5 is filled with geotextile 5-1, and the inner end of the hollow steel pipe 5 is also filled with geotextile 5-1. By filling and blocking the hollow steel pipe 5 with geotextile, the hollow steel pipe 5 is ensured to be hollow inside, thus avoiding the spraying port of the re-sprayed concrete. In addition, an iron wire 5-2 is threaded through the center of the geotextile 5-1 at the inner end. This is to allow the geotextile 5-1 inside the inner end of the hollow steel pipe 5 to be removed by pulling with the iron wire 5-2, so that the drill rod can be inserted for drilling.

[0145] In this embodiment, the square groove 6 is formed by chiseling. Firstly, it is used to chisel the wire 5-2 at the point where the sprayed concrete layer 4-4 extends before final setting, allowing the inner end of the hollow steel pipe 5 to be exposed. Secondly, it is used to install the anchor plate 8 at the protruding end of the system anchor 7, so that the anchor plate 8 is located in the square groove 6, thus preventing the anchor plate 8 from protruding from the sprayed concrete layer 4-4, thereby avoiding extensive re-spraying and only spraying concrete at the square groove 6 until it is flush with the sprayed concrete layer 4-4. Additionally, it is used to accommodate the protruding end of the system anchor 7, preventing it from extending beyond the sprayed concrete layer 4-4, thus avoiding the need for manual cutting of a large number of anchor bar ends.

[0146] In this embodiment, when used in practice, the specific method for the system anchor 7 to penetrate the second row of interlocking jet grouting piles 20 and the third row of interlocking jet grouting piles 30 in steps five and six is ​​carried out according to steps C01 to C02.

[0147] In this embodiment, during actual use, some system anchor bolts 7 penetrate the drilled sections of the first row of interlocking jet grouting piles 10, the second row of interlocking jet grouting piles 20, and the third row of interlocking jet grouting piles 30.

[0148] In this embodiment, it should be noted that cement mortar is injected between the system anchor bolt 7 and the remaining drilled section of the system anchor bolt hole.

[0149] In this embodiment, step C, until the resin anchoring agent extends and fills the upper left locking anchor hole penetrating the drilled section of the first row of interlocking jet grouting piles 10, specifically involves:

[0150] After the upper left anchor rod is in place in the borehole, the upper left anchor rod is extended from the end of the first row of interlocking jet grouting piles near the tunnel wall to the bottom of the upper left anchor rod borehole. This section is called the chemical anchoring section.

[0151] Furthermore, the volume of the resin anchoring agent bag is 1.2 times the volume of the gap between the inner wall of the upper left locking foot anchor drill hole and the outer wall of the upper left locking foot anchor in the agent anchoring section.

[0152] In this embodiment, the volume of the resin anchoring agent bag in the upper right anchor bolt drilling hole in step A03 and the upper right anchor bolt drilling hole in step B03 is the same as described above.

[0153] In this embodiment, the diameter of the system anchor bolt drill hole is 8mm to 10mm larger than the diameter of the system anchor bolt.

[0154] In this embodiment, during specific use, the initial support 1-11 of the upper left tunnel, the initial support 1-21 of the middle left tunnel, and the initial support 1-31 of the lower left tunnel are connected as one unit; the initial support 1-41 of the upper right tunnel, the initial support 1-51 of the middle right tunnel, and the initial support 1-61 of the lower right tunnel are connected as one unit; and the initial support 1-11 of the upper left tunnel and the initial support 1-41 of the upper right tunnel are tightly connected as one unit, thereby forming the tunnel initial support structure.

[0155] The temporary support structure for the middle partition wall consists of the upper temporary support structure 1-12, the middle temporary support structure 1-22, and the lower temporary support structure 1-32. After step seven, the temporary support structure for the middle partition wall needs to be removed.

[0156] In this embodiment, during actual use, the upper middle locking anchor, the middle middle locking anchor, and the lower middle locking anchor will be removed during the excavation process on the right side.

