Highway tunnel assembly type steel structure-concrete thin wall type reinforcing structure and design method

Abstract

The invention provides a highway tunnel assembly type steel structure-concrete thin wall type reinforcing structure which comprises multiple sets of supporting structures, the multiple sets of supporting structures are sequentially connected in the length direction of a tunnel, and each supporting structure comprises two sets of fixing bases arranged on the two sides of the bottom wall of the tunnel correspondingly; the two segment structures are symmetrically arranged on the two sides of the top wall of the tunnel, each segment structure comprises a thin-wall segment and supporting segments connected to the upper end and the lower end of the thin-wall segment, the thickness of each thin-wall segment is smaller than that of each supporting segment, and the supporting segments located at the lower ends of the thin-wall segments are connected with the tops of the fixing bases on the same side; the far ends of the two supporting pipe pieces located at the upper end of the thin-wall pipe piece are connected with each other. The invention further provides a design method of the highway tunnel assembly type steel structure-concrete thin wall type reinforcing structure. The thin-wall duct pieces are subjected to graded step-shaped thin-wall treatment, it can be guaranteed that the highway tunnel building limit is not affected by reinforcement, and sufficient clearance is provided for large vehicles to pass through the tunnel.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to an assembled steel structure-concrete thin-wall reinforcement structure and a design method for a highway tunnel. Background Art

[0002] The mileage of tunnels in my country, especially long and extra-long tunnels, has increased significantly. The role of tunnel structures in transportation has been continuously improved, and the requirements for smooth and safe operation have been continuously improved. With the continuous advancement of transportation construction, many tunnel projects have been transferred from the construction stage to the operation and maintenance stage. With the passage of operation time, the workload of treating defects in operating tunnels has increased sharply. A large number of tunnels have begun to suffer from structural defects, such as cracking, water seepage, and lining block loss. In mild cases, they will damage the visual beauty of the tunnel and distract the attention of drivers. In severe cases, they may directly cause safety accidents, resulting in significant economic losses and adverse social impacts. Therefore, it is particularly important to maintain and reinforce tunnels.

[0003] However, when maintaining the tunnel, new reinforcement structures need to be added, which will compress the internal space of the tunnel to a certain extent, resulting in a shortening of the clearance for large vehicles passing through the tunnel.

[0004] Therefore, how to maintain and reinforce the tunnel to improve its compressive resistance and bearing capacity, while reducing the compression of the tunnel's internal space to increase the safe distance for vehicles to pass, is a problem that needs to be solved in tunnel maintenance. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention proposes a highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure and a design method to solve the above problems.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention provides a prefabricated steel structure-concrete thin-wall reinforcement structure for a highway tunnel, comprising a plurality of support structures, wherein the support structures cover the inner wall of the existing structure of the tunnel in an annular direction, and the plurality of support structures are sequentially connected along the length direction of the tunnel, and the support structures include:

[0008] Two sets of fixed bases are respectively arranged on both sides of the bottom wall of the tunnel;

[0009] Two groups of segment structures are symmetrically arranged on both sides of the top wall of the tunnel. The segment structure includes thin-walled segments and supporting segments connected to the upper and lower ends of the thin-walled segments. The thickness of the thin-walled segments is less than the thickness of the supporting segments. The supporting segments located at the lower end of the thin-walled segments are connected to the top of the fixed base on the same side, and the far ends of the two supporting segments located at the upper end of the thin-walled segments are connected to each other.

[0010] Furthermore, the fixed base and the supporting segments are both concrete structures, and the thin-walled segments are steel structures.

[0011] Furthermore, the thin-walled tube segment includes a thinning portion and transition portions located at upper and lower ends of the thinning portion, the thickness of the thinning portion is smaller than the thickness of the transition portion, and the transition portion is stepped or obliquely thinned toward the thinning portion.

[0012] Furthermore, a plurality of interface tensile and shearing steel bars and T-shaped bolts are evenly and staggeredly distributed at the upper and lower ends of the thin-walled pipe segment.

[0013] Furthermore, a filling area is provided inside the thin-walled tube segment, and a plurality of criss-crossing reinforcing ribs are arranged in the filling area. Adjacent reinforcing ribs divide the filling area into a plurality of partitions, and the reinforcing ribs are provided with filling holes that connect the partitions.

