Double-ring hoop-shaped grouting reinforcement structure for tunnel underpassing existing pipeline and construction method thereof

Abstract

This application discloses a double-ring grouting reinforcement structure and its construction method for tunnels passing under existing pipelines. The structure includes a double-ring grouting reinforcement zone, comprising an arc-shaped curing zone located below the pipeline, a semi-circular grouting reinforcement zone connected to and enclosing the pipeline, and a grouting isolation zone partially surrounding the pipeline. The grouting isolation zone is formed by injecting composite fiber ultra-high performance cement grout into a semi-circular grouting channel within it. This application utilizes a micro-disturbance trenchless grouting reinforcement technology, eliminating the need for complete excavation of the underground pipeline's overburden, significantly reducing pipeline reinforcement costs. It is highly applicable in both densely populated urban areas and uninhabited areas with complex terrain, and has minimal impact on the surrounding topography, vegetation, and other natural landscapes, thus contributing to environmental protection. It is particularly suitable for the reinforcement of key underground pipelines with large diameters and ultra-long lengths under other construction disturbances.

Description

Technical Field

[0001] This application relates to the field of underground pipeline safety control technology, specifically to a double-ring grouting reinforcement structure for tunnels passing under existing pipelines and its construction method. Background Technology

[0002] Underground pipelines are responsible for supplying gas, water, electricity, communications, and sewage in cities. Their proper functioning ensures the normal operation of urban life, making underground pipeline networks crucial for urban residents' lives and production. Simultaneously, with the accelerating pace of urbanization in my country and the increasing urban population density, the number and length of underground pipelines are also increasing year by year. Existing underground pipeline laying methods include overhead burial, trench burial, and tunnel laying. After the pipelines are buried to the appropriate depth in the strata using different burial methods, during normal operation, both the internal pressure of the pipeline and the pressure of the external soil act on the pipeline. That is, in the initial stable state, the pipeline is mainly subjected to internal pressure, surrounding soil load, and overlying traffic load.

[0003] However, during tunnel construction beneath existing underground pipelines, the excavation disturbs the strata, causing deformation. This deformation further exerts additional stress and deformation on the underground pipelines. When the additional stress on the pipeline exceeds its own deformation resistance, damage can occur, including leakage, breakage, excessive deformation, or even explosion. Furthermore, because underground pipelines are concealed works, controlling and maintaining their settlement and deformation is more difficult than for above-ground facilities. Based on indoor model tests, this invention employs an outer ring reinforcement technique for existing pipelines. Tunnel excavation model tests revealed that within a range twice the tunnel diameter, reinforcing the existing pipeline significantly reduces deformation and stress. The maximum settlement and maximum positive and negative bending moments are both lower than those of pipelines without reinforcement. By strengthening local nodes, the overall stiffness of the underground pipeline increases, enhancing its resistance to deformation and stress, thus reducing the impact of tunnel excavation on the underground pipeline. Summary of the Invention

[0004] The purpose of this application is to provide a double-ring grouting reinforcement structure and its construction method for tunnels passing under existing pipelines. The structure uses an annular grouting hardening zone formed around the pipeline to circumferentially constrain the underground pipeline, thereby reducing further settlement deformation of the pipeline due to soil settlement, reducing the additional bending moment caused by pipeline bending deformation, and reducing the disturbance impact of tunnel construction on the underground pipeline. This can solve at least one of the technical problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] This application provides a double-ring grouting reinforcement structure for tunnels passing under existing pipelines, including:

[0007] The double-ring grouting reinforcement zone includes an arc-shaped curing zone located below the pipe, a semi-circular grouting reinforcement zone connected to and wrapping the pipe, and a grouting isolation zone that partially surrounds the pipe. The grouting isolation zone is formed by grouting and filling composite fiber ultra-high performance cement grouting material into the semi-circular grouting channel within it.

[0008] Optionally, the composite fiber ultra-high performance cement grouting material comprises, by weight, 290-310 parts of 42.5 grade ordinary silicate cement grout, 15 parts of water glass, 20 parts of grade 1 fly ash, 15 parts of S75 grade slag, 43 parts of grade 2 silica fume, 3 parts of naphthalene sulfonate water-reducing agent, 38 parts of complex recycled fiber, and 100-120 parts of water.

