Construction method for rapid and safe shield tunneling out of a hole based on lacustrine deposit soft water-rich stratum

Abstract

The application discloses a construction method for rapid and safe shield tunneling based on lacustrine deposit soft water-rich stratum, which comprises the following steps: 1, reinforcing the shield end; 2, tunneling by the shield machine; 3, removing the first layer of concrete structure; 4, removing the second layer of concrete structure; 5, removing the third layer of concrete structure; 6, grouting of the first grouting hole; 7, grouting of the second grouting hole; and 8, tunneling by the shield machine. In the application, the top of the second layer of concrete structure is removed first, so that the second layer of concrete structure is deformed, damaged, split and cracked during the tunneling by the shield machine, the speed of removal is greatly accelerated, the construction efficiency is improved, and the receiving time of the shield machine is shortened. The grouting hole assembly is grouted from the ground to the tunnel, water channels behind the segments are timely filled, the problems of slow grouting speed and small grouting range in the tunnel are solved, the purpose of rapid tunneling is achieved, and the effect of rapid water stopping at the tunnel portal is achieved.

Description

Technical Field

[0001] This invention belongs to the field of shield tunneling technology, and in particular relates to a construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata. Background Technology

[0002] During tunnel boring machine (TBM) construction, the presence of soft, water-rich strata, specifically lacustrine sedimentary formations containing peat, clay, silt, and sand, along with a high water table and high water content, poses significant challenges. These include end-face reinforcement failure, inability to quickly seal mud and sand inrushes at the tunnel entrance after exiting the tunnel, ground collapse, and severe end-face settlement. These situations necessitate emergency repairs, which prolong the TBM construction time and increase the risk of uncontrollable problems. Furthermore, the TBM receiving process may tear sections of the tunnel entrance curtain, increasing the risk of water inrushes. During exiting the tunnel, gaps in the curtain's hinge plates and segment seals, combined with the pressure of groundwater in the soft, water-rich strata, can cause leaks at the tunnel entrance and other locations. Without effective solutions, prolonged exit time exacerbates groundwater and soil erosion due to these common exit leaks, creating water channels and further increasing the risks of exit construction. During the reception process in conventional soft and water-rich strata, the long time required to excavate the tunnel portal and the untimely grouting reinforcement often result in the gaps between the back of the tunnel segments and the reinforced soil not being filled in time, leading to the formation of water flow channels. This increases the risk of water and mud inrush at the tunnel portal and extends the tunnel boring machine reception time. Summary of the Invention

[0003] The technical problem this invention aims to solve is to address the shortcomings of the existing technology by providing a construction method for rapid and safe tunneling of a shield tunneling machine based on lacustrine sedimentary soft and water-rich strata. This method involves first chiseling away the top of the second-layer concrete structure to create a chiseling channel. This causes deformation, breakage, and cracking of the second-layer concrete structure during the tunneling process, providing favorable conditions for the tunnel portal removal. Because the diaphragm wall cracks under the thrust of the shield machine, the chiseling speed is greatly accelerated, improving construction efficiency and shortening the shield machine's receiving time. During the shield tunneling process... During the tunnel boring machine's passage through the reinforced structure, grouting is performed using grouting holes opened from the ground into the tunnel. This promptly fills the water channels behind the tunnel segments, compensating for the slow grouting speed and small grouting area within the tunnel. It can quickly fill the gaps between the tunnel segments and the tunnel boring machine after passage, sealing the water channels in a timely manner. This allows for rapid exit of the tunnel after the tunnel boring machine has completely exited, reducing the impact on the surrounding environment and minimizing ground settlement. Simultaneously, it achieves rapid water sealing at the tunnel entrance, ensuring safe reception. Furthermore, it saves a significant amount of time for ground road restoration after the tunnel boring machine construction is completed, accelerating the construction progress.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata, characterized in that: the method includes the following steps:

[0005] Step 1: Reinforcement of the shield tunnel end, the process is as follows:

[0006] Step 101: Reinforce the station end using high-pressure jet grouting or triaxial mixing to form a reinforced body. Open multiple detection holes on the side of the reinforced body near the tunnel entrance and observe the total water flow in the detection holes. If the total water flow exceeds 30 liters / hour, proceed to step 102; otherwise, proceed to step 2.

[0007] Step 102: Fill the cracks in the reinforced body using the WSS two-liquid grouting method;

[0008] Step 2, Tunnel Boring Machine Excavation: The tunnel boring machine (TBM) excavates along the designed route into the reinforced body. When the cutterhead of the TBM reaches a distance of two rings of tunnel segments from the diaphragm wall, the excavation work is stopped, and the portal removal begins. The TBM's excavation speed is 10mm / min to 15mm / min, and the pressure at the top of the soil chamber is 70% of the normal value.

