Construction technology method of single side drift method for shallow buried and bias pressure large section highway tunnel

Abstract

The invention discloses a construction process method for the single-side drift method of a shallow-buried and bias-pressure large-section highway tunnel, which includes: drilling and blasting a small pilot tunnel on the mountain side for excavation, and on the premise of ensuring the construction space, minimizing the exposure of the main sliding surface and the main bedding plane in the excavation space, and carrying out permanent support on the mountain side; the construction process of the single-side drift method for the shallow-buried and bias-pressure large-section highway tunnel adopts a fast and safe construction method combining the drift method and the bench method. On the premise of ensuring the construction space in the early stage, the main sliding surface and the main bedding plane are minimized in the excavation space, increasing the safety of tunnel construction. Further, through the combination of permanent support and temporary support, the excavation is supported, effectively preventing large-area collapse of the surrounding rock of the heading face. At the same time, through the parallel operation of multiple machines, multiple types of work and multiple operations, the work efficiency is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of highway tunnel construction, and particularly relates to a construction process method for a single-side drift method of a shallow-buried and eccentrically loaded large-section highway tunnel. Background Technique

[0002] The single-side drift method, also known as the CD method and the middle diaphragm method, is mainly applicable to underground engineering construction with relatively poor geological conditions and unstable rock masses. During the excavation process of the single-side drift method, when multiple machines, multiple types of work, and multiple operations are carried out in parallel, the work efficiency can be effectively improved. The leading upper drift and the trailing upper drift respectively reserve a core soil, which can not only effectively prevent large-area collapses of the surrounding rock of the heading face, but also effectively ensure the personal safety of the operating personnel;

[0003] Compared with relatively weak surrounding rock, it is not recommended to use the single-side drift method in construction, because in relatively weak surrounding rock, the weak blasting effect is relatively poor, and in addition, the general blasting method will affect the support. Among them, the role of the middle diaphragm will be weakened, which will increase the occurrence of potential safety hazards in the actual construction process. In the existing construction process of the single-side drift method, there is no effective method to solve this problem;

[0004] Therefore, it is urgent to design a construction process for the single-side drift method applicable to shallow-buried and eccentrically loaded large-section tunnels to solve the above problems. Summary of the Invention

[0005] Aiming at the defects existing in the above-mentioned prior art, the purpose of the present invention is to provide a construction process method for the single-side drift method of a shallow-buried and eccentrically loaded large-section highway tunnel. Through this construction process method, the problems of low construction efficiency and low safety performance caused by possible large-area collapses can be effectively solved, and it has the characteristics of high construction efficiency and high safety performance.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A construction process method for the single-side drift method of a shallow-buried and eccentrically loaded large-section highway tunnel, including

[0008] (1) Excavate the working face of part Ⅰ on the mountain side

[0009] 1.1) Use the method of drilling and blasting a small pilot tunnel to blast and excavate the working face of part Ⅰ;

[0010] 1.2) After excavation, carry out permanent support on the mountain side of the working face of part Ⅰ, fill the rock wall cracks in advance, and reinforce the surrounding rock mass;

[0011] 1.3) Support the working face of part Ⅱ on the side away from the mountain of the working face of part Ⅰ with a steel frame support device;

[0012] 1.4) Further assemble the detachable anchor bolts to reinforce and support the working face of Section II;

[0013] 1.5) Assemble the rubber airbag support base and the rubber airbag on the steel frame support device, and place the rubber airbag between the right wall of the working face of Section II and the rubber airbag support base and keep it in a compressed state;

[0014] 1.6) After completing the support on both sides of the working face of Section I, carry out the excavation of the working face of Section I, and conduct the next pilot tunnel excavation work in units of 15 m;

[0015] 1.7) Deflate the rubber airbag, and remove the detachable anchor bolts and the steel frame support device;

[0016] (2) Excavation and expansion of the working faces of Sections II and III

[0017] Repeat steps 1.2) - 1.7) to carry out the excavation and expansion of the working faces of Sections II and III;

[0018] (3) Excavation of the working faces of Sections IV and V

[0019] 3.1) After completing the excavation and expansion of the working face of Section III, use the stepped excavation method to successively carry out stepped excavation on the working faces of Sections IV and V;

[0020] 3.2) After completion, carry out supplementary support work 2 m apart at Section V to strengthen the support;

[0021] 3.3) After the excavation of the working faces of Sections IV and V is completed, support the overall working face of the tunnel.

