A comprehensive treatment method for highway tunnel base diseases

Abstract

The application provides a comprehensive treatment method for highway tunnel base diseases, and belongs to the technical field of highway tunnels, and comprises the following steps: S1, for the case of tunnel bottom pavement cracking and arching, the deformation disease occurrence and development section of the maintenance road is set, and a structure lock foot is arranged; S2, for the case that the tunnel bottom disease state is moderate or severe, the tunnel bottom is reinforced through the measures of tunnel bottom anchor pipe, catheter grouting and tunnel bottom additional steel frame beam; S3, for the case that the tunnel bottom disease state is severe and extremely severe, a sleeve arch reinforcing lining is additionally arranged; S4, during the tunnel bottom reinforcement treatment process, temporary supports are arranged when the pavement and inverted arch filling are removed. The application solves the problem that with the continuous increase of traffic volume and traffic load, tunnel bottom defects and diseases gradually appear, such as pavement cracking, benching, subsidence, heave, arch foot sinking, maintenance road inclination and even arch wall lining cracking, and the like, which causes great safety hazards for tunnel operation and maintenance.

Description

Technical Field

[0001] This invention belongs to the field of highway tunnel technology, and more specifically, relates to a comprehensive treatment method for foundation defects in highway tunnels. Background Technology

[0002] Early highway tunnels, especially those traversing complex geological conditions such as soft and expansive rocks, often faced challenges due to a lack of experience in similar engineering projects, outdated technology, insufficient construction machinery and equipment, and inadequate construction organization and management. Consequently, problems such as deformation, heave, and subsidence of the tunnel foundation rock were not detected and effectively addressed in a timely manner. Over the next decade or so, with the continuous increase in traffic volume and load, tunnel defects and damage gradually became apparent, including road surface cracking, misalignment, subsidence, heave, arch foot subsidence, tilting of maintenance walkways, and even cracking of the arch lining. These issues posed significant safety hazards to tunnel operation and maintenance.

[0003] Due to operational and traffic-maintaining requirements, maintenance prioritizes quick repairs and reopening. Current treatments for such defects include adding under-arch support, tunnel floor grouting, repairing arch wall cracks, applying steel strips, and milling and repaving the road surface. These solutions focus on repair, and although repeated treatments have been implemented, the overall reinforcement of the tunnel structure and improvement of the surrounding rock's mechanical state are unsatisfactory, indicating a lack of structural approach. After repairs are completed and the tunnel is reopened, the defects often recur or even worsen.

[0004] Therefore, we propose a structural scheme suitable for the comprehensive treatment of foundation defects in in-service tunnels. Summary of the Invention

[0005] This invention provides a comprehensive treatment method for foundation defects in highway tunnels, which solves the problem that as traffic volume and load increase, tunnel foundation defects and defects gradually emerge, such as road surface cracking, misalignment, subsidence, heave, arch foot subsidence, maintenance road tilting, and even arch wall lining cracking, which pose great safety hazards to tunnel operation and maintenance.

[0006] In view of the above problems, the technical solution proposed by the present invention is as follows:

[0007] This invention provides a comprehensive treatment method for foundation defects in highway tunnels, comprising the following steps:

[0008] S1. For cases of cracking and arching of the tunnel floor pavement, and for sections where deformation defects occur and develop, monitoring and detection measures are taken, and structural locking feet are set according to the deformation development to control the adverse effects on the tunnel arch structure caused by the deterioration of the arch bottom support and lining conditions.

[0009] S2. When the tunnel bottom is in a moderate or severe condition, the surrounding rock at the tunnel bottom absorbs water, expands and softens, and the tunnel structure cannot bear the force generated by the plastic deformation and compression of the surrounding rock at the tunnel bottom, which causes the tunnel bottom to expand and heave. The tunnel bottom is reinforced by measures such as tunnel bottom anchor pipe, duct grouting and adding steel frame beams to the tunnel bottom.

[0010] S3, for tunnel floor defects of severe and extremely severe condition, the uplift has seriously affected the use of the tunnel and caused damage to the tunnel structure. In this case, a double arch is added to reinforce the lining and an inverted arch frame is set up to form a closed ring support structure.

