Bridge-tunnel integrated structure and construction method thereof

Abstract

The application discloses a bridge-tunnel combined structure and a construction method thereof. The bridge-tunnel combined structure comprises a frame type tunnel structure and a bridge arranged at the upper end of the tunnel structure. A shock absorption and isolation structure is arranged between the tunnel structure and the bridge. The shock absorption and isolation structure comprises a shock absorption and isolation layer arranged between the tunnel structure and the bridge and a plurality of energy dissipation rods arranged between the tunnel structure and the bridge. The upper and lower ends of the energy dissipation rods are respectively inserted into the upper end of the tunnel structure and the lower end of the bridge. A gap for displacement is arranged between the energy dissipation rods and the tunnel structure and / or the bridge. The technical scheme of the application improves the convenience of construction, reduces the construction difficulty and construction period, and reduces the construction measure cost. The scheme considers the shock absorption and isolation design of the bridge, so that the bridge and the tunnel structure are closely related, but the stress is relatively independent to a certain extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of highway and municipal bridge engineering, and particularly relates to a bridge-tunnel combined structure and a construction method thereof. BACKGROUND

[0002] With the development of cities, the land use of cities is increasingly nervous. In order to make full use of limited land resources, the city traffic is often used simultaneously on the ground and underground, and develops spatially. With the improvement of people's living standards, higher requirements are put forward for the living environment. In order to improve the quality of urban environment, the natural river in the city is often fully utilized in the design of the water-friendly environment during the urban planning and construction or landscape reconstruction. Therefore, under the multiple demands of ensuring the city landscape and improving the efficiency of urban traffic, more and more bridges and tunnels are combined in the construction of urban traffic. Both bridges and tunnels are very important structures in urban building structures, and have high design service life requirements, great construction difficulty, and high construction measure cost proportion. Therefore, the construction level and the economic investment are very high. In the past, the bridge-tunnel combined design often adopted a scheme of separate and independent construction, and various safety protection measures such as isolation piles were used during construction, which undoubtedly further increased the engineering cost. The commonly used construction scheme for the bridge overpass tunnel or the tunnel underpass bridge is to use a large-diameter pile + conversion beam scheme as shown in FIG. 1. The construction scheme significantly increases the cost of the lower structure of the bridge, has great construction organization difficulty, and has a long construction period. Figure 1

[0003] When designing a bridge structure, the overall safety of the structure under extreme conditions is often considered. Earthquake is a very destructive action, which often causes serious loss of life and property. Therefore, when designing such structures, reasonable measures should be taken to reduce the damage of earthquake to the structure, and the structure should be designed to reduce and isolate the earthquake, so as to ensure that the structure does not suffer serious damage when the earthquake occurs, and to ensure that the traffic line is not interrupted under certain conditions and the rescue passage is unobstructed. SUMMARY

[0004] The present application provides a bridge-tunnel combined structure and a construction method thereof, which improves the convenience of construction, reduces the construction difficulty and construction period, reduces the construction measure cost, and considers the seismic reduction and isolation design of the bridge. The bridge and tunnel structure are closely related, but the stress is relatively independent to a certain extent.

[0005] ​In a first aspect, to solve the above technical problems, the present application provides a bridge-tunnel combined structure, comprising a frame-type tunnel structure and a bridge arranged at the upper end of the tunnel structure, a seismic isolation structure is arranged between the tunnel structure and the bridge, the seismic isolation structure comprises a seismic isolation layer arranged between the tunnel structure and the bridge and a plurality of energy dissipation rods arranged between the tunnel structure and the bridge, the upper and lower ends of the energy dissipation rods are respectively inserted into the upper end of the tunnel structure and the lower end of the bridge, and a gap for displacement is arranged between the energy dissipation rods and the tunnel structure.

[0006] Further, a plurality of first insertion holes or a plurality of hollow first sleeves are arranged at the upper end of the tunnel structure and the seismic isolation layer, the lower end of each energy dissipation rod is inserted into the first insertion hole or the first sleeve in a one-to-one correspondence, and the inner diameter of the first insertion hole or the first sleeve is greater than the outer diameter of the energy dissipation rod, so as to form a gap for displacement between the energy dissipation rod and the tunnel structure.