[0022] Preferably, during the blasting excavation on both sides of the working face of Section I described in step 1.1), the slightly positive bench method is adopted, the upper half section is advanced 2.5 - 3 m, the footage per cycle is 2.0 - 2.5 m, and the main slip plane and the main bedding plane are exposed less in the excavation space.

[0023] Preferably, the permanent support described in step 1.2) includes advanced small pipes supported on the side wall of the working face of Section I on the mountain side. The advanced small pipes are seamless steel pipes with a diameter of φ42 mm, a wall thickness of 3.5 mm, and L = 4.0 m, and shotcrete C25 is sprayed on the heading face outside the advanced small pipes as a grout stop wall.

[0024] Preferably, the steel frame support device described in step 1.3) includes a foot frame and multiple layers of support upright frames;

[0025] The scaffold is fixed at the bottom of the tunnel between the working surfaces of part I and part II, and includes a base steel frame, a first foot steel, and a second foot steel that are connected to each other. The base steel frame is arranged on the upper side of the first foot steel and the second foot steel, and a rail groove is arranged on the base steel frame. The first foot steel is arranged on the side close to the working surface of part II, and two adjacent first foot steels are connected by a type-A connecting piece;

[0026] The supporting upright frame is installed on the scaffold, and adjacent front and rear supporting upright frames are connected by an upright frame connecting piece; the supporting upright frame includes a supporting vertical rod and a horizontal connecting rod. The supporting vertical rod is formed by connecting a number of first supporting pieces to each other. The adjacent first supporting pieces are connected by a type-B connecting piece. The horizontal connecting rod and the first supporting piece are connected by a type-C connecting piece. An adjustable connecting piece is arranged at the upper end of the first supporting piece at the top of the supporting upright frame, and the adjustable connecting piece is used in cooperation with a rubber airbag supporting base.

[0027] Preferably, a sliding piece is movably arranged in the rail groove. One end of the sliding piece is open, and a connecting card slot, a limiting connecting plate, and a bottom sliding protrusion are arranged on the sliding piece. The bottom sliding protrusion is arranged at the bottom of the sliding piece, and a limiting strip is arranged on the bottom sliding protrusion. The limiting strip is used in cooperation with a limiting groove arranged on the rail groove. The limiting connecting plate is arranged in the middle of the sliding piece, and a number of connecting holes are arranged on the connecting plate. The connecting holes are used in cooperation with the connecting holes arranged on the upper plane of the rail groove to fix the sliding piece. The connecting card slot is arranged at the upper end of the sliding piece and is connected to the lower end of the first supporting piece at the bottom of the supporting upright frame by a bolt.

[0028] Preferably, an auxiliary supporting piece is further installed on the first supporting piece of the supporting upright frame on the side close to the working surface of part II. The auxiliary supporting piece includes a first installation base and a first hydraulic piece. The first hydraulic piece is arranged at the front end of the first installation base and is used in cooperation with the side wall of the working surface of part II. Connecting plates are symmetrically arranged at the tail of the first installation base, and the connecting plates are connected to the first supporting piece by connecting bolts;

[0029] The adjustable connecting piece is installed at the upper end of the first supporting piece through a type-B connecting piece and includes a second installation base, a second hydraulic piece, and a rotating connecting piece. The second installation base is arranged at the bottom of the second hydraulic piece and is used with the type-B connecting piece. The rotating connecting piece is arranged at the end of the piston rod of the second hydraulic piece and is used in cooperation with the rubber airbag supporting base.

[0030] Preferably, the vertical frame connecting piece includes a connecting sleeve and a connecting rod. The connecting rod is movably inserted into the connecting sleeve, and a first locking tooth is arranged on the connecting rod. A locking block is rotatably arranged in a clamping groove on the connecting sleeve. A second locking block is arranged on the inner side surface of the locking block, and the second locking block is unidirectionally locked with the first locking tooth. U-shaped connecting heads are arranged at the distal ends of the connecting sleeve and the connecting rod, and the U-shaped connecting heads are connected to the first support member through connecting bolts.

[0031] Preferably, the bolt material of the detachable bolt described in step 1.4 adopts a hollow bolt, the material is HRB400 or Q345 steel, the length of a single bolt is 3.5 m, the size of the backing plate is 150 mm×150 mm×6 mm, and the exposed length during the construction of the bolt is not more than 100 mm.