[0009] Optionally, the water-cement ratio of the 42.5 grade ordinary silicate cement grout is 0.4 to 0.6; the cement grout seepage rate does not exceed 3% to 8%; and the naphthalene sulfonate water-reducing agent is a high-performance water-reducing agent with a water reduction rate of 18% to 25%.

[0010] Optionally, the complex recycled fiber includes ordinary steel fiber and recycled steel fiber from waste tires, with an aspect ratio of 45 to 50 and lengths of 3 mm, 5 mm, and 7 mm, mixed in a mass ratio of 4:2:1.

[0011] Optionally, one end of the double-ring grouting reinforcement zone is connected to the grout inlet end, and the other end is connected to the grout outlet end; the grout inlet end and the grout outlet end are excavated to a depth of 25-100cm at the average elevation of the leveled site, and the length and width of the excavation area are 6 times the diameter of the semi-circular grouting channel of the double-ring grouting reinforcement zone.

[0012] Optionally, the semi-circular grouting reinforcement zone is formed by grouting around the pipeline using a drilling rig, a grouting conduit connection device, and a vertical grouting conduit. The grouting conduit connection device consists of a cross-shaped grouting main pipe, five vertical grouting connection pipes, two L-shaped grouting connection pipes, four pipe connection tees, and several grouting sleeves connected by threads. The vertical grouting conduit is a steel grouting conduit with a diameter of 32mm. There are three grout outlets at the same height of the conduit, with an included angle of 120°. Grout outlet holes are also opened at the end of the grouting conduit to ensure that the grouting conduit can be grouted and reinforced in all directions.

[0013] Optionally, the arc-shaped curing zone is formed by grouting through a grouting pump and a grouting hose with a grout outlet in a semi-circular grouting channel drilled by the drill bit, drill control wire, and drill central control system acquisition vehicle; the grouting isolation zone is formed by grouting the composite fiber ultra-high performance cement grouting material into a semi-circular grouting channel formed by grouting the arc-shaped curing zone and then withdrawing the grouting hose.

[0014] Optionally, the grouting hose uses a 3-10mm steel spring as a support frame, is wrapped with a non-woven filter cloth layer, and then connected to a PE sleeve with a thickness of 2-5mm. The outermost layer is wrapped with nylon wire mesh, and pipe section connectors are set at both ends of the grouting hose to connect with steel locks.

[0015] Optionally, the grouting hose has multiple circular grout outlets within 1.4 times the diameter of the underground pipeline, with four outlets distributed on each cross-section within this range, and the spacing between each outlet is 100mm to 150mm. The grout outlets of the grouting hose have three forms based on the volume and shape of the outlet channel: within the central 0.4 times the diameter of the underground pipeline, the outlet channel is an inverted trapezoidal funnel shape with outlet angles of 97° and 67°; within the range of 0.4 to 0.9 times the diameter of the underground pipeline, the outlet channel is a cylinder with the same upper and lower cross-sectional area, with outlet angles of 105° and 75°; and within the range of 0.9 to 1.4 times the diameter of the underground pipeline, the outlet channel is an inverted cone shape, smaller at the top and larger at the bottom, with outlet angles of 111° and 81°.

[0016] This application also provides a construction method for the double-ring grouting reinforcement structure for tunnels passing under existing pipelines, including:

[0017] Step S1: Conduct a site survey around the grouting site to determine the surrounding geological conditions, the burial depth of existing pipelines, the horizontal position of the pipeline axis, the distance between the pipeline and the tunnel, the tunnel excavation diameter, and the direction of the pipeline and the tunnel within the grouting area.

[0018] Step S2: Complete the site leveling work, design the engineering drawings of the semi-circular grouting channel below the bottom of the pipeline based on the burial depth of the existing pipeline and the excavation diameter of the tunnel, calculate the length and depth to be drilled by the drilling rig, use the directional drilling device to determine the drilling trajectory, design the line channel, and determine the grout inlet and outlet ends of the semi-circular grouting channel based on the line channel.

[0019] Step S3: The drilling rig is started. While the drill bit is excavating the semi-circular channel, it pulls the grouting hose from the grout inlet end to the grout outlet end, thus completing the installation of a semi-circular grouting hose with gushing outlets arranged in a quincunx pattern within the bottom range of the pipe. The grout outlets are only installed within the pipe diameter range.