[0014] Furthermore, the thin-walled tube segments are respectively provided with anchor holes, grouting holes, air outlet holes, hoisting holes and tensioning holes;

[0015] A plurality of the anchor holes penetrate through both sides of the thin-walled segment and are distributed in a longitudinal plum blossom shape, and a first bolt sleeve is provided on the path of the anchor holes in the filling area;

[0016] The grouting holes and the air outlet holes respectively penetrate two sides of the thin-walled tube segment;

[0017] A plurality of the hoisting holes are provided on one side of the thin-walled segment close to the inner wall of the existing tunnel structure;

[0018] The plurality of tensioning holes are respectively opened on both sides of the transition portion connected to adjacent thin-walled segments, a second bolt sleeve is provided on one side of the tensioning hole located in the filling area, and a reaction force structure is provided outside the tensioning hole.

[0019] The present invention provides a design method for an assembled steel structure-concrete thin-walled reinforced structure of a highway tunnel, which is used to design an assembled steel structure-concrete thin-walled reinforced structure of a highway tunnel, including an inner wall of an existing structure of a tunnel and a reinforced structure, wherein the reinforced structure includes a supporting structure and a steel grouting layer between the supporting structure and the existing structure, wherein the thickness value of the steel structure portion is first obtained by making the bending moments of the steel bars and the steel structure equal, and then the thickness of different parts of the thin-walled pipe segment is obtained by making the bending resistance of the equal surfaces equal, and then the size of the steel bars and the stress condition of the steel bars are obtained by making the bending moment of the compression part of the existing structure equal to the tensile bending moment of the steel bars in the reinforced structure and the force balance principle.

[0020] Furthermore, considering thin-walling as the most unfavorable case, the theoretical value of the bending moment of the thin-walled segment should be greater than the bending moment of the support reaction force of the reinforced structure itself, and the design values ​​of the thickness of different parts of the thin-walled segment are obtained.

[0021] Furthermore, the minimum design value of the thickness of the thin-walled segment is solved jointly according to the steel bar bending moment formula and the steel structure bending moment formula, and then the minimum design value of the thickness of different parts of the thin-walled segment is obtained based on the equal bending performance of the equal surface. Through the above calculation and comparison, the minimum design value of the thickness of each part of the thin-walled segment under different conditions is obtained, and finally the maximum value is taken.

[0022] Furthermore, after the thin-walled segments are connected and assembled, each metal part is treated with an anti-corrosion coating.

[0023] It can be seen from the above technical scheme that the present invention provides a highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure and design method:

[0024] The assembled steel-concrete thin-walled reinforcement structure of the thin-walled segments and supporting segments not only meets the characteristics of fast and efficient assembly, but also has a flexible structure with a light weight. Therefore, the seismic force borne by buildings of the same fortification intensity and the same site is smaller, and the earthquake disaster caused is correspondingly weakened. The thin-walled segments adopt a graded stepped thin-wall treatment to ensure that the construction limit of the highway tunnel is not affected by the reinforcement, provide sufficient clearance for large vehicles to pass through the tunnel, and reduce the consumption of steel while ensuring that the strength of the components remains unchanged, further ensuring that the space of the construction limit is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation of the present invention, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0026] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0027] Figure 2 It is a structural schematic diagram of the tube segment structure in the present invention;

[0028] Figure 3 Schematic diagram of the internal structure of the thin-walled tube segment in the present invention;

[0029] Figure 4 It is a schematic diagram of the values ​​of various regions in the connection structure of the existing structure-reinforcement grouting layer-thin-walled pipe segment in the present invention;

[0030] Figure 5 It is a schematic diagram of the values ​​of various regions in the thin-walled tube segment of the present invention;

[0031] Reference numerals:

[0032] Fixed base 1;

[0033] Thin-walled segment 2, thinning portion 201, transition portion 202, interface tensile and shear reinforcement 203, T-shaped stud 204, filling area 205, reinforcing rib plate 206, filling hole 2061, anchor hole 207, grouting hole 208, air outlet hole 209, hoisting hole 210, tensioning hole 211, first bolt sleeve 212, second bolt sleeve 213;

[0034] Supporting segment 3;

[0035] Existing structure 4;

[0036] Rebar grouting layer 5. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the invention is not limited by the specific implementation disclosed below.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] like Figure 1-5 As shown, this embodiment provides a prefabricated steel-concrete thin-walled reinforcement structure for a highway tunnel, including multiple groups of supporting structures, which cover the inner wall of the existing structure 4 of the tunnel in a circumferential direction. The multiple groups of supporting structures are connected in sequence along the length direction of the tunnel, and the supporting structure includes two groups of fixed bases 1 and two groups of segment structures.