[0009] Step 3: Remove the first layer of concrete structure: Manually remove the first layer of concrete structure on the side of the diaphragm wall construction section away from the tunnel boring machine inside the tunnel portal, and then cut off the first layer of reinforcing steel structure; wherein, the diaphragm wall construction section is the area on the diaphragm wall with a cross-sectional area equal to that of the tunnel portal, and the central axis of the diaphragm wall construction section coincides with the central axis of the tunnel portal;

[0010] Step 4: Remove the second layer of concrete structure, as follows;

[0011] Step 401: Remove the top of the second-layer concrete structure until the top of the second-layer concrete structure is penetrated to form a removal channel, and then suspend the removal work; wherein the removal channel is laid out along the extension direction of the tunnel, and the height of the removal channel is 1 / 10 of the height of the second-layer concrete structure.

[0012] Step 402: Start the tunnel boring machine (TBM) and continue tunneling. When the TBM reaches the second layer of concrete structure and irregular cracks appear in the second layer, the TBM stops tunneling and continues to remove the second layer of concrete structure from top to bottom, removing up to 2 / 3 of the height of the second layer. The tunneling speed of the TBM is 8mm / min to 10mm / min, and the pressure at the top of the soil chamber is 50% of the normal value.

[0013] Step 403: Use a drilling and grouting machine to drill grouting hole assembly on the ground. The grouting hole assembly includes multiple first grouting holes, multiple second grouting holes, and multiple third grouting holes arranged along the extension direction of the tunnel.

[0014] Step 404: Install the curtain folding plate on the upper part of the tunnel entrance of the main structure of the station, with an installation height of 2 / 3 of the tunnel entrance height; continue to chisel away the remaining part of the second layer of concrete structure, and after the chiseling is completed, install the curtain folding plate on the lower part to complete the overall installation of the curtain folding plate;

[0015] Step 5: Remove the third layer of concrete structure: Start the tunnel boring machine and continue tunneling. When the cutterhead of the tunnel boring machine reaches the third layer of concrete structure, the cutterhead cuts the third layer of concrete structure and enters the area of ​​the second layer of concrete structure. At the same time, the second layer of steel reinforcement structure is cut off. When the amount of steel reinforcement in the second layer of steel reinforcement structure is cut off, the tunnel boring machine stops tunneling and the debris and excess steel reinforcement generated by cutting are cleaned up.

[0016] Step Six: Grouting of the First Grouting Hole, the process is as follows:

[0017] Step 601: Start the tunnel boring machine to continue tunneling. When the front shield of the tunnel boring machine passes through the curtain folding plate, tighten the curtain folding plate.

[0018] Step 602: When the tail shield of the tunnel boring machine reaches the first grouting hole, the drilling and grouting machine is used to grout into the water channel through the first grouting hole.

[0019] Step 7: Grouting of the second grouting hole: The tunnel boring machine continues to excavate. When the tail shield reaches the second grouting hole, the drilling and grouting machine is used to grout into the water channel through the second grouting hole. When the tail shield reaches a distance of 2m from the third grouting hole, the tunnel boring machine stops excavating.

[0020] Step 8, Tunnel Boring Machine Exit: After stopping tunneling for 1.5 hours, the tunnel boring machine is restarted to continue tunneling. When the cutterhead of the tunnel boring machine moves onto the support, the drilling and grouting machine is used to continue grouting into the water channel through the third grouting hole. After the grouting of the third grouting hole is completed, the entire tunnel boring machine exits the tunnel and moves onto the support.

[0021] The above-mentioned construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata is characterized in that: in step 101, the solidification body is a cubic structure, the length of the solidification body is equal to the length of the shield body, and the width and height of the solidification body are both 3m to 5m greater than the diameter of the tunnel.

[0022] The above-mentioned construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata is characterized in that: in step 101, the number of detection holes is five, of which one detection hole is located at the center of the tunnel, and the other four detection holes are located on the outer side of the center of the tunnel, and the other four detection holes are evenly distributed along the circumference of the tunnel; the depth of the detection hole is not less than 3m, and the diameter of the detection hole Φ is 45mm~50mm.

[0023] The above-mentioned construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata is characterized in that: in step three, the underground continuous wall construction section includes a first layer of concrete structure located on the side away from the shield machine, a third layer of concrete structure located on the side closer to the shield machine, and a second layer of concrete structure located between the third layer of concrete structure and the first layer of concrete structure; a first layer of reinforcing steel structure is provided between the first layer of concrete structure and the second layer of concrete structure, and a second layer of reinforcing steel structure is provided between the third layer of concrete structure and the second layer of concrete structure.

[0024] The above-mentioned construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata is characterized in that: in step 403, the first grouting hole is located at 1 / 3 of the length of the reinforced body, and multiple first grouting holes are arranged along the width direction of the tunnel; the second grouting hole is located at 2 / 3 of the length of the reinforced body, and multiple second grouting holes are arranged along the width direction of the tunnel; the third grouting hole is located at the connection between the reinforced body and the underground continuous wall, and multiple third grouting holes are arranged along the width direction of the tunnel.