[0020] Step S4: Use a grouting pump to simultaneously perform semi-circular grouting at both the inlet and outlet ends to form an arc-shaped solidification zone at the bottom of the pipe;

[0021] Step S5: After the grout has reached a certain strength, pull out the semi-circular grouting hose and fill the semi-circular grouting channel with cement grout to form a grouting isolation zone;

[0022] Step S6: After the bottom arc-shaped curing zone and grouting isolation zone below the bottom of the pipeline are completed, use drilling rig 5 to drill multiple vertical grouting channels in parallel, about 1.2 times the diameter of the pipeline, directly above the pipeline axis on the ground surface. The grouting channels in a row are arranged perpendicular to the pipeline axis. The drilling depth of the grouting channels increases with the distance from the pipeline excavation centerline and they are symmetrically distributed about the pipeline centerline. The ends of the multiple grouting channels form a semi-circular ring around the top of the pipeline.

[0023] Step S7: Insert vertical grouting pipes with grouting holes at the ends into multiple grouting channels and perform simultaneous grouting. The grout outlets are evenly arranged along the circumference of the pipes, and three grout outlets are set at each cross section to form a semi-circular grouting reinforcement zone. Together with the semi-circular grouting below the bottom of the pipe, they form a double-ring grouting reinforcement zone.

[0024] Step S8: Repeat steps S2 to S7, and perform ring-shaped grouting reinforcement with unequal intervals at each ring in the pipeline within a range of twice the tunnel excavation diameter. Within the tunnel excavation diameter, the grouting interval for each ring of the pipeline is 400 to 500 mm; within a range of 1 to 2 times the tunnel excavation diameter, the grouting interval for each ring is 1000 mm.

[0025] Step S9: Remove and clean all vertical grouting pipes and hoses, fill and compact all grouting channels, inlet and outlet ends with soil, dismantle the equipment, and clean the construction site.

[0026] The beneficial effects of this application are as follows:

[0027] 1. Composite fiber ultra-high performance cement grouting material, which is made by mixing cement with construction and industrial waste, is a cement grouting material with high strength, high adhesion and low porosity. It can significantly improve the soil strength and compression modulus within a certain range, and at the same time has strong water-stopping, filling and supporting functions.

[0028] 2. By adopting the construction method provided in this application, the pipeline is grouted in a lower semi-circle and an upper semi-circle to form a hoop-shaped grout. Within the main disturbance range of tunnel excavation, the soil around the pipeline is reinforced in a hoop-shaped manner. Under the action of the hoop, the deformation of the pipeline is constrained by the surrounding soil, the bending stiffness is increased, and the pipeline settlement is reduced. This effectively reduces the damage such as cracking and breakage caused by pipeline settlement, and reduces the risk of pipeline leakage at the reinforced point. The pipeline safety control under existing pipelines during tunnel construction is effectively improved, the risks in tunnel construction are reduced, and the future maintenance costs of existing pipelines are reduced.

[0029] 3. This application adopts a micro-disturbance trenchless grouting reinforcement technology, which eliminates the need for overall excavation of the underground pipeline overburden, greatly saving pipeline reinforcement costs. It is highly applicable in both densely populated urban areas and uninhabited areas with complex terrain, and has minimal impact on the surrounding strata, landforms, vegetation, and other natural landscapes, thus having a certain environmental protection effect. It is particularly suitable for the reinforcement of key projects of underground large-diameter ultra-long pipelines under other construction disturbances.

[0030] 4. The micro-disturbance trenchless reinforcement technology adopted in this application is relatively simple to operate, has a fast construction speed, causes little disturbance to the strata, has low equipment and reinforcement costs, and has significant social and economic benefits. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0032] Figure 1 This application provides a schematic diagram of the excavation of a semi-circular grouting channel at the bottom of a tunnel passing under an existing pipeline and the layout of the grouting hose.

[0033] Figure 2 This application provides a schematic diagram of the semi-circular grouting reinforcement area and the annular reinforcement zone area at the bottom of a tunnel passing under an existing pipeline.