[0041] Two sets of fixed bases 1 are respectively arranged on both sides of the bottom wall of the tunnel.

[0042] Two groups of segment structures are symmetrically arranged on both sides of the top wall of the tunnel. The segment structure includes a thin-walled segment 2 and a supporting segment 3 connected to the upper and lower ends of the thin-walled segment 2. The thickness of the thin-walled segment 2 is less than the thickness of the supporting segment 3. The supporting segment 3 located at the lower end of the thin-walled segment 2 is connected to the top of the fixed base 1 on the same side, and the far ends of the two supporting segments 3 located at the upper end of the thin-walled segment 2 are connected to each other.

[0043] Preferably, the fixed base 1 and the supporting segments 3 are both concrete structures, and the thin-walled segments 2 are steel structures.

[0044] Steel structures are flexible structures with a light weight. Therefore, buildings with the same fortification intensity and the same site are subjected to less earthquake force, and the earthquake disasters they bring are reduced accordingly. The use of steel structures in earthquake zones will reduce casualties and property losses, and have considerable comprehensive benefits. Steel structures have the advantages of high strength and light weight, and can generally reduce the weight of buildings by about 1 / 3. For example, the strength of steel is G550 and the strength grade of concrete is C25. The ratio of the strengths of the two is that for components of the same mass, the bearing capacity of steel structures is twice that of concrete; correspondingly, for components with the same bearing capacity, the weight of steel components is half that of concrete.

[0045] like Figure 2-Figure 5 As shown, the thin-walled segment 2 includes a thinning portion 201 and transition portions 202 located at the upper and lower ends of the thinning portion 201. The thinning portion 201 and the transition portion 202 are integrally formed, and the thickness of the thinning portion 201 is less than the thickness of the transition portion 202. The thin-walled segment 2 is designed to be thin-walled, which can ensure that the construction limit of the highway tunnel is not affected by reinforcement and provide sufficient clearance for large vehicles to pass through the tunnel. The transition portion 202 is thinned in a stepped or oblique direction toward the thinning portion 201. When multiple levels are used, its length l is not less than 5 cm and its height h is not less than 3 cm. The grading can reduce the consumption of steel while ensuring that the strength of the component remains unchanged, further ensuring that the space of the construction limit is not affected. After the thin-walled segment 2 is thinned, the structural width gradually becomes the width of the concrete part, so it is necessary to control the length of the thin-walled segment 2 to be no more than 10 cm at the maximum width.

[0046] Furthermore, multiple interfacial tensile and shearing steel bars 203 and T-shaped studs 204 are evenly distributed at the upper and lower ends of the thin-walled segment 2, respectively, to play a role in tensile and shearing. The size of the interfacial tensile and shearing steel bars 203 is consistent with the steel bars in the concrete, with a reserve of 10-15 cm; the T-shaped studs 204 are fixed on the thin-walled segment 2 in a welding form with a diameter of about 2 cm and a length of 3-5 cm, forming an inverted T shape; their distribution needs to be staggered, and the spacing between the T-shaped studs 204 and the interfacial tensile and shearing steel bars 203 is 15d on the outside to achieve the best effect when the thickness of the protective layer is met.

[0047] Specifically, a filling area 205 is provided inside the thin-walled segment 2, and a plurality of crisscross reinforcing ribs 206 are arranged in the filling area 205, which can not only ensure the strength and overall stability of the steel structure, but also save materials, and is light in weight for easy transportation and assembly. After the grouting between the existing structure 4 and the segment structure is completed, the filling area 205 is filled to form an assembled steel structure-concrete thin-walled reinforcement structure to improve the overall strength and stability. Adjacent reinforcing ribs 206 divide the filling area 205 into multiple partitions, and the reinforcing ribs 206 are provided with filling holes 2061 that connect the partitions. The diameter of the filling holes 2061 should be not less than 3 cm so that the concrete material can pass normally during filling. The spacing between the reinforcing ribs 206 should be greater than 15d and less than 30 cm, and the thickness should be 3-5 mm. The reinforcing ribs 206 are treated with welded steel mesh to improve the interface shear strength after backfilling.