[0025] The above-mentioned construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata is characterized in that: in steps 602, 7, and 8, the grouting volume in the first grouting hole, the second grouting hole, and the third grouting hole is 1 m³. 3 ~3m 3 The grouting pressure in the first grouting hole, the second grouting hole, and the third grouting hole is 0.3MPa~0.4MPa.

[0026] The above-mentioned construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata is characterized in that: in steps two to eight, during the tunneling process of the shield machine, grouting is injected directly into the water channel from inside the tunnel using a grouting machine; and in steps 602, seven, and eight, during the grouting process using the integrated drilling and grouting machine, grouting is simultaneously injected into the water channel from inside the tunnel using a grouting machine.

[0027] The above-mentioned construction method for rapid and safe tunneling of shield tunnels based on lacustrine sedimentary soft and water-rich strata is characterized in that: the grouting fluid used in the drilling and grouting machine and the grouting machine is prepared with a mass ratio of water glass to cement slurry of 1.2:1.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. In this invention, the top of the second-layer concrete structure is first chiseled away to form a chiseling channel at the top. This causes the second-layer concrete structure to deform, break, and crack during the tunnel boring machine's excavation process, providing favorable conditions for the removal of the tunnel portal. Because the diaphragm wall cracks under the thrust of the tunnel boring machine, the chiseling speed can be greatly accelerated, construction efficiency can be improved, and the tunnel boring machine's receiving time can be shortened.

[0030] 2. During the tunnel boring machine's passage through the reinforced body, this invention utilizes grouting holes opened from the ground into the tunnel to inject grout, promptly filling the water channels behind the tunnel segments. This compensates for the slow grouting speed and small grouting area within the tunnel, quickly filling the gaps between the tunnel segments and the tunnel boring machine, and sealing the water channels in a timely manner. This allows for rapid exit of the tunnel after the tunnel boring machine has completely exited, reducing the impact on the surrounding environment and minimizing ground settlement. Simultaneously, it achieves rapid water-stopping at the tunnel entrance, ensuring safe reception. Furthermore, it saves significant time for ground road restoration after the tunnel boring machine construction is completed, accelerating the construction progress.

[0031] 3. When the tail shield advances to the first grouting hole, the present invention uses the first grouting hole to inject grout into the water flow channel in order to quickly fill the area between the adjacent shield segment and the reinforced body, i.e. the water flow channel, and quickly form a strong water-stopping ring behind the shield segment.

[0032] 4. After grouting the second grouting hole is completed, the tunneling needs to be stopped for 1.5 hours to allow time for grouting reinforcement and grout solidification. This allows the water flow channel to be sealed to the maximum extent. At this time, the tunnel boring machine has not detached from the reinforced body and has not completely opened the water flow channel. In a static state, the grout can fill the water flow channel well and block the water flow channel to a large extent.

[0033] In summary, this invention first removes the top of the second-layer concrete structure, creating a removal channel. This causes deformation, breakage, and cracking of the second-layer concrete structure during tunnel boring machine (TBM) excavation, providing favorable conditions for portal removal. The cracking of the diaphragm wall under the thrust of the TBM greatly accelerates the removal process, improving construction efficiency and shortening the TBM's receiving time. During the TBM's passage through the reinforced structure, grouting is performed using grouting holes opened from the ground into the tunnel. This promptly fills the water channels behind the tunnel segments, compensating for the slow grouting speed and small grouting area within the tunnel. This quickly fills the gaps between the TBM segments and the TBM, sealing the water channels and enabling rapid exit after the TBM has completely exited the tunnel, reducing the impact on the surrounding environment and minimizing ground subsidence. Simultaneously, it achieves rapid water sealing at the portal, ensuring safe reception and saving significant time for ground restoration after TBM construction, thus accelerating the overall construction progress.

[0034] 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

[0035] Figure 1 This is a schematic diagram showing the location layout of the detection holes in this invention.

[0036] Figure 2 This is a structural schematic diagram of the underground continuous wall construction section of the present invention.

[0037] Figure 3 This is a schematic diagram showing the location layout of the grouting hole assembly of the present invention.

[0038] Figure 4 This is a schematic diagram of the construction state during grouting of the first grouting hole of the present invention.

[0039] Figure 5 This is a schematic diagram of the construction state during grouting of the second grouting hole of the present invention.

[0040] Figure 6 This is a schematic diagram of the construction state when the tunnel boring machine of the present invention has fully exited the tunnel.

[0041] Figure 7 This is a schematic diagram illustrating the construction process of simultaneous grouting on the ground and inside the tunnel according to the present invention.