[0034] Figure 3 A schematic diagram of a double-ring grouting reinforcement technology and its implementation method for tunnels passing under existing pipelines, provided in this application embodiment;

[0035] Figure 4 A schematic diagram of a semi-circular grouting hose device at the bottom of a pipeline passing under an existing pipeline in a tunnel, provided in an embodiment of this application.

[0036] Figure 5(a)-(c) are schematic diagrams of the cross-section and grout outlet structure of a grouting hose at the bottom of a tunnel passing under an existing pipeline provided in the embodiments of this application;

[0037] Figure 6 A schematic diagram of a vertical grouting conduit device for semi-circular grouting reinforcement above a pipeline passing under an existing pipeline in a tunnel, provided as an embodiment of this application;

[0038] Figure 7 A schematic diagram of the cross-sectional structure and grout outlet of a grouting conduit above a pipeline passing under an existing pipeline in a tunnel, provided as an embodiment of this application;

[0039] Figure 8 A schematic diagram of a grouting pipe connection device for simultaneous semi-circular grouting above a pipe passing under an existing pipeline in a tunnel, provided as an embodiment of this application;

[0040] Figure 9 This is a schematic diagram illustrating the grouting effect after a pipe passing under an existing pipeline in a tunnel, as provided in an embodiment of this application. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0043] The following, in conjunction with the accompanying drawings, provides a detailed description of the double-ring grouting reinforcement structure for tunnels passing under existing pipelines provided in this application, along with specific embodiments and application scenarios.

[0044] Please see Figures 1 to 8This application provides a double-ring grouting reinforcement structure for tunnels passing under existing pipelines, including a double-ring grouting reinforcement zone 29, an arc-shaped curing strip 23 located below the pipeline, a semi-circular grouting reinforcement zone 25 connected to and wrapping the pipeline, and a grouting isolation strip 24 partially surrounding the pipeline. The grouting isolation strip 24 is formed by filling composite fiber ultra-high performance cement grouting material into the semi-circular grouting channel within it.

[0045] Specifically, the composite fiber ultra-high performance cement grouting material, by weight, includes 290-310 parts of 42.5 grade ordinary silicate cement grout, 15 parts of water glass, 20 parts of grade 1 fly ash, 15 parts of S75 grade slag, 43 parts of grade 2 silica fume, 3 parts of naphthalene sulfonate water-reducing agent, 38 parts of complex recycled fiber, and 100-120 parts of water.

[0046] The water-cement ratio of the 42.5 grade ordinary silicate cement grout is 0.4 to 0.6; the cement grout seepage rate does not exceed 3% to 8%; and the naphthalene sulfonate water-reducing agent is a high-performance water-reducing agent with a water reduction rate of 18% to 25%.

[0047] The complex recycled fiber includes ordinary steel fiber and recycled steel fiber from waste tires. The three types of steel fibers with an aspect ratio of 45 to 50 and lengths of 3 mm, 5 mm and 7 mm are mixed in a mass ratio of 4:2:1.

[0048] The arc-shaped curing zone 23 is formed by grouting through a semi-circular grouting channel drilled by a grouting channel drilling device consisting of a drill bit 3, a drill control wire 4, and a drill central control system acquisition vehicle 5, using a grouting pump 22 to pressurize the grout through a grouting hose 6 with a grout outlet 13.

[0049] It should be further explained that the grouting channel drilling rig is installed above the pipeline, next to the grout outlet 1 and the grout inlet 2 on the ground surface.

[0050] The grouting isolation zone 24 is formed by grouting the composite fiber ultra-high performance cement grouting material into the semi-circular grouting channel formed by the grouting hose 6 after grouting the arc-shaped curing zone 23 and then pulling out the grouting hose 6.

[0051] The grouting hose 6 uses a 3-10mm steel spring as a support frame 7, is wrapped with a non-woven filter cloth layer 8, and then connected to a PE sleeve 9 with a thickness of 2-5mm. The outermost layer is wrapped with nylon wire mesh 10. The two ends of the grouting hose 6 are provided with pipe section connectors 11 and connected to steel buckles 12.