[0007] Further, a plurality of second insertion holes or a plurality of hollow second sleeves are arranged at the lower end of the bridge, the upper end of each energy dissipation rod is inserted into the second insertion hole or the second sleeve in a one-to-one correspondence, and the inner diameter of the second insertion hole or the second sleeve is greater than the outer diameter of the energy dissipation rod, so as to form a gap for displacement between the energy dissipation rod and the bridge.

[0008] Further, the bridge comprises at least two force transfer piers arranged at intervals on the seismic isolation layer, bridge piers arranged on the force transfer piers, and a main beam transversely arranged on the plurality of bridge piers, and the energy dissipation rods are arranged between the force transfer piers and the tunnel structure.

[0009] Further, a limiting baffle beam is arranged at the top end of the tunnel structure and surrounds the outer periphery of the force transfer piers at both ends of the bridge, and an elastic member is arranged between the limiting baffle beam and the force transfer piers.

[0010] Further, the force transfer piers are arranged along the width of the tunnel structure, a plurality of energy dissipation rods are arranged at intervals in the length direction of the force transfer piers, and at least one row of energy dissipation rods are arranged in the width direction of the force transfer piers.

[0011] Further, the tunnel structure comprises a bottom plate arranged on the foundation, at least two vertical walls arranged at intervals on the bottom plate in the width direction of the bottom plate, and a top plate arranged at the top end of the vertical walls, and at least one tunnel is formed by the bottom plate, the vertical walls and the top plate, so that the cross section of the tunnel structure is a single-hole or multi-hole box-shaped cross section.

[0012] Further, the tunnel structure further comprises a plurality of reinforcing piles arranged at the bottom of the bottom plate and inserted into the foundation.

[0013] In a second aspect, the present application further provides a construction method of a bridge-tunnel combined structure for constructing the bridge-tunnel combined structure of any one of the first aspect, comprising the following steps:

[0014] S1, excavating a foundation pit and performing foundation pit support construction;

[0015] S2, treating a bearing foundation, if the bearing capacity of the foundation does not meet the design requirements, the foundation needs to be reinforced, and the surface of the ground layer at the design elevation needs to be treated for surface leveling;

[0016] S3, pouring a cushion layer on the bearing foundation and performing leveling and sloping treatment;

[0017] S4, pouring a bottom plate, a vertical wall and a top plate in sequence on the cushion layer by using reinforced concrete to enclose a tunnel having at least one tunnel between the bottom plate, the vertical wall and the top plate, and reserving a plurality of first insertion holes on the top plate for corresponding insertion of energy dissipation rods or pre-burying a plurality of first sleeves for corresponding insertion of energy dissipation rods, the inner diameter of the first insertion hole or the first sleeve being greater than the outer diameter of the energy dissipation rod;

[0018] S5, performing construction of a tunnel inner road surface or a track;

[0019] S6, constructing a shock isolation layer on the top plate;

[0020] S7, inserting energy dissipation rods into the first insertion hole or the first sleeve first, constructing a force transmission pile cap and a bridge pier on the shock isolation layer, and providing a plurality of second insertion holes on the force transmission pile cap for corresponding insertion of energy dissipation rods or pre-burying a plurality of second sleeves for corresponding insertion of energy dissipation rods, the inner diameter of the second insertion hole or the second sleeve being greater than the outer diameter of the energy dissipation rod;

[0021] S8, constructing a bridge under road or river channel paving structure; if it is a river channel, first, the river water needs to be drained, then a water isolation layer is paved on the shock isolation layer on the tunnel structure, and then a river bottom hardening paving structure and a river bank retaining wall structure on both sides are constructed in sequence; if it is a bridge under road, the water isolation layer is directly paved and compacted, and then the retaining wall structures on both sides and the road surface structure are constructed in sequence;

[0022] S9, erecting a support to construct and pour a main beam of the bridge;

[0023] S10, completing construction of bridge deck paving and bridge auxiliary facilities such as railings.

[0024] Further, in step S7, when the bridge pier and the force transmission pile cap are prefabricated, the prefabricated integrated component composed of the bridge pier and the force transmission pile cap is transported to the site, and then hoisted and installed to the design position by a crane; when the bridge pier and the force transmission pile cap are cast in situ, a layer of sand is paved on the shock isolation layer, and then the force transmission pile cap and the bridge pier are cast in sequence by binding steel bars on the sand layer.

[0025] The application has the following beneficial effects:

[0026] (1) The bridge-tunnel combined structure can effectively reduce the mutual influence of the bridge and the tunnel structure during construction, and the construction organization is relatively convenient, and the cost of construction safety protection measures is relatively low.