[0157] In summary, the method of this invention is simple in steps and reasonable in design. First, three rows of interlocking jet grouting piles are constructed before excavation in the water-rich soil area to be constructed. The left locking anchor, the middle locking anchor, and the right locking anchor are then anchored to the three rows of interlocking jet grouting piles, and the system anchors in the initial support are also anchored to the interlocking jet grouting piles. This strengthens the initial support of the tunnel, ensures safe and reliable excavation of the tunnel body, enables the tunnel to safely pass through the water-rich soil strata, and ensures the stability of the tunnel structure.

[0158] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for water-rich large-section soil tunnel excavation construction, characterized in that, The method comprises the following steps: Step one, construction of rotary jet grouting piles in the water-rich soil area to be constructed: Step 101, determining the center points of the first row of interlocking rotary jet grouting piles, the center points of the second row of interlocking rotary jet grouting piles, and the center points of the third row of interlocking rotary jet grouting piles in the water-rich soil area to be constructed; wherein the horizontal distance between the center points of the first row of interlocking rotary jet grouting piles and the left outer sidewall of the tunnel to be constructed is 2m-3m, the horizontal distance between the center points of the second row of interlocking rotary jet grouting piles and the outer sidewall of the middle partition wall is 2m-3m, and the horizontal distance between the center points of the third row of interlocking rotary jet grouting piles and the right outer sidewall of the tunnel to be constructed is 2m-3m; the above three rows are controlled in distance based on the tunnel structure, a horizontal distance of 2m-3m is passed in the direction perpendicular to the tunnel axis to ensure a reasonable distance between the rotary jet grouting piles and the tunnel excavation area, and a pile core distance of 400mm is passed in the direction parallel to the tunnel axis to ensure interlocking of piles in the same row; Step 102, vertically constructing the first row of interlocking rotary jet grouting piles (10) at the center points of the first row of interlocking rotary jet grouting piles; wherein the first row of interlocking rotary jet grouting piles (10) comprises a plurality of first rotary jet grouting piles that are sequentially interlocked, and the bottom of each first rotary jet grouting pile extends into the bearing layer of the water-rich soil area to be constructed; Step 103, vertically constructing the second row of interlocking rotary jet grouting piles (20) at the center points of the second row of interlocking rotary jet grouting piles; wherein the second row of interlocking rotary jet grouting piles (20) comprises a plurality of second rotary jet grouting piles that are sequentially interlocked, and the bottom of each second rotary jet grouting pile extends into the bearing layer of the water-rich soil area to be constructed; Step 104, vertically constructing the third row of interlocking rotary jet grouting piles (30) at the center points of the third row of interlocking rotary jet grouting piles; wherein the third row of interlocking rotary jet grouting piles (30) comprises a plurality of third rotary jet grouting piles that are sequentially interlocked, and the bottom of each third rotary jet grouting pile extends into the bearing layer of the water-rich soil area to be constructed; Step two, left upper pilot excavation and initial support: The left upper pilot is excavated from back to front along the tunnel longitudinal direction in the water-rich soil area to be constructed, and the left upper pilot hole (1-1) formed by the excavation of the left upper pilot is simultaneously supported on the left side and upper part to form a left side and upper part hole initial support (1-11) and an upper part middle partition wall temporary support structure (1-12); wherein the left upper part locking anchor rod (1-13) of the left side and upper part hole initial support (1-11) penetrates the first row of interlocking rotary jet grouting piles (10) obliquely, the middle upper part locking anchor rod (1-14) in the upper part middle partition wall temporary support structure (1-12) penetrates the second row of interlocking rotary jet grouting piles (20) obliquely, and the system anchor rod (7) of the left side and upper part hole initial support (1-11) penetrates the first row of interlocking rotary jet