[0052] Each cross-section of the grouting hose 6 has four grout outlets 13. The grout outlets of the grouting hose 6 have three forms based on the volume and shape of the outlet channel: within the central 0.4 times the diameter of the underground pipe, the outlet channel is an inverted trapezoidal funnel shape with outlet angles of 97° and 67°; within the 0.4 to 0.9 times the diameter of the underground pipe, the outlet channel is a cylinder with the same upper and lower cross-sectional area, with outlet angles of 105° and 75°; within the 0.9 to 1.4 times the diameter of the underground pipe, the outlet channel is an inverted cone shape, smaller at the top and larger at the bottom, with outlet angles of 111° and 81°. The grout outlets of the grouting hose are located approximately within 1.4 times the diameter of the underground ultra-long pipe.

[0053] The semi-circular grouting reinforcement zone 25 is formed by grouting around the pipeline through the drilling rig 5, the grouting pipe connection device 17 and the vertical grouting pipe 14.

[0054] The grouting conduit connection device 17 is composed of a cross-shaped grouting main pipe 18, five vertical grouting connection pipes 19, two L-shaped grouting connection pipes 20, four pipe connecting tees 26, and several grouting sleeves 21 connected by threads.

[0055] The vertical grouting conduit 14 is a steel grouting conduit with a diameter of 32mm. There are three grout outlets 15 at the same height of the conduit, and the included angle of the grout outlets is 120°. Grout outlet holes 16 are also opened at the end of the grouting conduit to ensure that the grouting conduit can be grouted and reinforced in all directions.

[0056] One end of the double-ring grouting reinforcement zone 29 is connected to the grout inlet end 2, and the other end is connected to the grout outlet end 1. The grout inlet end 2 and the grout outlet end 1 are excavated to a depth of 25-100cm at the average elevation of the flat site. The length and width of the excavation area are 6 times the diameter of the semi-circular grouting channel of the double-ring grouting reinforcement zone 29.

[0057] Reference Figure 1-3 and Figure 9 This application also provides a construction method for a double-ring grouting reinforcement structure for tunnels passing under existing pipelines, including the following steps:

[0058] Step S1: Conduct a site survey around the grouting site to determine the surrounding geological conditions, the burial depth of existing pipelines, the horizontal position of the pipeline axis, the distance between the pipeline and the tunnel, the tunnel excavation diameter, and the direction of the pipeline and the tunnel within the grouting area.

[0059] It should be noted that before step S1, there is also the step of: conducting a rigorous investigation of the existing underground ultra-long pipeline's operating conditions, clarifying the pipeline's axis distribution, diameter, wall thickness, material, and the disturbance impact of nearby structures on the pipeline.

[0060] Step S2: Complete the site leveling work, design the engineering drawings of the semi-circular grouting channel below the bottom of the pipeline based on the burial depth of the existing pipeline and the excavation diameter of the tunnel, calculate the length and depth to be drilled by the drilling rig, use the directional drilling device to determine the drilling trajectory, design the line channel, and determine the grout inlet and outlet ends of the semi-circular grouting channel based on the line channel.

[0061] It should be noted that after determining the grout inlet end 2 and grout outlet end 1 of the semi-circular grouting channel, the grout inlet end 2 and grout outlet end 1 of the corresponding area are drilled to ensure that the directional drilling rig can perform positioning drilling.

[0062] Step S3: The drilling rig is started. While the drill bit is excavating the semi-circular channel, it pulls the grouting hose from the grout inlet end to the grout outlet end, thus completing the installation of a semi-circular grouting hose with gushing outlets arranged in a quincunx pattern within the bottom range of the pipe. The grout outlets are only installed within the pipe diameter range.

[0063] It should be noted that after the drilling rig 5 enters the site, it will carry out directional drilling construction according to the design route. While the drill bit 3 is drilling, the grouting hose 6 at the bottom of the pipe is pulled into the semi-circular grouting channel through the pipe section connector 11 and the steel lock 12.

[0064] Step S4: Use a grouting pump to simultaneously perform semi-circular grouting at the grout inlet end 2 and the grout outlet end 1 to form an arc-shaped solidification zone 23 at the bottom of the pipe;

[0065] Step S5: After the grout has reached a certain strength, pull out the semi-circular grouting hose and fill the semi-circular grouting channel with cement grout to form a grouting isolation zone;

[0066] Specifically, after grouting the grouting hose 6, the grouting hose 6 is pulled out from the semi-circular grouting channel using the steel locking buckle 12. The mud pump 22 is used to grout the inlet end 2 and the outlet end 1. The drilled grouting channel is filled with cement grout. After the cement grout solidifies, a grouting isolation zone 24 is formed.