[0011] S4, during the reinforcement and treatment of the tunnel bottom, the unloading free surface generated when removing the road surface and the invert arch filling, before the invert arch filling is removed, a row of grouting pipes are laid at the arch foot lining on both sides of the diseased section, and temporary supports are set up before the invert arch filling is removed.

[0012] S5. At the same time, during the construction process, displacement and deformation measurement sections are set up, and pressure and deformation data acquisition elements are buried to monitor the structural performance after treatment.

[0013] S6, to renovate and restore the tunnel floor drainage system and cable trench facilities;

[0014] S7 involves rebuilding and reinforcing the road surface structure and restoring road markings.

[0015] As a preferred embodiment of the present invention, the measures for controlling the adverse effects of the tunnel arch structure in step S1 are as follows:

[0016] S11 Before steel pipe pile reinforcement, the cable trenches and drainage ditches on both sides of the road surface are removed. 4.5m long steel pipes with a diameter of 89mm and a wall thickness of 6mm are used to drill holes and grout the base of the left and right side walls and the bottom plate of the cable trench. After the lining and base are completed, the road surface is reinforced by grouting.

[0017] As a preferred embodiment of the present invention, in step S2, the spacing between sections with defects in the invert arch and Class V surrounding rock is 1m, the spacing between sections with good structural condition in Class V surrounding rock and Class IV surrounding rock is 1.5m, the grouting material is cement grout, and the water-cement ratio of the cement grout is 1:0.75-1:1.5. The measures for reinforcing the tunnel foundation are as follows:

[0018] S21, Tunnel Bottom Grouting: Before tunnel bottom grouting, the asphalt layer of the road surface is removed, and grouting is carried out using 4.5m long steel pipes with a 51mm grouting diameter and a 3.5mm wall thickness. The grouting steel pipes are arranged in a quincunx pattern.

[0019] S22, a steel frame beam, has two rows of 51×3.5mm grouting anchor pipes installed on both sides of the tunnel bottom corner. The anchor pipes are welded to the longitudinal channel steel. The anchor pipes are 4.5m long and spaced 1m apart longitudinally. The grouting slurry is cement slurry. I-18 steel is used as transverse support, with a longitudinal spacing of 1m. I-14 steel is used as longitudinal support. The I-18 longitudinal steel is welded to the bottom corner channel steel and the I-14 steel to form an integrally stressed steel frame beam system.

[0020] As a preferred embodiment of the present invention, step S3 further includes:

[0021] S31, Embedded arch reinforcement treatment, for the V-class surrounding rock tunnel with insufficient thickness of the bottom structure layer and serious defects, the lining of the arch wall has cracks and local spalling, and the road surface defects are serious. It is necessary to reinforce the whole structure and adopt the embedded arch closed arch method for treatment.

[0022] As a preferred embodiment of the present invention, the specific treatment measures in step S31 are as follows:

[0023] S311, after completing the construction of the lining locking foot and the temporary arch support within the scope of the operation, the lining trench excavation will be carried out.

[0024] S312, install the arch steel frame, fix it with L-shaped anchors, and set two grouting small pipes with a diameter of 51mm and a wall thickness of 3.5mm at the arch frame to lock the feet;

[0025] S313, the original maintenance road and road surface within the transverse range will be demolished;

[0026] S314, the tunnel bottom is excavated using the skip-slot method, and the foundation excavation is carried out using the pull-slot method, with a step distance of not less than 10m and a slot width of not more than 2m;

[0027] S315, after excavating to the bedrock surface at the bottom of the tunnel, remove the surface debris and replace it with a C15 concrete stabilized base course with a thickness of not less than 50cm;

[0028] S316, due to the poor integrity and bearing capacity of the surrounding rock at the base, grouting pipes with a diameter of 51mm and a wall thickness of 3.5mm are added, with a circumferential spacing of 1m;

[0029] S317, after the base is replaced and leveled, the assembled I-18 steel inverted arch frame is lowered and anchored to the upper arch foot bolts.

[0030] S318, after the steel mesh is hung on the reinforced section of the arch, C30 fiber concrete is sprayed, and the thickness of the protective layer of the arch frame is not less than 4cm.