[0042] Figure 8 This is a flowchart of the method of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1—Entrance; 2—Solidified body; 3—Detection hole;

[0045] 4—Shield tunneling machine; 5—Cutoff head; 6—Diaphragm wall;

[0046] 7—First layer concrete structure; 8—First layer reinforced concrete structure; 9—Second layer concrete structure;

[0047] 10—Shield tunnel segments; 11—Ground surface; 12—Drilling and grouting machine;

[0048] 13—Tunnel; 14—Grouting machine; 15—Third layer concrete structure;

[0049] 16—Second layer steel reinforcement structure; 17—Front shield; 18—Curtain folding plate;

[0050] 19—First grouting hole; 20—Water flow channel; 21—Second grouting hole;

[0051] 22—Third grouting hole; 23—Tail shield; 24—Formation;

[0052] 25—The main structure of the station. Detailed Implementation

[0053] like Figures 1 to 8 The method shown is a rapid and safe tunneling method for shield tunneling based on lacustrine sedimentary soft and water-rich strata. The method includes the following steps:

[0054] Step 1: Reinforcement of the shield tunnel end, the process is as follows:

[0055] Step 101: Reinforce the station end using high-pressure jet spraying or triaxial mixing to form a reinforced body 2 at the station end. Open multiple detection holes 3 on the side of the reinforced body 2 near the tunnel entrance 1 and observe the total flow rate in the detection holes 3. If the total flow rate exceeds 30 liters / hour, proceed to step 102; otherwise, proceed to step 2.

[0056] Step 102: Fill the cracks of the reinforced body 2 using the WSS two-liquid grouting method;

[0057] Step 2, Tunnel Boring Machine Excavation: Tunnel Boring Machine 4 excavates along the designed route into the reinforced body 2. When the cutterhead 5 of Tunnel Boring Machine 4 reaches a distance of two rings of tunnel segments from the diaphragm wall 6, the excavation work is stopped, and the portal removal begins. The tunneling speed of Tunnel Boring Machine 4 is 10mm / min to 15mm / min, and the pressure at the top of the soil chamber is 70% of the normal value.

[0058] Step 3: Remove the first layer of concrete structure: Manually remove the first layer of concrete structure 7 on the side of the diaphragm wall construction section away from the tunnel boring machine 4 inside the portal 1, and then cut the first layer of steel reinforcement structure 8; wherein, the diaphragm wall construction section is the area on the diaphragm wall 6 with a cross-sectional area equal to that of the portal 1, and the central axis of the diaphragm wall construction section coincides with the central axis of the portal 1.

[0059] Step 4: Remove the second layer of concrete structure, as follows;

[0060] Step 401: Remove the top of the second layer of concrete structure 9 until the top of the second layer of concrete structure 9 is penetrated to form a removal channel, and then suspend the removal work; wherein the removal channel is arranged along the extension direction of the tunnel 13, and the height of the removal channel is 1 / 10 of the height of the second layer of concrete structure 9.

[0061] Step 402: Start the tunnel boring machine 4 and continue tunneling. When the tunnel boring machine 4 reaches the second layer of concrete structure 9 and irregular cracks appear in the second layer of concrete structure 9, the tunnel boring machine 4 stops tunneling and continues to remove the second layer of concrete structure 9 from top to bottom. The removal height is 2 / 3 of the height of the second layer of concrete structure 9. The tunneling speed of the tunnel boring machine 4 is 8mm / min to 10mm / min, and the pressure value at the top of the soil chamber is 50% of the normal value.

[0062] Step 403: Use the drilling and grouting machine 12 to drill grouting hole assembly on the ground 11. The grouting hole assembly includes a plurality of first grouting holes 19, a plurality of second grouting holes 21, and a plurality of third grouting holes 22 arranged along the extension direction of the tunnel 13.

[0063] Step 404: Install the curtain folding plate 18 on the upper part of the portal 1 of the main structure 25 of the station, with an installation height of 2 / 3 of the height of the portal 1; continue to chisel away the remaining part of the second layer of concrete structure 9, and after the chiseling is completed, install the curtain folding plate 18 on the lower part to complete the overall installation of the curtain folding plate 18.

[0064] Step 5: Remove the third layer of concrete structure: Start the tunnel boring machine 4 and continue tunneling. When the cutterhead 5 of the tunnel boring machine 4 reaches the third layer of concrete structure 15, the cutterhead 5 cuts the third layer of concrete structure 15 and enters the area of ​​the second layer of concrete structure 9. At the same time, it cuts the second layer of steel reinforcement structure 16. When the amount of steel reinforcement cut in the second layer of steel reinforcement structure 16 reaches 80%, the tunnel boring machine 4 stops tunneling and cleans up the slag and excess steel reinforcement generated by cutting.

[0065] Step Six: Grouting of the First Grouting Hole, the process is as follows:

[0066] Step 601: Start the tunnel boring machine 4 to continue tunneling. When the front shield 17 of the tunnel boring machine 4 exits the curtain folding plate 18, tighten the curtain folding plate 18.

[0067] Step 602: When the tail shield 23 of the tunnel boring machine 4 moves to the first grouting hole 19, the drilling and grouting machine 12 is used to grout into the water flow channel 20 through the first grouting hole 19.

[0068] Step 7: Grouting of the second grouting hole: The tunnel boring machine 4 continues to excavate. When the tail shield 23 reaches the second grouting hole 21, the drilling and grouting machine 12 grouts into the water channel 20 through the second grouting hole 21. When the tail shield 23 reaches a distance of 2m from the third grouting hole 22, the tunnel boring machine 4 stops excavating.