[0067] Step S6: After the bottom arc-shaped curing zone 23 and the grouting isolation zone 24 are completed, at a distance of about 1.2 times the diameter of the pipe, directly above the ground surface along the pipe axis, use drilling rig 5 to drill multiple vertical grouting channels in parallel. The grouting channels are arranged perpendicular to the pipe axis. The drilling depth of the grouting channels increases with the distance from the pipe excavation centerline and they are symmetrically distributed about the pipe centerline. The ends of the multiple grouting channels form a semi-circular ring around the top of the pipe.

[0068] Step S7: Insert vertical grouting pipes with grouting holes at the ends into multiple grouting channels and perform simultaneous grouting. The grout outlets are evenly arranged along the circumference of the pipes, and three grouting holes 15 are set at each cross section to form a semi-circular grouting reinforcement zone 25, which together with the semi-circular grouting below the bottom of the pipe forms a double-ring hoop grouting reinforcement zone 29.

[0069] Step S8: Repeat steps S2 to S7, and perform ring-shaped grouting reinforcement with unequal intervals at each ring in the pipeline within a range of twice the tunnel excavation diameter. Within the tunnel excavation diameter, the grouting interval for each ring is 400-500mm; within a range of 1 to 2 times the tunnel excavation diameter, the grouting interval for each ring is 1000mm.

[0070] Step S9: Remove and clean all vertical grouting pipes 14 and grouting hoses 6, fill and compact all grouting channels with soil at the inlet end 2 and outlet end 1, disassemble the equipment, and clean the construction site.

[0071] The beneficial effects of this application are as follows:

[0072] 1. Composite fiber ultra-high performance cement grouting material, which is made by mixing cement with construction and industrial waste, is a cement grouting material with high strength, high adhesion and low porosity. It can significantly improve the soil strength and compression modulus within a certain range, and at the same time has strong water-stopping, filling and supporting functions.

[0073] 2. By adopting the construction method provided in this application, the pipeline is grouted in a lower semi-circle and an upper semi-circle to form a hoop-shaped grout. Within the main disturbance range of tunnel excavation, the soil around the pipeline is reinforced in a hoop-shaped manner. Under the action of the hoop, the deformation of the pipeline is constrained by the surrounding soil, the bending stiffness is increased, and the pipeline settlement is reduced. This effectively reduces the damage such as cracking and breakage caused by pipeline settlement, and reduces the risk of pipeline leakage at the reinforced point. The pipeline safety control under existing pipelines during tunnel construction is effectively improved, the risks in tunnel construction are reduced, and the future maintenance costs of existing pipelines are reduced.

[0074] 3. This application adopts a micro-disturbance trenchless grouting reinforcement technology, which eliminates the need for overall excavation of the underground pipeline overburden, greatly saving pipeline reinforcement costs. It is highly applicable in both densely populated urban areas and uninhabited areas with complex terrain, and has minimal impact on the surrounding strata, landforms, vegetation, and other natural landscapes, thus having a certain environmental protection effect. It is particularly suitable for the reinforcement of key projects of underground large-diameter ultra-long pipelines under other construction disturbances.

[0075] 4. The micro-disturbance trenchless reinforcement technology adopted in this application is relatively simple to operate, has a fast construction speed, causes little disturbance to the strata, has low equipment and reinforcement costs, and has significant social and economic benefits.