[0031] As a preferred embodiment of the present invention, step S4 further includes:

[0032] S41, before lining trenching or tunnel bottom excavation, a temporary steel frame support is erected, and a circumferential steel arch frame is erected with a longitudinal spacing of 1m. Each arch frame unit segment is connected by welded steel plate bolts. Longitudinal connecting steel bars are set between the arch frames with a circumferential spacing of 1m. The arch frames are fixed to the secondary lining with wedges. The circumferential steel arch frame layout extends to both sides of the tunnel bottom excavation section by one section of secondary lining length.

[0033] As a preferred embodiment of the present invention, the drainage facility modification in step S6 is as follows:

[0034] For the arched section of the tunnel pavement in S61, if the original design was a concrete circular pipe trench, a reinforced concrete rectangular structure shall be constructed by casting in place without changing the original drainage cross-section and longitudinal slope of the drainage ditch. The drainage cross-section shall have a net width of 30cm and a net height of 55cm. The bottom elevation of the ditch shall be consistent with the original design elevation of the pipe trench bottom. A precast concrete cover plate shall be installed on the top, with dimensions of 50cm x 50cm and a thickness of 15cm. The top surface of the cover plate shall be flush with the top surface of the concrete pavement slab. An end sealing wall shall be cast at the connection point with the pipe trench.

[0035] As a preferred technical solution of the present invention, in step S7, when road surface sections with longitudinal cracks, misalignments, and subsidence appear in local sections, and when road surface restoration is carried out in sections where tunnel bottom grouting reinforcement and invert replacement are performed, road surface reinforcement is adopted for treatment. The specific treatment measures are as follows:

[0036] S71, remove roadside ditches, asphalt pavement, pavement panels and base course;

[0037] S72, restore the road base layer according to the design;

[0038] S73 uses 12mm diameter steel bars with a spacing of 15mm to tie the double-layer steel mesh of the road surface panel;

[0039] S74, integrally cast C40 reinforced concrete panel (6).

[0040] As a preferred embodiment of the present invention, the specific monitoring of the structural performance after treatment in step S5 is as follows:

[0041] S51, a level, precision level, indium steel ruler or measuring rod shall be set up at the location of arch subsidence for monitoring, and shall be set up in the reinforcement construction area;

[0042] S52, perform peripheral convergence, set up convergence meters around the reinforced construction area, set up a cross section every 10m, and set up 2 pairs of measuring points in each cross section;

[0043] S53, a precision level or indium steel ruler is installed at the bottom drum. It is installed during the replacement and treatment of the tunnel bottom. A section is set every 10m, and at least 3 measuring points are set at each section.

[0044] S54, strain gauges, stress gauges and pressure gauges are installed in the concrete of each representative section, and 11 measuring points are set in each cross section for stress monitoring.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] (1) This invention controls the tunnel arch structure by setting up structural locking feet, creating a safe and stable working environment for subsequent tunnel bottom treatment. The tunnel bottom is reinforced by adding steel frame beams to the tunnel bottom through grouting with tunnel bottom anchor rods or anchor pipes and guide pipes. The lining is reinforced by adding arched reinforcement, which improves the overall strength and stability of the structure. Temporary supports should be set up in time when the invert arch filling is removed to reduce the construction risk of foundation treatment. The modification of the tunnel bottom drainage structure effectively ensures the stability of the tunnel foundation structure.

[0047] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the process for a comprehensive treatment method for foundation defects of highway tunnels disclosed in this invention;

[0049] Figure 2 This is a schematic diagram of a treatment scheme for a comprehensive treatment method for foundation defects of highway tunnels disclosed in this invention;

[0050] Figure 3 This is a design drawing of a temporary arch support for a tunnel, which is applicable to a comprehensive treatment method for foundation defects in highway tunnels, as disclosed in this invention.

[0051] Figure 4 This is a design drawing for grouting reinforcement of the tunnel bottom without an inverted arch section, which is applicable to the comprehensive treatment method of foundation defects in highway tunnels as disclosed in this invention.

[0052] Figure 5 This invention discloses a design drawing for grouting reinforcement of the tunnel bottom in the arch section, applicable to a comprehensive treatment method for foundation defects in highway tunnels.