[0069] Step 8, Tunnel Boring Machine Exit: After 1.5 hours of stopping tunneling, Tunnel Boring Machine 4 is restarted to continue tunneling. When the cutterhead 5 of Tunnel Boring Machine 4 moves onto the support, the drilling and grouting machine 12 continues to grout into the water channel 20 through the third grouting hole 22. After the grouting of the third grouting hole 22 is completed, Tunnel Boring Machine 4 completely exits the tunnel and moves onto the support.

[0070] In this invention, the top of the second-layer concrete structure 9 is first chiseled away to form a chiseling channel at the top. This causes the second-layer concrete structure 9 to deform, break, and crack during the tunneling process of the tunnel boring machine 4, providing favorable conditions for the removal of the tunnel portal. Because the diaphragm wall cracks under the thrust of the tunnel boring machine, the chiseling speed can be greatly accelerated, the construction efficiency can be improved, and the receiving time of the tunnel boring machine 4 can be shortened.

[0071] During the process of the tunnel boring machine 4 passing through the reinforced body 2, the present invention utilizes grouting hole components opened from the ground 11 into the tunnel 13 to inject grout, promptly filling the water flow channel behind the tunnel segments. This compensates for the slow grouting speed and small grouting range inside the tunnel, and can quickly fill the gap between the tunnel segments 10 and the tunnel boring machine 4 after passage, sealing the water flow channel 20 in a timely manner. After the tunnel boring machine 4 has completely exited the tunnel, it achieves the purpose of rapid exit, reducing the impact on the surrounding environment and reducing ground settlement. At the same time, it can achieve a rapid water-stopping effect at the tunnel entrance, ensuring safe reception. It also saves a lot of time for ground road restoration after the completion of the tunnel boring construction, thus accelerating the construction progress.

[0072] When the tail shield 23 advances to the first grouting hole 19, the present invention uses the first grouting hole 19 to inject grout into the water flow channel 20 in order to quickly fill the area between the adjacent shield segment 10 and the solidified body 2, i.e. the water flow channel 20, and quickly form a strong water-stopping ring behind the shield segment 10.

[0073] After grouting is completed at the second grouting hole 21, the tunneling needs to be stopped for 1.5 hours to allow time for grouting reinforcement and grout solidification. This allows the water flow channel 20 to be sealed to the maximum extent. At this time, the tunnel boring machine 4 has not detached from the reinforcement body 2 and has not completely opened the water flow channel 20. In a static state, the grout can fill the water flow channel 20 well and block the water flow channel 20 to a large extent.

[0074] It should be noted that, due to the separate excavation of the diaphragm wall construction section in steps three to five, combined with the tunneling of the tunnel boring machine 4, the excavation speed of the diaphragm wall construction section is accelerated; in steps six to eight, the combination of ground grouting and tunnel grouting is used to seal the water flow channel 20 in a timely manner, which can immediately achieve the effect of sealing the water inflow at the tunnel entrance after the tunnel boring machine 4 exits the tunnel, greatly shortening the receiving time of the tunnel boring machine 4.

[0075] In actual construction, in step one, the station end is reinforced in stratum 24 to form reinforced body 2. In step two, before the tunnel boring machine 4 enters the reinforced body 2, i.e., when the distance between the tunnel boring machine 4 and the underground continuous wall 6 is 6m, dewatering wells are constructed. Because premature dewatering increases the impact of surrounding environmental settlement, dewatering is carried out after the tunnel boring machine enters the reinforced area to reduce the impact on the surrounding environment. Furthermore, the dewatering wells must be constructed after all reinforcement processes are completed to avoid cement slurry clogging the well pipes during the reinforcement process. During the excavation within the reinforced body 2, the soil pressure is gradually reduced to prepare for exiting the tunnel.

[0076] In step three, when removing the first layer of concrete structure 7, the excavated concrete needs to be removed to prevent the debris from accumulating inside the hole.

[0077] In steps 401 and 402, during the tunneling process, the diaphragm wall portal structure, under the thrust of the tunnel boring machine 4 and the earth pressure, and due to the passage formed by the top concrete of the second layer of the diaphragm wall, deforms, breaks, and cracks, providing favorable conditions for the portal removal. The portal removal is entirely manual, involving high-strength concrete and a confined working space, making construction quite difficult. However, the cracks in the diaphragm wall caused by the tunnel boring machine's thrust greatly accelerate the removal process, improving efficiency. It is important to note that construction work in front of the portal must be suspended during the tunneling process of the tunnel boring machine 4 to prevent concrete fragments from breaking off and injuring workers.