[0032] Preferably: The staggered excavation described in step 3.1 is a step where the working faces of parts Ⅳ and Ⅴ are staggered by 1 - 1.5 m. Before excavation, it is necessary to measure and release the excavation contour line along the excavation surface, drill and blast a small pilot tunnel, and then carry out 1 or 2 times of excavation expansion. The excavation surface should be kept as vertical as possible. When excavating the lower bench, keep a distance of 1 - 1.5 m from the heading face to facilitate backhoe slag removal.

[0033] Preferably, the process of supporting the overall working face of the tunnel described in step 3.3 includes:

[0034] (1) After the overall excavation of the tunnel is completed, immediately carry out the construction of steel arch support, locking foot bolts and shotcrete with wire mesh, and lay a φ6@15*15 steel mesh;

[0035] (2) Further evenly spray concrete with a thickness of 5 - 10 cm for enhanced support.

[0036] The beneficial effects of the present invention are as follows: The present invention discloses a construction process method for a single - side drift method of a shallow - buried and eccentric - pressure large - section highway tunnel. Compared with the prior art, the improvements of the present invention are as follows:

[0037] (1) The present invention proposes a construction process method for a single - side drift method of a shallow - buried and eccentric - pressure large - section highway tunnel. This construction process of the single - side drift method for the shallow - buried and eccentric - pressure large - section highway tunnel adopts a fast and safe construction method combining the drift method and the bench method. On the premise of ensuring the construction space in the early stage, the main sliding surface and the main bedding plane are exposed in the excavation space as little as possible, increasing the safety of tunnel construction. Further, through the combination of permanent support and temporary support, support and excavation are carried out, effectively preventing large - area collapse of the surrounding rock of the heading face. At the same time, through multi - machine, multi - type of work and multi - operation parallel operation, the work efficiency is effectively improved;

[0038] (2) The construction technology of the single-side drift method for the shallow-buried and bias-pressure large-section highway tunnel is based on the basic principles of the New Austrian Tunneling Method. The whole tunnel is divided into five sections and excavated step by step from left to right. The drift section is approximately elliptical, and the peripheral contour is smooth, which can avoid stress concentration and is beneficial to controlling the settlement of the vault. After the overall structure is relatively stable, the fourth and fifth parts are excavated in upper and lower benches, which is beneficial to mechanized operation and has a relatively fast progress. When carrying out the excavation work for each section, relevant personnel can reasonably utilize the short-term stability of the surrounding rock, use anchor bolts and rubber airbags to ensure the stability of the structure, and reasonably utilize the drift method, which can effectively improve the economic and social benefits to a certain extent. In the specific construction process, it can also save project costs, reduce the investment in labor costs, effectively control the entire project cycle, thereby effectively improving the construction efficiency of the construction unit. Compared with the traditional partial excavation method, this method can not only reduce the time in the connection of construction processes, but also, on the basis of improving the tunnel construction level and ensuring the safety of project construction, provide an effective reference basis for the construction quality control of the tunnel, and can effectively solve the problems of low construction efficiency and possible large-area collapse resulting in low safety performance, and has the advantages of high construction efficiency and high safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 FIG. is a construction schematic diagram of the single-side drift method for the shallow-buried and bias-pressure large-section highway tunnel of the present invention.

[0040] Figure 2 FIG. is a structural schematic diagram of the retractable steel frame of the present invention.

[0041] Figure 3 FIG. is a structural schematic diagram of the scaffold of the present invention.

[0042] Figure 4 FIG. is a structural schematic diagram of the sliding member of the present invention.

[0043] Figure 5 FIG. is a structural schematic diagram of the first support member of the present invention.

[0044] Figure 6 FIG. is a structural schematic diagram of the type A connecting member of the present invention.

[0045] Figure 7 FIG. is a structural schematic diagram of the type B connecting member of the present invention.

[0046] Figure 8 FIG. is a structural schematic diagram of the type C connecting member of the present invention.

[0047] Figure 9 FIG. is a structural schematic diagram of the auxiliary support member of the present invention.

[0048] Figure 10 FIG. is a structural schematic diagram of the vertical frame connecting member of the present invention.

[0049] Figure 11 It is a structural schematic diagram of the adjustable connecting piece of the present invention.

[0050] Figure 12 It is a schematic structural diagram of the detachable anchor of the present invention.