[0053] Figure 6 This invention discloses a design drawing for reinforcing a steel frame beam at the bottom of a tunnel with an inverted arch section, applicable to a comprehensive treatment method for foundation defects in highway tunnels.

[0054] Figure 7This is a tunnel bottom grouting and steel anchor frame reinforcement design drawing disclosed in this invention, which is applicable to the comprehensive treatment of foundation defects in highway tunnels.

[0055] Figure 8 This is a nested arch design drawing of a comprehensive treatment method for foundation defects of highway tunnels disclosed in this invention;

[0056] Figure 9 This is a schematic diagram of a pre-construction spliced ​​circular pipe trench, which is a method for comprehensive treatment of foundation defects in highway tunnels disclosed in this invention.

[0057] Figure 10 This is a schematic diagram of the tunnel drainage blind ditch renovation scheme disclosed in this invention, which is applicable to the comprehensive treatment method of highway tunnel foundation defects.

[0058] Figure 11 This is a cross-sectional view of the reinforcement of a C40 reinforced concrete pavement slab, which is applicable to a comprehensive treatment method for foundation defects of highway tunnels as disclosed in this invention.

[0059] Figure 12 This is a reference diagram showing the layout of monitoring points after treatment of a comprehensive treatment method for foundation defects of highway tunnels disclosed in this invention;

[0060] Explanation of reference numerals in the attached drawings: 1. Steel pipe pile; 2. Circumferential steel arch; 3. Anchor pipe; 4. Grouting steel pipe; 5. Asphalt concrete layer; 6. C40 reinforced concrete panel; 7. C25 concrete base layer; 8. Reinforcing mesh layer; 9. Steel frame beam reinforcement structure; 10. Channel steel; 11. I-beam; 12. C30 concrete leveling layer; 13. Positioning anchor; 14. C15 concrete stabilized base layer; 15. C30 fiber reinforced concrete; 16. C30 self-compacting shrinkage-compensating concrete; 17. C20 plain concrete base layer; 18. MF7 plastic blind drain; 19. EVA / ECB composite waterproof layer; 20. HDPE perforated corrugated pipe; 21. Transverse flexible permeable pipe; 22. Precast concrete cover plate; 23. C30 concrete trench body; 24. Longitudinal reinforcement; 25. Transverse reinforcement; 26. Convergence device;

[0061] A. Arch settlement measuring point; B. Support internal stress measuring point; C. Bottom heave deformation measuring point; D. Original tunnel inner contour; E. Reinforced lining inner contour; F. Original tunnel construction clearance; X. Tunnel forward direction. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0064] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0065] Example 1

[0066] See attached document Figure 1-2 As shown, the present invention provides a technical solution: a method for comprehensive treatment of foundation defects in highway tunnels, comprising the following steps:

[0067] S1. For the situation of cracking and arching of the tunnel bottom pavement, monitoring and detection measures are taken for the sections where deformation defects occur and develop. Based on the development of deformation, structural locking feet are set to control the adverse effects on the tunnel arch structure caused by the deterioration of the arch bottom support and lining conditions, so as to create a safe and stable working environment for subsequent tunnel bottom treatment.

[0068] S2. When the tunnel bottom is in a moderate or severe condition, the surrounding rock at the tunnel bottom absorbs water, expands and softens, and the tunnel structure cannot bear the force generated by the plastic deformation and compression of the surrounding rock at the tunnel bottom, which causes the tunnel bottom to expand and heave. The tunnel bottom is reinforced by measures such as tunnel bottom anchor pipe, duct grouting and adding steel frame beams to the tunnel bottom.

[0069] S3. For tunnel floor defects that are severe or extremely severe, the uplift has seriously affected the use of the tunnel and caused damage to the tunnel structure. In order to prevent the continued deformation of the invert arch structure from endangering the stability of the tunnel structure, a double arch reinforcement lining is added, and an invert arch frame is set up to form a closed ring support structure, thereby improving the overall strength and stability of the structure.

[0070] S4. During the reinforcement and treatment of the tunnel bottom, the unloaded free surface generated during the removal of the road surface and the invert arch filling is designed to ensure the overall stability of the tunnel structure. Before the removal of the invert arch filling, a row of grouting pipes is installed at the arch foot lining on both sides of the defective section. Temporary supports are set up before the invert arch filling is removed to reduce the construction risk of the foundation treatment.