[0078] In step five, the excavated soil generated during the cutting of the third-layer concrete structure 15 by the tunnel boring machine 4 is transported to the surface by a battery-powered vehicle. It is important to note that after the cutterhead 5 reaches the third-layer concrete structure 15, due to the prolonged shutdown of the tunnel boring machine in the water-rich strata, some water accumulates in the cutterhead's soil chamber. This water may flow out the moment the diaphragm wall is penetrated, requiring timely pumping of the water from the tunnel receiving shaft. Additionally, at this point, the cutterhead 5 is positioned inside the curtain and has not completely penetrated it. While the outer side of the cutterhead and the reinforcement 2 are tightly fitted, the high groundwater pressure inevitably creates a small initial water flow channel in the soft, water-rich soil strata, leading to initial water inrush at the tunnel portal. During this process, one ring of tunnel segments needs to be pre-stored inside tunnel 13, and another ring above the battery-powered vehicle, achieving the goal of storing two rings of tunnel segments within the tunnel. This allows the tunnel boring machine 4 to pass through the folding plate continuously and quickly, reducing the time spent at the critical position of the folding plate at the tunnel portal. After clearing away the debris, the concrete debris and excess steel bars at the bottom of the steel ring should be cleaned separately to prevent concrete residue from damaging the curtain flaps during the tunnel boring machine's exit. One of the most common reasons for incomplete sealing of water leakage during tunnel boring machine exit is that the bottom curtain flap is damaged and continues to leak, preventing the tunnel entrance from being sealed quickly.

[0079] In step 602, the water flow channel 20 is formed due to the difference between the shield excavation diameter of the tunnel boring machine 4 and the outer diameter of the shield segment 10. The drilling depth of the first grouting hole 19 is calculated based on the shield burial depth. If a sudden increase in drilling speed or a distance of 30cm to 50cm from the shield segment 10 occurs during drilling, drilling is stopped, and ground grouting begins. The parameters of the grouting fluid used for ground grouting and tunnel grouting are the same. The purpose of grouting the first grouting hole 19 is to quickly fill the area between the adjacent shield segment 10 and the reinforced body 2, i.e., the water flow channel 20, and quickly form a strong water-stopping ring behind the shield segment 10. After the grouting pressure or grouting volume reaches the target, continue lifting the drill rod by 1 meter and re-grout. The purpose of grouting at this time is to quickly fill the cracks caused by the settlement of the ground reinforced soil after the tunnel boring machine passes through the reinforced area, and to promptly fill the rock mass cracks with grout to seal the cracks in the reinforced soil, thereby achieving the effect of filling the rock mass cracks and creating water flow channels.

[0080] In step seven, when the tail shield 23 travels to a distance of 2m from the edge of the solidified body 2, the tunnel boring machine 4 needs to stop tunneling for 1.5 hours to allow time for grouting reinforcement and grout solidification. After the second grouting hole 21 is fully grouted, the early-stage water flow channel 20 is sealed to the maximum extent. At this time, the tunnel boring machine 4 has not detached from the solidified body 2 and has not completely opened the water flow channel 20. In a static state, the grout can fill the water flow channel 20 well and can block the water flow channel 20 to a large extent.

[0081] In this embodiment, in step 101, the solid reinforcement 2 is a cubic structure, the length of the solid reinforcement 2 is equal to the length of the shield body, and the width and height of the solid reinforcement 2 are 3m to 5m greater than the diameter of the tunnel 13.

[0082] During actual construction, the length of the reinforcement body 2 is equal to the length of the shield body, which is 9m; the diameter of the tunnel 13 is 6.2m, and the width and height of the reinforcement body 2 are both 6m greater than the diameter of the tunnel 13, that is, 3m at each end, and the width and height of the reinforcement body 2 are both 12.2m.

[0083] like Figure 1 As shown in this embodiment, in step 101, the number of detection holes 3 is five. Of the five detection holes 3, one detection hole 3 is located at the center of the tunnel 13, and the other four detection holes 3 are located on the outer side of the center of the tunnel 13, and the other four detection holes 3 are evenly distributed along the circumference of the tunnel 13. The depth of the detection hole 3 is not less than 3m, and the diameter Φ of the detection hole 3 is 45mm~50mm.

[0084] In actual construction, the depth of the detection hole 3 is preferably 3m, and the diameter Φ of the detection hole 3 is preferably 48mm.

[0085] like Figure 2 As shown in this embodiment, in step three, the underground continuous wall construction section includes a first layer of concrete structure 7 located on the side away from the tunnel boring machine 4, a third layer of concrete structure 15 located on the side close to the tunnel boring machine 4, and a second layer of concrete structure 9 located between the third layer of concrete structure 15 and the first layer of concrete structure 7; a first layer of reinforcing steel structure 8 is provided between the first layer of concrete structure 7 and the second layer of concrete structure 9, and a second layer of reinforcing steel structure 16 is provided between the third layer of concrete structure 15 and the second layer of concrete structure 9.

[0086] like Figure 3 As shown, in this embodiment, in step 403, the first grouting hole 19 is located at 1 / 3 of the length of the reinforced body 2, and a plurality of the first grouting holes 19 are arranged along the width direction of the tunnel 13; the second grouting hole 21 is located at 2 / 3 of the length of the reinforced body 2, and a plurality of the second grouting holes 21 are arranged along the width direction of the tunnel 13; the third grouting hole 22 is located at the connection between the reinforced body 2 and the underground continuous wall 6, and a plurality of the third grouting holes 22 are arranged along the width direction of the tunnel 13.