[0048] When making thin-walled pipe segments 2, it is necessary to lay a double layer of steel mesh on the outside of the thin-walled pipe segments 2, and connect the bottom layer to the thin-walled pipe segments 2 by welding, so that the upper steel mesh is more tightly connected to the grouting part, wherein the spacing between the steel meshes is not greater than 15 cm, and the diameter of the steel bars in the steel mesh is not greater than 8 cm, so as to achieve the best interface treatment effect.

[0049] Furthermore, the thin-walled segment 2 is provided with anchor holes 207 , grouting holes 208 , air outlet holes 209 , hoisting holes 210 and tensioning holes 211 .

[0050] A plurality of anchor holes 207 penetrate both sides of the thin-walled segment 2 and are distributed in a longitudinal plum blossom shape. A first bolt sleeve 212 is provided on the path of the anchor holes 207 located in the filling area 205 to form an internal and external isolation to prevent the leakage of materials after grouting and filling. The thin-walled segment 2-rebar grouting layer 5-existing structure 4 are connected through the anchor holes 207 to enhance the strength and stability of the structure. A plurality of anchor holes 207 are distributed at the central axis of the thin-walled segment 2 and arranged according to the four-equal-dividing line; when the spacing of the thin-walled segment 2 is not greater than 1m, it is arranged in a ring / 60cm in the longitudinal direction. When the width of the thin-walled segment 2 is 60cm, one row of anchor holes 207 is arranged in the longitudinal direction, and when it is 1.2m, two rows of anchor holes 207 are arranged.

[0051] The grouting holes 208 and the air outlet holes 209 respectively penetrate the two sides of the thin-walled segment 2. When the thin-walled segment 2 is manufactured, a sleeve is reserved in advance to form a through hole. After the segment is assembled, grouting is performed through the grouting holes 208 to facilitate rapid grouting. When setting the grouting holes 208, it is necessary to reserve the air outlet holes 209 at the same time to determine whether the grout is filled. The air outlet holes 209 are arranged in parallel in the filling area 205, and the distance between the two holes is not greater than 2m.

[0052] A plurality of lifting holes 210 are opened on one side of the thin-walled segment 2 close to the inner wall of the existing structure 4 of the tunnel. The lifting holes 210 are used to connect the lifting equipment with the thin-walled segment 2 to achieve accurate installation of the thin-walled segment 2. The position, number and size of the lifting holes 210 need to meet the requirements of the lifting operation to ensure a smooth lifting process. The lifting holes 210 are provided with four M24×80 lifting holes 210, which are symmetrically arranged at 520mm from the steel structure part, 200mm from the center line and 2055mm from the steel structure part, and four M24×80 lifting holes 210 are symmetrically arranged at 200mm from the center line.

[0053] A plurality of tensioning holes 211 are respectively opened on both sides where the transition portion 202 is connected to the adjacent thin-walled segments 2. A second bolt sleeve 213 is provided on one side of the tensioning hole 211 located in the filling area 205, and a reaction force structure is provided on the outside of the tensioning hole 211 to prevent structural damage during the tensioning process. After assembly is completed, prestressed screws are used to apply pre-tightening action to the front and rear thin-walled segments 2 to make the structure more stable.

[0054] The present invention meets the characteristics of fast and efficient assembly, can be factory-produced and assembled on site, has a small usage amount, and is a green, environmentally friendly, and sustainable circular building.

[0055] The present embodiment provides a design method for a prefabricated steel structure-concrete thin-walled reinforced structure of a highway tunnel, which is used to design a prefabricated steel structure-concrete thin-walled reinforced structure of a highway tunnel, including an inner wall of an existing structure 4 of the tunnel and a reinforced structure, wherein the reinforced structure includes a support structure and a steel grouting layer 5 between the support structure and the existing structure 4. The bending and compression resistance performance is mainly considered in the reinforced structure and the existing structure 4. The thickness value d of the steel structure part can be preliminarily obtained by firstly making the bending moment of the steel bar and the steel structure equal to each other. 1 , and then the thickness d of different parts of the thin-walled tube segment 2 can be obtained by equalizing the bending resistance of the equal surface. 1 ,d 2 ,d 3 ,d 4 Then, through the principle that the bending moment of the compression part of the existing structure 4 is equal to the tensile bending moment of the steel bars in the reinforced structure and the principle of force balance, the steel bar size and steel bar stress condition are obtained.