[0071] S5. At the same time, during the construction process, displacement and deformation measurement sections are set up, and pressure and deformation data acquisition elements are buried to monitor the structural performance after treatment.

[0072] S6, to renovate and restore the tunnel floor drainage system and cable trench facilities;

[0073] S7 involves rebuilding and reinforcing the road surface structure and restoring road markings.

[0074] The embodiments of the present invention are also implemented through the following technical solutions.

[0075] In embodiments of the present invention, such as Figure 3 As shown, the measures to control the adverse effects on the tunnel arch structure in steps S1 and S4 are as follows:

[0076] S11 Before reinforcing the steel pipe pile 1, remove the cable trench covers on both sides. Use 4.5m long steel pipes with a diameter of 89mm and a wall thickness of 6mm to drill holes and grout the base of the left and right side walls and the bottom plate of the cable trench. After completing the lining and grouting, reinforce the road surface by grouting.

[0077] In addition, the steel pipe wall thickness is 6mm, no holes are made within 50cm of the end, and grouting holes are set at 15cm intervals for the rest of the pipe. The hole diameter is 12mm, the grouting pressure is 0.5-1.5MPa, and the grouting material is cement grout. The water-cement ratio of cement grout is 1:0.75 to 1:1.5, but it must be determined by on-site test and can only be used after meeting the design requirements.

[0078] S4. Before lining trenching or tunnel bottom excavation, temporary steel frame support is erected, and circumferential steel arch frames 2 are erected with a longitudinal spacing of 1m. Each arch frame unit segment is connected by welded steel plate bolts for easy installation and dismantling. Longitudinal connecting steel bars are set between the arch frames with a circumferential spacing of 1m. The arch frames are fixed to the secondary lining with wedges. The construction method is to extend the circumferential steel arch frame 2 to both sides of the tunnel bottom excavation section by one section of secondary lining length, with a construction length of 6 to 12m.

[0079] In embodiments of the present invention, based on the characteristics of tunnel defects and according to the severity of the defects, tunnel bottom grouting reinforcement is selected as the primary treatment. For tunnel pavement cracks, misalignments, and tilted / deformed sections of the maintenance road, ground-penetrating radar detection reveals varying degrees of defects in the tunnel bottom structural layer. Given the good service condition of the arch wall structure and the unsuitability for replacing the invert arch structure in certain sections, tunnel bottom grouting reinforcement is adopted as the main treatment measure. This can be combined with the use of steel frame beams and steel anchor frames. Figure 4-5 As shown,

[0080] In step S2, the spacing between sections with defects in the invert arch and Class V surrounding rock is 1m, while the spacing between sections with better structural condition in Class V surrounding rock and Class IV surrounding rock is 1.5m. The grouting material is cement grout, with a water-cement ratio of 1:0.75-1:1.5. The measures for reinforcing the tunnel foundation are as follows:

[0081] S21, Tunnel Bottom Grouting: Before tunnel bottom grouting, the asphalt layer of the road surface is removed, and grouting is carried out using 4.5m long steel pipes with a diameter of 51mm and a wall thickness of 3.5mm. The grouting steel pipes are arranged in a quincunx pattern.

[0082] S22, as Figure 6 As shown, for the steel frame beam, two rows of 51×3.5mm grouting anchor pipes 3 are installed on both sides of the bottom corner of the tunnel. The anchor pipes 3 are welded to the longitudinal channel steel 10. The anchor pipes 3 are 4.5m long and arranged with a longitudinal spacing of 1m. The grouting slurry is cement single liquid slurry (cement-water glass double slurry is used in water-rich areas). I-18 steel is arranged side by side as transverse support with a longitudinal spacing of 1m. I-14 steel is used as longitudinal steel support. The I-18 longitudinal steel is welded to the bottom corner channel steel 10 and the I-14 steel to form an integrally stressed steel frame beam system.

[0083] In addition, such as Figure 7 As shown, the construction methods and steps for the anchor bolt steel frame and grouting are the same as those for step S22.