[0087] In this embodiment, in steps 602, 7, and 8, the grouting volume in the first grouting hole 19, the second grouting hole 21, and the third grouting hole 22 is 1m³. 3 ~3m3 The grouting pressure in the first grouting hole 19, the second grouting hole 21 and the third grouting hole 22 is 0.3MPa~0.4MPa.

[0088] like Figure 7 As shown, in this embodiment, during steps two to eight, the tunnel boring machine 4 uses a grouting machine 14 to directly inject grout into the water channel 20 from inside the tunnel 13 during the tunneling process; and in steps 602, seven and eight, during the grouting process using the drilling and grouting machine 12, the grouting machine 14 is used simultaneously to inject grout into the water channel 20 from inside the tunnel 13.

[0089] During actual construction, the grouting volume inside the tunnel was 0.3 m³. 3 ~0.6m 3 Grouting is carried out ring by ring; surface grouting and tunnel grouting are conducted simultaneously to accelerate the formation of the water-stop ring and quickly seal the water flow channels behind the tunnel segments. Additionally, during surface grouting, grout may flow into dewatering wells from underground fissures, potentially clogging the well pumps; therefore, dewatering operations are suspended at this time. During this period, it is necessary to intensify monitoring of the tunnel segments, including monitoring crown settlement and horizontal convergence, to prevent excessive grouting pressure from damaging the segments or compromising their waterproof seal. Meanwhile, the tunnel boring machine continues to excavate and assemble the tunnel segments according to the normal construction procedure.

[0090] In this embodiment, the grouting fluid used when grouting with the drilling and grouting machine 12 and the grouting machine 14 is prepared with a mass ratio of water glass to cement grout of 1.2:1.

[0091] In actual construction, the water glass used is 35BE~40BE concentration, the grouting volume is 1.2m³~1.5m³, and the grouting sequence is top to bottom, symmetrical and uniform grouting from left to right, grouting ring by ring. The main purpose of increasing the volume of water glass during grouting is to quickly stop water behind the tunnel lining segments, and secondly to accelerate the initial setting of the synchronously injected grout.

[0092] 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 construction method for rapid and safe tunneling of shield tunnels in lacustrine sedimentary soft, water-rich strata, characterized in that: The method includes the following steps: Step 1: Reinforcement of the shield tunnel end, the process is as follows: Step 101: Reinforce the station end using high-pressure jet spraying or triaxial mixing to form a reinforced body (2) at the station end. On the reinforced body (2), open multiple detection holes (3) on the side near the tunnel entrance (1) and observe the total flow rate in the detection holes (3). If the total flow rate exceeds 30 liters / hour, proceed to step 102; otherwise, proceed to step 2. Step 102: The solidified body (2) is filled with crack grout using the WSS two-liquid grouting method; Step 2, Tunneling: The tunnel boring machine (4) tunnels along the designed route into the reinforced body (2). When the cutterhead (5) of the tunnel boring machine (4) reaches a distance of two rings of tunnel segments from the underground continuous wall (6), the tunneling work is stopped and the portal removal begins. The tunneling speed of the tunnel boring machine (4) is 10 mm / min to 15 mm / min, and the pressure at the top of the soil chamber is 70% of the normal value. Step 3: Remove the first layer of concrete structure: Manually remove the first layer of concrete structure (7) on the side of the underground continuous wall construction section away from the tunnel boring machine (4) inside the portal (1), and then cut the first layer of steel reinforcement structure (8); wherein, the underground continuous wall construction section is the area on the underground continuous wall (6) with the same cross-sectional area as the portal (1), and the central axis of the underground continuous wall construction section coincides with the central axis of the portal (1); Step 4: Remove the second layer of concrete structure, as follows: Step 401: Remove the top of the second layer of concrete structure (9) until the top of the second layer of concrete structure (9) is penetrated to form a removal channel, and then stop the removal work; wherein the removal channel is laid out along the extension direction of the tunnel (13), and the height of the removal channel is 1 / 10 of the height of the second layer of concrete structure (9). Step 402: Start the tunnel boring machine (4) and continue tunneling. When the tunnel boring machine (4) reaches the second layer of concrete structure (9) and irregular cracks appear in the second layer of concrete structure (9), the tunnel boring machine (4) stops tunneling and continues to remove the second layer of concrete structure (9) from top to bottom. The removal height is 2 / 3 of the height of the second layer of concrete structure (9). The tunneling speed of the tunnel boring machine (4) is 8mm / min to 10mm / min, and the pressure value at the top of the soil chamber is 50% of the normal value. Step 403: Use a drilling and grouting machine (12) to drill a grouting hole assembly on the ground (11). The grouting hole assembly includes a plurality of first grouting holes (19), a plurality of second grouting holes (21), and a plurality of third grouting holes (22) arranged along the extension direction of the tunnel (13). Step 404: Install the curtain folding plate (18) on the upper part of the portal (1) of the main structure (25) of the station, with an installation height of 2 / 3 of the height of the portal (1); continue to chisel away the remaining part of the second layer of concrete structure (9), and after the chiseling is completed, install the curtain folding plate (18) on the lower part to complete the overall installation of the curtain folding plate (18); Step 5: Remove the third layer of concrete structure: Start the tunnel boring machine (4) and continue tunneling. When the cutterhead (5) of the tunnel boring machine (4) reaches the third layer of concrete structure (15), the cutterhead (5) cuts the third layer of concrete structure (15) and enters the area of ​​the second layer of concrete structure (9). At the same time, the second layer of steel reinforcement structure (16) is cut off. When the amount of steel reinforcement cut off in the second layer of steel reinforcement structure (16) reaches 80%, the tunnel boring machine (4) stops tunneling and cleans up the slag and excess steel reinforcement generated by cutting. Step Six: Grouting of the First Grouting Hole, the process is as follows: Step 601: Start the tunnel boring machine (4) and continue tunneling. When the front shield (17) of the tunnel boring machine (4) exits the curtain folding plate (18), tighten the curtain folding plate (18). Step 602: When the tail shield (23) of the tunnel boring machine (4) moves to the first grouting hole (19), the drilling and grouting machine (12) is used to grout into the water channel (20) through the first grouting hole (19); Step 7, Grouting of the second grouting hole: The tunnel boring machine (4) continues to excavate. When the tail shield (23) reaches the second grouting hole (21), the drilling and grouting machine (12) grouts into the water channel (20) through the second grouting hole (21). When the tail shield (23) reaches a distance of 2m from the third grouting hole (22), the tunnel boring machine (4) stops excavating. Step 8, Tunnel Boring Machine Exit: After stopping tunneling for 1.5 hours, the tunnel boring machine (4) is restarted to continue tunneling. When the cutterhead (5) of the tunnel boring machine (4) moves onto the support, the drilling and grouting machine (12) continues to grout into the water channel (20) through the third grouting hole (22). After the grouting of the third grouting hole (22) is completed, the tunnel boring machine (4) completely exits the tunnel and moves onto the support. In step three, the underground continuous wall construction section includes a first layer of concrete structure (7) located on the side away from the shield machine (4), a third layer of concrete structure (15) located on the side close to the shield machine (4), and a second layer of concrete structure (9) located between the third layer of concrete structure (15) and the first layer of concrete structure (7); a first layer of steel reinforcement structure (8) is provided between the first layer of concrete structure (7) and the second layer of concrete structure (9), and a second layer of steel reinforcement structure (16) is provided between the third layer of concrete structure (15) and the second layer of concrete structure (9).