[0056] After the overall fabrication of the segment structure is completed, before assembly, the thin-walled segment 2 is considered as the most unfavorable situation. The theoretical value of the bending moment of the thin-walled segment 2 should be greater than the bending moment of the support reaction force of the reinforced structure itself. Therefore, the design value d' of the thickness of different parts of the thin-walled segment 2 can be obtained. 1 , d' 2 , d' 3 , d' 4 .

[0057] Considering that the stress on the concrete reinforcement inside the reinforced structure is less than or equal to the design strength of the thin-walled segment 2, the minimum design value d of the thickness of a certain part of the thin-walled segment 2 is solved by combining the reinforcement moment formula and the steel structure moment formula. 1 ” Then, according to the equal bending performance of the equal surface, the minimum design value d of the thickness of different parts of the thin-walled tube segment 2 can be obtained. 1 ” ,d 2 ” ,d 3 ” ,d 2 ” Through the above calculation and comparison, the minimum design value d of the thickness of each part of the thin-walled tube segment 2 under different conditions is obtained. 3 , d' 3 ,d 3 ” , in order to satisfy the above conditions at the same time, the maximum value can be taken.

[0058] Specifically, for the overall structure of the supporting structure, through the same principle of bending resistance in the same plane, after the type of thin-walled segment 2 is formulated, the thickness of each part of the thin-walled segment 2 is designed and verified. By using the bending moment generated in the compression zone of the existing structure 4 to be the same as the bending moment of the reinforced structure; the concrete reinforcement force in the reinforced structure is less than or equal to the design strength of the thin-walled segment 2, the minimum thickness d of each part of the thin-walled segment 2 after assembly can be designed. 1 ,d 2 ,d 3 ,d 4 .

[0059] M=A S1 ·f sd (l R +l C -x d -a S1 )+A S2 ·f sd ·(l C -x d +a S1 )

[0060] M=M G =A S ·f sd ·(l C -2a S )

[0061] A S1 : The area of ​​steel bars in the lower part of the tension zone of the reinforced structure;

[0062] A S2 : The area of ​​steel bars in the upper tensile zone of the reinforced structure;

[0063] f sd : Design value of tensile strength of stress-bearing steel bars:

[0064] l R : Width of reinforcement area;

[0065] l C : Existing structure width value:

[0066] x d : Width of compression zone of existing structure:

[0067] a S1 : Thickness of concrete protective layer of reinforced structure.

[0068] N=A S2 ·f sd +A S1 ·f sd -x d ·f c

[0069] A S1 : The area of ​​steel bars in the lower part of the tension zone of the reinforced structure;

[0070] A S2 : The area of ​​steel bars in the upper tensile zone of the reinforced structure;

[0071] f sd : Design value of tensile strength of stress-bearing steel bars:

[0072] x d : Width of compression zone of existing structure:

[0073] f c : Design value of concrete compressive strength

[0074] From this, we can get the size A of the steel bars in the concrete of the thin-walled segment 2 S1 , A S1 Similarly, the thickness of each part of the thin-walled tube segment 2 can be calculated according to the above formula;

[0075] When the structure is multi-level ladder:

[0076] According to the same bending performance of equal surfaces, the conversion coefficient & between the thin-walled segment 2 and the steel bar tensile performance is set to obtain:

[0077] d As ·l As =d 1 ·l 1 &

[0078] d 1 ·l 1 =d 2 ·l2 =d 3 ·l 3

[0079] To ensure the rationality of the structural design, when the width of the thin-walled segment 2 steel structure reaches the maximum value, the thickness of the steel structure on the opposite front and rear surfaces should be consistent, so d 1 =d 4

[0080] d 1 ,d 2 ,d 3 ,d 4 : Thickness values ​​of different parts of thin-walled segment steel structure;

[0081] l 1 , l 2 , l 3 : Width values ​​of different parts of thin-walled segment steel structure;

[0082] d As : diameter of steel bars in concrete part;

[0083] &: Conversion coefficient of thin-walled segment and steel bar tensile performance & = 1.2;

[0084] l As : The distance between the steel bars and the interface in the concrete part.

[0085] Through the above calculation, we can get d in the corresponding case 1 ,d 2 ,d 3 ,d 4 .