[0051] Among them: 1. Primary support lining, 2. Retractable steel frame assembled support, 3. Removable anchor, 4. Rubber airbag support base, 5. Rubber airbag, 6. Staggered 1 to 1.5m step excavation, 7. Secondary lining, 8. Foot frame, 81. Base steel frame, 82. First foot steel, 83. Second foot steel, 84. Clearance groove, 85. Sliding piece, 851. Connecting slot, 852. Limit connecting plate, 853. Bottom sliding protrusion, 854. Limiting bar, 86. Rail groove, 9. Support pole, 91. First support member, 10. Horizontal connecting rod, 11. Frame connecting piece, 111 .U-shaped connecting head, 112. Connecting sleeve, 113. Connecting rod, 114. Slot, 115. Locking block, 116. First locking tooth, 117. Second locking block, 12. Auxiliary support member, 121. First mounting base, 122. Connecting plate, 123. First hydraulic member, 13. Type B connecting member, 131. First connecting plate, 14. Adjustable connecting member, 141. Second mounting base, 142. Second hydraulic member, 143. Rotating connecting member, 15. Type A connecting member, 151. Second connecting plate, 16. Type C connecting member, 161. Third connecting plate. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0053] Example 1: Refer to the attached Figure 1 The construction process of a shallow-buried, biased, large-section highway tunnel using a single-sidewall pilot tunnel method is shown, including:

[0054] (1) Excavation of the working face I on the mountain side

[0055] 1.1) Blasting excavation of Section I working face was carried out using the drilling and blasting method of small pilot holes. While ensuring construction space, a slightly positive step method was used, with the upper section advanced 2.5-3m. Five air-leg rock drills were used for drilling, and smooth blasting was performed, with each cycle delivering 2.0-2.5m of footage. This was done to minimize the exposure of the main sliding surface and the main layer interface within the excavation space. Loading was done with a front-end shovel loader and transportation was done with dump trucks.

[0056] 1.2) After excavation, permanent support is carried out on the mountain - side of the working face of Section Ⅰ. The permanent support includes grouting with φ42mm seamless steel pipes with a wall thickness of 3.5mm and a length L = 4.0m of advanced small pipes to fill the cracks in the rock wall in advance and reinforce the surrounding rock mass. Shotcrete of C25 is sprayed on the heading face as a grout - proof wall to prevent liquid leakage.

[0057] 1.3) For the working face of Section Ⅱ on the side of the working face of Section Ⅰ far from the mountain, a steel - frame support device 2 is used for support; at the same time, before support, it is necessary to check whether the cross - section is under - excavated. If there is under - excavation, it is necessary to complete the treatment before constructing the steel frame. According to the design drawings, the control points of the steel frame are marked on the cross - section, and the steel frame is assembled according to the marked points to ensure the stability of the steel - frame support device 2. After the installation of the steel frame is completed, a re - check is required.

[0058] 1.4) Further assemble the removable anchor bolts 3 to reinforce and support the working face of Section Ⅱ, enhance the safety of the surrounding rock, and prevent collapse during the excavation process. The construction content of the anchor bolts mainly includes processes such as drilling, installing the conduit, grouting, and effect inspection. During the installation of the anchor bolts, the exposed length of the anchor bolts is not more than 100mm, and the exposed length of the foot - locking anchor pipes is preferably just welded to the steel frame. The grouting must be full and dense. If the slurry is not full, it should be replenished in time. For the hollow grouting anchor bolts, attention should be paid to the exhaust problem. The grouting can be stopped only after the slurry comes out from the exhaust hole.

[0059] 1.5) Assemble the rubber - air - bag support base 4 and the rubber air - bag 5 on the steel - frame support device 2, so that the rubber air - bag 5 is arranged between the right wall of the working face of Section Ⅱ and the rubber - air - bag support base 4 and is in a compressed state for support to prevent unnecessary losses caused by leakage or water - inrush and mud - burst.

[0060] 1.6) After completing the support on both sides of the working face of Section Ⅰ, the excavation of the working face of Section Ⅰ is carried out, and the next pilot - tunnel excavation work is carried out in units of 15m.

[0061] 1.7) Deflate the rubber air - bag 5, and remove the removable anchor bolts 3 and the steel - frame support device 2.

[0062] (2) Expansion excavation of the working faces of Sections Ⅱ and Ⅲ

[0063] Repeat steps 1.2) - 1.7) to carry out the expansion excavation of the working faces of Section Ⅱ and Section Ⅲ.