[0084] In an embodiment of the present invention, step S3 further includes:

[0085] S31, Embedded arch reinforcement treatment, for the V-class surrounding rock tunnel with insufficient thickness of the bottom structure layer and serious defects, the lining of the arch wall has cracks and local spalling, and the road surface defects are serious. It is necessary to reinforce the whole structure and adopt the embedded arch closed arch method for treatment.

[0086] In an embodiment of the present invention, the specific treatment measures in step S31 are as follows:

[0087] S311, after completing the construction of the lining locking foot and the temporary arch support within the scope of the operation, the lining trench excavation will be carried out.

[0088] S312, install the arch steel frame, fix it with L-shaped anchors, and set two grouting small pipes with a diameter of 51mm and a wall thickness of 3.5mm at the arch frame to lock the feet;

[0089] S313, the original maintenance road and road surface within the transverse range will be demolished;

[0090] S314, the tunnel bottom is excavated using the skip-slot method, and the foundation excavation is carried out using the pull-slot method, with a step distance of not less than 10m and a slot width of not more than 2m;

[0091] S315, after excavating to the bedrock surface at the bottom of the tunnel, remove the surface debris and replace it with C15 concrete stabilized base course 14, with a thickness of not less than 50cm;

[0092] S316, due to the poor integrity and bearing capacity of the surrounding rock at the base, grouting pipes with a diameter of 51mm and a wall thickness of 3.5mm are added, with a circumferential spacing of 1m;

[0093] S317, after the base is replaced and leveled, the assembled I-18 steel inverted arch frame is lowered and anchored to the upper arch foot bolts.

[0094] S318, after the steel mesh is hung on the reinforced section of the arch, C30 fiber concrete 15 is sprayed, and the thickness of the protective layer of the arch frame is not less than 4cm.

[0095] In embodiments of the present invention, such as Figure 9-10 As shown, the tunnel drainage facilities are modified in step S6 as follows:

[0096] In section S61, the arching section of the tunnel pavement has experienced local displacement of the pipe trench due to the backfilling of the invert arch. This has led to the detachment and damage of the pipe trench interfaces, resulting in poor longitudinal drainage and water infiltration. This has reduced the strength and bearing capacity of the foundation rock, affecting structural safety. The original 30cm inner diameter concrete circular pipe trench, base, and crushed stone filter layer were removed from the damaged arching section. Without altering the original drainage cross-section and longitudinal slope of the drainage ditch, a reinforced concrete rectangular structure was constructed using a cast-in-place formwork method. The drainage cross-section has a net width of 30cm and a net height of 55cm. The bottom elevation of the ditch is consistent with the original design elevation of the pipe trench. A precast concrete cover plate 22 is installed on top, with dimensions of 50cm x 50cm and a thickness of 15cm. The top surface of the cover plate is flush with the top surface of the concrete pavement slab. An end sealing wall is poured at the junction with the pipe trench to ensure a smooth connection between the rectangular blind ditch and the original designed pipe trench, preventing leakage.

[0097] In an embodiment of the present invention, when restoring the road surface in step S7 in sections with longitudinal cracks, misalignments, and subsidence, as well as sections undergoing tunnel bottom grouting reinforcement and invert replacement, road surface reinforcement is used for treatment. The specific treatment measures are as follows:

[0098] S71, remove roadside ditches, asphalt pavement, pavement panels and base course;

[0099] S72, restore the road base layer according to the design;

[0100] S73 uses 12mm diameter steel bars with a spacing of 15mm to tie the double-layer steel mesh of the road surface panel;

[0101] S74, integrally cast C40 reinforced concrete panel 6.

[0102] In embodiments of the present invention, such as Figure 12 As shown, the specific monitoring of structural performance after treatment in S5 is as follows:

[0103] S51, a level, precision level, indium steel ruler or measuring rod shall be set up at the location of arch subsidence for monitoring, and shall be set up in the reinforcement construction area;

[0104] S52, perform peripheral convergence, set up convergence meters around the reinforced construction area, set up a cross section every 10m, and set up 2 pairs of measuring points in each cross section;

[0105] S53, a precision level or indium steel ruler is installed at the bottom drum. It is installed during the replacement and treatment of the tunnel bottom. A section is set every 10m, and at least 3 measuring points are set at each section.