2. The construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata according to claim 1, characterized in that: In step 101, the solid body (2) is a cubic structure. The length of the solid body (2) is equal to the length of the shield body. The width and height of the solid body (2) are both 3m to 5m greater than the diameter of the tunnel (13).

3. The construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata according to claim 1, characterized in that: In step 101, there are five detection holes (3). One detection hole (3) is located at the center of the tunnel (13), and the other four detection holes (3) are located on the outer side of the center of the tunnel (13). The other four detection holes (3) are evenly distributed along the circumference of the tunnel (13). The depth of the detection hole (3) is not less than 3m, and the diameter Φ of the detection hole (3) is 45mm~50mm.

4. The construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata according to claim 1, characterized in that: In step 403, the first grouting hole (19) is located at 1 / 3 of the length of the solidified body (2), and a plurality of the first grouting holes (19) are arranged along the width direction of the tunnel (13); the second grouting hole (21) is located at 2 / 3 of the length of the solidified body (2), and a plurality of the second grouting holes (21) are arranged along the width direction of the tunnel (13); the third grouting hole (22) is located at the connection between the solidified body (2) and the underground continuous wall (6), and a plurality of the third grouting holes (22) are arranged along the width direction of the tunnel (13).

5. The construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata according to claim 1, characterized in that: In steps 602, 7, and 8, the grouting volume in the first grouting hole (19), the second grouting hole (21), and the third grouting hole (22) is 1 m³. 3 ~3m 3 The grouting pressure in the first grouting hole (19), the second grouting hole (21) and the third grouting hole (22) is 0.3MPa~0.4MPa.

6. The construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata according to claim 1, characterized in that: In steps two through eight, during the tunneling process of the shield machine (4), grouting machine (14) is used to directly inject grout into the water channel (20) from inside the tunnel (13); and in steps 602, seven and eight, during the grouting process using the drilling and grouting machine (12), grouting machine (14) is used simultaneously to inject grout into the water channel (20) inside the tunnel (13).

7. The construction method for rapid and safe tunneling of shield tunneling machines based on lacustrine sedimentary soft and water-rich strata according to claim 6, characterized in that: The grouting fluid used when grouting with the drilling and grouting machine (12) and the grouting machine (14) is prepared with a mass ratio of water glass to cement grout of 1.2:1.

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