[0064] (3) Excavation of the working faces of Sections Ⅳ and Ⅴ

[0065] 3.1) After the excavation of the working face in Part III is completed, in order to ensure the integrity of each joint structure, the steps for excavation in Parts IV and V are staggered by 1 - 1.5 m. Before the staggered excavation by 1 - 1.5 m, the surveyors need to measure and mark the excavation contour line along the excavation face, drill and blast a small pilot tunnel, and then conduct one or two rounds of excavation, keeping the excavation face as vertical as possible. When excavating the lower bench, keep a distance of 1 - 1.5 m from the heading face to facilitate backhoe slag removal;

[0066] 3.2) After completion, carry out reinforcement support work with a difference of 2 m in Part V to strengthen the support;

[0067] 3.3) After the excavation of the working faces in Parts IV and V is completed, support the overall working face of the tunnel. Specifically, lay a steel mesh of φ6@15*15 on the completed top, and further evenly spray concrete with a thickness of 5 - 10 cm to strengthen the support. Immediately after excavation, carry out the construction of steel arch support, locking foot bolts and shotcrete. Lay a steel mesh of φ6@15*15, and re-spray concrete with a thickness of 5 - 10 cm to the designed thickness.

[0068] During construction, first carry out the excavation work in Section I of the tunnel. On the premise of ensuring the construction space, minimize the exposure of the main sliding surface and the main bedding plane in the excavation space. Before the tunnel excavation, carry out advanced support. Use φ42 mm seamless steel pipes with a wall thickness of 3.5 mm and L = 4.0 m advanced small pipes for grouting to fill the rock fissures in advance and reinforce the surrounding rock mass. After excavation, carry out permanent primary support lining for the part 1 near the mountain, and carry out assembled support with a telescopic steel frame 2 for the right part of I. While assembling the detachable bolt device 3, assemble the support base 4 of the rubber airbag on the telescopic steel frame structure 2. Further set the rubber airbag 5 between the right wall of the tunnel and the support base 4 and keep it in a compressed state to carry out support to prevent losses caused by leakage or sudden mud and water inrush. After the excavation of Section I is completed, while carrying out the excavation support of the pilot tunnel, carry out excavation in units of 15 m. Deflate the rubber airbag 5, and remove the detachable bolt 3, the telescopic assembled steel frame 2 and the rubber airbag base 4. Repeat the above steps for the excavation work in Sections II and III. After Sections II and III are completed, the remaining part is excavated by the bench method. In order to ensure the integrity of each joint structure, the part 6 is excavated with a stagger of 1 - 1.5 m. After completion, carry out reinforcement support work with a difference of 2 m in the fifth part to strengthen the support. After the overall excavation work is completed, lay a steel mesh of φ6@15*15 on the top and further evenly spray concrete with a thickness of 5 - 10 cm to complete the strengthening support of 7.

[0069] The construction process of the shallow-buried, biased, large-section highway tunnel with a single-sidewall pilot tunnel method designed in the present invention: By adopting a fast and safe construction method combining the pilot tunnel method with the step method, the main sliding surface and the main layer interface are exposed as little as possible in the excavation space while ensuring construction space in the early stage, thereby increasing the safety of tunnel construction. Furthermore, by combining permanent support with temporary support, support and expansion are carried out, effectively preventing large-scale collapse of the surrounding rock of the face. At the same time, by using multiple machines, multiple types of work, and multiple operations in parallel, work efficiency is effectively improved.

[0070] Moreover, by dividing the entire tunnel into five sections and then carrying out excavation work on each of the sections, during the excavation process, relevant personnel can reasonably use the stability of the surrounding rock in a short time, use anchor rods and rubber airbags to ensure the stability of the structure, and reasonably use the pilot tunnel method, which can effectively improve economic and social benefits to a certain extent. In the specific construction process, it can also save project costs, reduce investment in related labor costs, and effectively control the entire project cycle, thereby effectively improving the construction efficiency of the construction unit. Compared with the traditional partial excavation method, this method can not only reduce the time in the connection of construction processes, but also provide an effective reference basis for tunnel construction quality control on the basis of improving the level of tunnel construction and ensuring the safety of engineering construction. The present invention has a reasonable design, obvious economic benefits, and good practical value.

[0071] Example 2: Refer to the attached Figures 2 - 12 As shown, the difference from Example 1 is that, in order to facilitate the support of the tunnel face of the working face of Section II and prevent collapse, the steel frame support device 2 described in step 1.3 includes a foot frame 8 and a multi-layer support frame;

[0072] The foot frame 8 is fixed to the bottom of the tunnel between the working faces of section I and section II, and includes a base steel frame 81, a first foot steel 82, and a second foot steel 83 connected to each other. The base steel frame 81 is arranged on the upper side of the first foot steel 82 and the second foot steel 83, and plays a connecting and supporting role (forming a triangle with the support frame to increase the contact area with the ground and improve stability). A rail groove 86 is provided on the base steel frame 81. The first foot steel 82 is arranged on the side near the working face of section II, and two adjacent first foot steels 82 are connected by an A-type connector 15. A multi-layer support system is formed by multiple layers of adjacent support frames.