[0076] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0077] Furthermore, it should be noted that the scope of the methods and systems in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions in a substantially simultaneous manner or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0078] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A double-ring grouting reinforcement structure for tunnels passing under existing pipelines, characterized in that, include: The double-ring grouting reinforcement zone (29) includes an arc-shaped curing strip (23) located below the pipe, a semi-circular grouting reinforcement zone (25) connected to and wrapping the pipe with the arc-shaped curing strip (23), and a grouting isolation strip (24) partially surrounding the pipe. The grouting isolation strip (24) is formed by grouting and filling composite fiber ultra-high performance cement grouting material into the semi-circular grouting channel inside it. One end of the double-ring grouting reinforcement zone (29) is connected to the grout inlet end (2), and the other end is connected to the grout outlet end (1). The arc-shaped curing zone (23) is formed by grouting through a grouting pump (22) and a grouting hose (6) with a grout outlet (13) in a semi-circular grouting channel drilled by the drill bit (3), the drill control wire (4), and the drill central control system acquisition vehicle; the grouting isolation zone (24) is formed by grouting the arc-shaped curing zone (23) with the grouting hose (6) and then pulling out the grouting hose (6) to fill the semi-circular grouting channel with the composite fiber ultra-high performance cement grouting material; the semi-circular grouting reinforcement zone (25) is formed by grouting around the pipeline through the drill (5), the grouting conduit connection device (17), and the vertical grouting conduit (14); Directly above the pipeline axis on the ground surface, within a range of about 1.2 times the diameter of the pipeline, multiple vertical grouting channels are drilled side by side using a drilling rig (5). The grouting channels are arranged perpendicular to the pipeline axis. The drilling depth of the grouting channels increases with the distance from the pipeline excavation centerline and they are symmetrically distributed about the pipeline centerline. The ends of the multiple grouting channels form a semi-circular ring around the top of the pipeline. A vertical grouting conduit (14) with grouting holes at the end is inserted into multiple grouting channels for simultaneous grouting. Grouting holes (15) are evenly arranged along the circumference of the conduit, and three grouting holes (15) are set at each cross section to form a semi-circular grouting reinforcement zone (25), which together with the semi-circular grouting below the bottom of the pipe forms a double-ring hoop grouting reinforcement zone (29).

2. The double-ring hoop grouting reinforcement structure for tunnels passing under existing pipelines as described in claim 1, characterized in that, The composite fiber ultra-high performance cement grouting material, by weight, includes 290-310 parts of 42.5 grade ordinary silicate cement grout, 15 parts of water glass, 20 parts of grade 1 fly ash, 15 parts of S75 grade slag, 43 parts of grade 2 silica fume, 3 parts of naphthalene sulfonate water-reducing agent, 38 parts of complex recycled fiber, and 100-120 parts of water.

3. The double-ring hoop grouting reinforcement structure for tunnels passing under existing pipelines as described in claim 2, characterized in that, The water-cement ratio of the 42.5 grade ordinary silicate cement grout is 0.4 to 0.6; the cement grout seepage rate does not exceed 3% to 8%; and the naphthalene sulfonate water-reducing agent is a high-performance water-reducing agent with a water reduction rate of 18% to 25%.

4. The double-ring hoop grouting reinforcement structure for tunnels passing under existing pipelines according to claim 2, characterized in that, The complex recycled fiber includes ordinary steel fiber and recycled steel fiber from waste tires. The three types of steel fibers with an aspect ratio of 45 to 50 and lengths of 3 mm, 5 mm and 7 mm are mixed in a mass ratio of 4:2:

1.

5. The double-ring hoop grouting reinforcement structure for tunnels passing under existing pipelines according to claim 1, characterized in that, The grout inlet (2) and grout outlet (1) are excavated to a depth of 25-100cm at the average elevation of the flat site. The length and width of the excavation area are 6 times the diameter of the semi-circular grouting channel of the double-ring grouting reinforcement zone (29).

6. The double-ring hoop grouting reinforcement structure for tunnels passing under existing pipelines according to claim 4, characterized in that, The grouting conduit connection device (17) is formed by connecting a cross-shaped grouting main pipe (18), five vertical grouting connection pipes (19), two L-shaped grouting connection pipes (20), four pipe connection tees (26), and several grouting sleeves (21) by threaded connection; the vertical grouting conduit (14) is a steel grouting conduit with a diameter of 32mm. There are three grout outlets (15) at the same height of the conduit. The included angle of the grout outlets is 120°. Grout outlet holes (16) are also opened at the end of the grouting conduit to ensure that the grouting conduit can be grouted and reinforced in all directions.

7. The double-ring hoop grouting reinforcement structure for tunnels passing under existing pipelines as described in claim 6, characterized in that, The grouting hose (6) uses a 3-10mm steel spring as a support frame (7), is wrapped with a non-woven filter cloth layer (8), and then connected with a PE sleeve (9) with a thickness of 2-5mm. The outermost layer is wrapped with nylon wire mesh (10). The two ends of the grouting hose (6) are provided with pipe section connectors (11) and connected to steel buckles (12).