[0106] S54, strain gauges, stress gauges and pressure gauges are installed in the concrete of each representative section, and 11 measuring points are set in each cross section for stress monitoring.

[0107] In addition, from bottom to top, the following layers are: a 30cm thick (40cm thick for sections without an inverted arch) C25 reinforced concrete pavement base course, a 26cm thick C40 reinforced concrete pavement slab, and an asphalt concrete pavement layer (4cm fine-grained asphalt mastic aggregate mixture (SMA-13) and 6cm medium-grained modified asphalt concrete (AC-20C)).

[0108] In addition, to prevent the seepage and accumulation of tunnel cleaning water, a 1cm thick asphalt surface treatment layer is installed between the asphalt concrete surface layer and the C40 cast-in-place cement concrete slab.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

[0110] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

Claims

1. A method for comprehensive treatment of foundation defects in highway tunnels, characterized in that, Includes the following steps: S1. For cases of cracking and arching of the tunnel floor pavement, and for sections where deformation defects occur and develop, monitoring and detection measures are taken, and structural locking feet are set according to the deformation development to control the adverse effects on the tunnel arch structure caused by the deterioration of the arch bottom support and lining conditions. Among them, the measures to control the adverse effects of the tunnel arch structure are: S11, before the steel pipe pile (1) is reinforced, the cable trench and drainage ditch on both sides of the road are removed. A 4.5m long steel pipe with a diameter of 89mm and a wall thickness of 6mm is used to drill and grout the foot of the left and right side walls and the bottom plate of the cable trench. After the lining and footing are completed, the road surface is reinforced by grouting. S2. When the tunnel floor is in a moderate or severe condition, the surrounding rock absorbs water, expands, and softens. The tunnel structure cannot withstand the forces generated by the plastic deformation and compression of the surrounding rock, leading to tunnel floor expansion and heave. The tunnel floor is reinforced by using anchor pipes, grouted ducts, and adding steel frame beams. Specifically, for Class V surrounding rock with defects in the invert section, the spacing is 1m; for Class V surrounding rock with better structural condition and Class IV surrounding rock sections, the spacing is 1.5m. The grouting material is cement grout with a water-cement ratio of 1:0.75-1:1.

5. The measures for reinforcing the tunnel foundation are as follows: S21, Tunnel bottom grouting, before tunnel bottom grouting, remove the asphalt layer of the road surface, and use a 4.5m long steel pipe with a diameter of 51mm and a wall thickness of 3.5mm for grouting. The grouting steel pipe (4) is arranged in a quincunx pattern. S22, steel frame beam, two rows of 51×3.5mm grouting anchor pipes (3) are installed on both sides of the bottom corner of the tunnel. The anchor pipes (3) are welded to the longitudinal channel steel (10). The anchor pipes (3) are 4.5m long and arranged with a longitudinal spacing of 1m. The grouting slurry is cement single liquid slurry. I-18 steel is arranged in parallel as horizontal support with a longitudinal spacing of 1m. I-14 steel is used as longitudinal steel support. I-18 longitudinal steel is welded to the bottom corner channel steel (10) and I-14 steel to form an integrally stressed steel frame beam system. S3, for tunnel floor defects of severe and extremely severe levels, where the uplift has seriously affected tunnel use and damaged the tunnel structure, an additional arch reinforcement lining is added, and an inverted arch frame is installed to form a closed ring support structure. The specific steps include: S31, Embedded arch reinforcement treatment, for the V-class surrounding rock tunnel with insufficient thickness of the bottom structure layer and serious defects, the lining of the arch wall has cracks and local spalling, and the road surface defects are serious. It is necessary to reinforce the whole structure and adopt the embedded arch closed arch method for treatment. The specific treatment measures in step S31 are as follows: S311, after completing the construction of the lining locking foot and the temporary arch support within the scope of the operation, the lining trench excavation will be carried out. S312, install the arch steel frame, fix it with L-shaped anchors, and set two grouting small pipes with a diameter of 51mm and a wall thickness of 3.5mm at the arch frame to lock the feet; S313, the original maintenance road and road surface within the transverse range will be demolished; S314, the tunnel bottom is excavated using the skip-slot method, and the foundation excavation is carried out using the pull-slot method, with a step distance of not less than 10m and a slot width of not more than 2m; S315, after excavating to the bedrock surface at the bottom of the tunnel, remove the surface debris and replace it with C15 concrete stabilized base (14) with a thickness of not less than 50cm; S316, due to the poor integrity and bearing capacity of the surrounding rock at the base, grouting pipes with a diameter of 51mm and a wall thickness of 3.5mm are added, with a circumferential spacing of 1m; S317 After the base is replaced and leveled, the assembled I-18 steel arch frame is lowered and anchored to the upper arch foot bolts. S318, after the steel mesh is hung on the reinforced section of the arch, C30 fiber concrete (15) is sprayed, and the thickness of the protective layer of the arch frame is not less than 4cm. S4, during the reinforcement and treatment of the tunnel bottom, the unloading free surface generated when removing the road surface and the invert arch filling, before the invert arch filling is removed, a row of grouting pipes are laid at the arch foot lining on both sides of the diseased section, and temporary supports are set up before the invert arch filling is removed. S5. At the same time, during the construction process, displacement and deformation measurement sections are set up, and pressure and deformation data acquisition elements are buried to monitor the structural performance after treatment. S6, to renovate and restore the tunnel floor drainage system and cable trench facilities; S7 involves rebuilding and reinforcing the road surface structure and restoring road markings.