grouting piles (10); Step three, left middle pilot excavation and initial support: The left middle pilot tunnel is excavated from back to front along the longitudinal direction of the tunnel in the water-rich soil area under construction, and the left middle pilot tunnel hole body (1-2) formed by excavation is simultaneously subjected to left middle initial support in the process of left middle pilot tunnel excavation, to form left middle hole body initial support (1-21) and middle partition wall temporary support structure (1-22); wherein the left middle locking anchor rod (1-23) of the left middle hole body initial support (1-21) penetrates the first row of occlusion rotary jet piles (10) obliquely, the middle locking anchor rod (1-24) in the middle partition wall temporary support structure (1-22) penetrates the second row of occlusion rotary jet piles (20) obliquely, and the system anchor rod of the left middle hole body initial support (1-21) penetrates the first row of occlusion rotary jet piles (10); Step four, left lower pilot tunnel invert excavation and initial support: The left lower pilot tunnel and the bottom invert are excavated together from back to front along the longitudinal direction of the tunnel in the water-rich soil area under construction, and the left lower pilot tunnel hole body (1-3) and the left bottom invert excavation surface (1-71) formed by excavation are simultaneously subjected to initial support in the process of left lower pilot tunnel and bottom invert excavation together, to form left lower hole body initial support (1-31) and lower middle partition wall temporary support structure (1-32) and closed loop left hole lower invert initial support (1-72); wherein the left lower locking anchor rod (1-33) of the left lower hole body initial support (1-31) penetrates the first row of occlusion rotary jet piles (10) obliquely, the middle lower locking anchor rod (1-34) of the lower middle partition wall temporary support structure (1-32) penetrates the second row of occlusion rotary jet piles (20) obliquely, and the system anchor rod of the left lower hole body initial support (1-31) penetrates the first row of occlusion rotary jet piles (10); Step five, right upper pilot tunnel excavation and initial support: The right upper pilot tunnel is excavated from back to front along the longitudinal direction of the tunnel in the water-rich soil area under construction, and the right upper pilot tunnel hole body (1-4) formed by excavation is simultaneously subjected to right side upper initial support in the process of right upper pilot tunnel excavation, to form right side upper hole body initial support (1-41); wherein the right upper locking anchor rod (1-43) of the right side upper hole body initial support (1-41) penetrates the third row of occlusion rotary jet piles (30) obliquely, and the system anchor rod of the right side upper hole body initial support (1-41) penetrates the third row of occlusion rotary jet piles (30); Step six, right middle pilot tunnel excavation and initial support: The right middle pilot tunnel is excavated from back to front along the longitudinal direction of the tunnel in the water-rich soil area under construction, and the right middle pilot tunnel hole body (1-5) formed by excavation is simultaneously subjected to right side middle initial support in the process of right middle pilot tunnel excavation, to form right side middle hole body initial support (1-51); wherein the right middle locking anchor rod (1-53) of the right side middle hole body initial support (1-51) penetrates the third row of occlusion rotary jet piles (30) obliquely, and the system anchor rod of the right side middle hole body initial support (1-51) penetrates the third row of occlusion rotary jet piles (30); Step seven, right lower pilot tunnel invert excavation and initial support: The right lower guide pit and the bottom inverted arch are excavated together from back to front along the tunnel longitudinal direction in the rich water soil area, the right lower guide pit hole body (1-6) and the right bottom inverted arch excavation face (1-73) are simultaneously supported during the excavation of the right lower guide pit and the bottom inverted arch, the right lower hole body primary support (1-61) and the closed ring right hole lower inverted arch primary support (1-74) are formed, wherein the right lower locking foot anchor rod (1-63) of the right lower hole body primary support (1-61) penetrates the third row of occlusion rotary jet piles (30), and the system anchor rod of the right lower hole body primary support (1-61) penetrates the third row of occlusion rotary jet piles (30).