[0086] After the overall structure of the thin-walled segment 2 is completed, before assembly, the thin-walling is considered as the most unfavorable situation, and the overall structural load is regarded as a uniformly distributed load, so as to obtain the minimum design value d' of the thickness of the thin-walled segment 2. At this time, the left and right supports are reaction forces with a magnitude of F 1 =F 2 , which is 1 / 2 of the overall weight of the structure.

[0087] M a =F 1 ·d a

[0088] M a : design value of bending moment;

[0089] F 1 : Support reaction force value;

[0090] d a ; Effective distance of support reaction force;

[0091] According to the equal bending performance of the plane, the design value coefficient and backfill concrete are set considering the performance of the thin-walled segment 2, which needs to meet the following requirements:

[0092] M t >1.2M a

[0093] M t : Theoretical value of bending moment of thin-walled segment;

[0094] M t1 =f d ·h 1 ·d' 1 l

[0095] M t2 =f d ·h 2 ·d' 2 l

[0096] M t3 =f d ·h 3 ·d' 3 l

[0097] h 1 、h 2 、h 3 : Width values ​​of different parts of thin-walled segments;

[0098] d' 1 , d' 2 , d' 3 :Thickness values ​​of different parts of thin-walled segments

[0099] According to the above calculation, we can get d' 1 , d' 2 , d' 3 Design value.

[0100] Considering that the stress on the concrete reinforcement inside the reinforced structure is less than or equal to the design strength of the steel structure, the safety factor should be set to meet αM t ≥M G ,

[0101] M G =f sd ·(h x -x d )·A S

[0102] M G : Design strength value of concrete reinforcement;

[0103] h x : Width of concrete structure in the reinforced structure;

[0104] xd : protective layer thickness value;

[0105] α: Safety factor is 1.4

[0106] It can be concluded that concrete h x Design value, in structural design, it is known that h x = h, through M t =f d ·h·d ” l can be derived 1 ” ,d 2 ” ,d 3 ” Minimum design value.

[0107] Through the above calculations and comparisons, we can find that d 3 , d' 3 ,d 3 ” The minimum design value is to take the maximum value among the above conditions to satisfy them all at the same time.

[0108] To be more specific, taking an actual example, the existing structure is C35 concrete, 20 cm thick, 1 meter in the longitudinal direction, and the steel bars are arranged according to C22@200. The thin-walled segment 2 is designed in a graded stepped manner, and its minimum width is l 3 =5cm, l 2 =10cm, l 3 =15cm, the overall deadweight of the supporting structure is set to 2t, the length is 4.5m, and the filling area 205 is backfilled with C60 concrete.

[0109] M=A S1 ·f sd (l R +l C -x d -a S1 )+A S2 ·f sd ·(l C -x d +a S1 )

[0110] M=M G =A S ·f sd ·(l C -2a S )

[0111] N=A S2 ·f sd +A S1 ·f sd -x d ·fc

[0112] The simultaneous equations can be solved to give A S1 =63mm 2 , and the steel bar value in the reinforced structure should be C10;

[0113] d As ·l As =d 1 ·l 1 &

[0114] d 1 ·l 1 =d 2 ·l 2 =d 3 ·l 3

[0115] We can solve for d 1 Should be greater than 1.2 mm, so take d 1 =1.2 mm d 2 =1.8mm d 3 =3.6mm.

[0116] M a =F 1 ·d a

[0117] M t >1.1M a

[0118] M t1 =f d ·h 1 ·d' 1 ·l

[0119] The simultaneous equations can be solved to give d' 1 =1.8mm, so we can get: d' 1 =1.8mm d' 2 =2.7mm d' 3

[0120] =5.4mm.

[0121] M G =f sd ·(h x -x d )·A S ,

[0122] αM t ≥M G

[0123] M t =f d·h·d ” l

[0124] The simultaneous equations can be solved to give d 1 ” =1.3, so we can get: d 1 ” =1.3 mm d 2 ” =1.9 mm d 3 ” =3.9mm

[0125] According to the above calculation, select the weakest point d of thin-walled segment 2 3 For comparison, in order to meet safety requirements, the above three d are selected in the most extreme case. 3 So in this case, we choose d 3 Take 5.4mm, so d 1 =1.8mmd 2 =2.7 mm d 3 =5.4mm.