8. The double-ring grouting reinforcement structure for tunnels passing under existing pipelines according to claim 7, characterized in that, The grouting hose (6) has multiple circular grout outlets (13) within 1.4 times the diameter of the underground pipeline. Four grout outlets (13) are distributed on each cross-section within this range, and the spacing between each grout outlet (13) is 100mm to 150mm. The grout outlets (13) of the grouting hose (6) have three forms according to the volume shape of the grout outlet channel. Within the middle 0.4 times the diameter of the underground pipeline, the grout outlet channel is an inverted trapezoidal funnel shape, and the included angle of the grout outlets (13) is 97° and 67°. Within the range of 0.4 to 0.9 times the diameter of the underground pipeline, the grout outlet channel is a cylinder with the same upper and lower cross-sectional area, and the included angle of the grout outlets (13) is 105° and 75°. Within the range of 0.9 to 1.4 times the diameter of the underground pipeline, the grout outlet channel is an inverted cone shape with a smaller upper part and a larger lower part, and the included angle of the grout outlets (13) is 111° and 81°.

9. A construction method for a double-ring grouting reinforcement structure for tunnels passing under existing pipelines as described in any one of claims 5-8, characterized in that, include: Step S1: Conduct a site survey around the grouting site to determine the surrounding geological conditions, the burial depth of existing pipelines, the horizontal position of the pipeline axis, the distance between the pipeline and the tunnel, the tunnel excavation diameter, and the direction of the pipeline and the tunnel within the grouting area. Step S2: Complete the site leveling work, design the engineering drawings of the semi-circular grouting channel below the bottom of the pipeline based on the burial depth of the existing pipeline and the excavation diameter of the tunnel, calculate the length and depth to be drilled by the drilling rig, determine the drilling trajectory using the directional drilling device, design the line channel, and determine the grout inlet end (2) and grout outlet end (1) of the semi-circular grouting channel based on the line channel. Step S3: The drilling rig is started, and while the drill bit is excavating the semi-circular grouting channel, the grouting hose (6) is pulled in from the grout inlet end (2) and out from the grout outlet end (1), thus completing the setting of a semi-circular grouting hose (6) with a plum blossom-shaped grout outlet within the bottom range of the pipe, and the grout outlet (13) is only arranged within the pipe diameter range; Step S4: Use the grouting pump (22) to simultaneously perform semi-circular grouting at the grout inlet end (2) and the grout outlet end (1) to form an arc-shaped solidification zone (23) at the bottom of the pipe. Step S5: After the grout has reached a certain strength, pull out the semi-circular grouting hose (6) and fill the semi-circular grouting channel with cement grout to form a grouting isolation zone (24). Step S6: After the bottom arc-shaped curing zone (23) and grouting isolation zone (24) below the bottom of the pipeline are completed, at a distance of about 1.2 times the diameter of the pipeline, use a drilling rig (5) to drill multiple vertical grouting channels in parallel. The grouting channels are arranged perpendicular to the pipeline axis. The drilling depth of the grouting channels increases with the distance from the pipeline excavation centerline and they are symmetrically distributed about the pipeline centerline. The ends of the multiple grouting channels form a semi-circular ring above the pipeline. Step S7: Insert vertical grouting pipes (14) with grouting holes (16) at the ends into multiple grouting channels and perform simultaneous grouting. The grout outlet holes (15) are evenly arranged along the circumference of the pipe. Three grout outlet holes (15) are set at each cross section to form a semi-circular grouting reinforcement area (25), which together with the semi-circular grouting below the bottom of the pipe forms a double-ring hoop grouting reinforcement area. Step S8: Repeat steps S2 to S7, and perform ring-shaped grouting reinforcement with unequal intervals at each ring in the pipeline within a range of twice the tunnel excavation diameter. Within the tunnel excavation diameter, the grouting interval for each ring of the pipeline is 400 to 500 mm; within a range of 1 to 2 times the tunnel excavation diameter, the grouting interval for each ring is 1000 mm. Step S9: Remove and clean all vertical grouting pipes (14) and grouting hoses (6), fill all grouting channels with soil at the inlet (2) and outlet (1), disassemble the equipment, and clean the construction site.

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