2. The method for comprehensive treatment of foundation defects in highway tunnels according to claim 1, characterized in that, Step S4 further includes: S41, before lining trenching or tunnel bottom excavation, a temporary steel frame support is erected, and a circumferential steel arch frame (2) is erected with a longitudinal spacing of 1m. Each arch frame unit segment is connected by welded steel plate bolts. Longitudinal connecting steel bars are set between the arch frames with a circumferential spacing of 1m. The arch frames and the secondary lining are fixed with wedges. The circumferential steel arch frame (2) is laid out by extending one section of secondary lining length on both sides of the tunnel bottom excavation section.

3. The method for comprehensive treatment of foundation defects in highway tunnels according to claim 1, characterized in that, The drainage facility modification in step S6 is as follows: S61, the arched section of the tunnel pavement, if the original design is a concrete circular pipe trench, under the premise of not changing the original drainage section and the longitudinal slope of the drainage ditch, a reinforced concrete rectangular structure is set by cast-in-place method. The drainage section has a net width of 30cm and a net height of 55cm. The bottom elevation of the ditch is consistent with the original design elevation of the pipe trench bottom. A precast concrete cover plate (22) is set on the top. The cover plate has a length and width of 50cm×50cm and a thickness of 15cm. The top surface of the cover plate is flush with the top surface of the concrete pavement panel. An end sealing wall is poured at the connection position with the pipe trench.

4. The method for comprehensive treatment of foundation defects in highway tunnels according to claim 1, characterized in that, In step S7, when restoring the road surface in sections with longitudinal cracks, misalignments, and subsidence, as well as sections undergoing tunnel bottom grouting reinforcement and invert replacement, road surface reinforcement is used for treatment. The specific treatment measures are as follows: S71, remove roadside ditches, asphalt pavement, pavement panels and base course; S72, restore the road base layer according to the design; S73 uses 12mm diameter steel bars with a spacing of 15mm to tie the double-layer steel mesh of the road surface panel; S74, integrally cast C40 reinforced concrete panel (6).

5. A method for comprehensive treatment of foundation defects in highway tunnels according to claim 1, characterized in that, The specific monitoring of the post-treatment structural performance in S5 is as follows: S51, a level, precision level, indium steel ruler or measuring rod shall be set up at the location of arch subsidence for monitoring, and shall be set up in the reinforcement construction area; S52, perform peripheral convergence, set up convergence meters around the reinforced construction area, set up a cross section every 10m, and set up 2 pairs of measuring points in each cross section; S53, a precision level or indium steel ruler is installed at the bottom drum. It is installed during the replacement and treatment of the tunnel bottom. A section is set every 10m, and at least 3 measuring points are set at each section. S54, strain gauges, stress gauges and pressure gauges are installed in the concrete of each representative section, and 11 measuring points are set in each cross section for stress monitoring.

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