[0073] The support upright frame is installed on the scaffold 8, and adjacent front and rear support upright frames are connected by upright frame connectors 11 to form an integral support structure; the support upright frame includes support vertical poles 9 and horizontal connecting rods 10, the support vertical poles 9 are formed by connecting a number of interconnected first support members 91, the adjacent first support members 91 are connected by B-type connectors 13, the horizontal connecting rods 10 are connected to the first support members 91 by C-type connectors 16, and an adjustable connector 14 is provided at the upper end of the first support member 91 at the top of the support upright frame, the adjustable connector 14 is used in cooperation with the rubber airbag support base 4, and when in use, the overall height and inclination of the rubber airbag support base 4 are adjusted by the adjustable connector 14, so that the rubber airbag 5 is in a squeezed state to apply prestress.

[0074] Preferably, a sliding member 85 is movably arranged in the rail groove 86, one end of the sliding member 85 is open, and a connecting card slot 851, a limiting connecting plate 852 and a bottom sliding protrusion 853 are arranged on the sliding member 85, the bottom sliding protrusion 853 is arranged at the bottom of the sliding member 85, a limiting strip 854 is arranged on the bottom sliding protrusion 853, the limiting strip 854 is used in cooperation with the limiting groove arranged on the rail groove 86, and by the cooperation of the limiting strip 854 and the limiting groove, the sliding member 85 slides along the rail groove 86, the limiting connecting plate 852 is arranged in the middle of the sliding member 85, and a number of connecting holes are arranged on the connecting plate 852, the connecting holes are used in cooperation with the connecting holes arranged on the upper plane of the rail groove 86, and when in use, the sliding member 85 is fixed by the connecting effect of connecting bolts, the connecting card slot 851 is arranged at the upper end of the sliding member 85 and is connected to the lower end of the first support member 91 at the bottom of the support upright frame by bolts.

[0075] Preferably, an auxiliary support member 12 is further installed on the first support member 91 of the support upright frame on the side close to the II-section working face, the auxiliary support member 12 includes a first mounting base 121 and a first hydraulic member 123, the first hydraulic member 123 is arranged at the front end of the first mounting base 121 and is used in cooperation with the side wall of the II-section working face to support the side wall of the II-section working face, and connecting plates 122 are symmetrically arranged at the tail of the first mounting base 121, the connecting plates 122 are connected to the first support member 91 by connecting bolts to form a support system to support the side wall of the II-section working face.

[0076] Preferably, the adjustable connecting member 14 is installed at the upper end of the first support member 91 through the B-type connecting member 13, and includes a second mounting base 141, a second hydraulic member 142, and a rotating connecting member 143. The second mounting base 141 is disposed at the bottom of the second hydraulic member 142 and is used with the B-type connecting member 13. The rotating connecting member 143 is disposed at the end of the piston rod of the second hydraulic member 142 and is used in cooperation with the rubber airbag support base 4. During use, the overall height and inclination of the rubber airbag support base 4 are adjusted by the telescopic movement of the second hydraulic member 142, so that the rubber airbag 5 is in a compressed state to apply prestress.

[0077] Preferably, the vertical frame connecting member 11 includes a connecting sleeve 112 and a connecting rod 113. The connecting rod 113 is movably inserted into the connecting sleeve 112, and a first locking tooth 116 is provided on the connecting rod 113. A locking block 115 is rotatably disposed in a card slot 114 on the connecting sleeve 112. A second locking block 117 is provided on the inner side surface of the locking block 115. The second locking block 117 and the first locking tooth 116 are unidirectionally locked (that is, when moving the adjacent two support vertical frames away from each other, the second locking block 117 and the first locking tooth 116 can slide away from each other. When subjected to the squeezing force of the II working face, causing the adjacent two support vertical frames to move towards each other, the second locking block 117 and the first locking tooth 116 are locked with each other to achieve locking); and U-shaped connecting heads 111 are provided at the distal ends of both the connecting sleeve 112 and the connecting rod 113. The U-shaped connecting heads 111 are connected to the first support member 91 through connecting bolts to form a complete support system.