[0126] Preferably, alloy elements are added to the steel of the thin-walled tube segment 2 during the manufacturing process, and zinc alloy coating treatment is performed to improve the anti-corrosion performance; after the thin-walled tube segment 2 is connected and assembled, each metal part is treated with an anti-corrosion coating to improve the anti-corrosion performance of the steel structure itself. After the steel structure is manufactured, sacrificial anode protection is used, and zinc alloy is installed on the upper and lower parts of the thin-walled tube segment 2 to improve the corrosion of the steel structure. The thin-walled tube segment 2 is sprayed with fire-retardant paint and encapsulated with steel wire mesh refractory mortar to prevent heat transfer. After the tube segment is assembled, a fireproof board is installed on the inside of the thin-walled tube segment 2 to prevent fire and improve structural strength.

[0127] During the manufacturing process, the steel of the thin-walled tube segment 2 is added with alloy elements with corrosion resistance (such as chromium, nickel, cobalt, copper, etc.), which fundamentally improves the corrosion resistance of the steel compared with ordinary steel, so as to improve its corrosion resistance. Before the thin-walled tube segment 2 is assembled, each part of the thin-walled tube segment 2 is immersed in molten zinc liquid to form a zinc alloy coating on the surface of the steel. Hot-dip galvanizing is applicable to steel structural components of various shapes and can greatly improve the corrosion resistance.

[0128] After the thin-walled tube segment 2 is connected and assembled, each metal part needs to be treated with an anti-corrosion coating. Before the anti-corrosion treatment, the surface of the thin-walled tube segment 2 should be thoroughly cleaned, rust-free and polished to ensure that the surface is clean and dry. During the process, polyurethane coating or chlorinated rubber coating should be used, and attention should be paid to the uniform application of the coating to avoid problems such as missing coating and bubbling, so as to improve the anti-corrosion performance of the thin-walled tube segment 2 itself.

[0129] After the thin-walled tube segment 2 is manufactured, the thin-walled tube segment 2 is protected by a sacrificial anode. Zinc alloy, magnesium alloy or aluminum alloy is installed on the top and bottom surfaces of the filling area 205 as a sacrificial anode. After backfilling is completed, the backfilling material is used as a medium to form an electrochemical circuit for the thin-walled tube segment 2 as a whole, which plays a role in delaying corrosion.

[0130] After the anti-corrosion treatment is completed, the resistance testing instrument is installed inside the filling area 205, and the monitoring circuit is connected to the upper and lower ends of the reinforcing rib plate 206 so that the current runs through the entire thin-walled tube segment 2 to ensure real-time monitoring of all parts of the thin-walled tube segment 2. After calibration, it is sealed to monitor the resistance and conductivity of the thin-walled tube segment 2 and the anode metal. When the degree of corrosion gradually increases, its resistance also gradually increases. Combined with the corrosion rate and corrosion mechanism of the metal material, the degree of corrosion of the metal sample, when the resistance reaches 15% of the original value, manual inspection of the specific situation is required. When it reaches 50%, the degree of corrosion is relatively serious, the bearing capacity of the thin-walled tube segment 2 decreases, and repair treatment is required. In this way, the corrosion condition of the thin-walled tube segment 2 can be monitored in real time, providing an important basis for equipment maintenance, repair and replacement.

[0131] The fire resistance of the thin-walled segment 2 will be greatly improved after being treated with fire retardant coating. Fire retardant coating is applied on the surface of the thin-walled segment 2 to form an insulation layer to prevent heat transfer. Since the tunnel is in a relatively closed space, thick coating is required during spraying. The coating thickness is greater than 7mm and less than or equal to 45mm. It has a granular surface, low density, and low thermal conductivity, which greatly improves the fire resistance limit. In addition, the coating thickness is relatively thick, non-flammable, good insulation and fire resistance time. After the manufacture of the thin-walled segment 2 is completed, thick coating and concrete backfilling will greatly improve the fire resistance of the structure.

[0132] In addition, the thin-walled tube segment 2 can also be encapsulated, and the fireproof material can be wrapped inside the thin-walled tube segment 2 to form a heat insulation layer. After the tube segment assembly is completed, wire mesh refractory mortar and fireproof board can be used to prevent fire and enhance a certain strength.