2. A water-rich, large cross-section, soil tunnel excavation construction method according to claim 1, characterized in that: The installation of the left upper locking foot anchor rod (1-13), the left middle locking foot anchor rod (1-23) and the left lower locking foot anchor rod (1-33) is specifically as follows: Step A, drilling a left upper locking foot anchor rod hole at a designed position of the left upper locking foot anchor rod (1-13); Step B, placing a resin anchoring agent medicine bag into the bottom of the left upper locking foot anchor rod hole through the left upper locking foot anchor rod hole; Step C, installing the left upper locking foot anchor rod (1-13) in the left upper locking foot anchor rod hole, and after the resin anchoring agent medicine bag is inserted into the hole, the resin anchoring agent is stirred and filled along the length direction of the left upper locking foot anchor rod hole, until the resin anchoring agent extends and fills the hole section penetrated by the left upper locking foot anchor rod (1-13) through the first row of occlusion rotary jet piles (10), and the installation of the left upper locking foot anchor rod (1-13) is completed; Step D, installing the left middle locking foot anchor rod (1-23) and the left lower locking foot anchor rod (1-33) according to the method of steps A to C.

3. A water-rich, large cross-section, soil tunnel excavation construction method according to claim 1, characterized in that: The installation of the left upper locking foot anchor rod (1-13), the left middle locking foot anchor rod (1-23) and the left lower locking foot anchor rod (1-33) is specifically as follows: Step A01, drilling a middle upper locking foot anchor rod hole at a designed position of the middle upper locking foot anchor rod (1-14); Step A02, placing a resin anchoring agent medicine bag into the bottom of the middle upper locking foot anchor rod hole through the middle upper locking foot anchor rod hole; Step A03, installing the middle upper locking foot anchor rod (1-14) in the middle upper locking foot anchor rod hole, and after the resin anchoring agent medicine bag is inserted into the hole, the resin anchoring agent is stirred and filled along the length direction of the middle upper locking foot anchor rod hole, until the resin anchoring agent extends and fills the hole section penetrated by the middle upper locking foot anchor rod (1-14) through the second row of occlusion rotary jet piles (20), and the installation of the middle upper locking foot anchor rod (1-14) is completed; Step A04, installing the middle middle locking foot anchor rod (1-24) and the middle lower locking foot anchor rod (1-34) according to the method of steps A01 to A03.

4. A water-rich, large cross-section, earthwork tunnel excavation construction method according to claim 1, characterized in that: The installation of the left upper locking foot anchor rod (1-13), the left middle locking foot anchor rod (1-23) and the left lower locking foot anchor rod (1-33) is specifically as follows: Step B01, drilling a right upper locking foot anchor rod hole at a designed position of the right upper locking foot anchor rod (1-43); Step B02, placing a resin anchoring agent medicine bag into the bottom of the right upper locking foot anchor rod hole through the right upper locking foot anchor rod hole; Step B03, installing the right upper locking foot anchor rod (1-43) in the right upper locking foot anchor rod hole, and after the resin anchoring agent medicine bag is inserted into the hole, the resin anchoring agent is stirred and filled along the length direction of the right upper locking foot anchor rod hole, until the resin anchoring agent extends and fills the hole section penetrated by the right upper locking foot anchor rod (1-43) through the third row of occlusion rotary jet piles (30), and the installation of the right upper locking foot anchor rod (1-43) is completed; Step B04, installing the right middle locking foot anchor rod (1-53) and the right lower locking foot anchor rod (1-63) according to the method of steps B01 to B03. Step B02, the resin anchor agent bag is put into the hole bottom of the right upper locking foot anchor hole through the right upper locking foot anchor hole drilling; Step B03, the right upper locking foot anchor (1-43) is installed in the right upper locking foot anchor hole, and after the resin anchor agent bag is inserted into the drilling, the anchor agent is stirred by rotation and filled along the length direction of the right upper locking foot anchor hole, until the resin anchor agent extends and fills the drilling section of the right upper locking foot anchor penetrating the third row of the bite rotary jet pile (30), and the installation of the right upper locking foot anchor (1-43) is completed; Step B04, the installation of the right middle locking foot anchor (1-53) and the right lower locking foot anchor (1-63) is completed according to the method of step B01 to step B03.