[0078] Preferably, the A-type connecting member 15 includes two symmetrically arranged second mounting bases 151, and the second mounting bases 151 are connected by connecting bolts.

[0079] Preferably, the B-type connecting member 13 includes two symmetrically arranged first connecting pieces 131, and the first connecting pieces 131 are connected by connecting bolts.

[0080] Preferably, the C-type connecting member 16 includes two symmetrically arranged third connecting pieces 161, and the third connecting pieces 161 are connected by connecting bolts.

[0081] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction technology method for the single-side drift method of a shallow-buried and bias-pressure large-section highway tunnel, characterized in that it includes (1) Excavating the working face of Section I on the mountain side 1.1) The blasting excavation of the working face of Section I is carried out by the method of drilling and blasting small pilot tunnels; 1.2) After excavation, permanent support is carried out on the mountain - side of the working face of Section I, the rock wall fissures are filled in advance, and the surrounding rock mass is reinforced; 1.3) The working face of Section II on the side of the working face of Section I away from the mountain is supported by the steel frame support device (2); 1.4) The detachable anchor rod (3) is further assembled to reinforce and support the working face of Section II; 1.5) The rubber airbag support base (4) and the rubber airbag (5) are assembled on the steel frame support device (2), so that the rubber airbag (5) is arranged between the right wall of the working face of Section II and the rubber airbag support base and is in a compressed state; 1.6) After the support on both sides of the working face of Section I is completed, the excavation of the working face of Section I is carried out, and the next pilot tunnel excavation work is carried out in units of 15 m; 1.7) The rubber airbag (5) is deflated, and the detachable anchor rod (3) and the steel frame support device (2) are removed; (2) Expansion excavation of the working faces of Sections II and III Repeat steps 1.2) - 1.7) to carry out the expansion excavation of the working faces of Section II and Section III; (3) Excavation of the working faces of Sections IV and V 3.1) After the expansion excavation of the working face of Section III is completed, the stepped excavation method is used to carry out stepped excavation of the working faces of Sections IV and V in sequence; 3.2) After completion, reinforcement support work is carried out at a difference of 2 m in Section V to strengthen the support; 3.3) After the excavation of the working faces of Sections IV and V is completed, the overall working face of the tunnel is supported.

2. The construction process method of the single-side drift method for a shallow-buried and eccentrically loaded large-section highway tunnel according to claim 1, characterized in that: During the blasting excavation on both sides of the working face of Section I described in step 1.1), the slightly positive - step method is adopted, the upper half - section is 2.5 - 3 m ahead, the footage per cycle is 2.0 - 2.5 m, and the main slip plane and the main bedding plane are less exposed in the excavation space.

3. The construction process method of the single-side drift method for a shallow-buried and eccentrically loaded large-section highway tunnel according to claim 1, characterized in that: The permanent support described in step 1.2) includes the advanced small - diameter pipes supported on the side wall of the working face of Section I on the mountain - side. The advanced small - diameter pipes are seamless steel pipes with a diameter of φ42 mm, a wall thickness of 3.5 mm, and L = 4.0 m. And shotcrete of C25 is sprayed on the face outside the advanced small - diameter pipes as a grout - stopping wall.

4. The construction process method of the single-side drift method for a shallow-buried and eccentrically loaded large-section highway tunnel according to claim 1, characterized in that: The steel frame support device (2) described in step 1.3) includes a foot - frame (8) and multiple layers of support upright frames; The foot - frame (8) is fixed at the bottom of the tunnel between the working face of Section I and the working face of Section II, and includes a base steel frame (81), a first foot - steel (82) and a second foot - steel (83) which are connected to each other. Among them, the base steel frame (81) is arranged on the upper side of the first foot - steel (82) and the second foot - steel (83), and a rail groove (86) is arranged on the base steel frame (81). The first foot - steel (82) is arranged on the side close to the working face of Section II, and two adjacent first foot - steels (82) are connected by a type - A connecting piece (15); The supporting vertical frame is installed on the scaffold (8), and adjacent front and rear supporting vertical frames are connected by vertical frame connectors (11); the supporting vertical frame includes a supporting vertical rod (9) and a horizontal connecting rod (10), the supporting vertical rod (9) is formed by connecting a plurality of mutually connected first supporting members (91), the adjacent first supporting members (91) are connected by B-type connectors (13), the horizontal connecting rod (10) is connected to the first supporting member (91) by a C-type connector (16), and an adjustable connector (14) is arranged at the upper end of the first supporting member (91) at the top of the supporting vertical frame, and the adjustable connector (14) is used in cooperation with the rubber airbag supporting base (4).