[0133] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the various embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure, characterized in that: It comprises a plurality of groups of supporting structures, wherein the supporting structures cover the inner wall of the existing structure of the tunnel in an annular direction, and the plurality of groups of supporting structures are sequentially connected along the length direction of the tunnel, and the supporting structures comprise: Two sets of fixed bases are respectively arranged on both sides of the bottom wall of the tunnel; Two groups of segment structures are symmetrically arranged on both sides of the top wall of the tunnel. The segment structure includes thin-walled segments and supporting segments connected to the upper and lower ends of the thin-walled segments. The thickness of the thin-walled segments is less than the thickness of the supporting segments. The supporting segments located at the lower end of the thin-walled segments are connected to the top of the fixed base on the same side, and the far ends of the two supporting segments located at the upper end of the thin-walled segments are connected to each other.

2. The highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure according to claim 1 is characterized in that: The fixed base and the supporting segments are both concrete structures, and the thin-walled segments are steel structures.

3. The highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure according to claim 1 or 2, characterized in that: The thin-walled tube sheet includes a thinning portion and transition portions located at upper and lower ends of the thinning portion. The thickness of the thinning portion is smaller than the thickness of the transition portion, and the transition portion is stepped or obliquely thinned toward the thinning portion.

4. The highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure according to claim 1 or 2, characterized in that: The upper and lower ends of the thin-walled pipe segment are respectively and evenly distributed with a plurality of interface tensile and shearing steel bars and T-shaped bolts.

5. The highway tunnel assembled steel structure-concrete thin-wall reinforcement structure according to claim 1 or 2, characterized in that: A filling area is provided inside the thin-walled tube segment, and a plurality of criss-cross reinforcing rib plates are arranged in the filling area. Adjacent reinforcing rib plates divide the filling area into a plurality of partitions, and the reinforcing rib plates are provided with filling holes that connect the partitions.

6. The highway tunnel prefabricated steel structure-concrete thin-wall reinforcement structure according to claim 5 is characterized in that: The thin-walled segments are respectively provided with anchor holes, grouting holes, air outlet holes, hoisting holes and tensioning holes; A plurality of the anchor holes penetrate through both sides of the thin-walled segment and are distributed in a longitudinal plum blossom shape, and a first bolt sleeve is provided on the path of the anchor holes in the filling area; The grouting holes and the air outlet holes respectively penetrate two sides of the thin-walled tube segment; A plurality of the hoisting holes are provided on one side of the thin-walled segment close to the inner wall of the existing tunnel structure; The plurality of tensioning holes are respectively opened on both sides of the transition portion connected to adjacent thin-walled segments, a second bolt sleeve is provided on one side of the tensioning hole located in the filling area, and a reaction force structure is provided outside the tensioning hole.

7. A design method for a highway tunnel prefabricated steel structure-concrete thin-walled reinforcement structure, used for designing a highway tunnel prefabricated steel structure-concrete thin-walled reinforcement structure as claimed in any one of claims 1 to 6, characterized in that: It includes the inner wall and reinforced structure of the existing structure of the tunnel. The reinforced structure includes the supporting structure and the steel grouting layer between the supporting structure and the existing structure. The thickness of the steel structure part is firstly obtained by the equality of the bending moment of the steel bar and the steel structure, and then the thickness of different parts of the thin-walled segment is obtained by the equality of the bending resistance of the equal surface. Then, the size of the steel bar and the stress condition of the steel bar are obtained by the principle of equality of the bending moment of the compressive part of the existing structure and the tensile bending moment of the steel bar in the reinforced structure and the principle of force balance.

8. The design method of the assembled steel-concrete thin-wall reinforcement structure of a highway tunnel according to claim 7 is characterized in that: Considering thin-walling as the most unfavorable case, the theoretical value of the bending moment of the thin-walled segment should be greater than the bending moment of the support reaction force of the reinforced structure itself, and the design values ​​of the thickness of different parts of the thin-walled segment are obtained.

9. The design method of the assembled steel-concrete thin-wall reinforcement structure of a highway tunnel according to claim 8 is characterized in that: The minimum design value of the thickness of the thin-walled segment is solved jointly by the steel bar bending moment formula and the steel structure bending moment formula, and then the minimum design value of the thickness of different parts of the thin-walled segment is obtained based on the equal bending performance of the equal surface. Through the above calculation and comparison, the minimum design value of the thickness of each part of the thin-walled segment under different conditions is obtained, and finally the maximum value is taken.

10. The design method of the assembled steel structure-concrete thin-wall reinforcement structure of a highway tunnel according to claim 7, characterized in that: After the thin-walled pipe segments are connected and assembled, each metal part is treated with an anti-corrosion coating.

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