5. A water-rich, large cross-section, earthwork tunnel excavation construction method according to claim 1, characterized in that: In step two, the left upper hole body initial support (1-11) is formed, and the specific process is as follows: Step 201, the left upper guide hole hole body (1-1) is formed by excavating the left upper guide hole upper part from back to front along the tunnel longitudinal direction in the constructed water-rich soil area; Step 202, the initial spraying concrete is sprayed on the inner side wall of the left upper guide hole hole body (1-1) to form an initial spraying concrete spraying layer (4-1); Step 203, a plurality of steel arches (4) are installed in the initial spraying concrete spraying layer (4-1) along the tunnel longitudinal extension direction; wherein the outer side of the steel arch (4) and the initial spraying concrete spraying layer (4-1) are hung with a steel mesh (4-5), the outer sides of a plurality of steel arches (4) are welded with outer longitudinal connecting ribs (4-3), the steel mesh (4-5) and the outer longitudinal connecting rib (4-3) are bound, and the steel mesh (4-5) is laid on the initial spraying concrete spraying layer (4-1); Step 204, inner longitudinal connecting ribs (4-2) are welded on the inner sides of a plurality of steel arches (4); wherein the lower part of the steel arch (4) is constructed with a locking foot anchor to reinforce the steel arch (4); Step 205, according to the system anchor design spacing, geotextile (5-1) is filled in the outer end of the hollow steel pipe (5), and then the hollow steel pipe (5) is installed between adjacent two steel arches (4); wherein the outer end of the hollow steel pipe (5) near the left upper guide hole hole body (1-1) penetrates the steel mesh (4-5) and is attached to the initial spraying concrete spraying layer (4-1), the outer side wall of the outer end of the hollow steel pipe (5) is welded with the outer longitudinal connecting rib (4-3), the inner end of the hollow steel pipe (5) extends out of the inner longitudinal connecting rib (4-2) by 1mm-2mm, the outer side wall of the inner end of the hollow steel pipe (5) is welded with the inner longitudinal connecting rib (4-2), and the length direction of the hollow steel pipe (5) is perpendicular to the length direction of the outer longitudinal connecting rib (4-3) and the inner longitudinal connecting rib (4-2); Step 206, geotextile (5-1) is filled in the inner end of the hollow steel pipe (5), and an iron wire (5-2) is arranged in the center of the geotextile (5-1); Step 208, the secondary spraying concrete forms a secondary spraying concrete spraying layer (4-4); Step 209, before the final setting of the re-sprayed concrete layer (4-4), a square groove (6) is formed at the extension of the iron wire (5-2) by chiseling, until the bottom of the square groove (6) is flush with the inner end of the hollow steel pipe (5); Step 20A, the iron wire (5-2) is operated to pull out the geotextile (5-1) filled in the inner end of the hollow steel pipe (5); Step 20B, drilling along the hollow steel pipe (5) to form a system anchor hole, and installing a system anchor (7) in the system anchor hole; wherein the system anchor (7) extends into the surrounding rock of the left upper pilot hole (1-1); Step 20C, installing an anchor pad (8) at the extension end of the system anchor (7); wherein the anchor pad (8) is located in the square groove (6); Step 20D, spraying concrete at the square groove (6) to flush with the re-sprayed concrete layer (4-4), completing the initial support of the left upper hole body; Step 20E, according to the method described in steps 201 to 20D, the left middle pilot hole is excavated to form a left middle pilot hole (1-2) and complete the initial support (1-21) of the left middle hole body in the rich water soil area along the tunnel longitudinal direction from back to front; Step 20F, according to the method described in steps 201 to 20D, the left lower pilot hole is excavated to form a left lower pilot hole (1-3) and complete the initial support (1-31) of the left lower hole body in the rich water soil area along the tunnel longitudinal direction from back to front.

6. A water-rich, large cross-section, earthwork tunnel excavation construction method according to claim 1, characterized in that: The specific process of the system anchor (7) penetrating the first row of engaged rotary piles (10), the second row of engaged rotary piles (20) and the third row of engaged rotary piles (30) in steps two to four is as follows: Step C01, a resin anchor agent bag is placed into the hole bottom of the system anchor hole through the system anchor hole in step 20B; Step C02, the system anchor (7) is installed in the system anchor hole, and after the system anchor (7) is inserted into the drill hole with the resin anchor agent bag by rotating the drill, the anchor agent is stirred by rotation and filled along the length direction of the system anchor hole, until the resin anchor agent extends and fills the drill hole section penetrating the first row of engaged rotary piles (10), the second row of engaged rotary piles (20) and the third row of engaged rotary piles (30), completing the installation of the system anchor (7).

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