5. The construction process method of the single-side drift method for a shallow-buried and bias-pressure large-section highway tunnel according to claim 4, characterized in that: A sliding member (85) is movably arranged in the rail groove (86), one end of the sliding member (85) is open, and a connecting card slot (851), a limiting connecting plate (852) and a bottom sliding protrusion (853) are arranged on the sliding member (85), the bottom sliding protrusion (853) is arranged at the bottom of the sliding member (85), a limiting strip (854) is arranged on the bottom sliding protrusion (853), the limiting strip (854) is used in cooperation with the limiting groove arranged on the rail groove (86), the limiting connecting plate (852) is arranged in the middle of the sliding member (85), and a plurality of connecting holes are arranged on the connecting plate (852), and the connecting holes are used in cooperation with the connecting holes arranged on the upper plane of the rail groove (86) to fix the sliding member (85), the connecting card slot (851) is arranged at the upper end of the sliding member (85) and is connected to the lower end of the first supporting member (91) at the bottom of the supporting vertical frame by a bolt.

6. The construction process method of the single-side drift method for a shallow-buried and eccentrically loaded large-section highway tunnel according to claim 4, characterized in that: An auxiliary supporting member (12) is further installed on the first supporting member (91) of the supporting vertical frame on the side close to the II working face, the auxiliary supporting member (12) includes a first installation base (121) and a first hydraulic member (123), the first hydraulic member (123) is arranged at the front end of the first installation base (121) and is used in cooperation with the side wall of the II working face, and connecting plates (122) are symmetrically arranged at the tail of the first installation base (121), and the connecting plates (122) are connected to the first supporting member (91) by connecting bolts; The adjustable connector (14) is installed at the upper end of the first supporting member (91) through a B-type connector (13), and includes a second installation base (141), a second hydraulic member (142) and a rotating connector (143), the second installation base (141) is arranged at the bottom of the second hydraulic member (142) and is used with the B-type connector (13), and the rotating connector (143) is arranged at the end of the piston rod of the second hydraulic member (142) and is used in cooperation with the rubber airbag supporting base (4).

7. The construction process method of the single-side drift method for a shallow-buried and bias-pressure large-section highway tunnel according to claim 4, characterized in that: The described vertical frame connector (11) includes a connecting sleeve (112) and a connecting rod (113). The connecting rod (113) is movably inserted into the connecting sleeve (112), and a first locking tooth (116) is provided on the connecting rod (113). A locking block (115) is rotatably arranged in a slot (114) on the connecting sleeve (112). A second locking block (117) is provided on the inner side surface of the locking block (115), and the second locking block (117) is unidirectionally locked with the first locking tooth (116). U-shaped connecting heads (111) are provided at the distal ends of both the connecting sleeve (112) and the connecting rod (113), and the U-shaped connecting heads (111) are connected to the first support member (91) through connecting bolts.

8. The construction process method of the single-side drift method for a shallow-buried and bias-pressure large-section highway tunnel according to claim 1, characterized in that: The bolt material of the detachable bolt described in Step 1.4 is a hollow bolt, made of HRB400 or Q345 steel, with a single bolt length of 3.5 m, a backing plate size of 150 mm × 150 mm × 6 mm, and the exposed length during the bolt construction not exceeding 100 mm.

9. The construction process method of the single-side drift method for a shallow-buried and bias-pressure large-section highway tunnel according to claim 1, characterized in that: The stepped excavation described in step 3.1 is a step where the working faces of parts Ⅳ and Ⅴ are staggered by 1 - 1.5 m. Before excavation, it is necessary to measure and release the excavation contour line along the excavation surface, drill and blast a small pilot tunnel, and then conduct 1 or 2 times of enlarged excavation. The excavation surface should be kept as vertical as possible. When excavating the lower bench, keep a distance of 1 - 1.5 m from the heading face to facilitate backhoe slag removal.

10. The construction process method of the single-side drift method for a shallow-buried and bias-pressure large-section highway tunnel according to claim 1, characterized in that: The process of supporting the overall working face of the tunnel described in step 3.3 includes: (1) After the overall excavation of the tunnel is completed, immediately carry out the construction of steel arch support, foot-locking bolts and shotcrete with wire mesh, and lay a φ6@15*15 steel mesh. (2) Further evenly spray concrete with a thickness of 5 - 10 cm for enhanced support.

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