[0027] (2) The bridge adopts a seismic isolation design, and a seismic isolation layer is arranged between the upper bridge and the tunnel structure to separate the two, and energy dissipation bars are used to connect the two to closely associate the bridge and the tunnel structure, but the stress is relatively independent to a certain extent, and the energy dissipation bars have a gap between the bridge and / or the tunnel structure, so that the entire bridge can slide on the seismic isolation layer of the tunnel structure, thereby playing a seismic isolation role. In particular, a limiting baffle beam for limiting the sliding displacement stroke of the bridge is arranged on the top plate, and an elastic layer is arranged between the limiting baffle beam and the force transmission pile cap, so that the entire bridge structure can slide within a certain displacement range, and when the sliding displacement is too large, the limiting baffle beam limits the sliding of the bridge, and the elastic layer can reduce the force borne by the limiting baffle beam and form elastic contact to avoid damage caused by collision during hard contact, thereby improving the damping effect.

[0028] (3) In addition, a plurality of energy dissipation bars are arranged between the bridge and the tunnel structure, the energy dissipation bars can be lead bars or mild steel bars, the upper and lower ends of the energy dissipation bars are arranged in rigid sleeves embedded in the top plate and the force transmission pile cap, and there is a certain gap between the energy dissipation bars and the rigid sleeves, and within the gap displacement range, the entire bridge structure can slide on the seismic isolation layer. Based on the above-mentioned seismic isolation component arrangement, when an earthquake occurs, the entire bridge structure can slide on the seismic isolation layer, effectively reducing the transmission of the earthquake action to the bridge structure, and as the earthquake action increases, the sliding displacement of the bridge increases, and when the gap between the energy dissipation bar and the rigid sleeve is exceeded, the energy dissipation bar starts to generate a reverse force, and the energy dissipation bar reciprocates in the rigid sleeve along with the sliding of the bridge, thereby dissipating the earthquake energy through the yield hysteresis of the energy dissipation bar, effectively reducing the earthquake energy transmitted to the bridge structure, ensuring the overall safety of the bridge structure under the action of the earthquake, and ensuring that the bridge structure remains basically intact in the event of an extreme earthquake disaster, thereby ensuring the continuity of the rescue traffic lifeline; this scheme is suitable for bridge and tunnel combined structures, including but not limited to cases where the land is relatively scarce and the seismic intensity is high.

[0029] (4) The bridge also adopts an enlarged force transmission pile cap arranged on the top plate of the tunnel structure, without the need for deep and long pile foundations, thereby avoiding the use of large pile-forming equipment, so that the bridge and tunnel combined structure can greatly save engineering costs and have good economic efficiency.

[0030] (5) The bridge-tunnel combined structure is suitable for the solution of multiple three-dimensional traffic, ground roads are arranged on the bridge, underground roads are arranged in the tunnel, and the bridge bottom can be arranged as a river channel, a pedestrian channel or a road according to the environment and planning conditions, thereby providing a cross key node solution for the spatial development of traffic for the area with limited land use conditions and large traffic volume.

[0031] Additional aspects and advantages of the present application will be described in the description that follows, and will become apparent from the description, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and together with the description serve to explain the principles of the present application, and, wherein:

[0033] Figure 1 It is a schematic view of the bridge-tunnel combined structure in the prior art;

[0034] Figure 2 It is a schematic view of the bridge-tunnel combined structure in the embodiment;

[0035] Figure 3 It is a schematic view of the bridge-tunnel combined structure in the embodiment;

[0036] Figure 4 It is a partial view of the seismic mitigation structure arranged between the bridge and the tunnel structure in the embodiment. DETAILED DESCRIPTION

[0037] In order to more fully understand the technical content of the present application, the present application will be further introduced and described below in combination with the drawings and specific embodiments; it should be noted that the description of "first", "second" and the like in the text is used to distinguish different components and the like, and does not represent the sequence, nor limit the "first" and "second" to be different types.

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings of the embodiments of the present application; obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments; based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] Embodiment 1

[0040] As Figures 2-4As shown, the bridge-tunnel integrated structure shown in the embodiment comprises a frame type tunnel structure and a bridge arranged at the upper end of the tunnel structure; wherein the tunnel structure comprises a bottom plate 10 arranged on a foundation 21, at least two vertical walls 9 arranged on the bottom plate 10 in the width direction of the bottom plate 10, and a top plate 8 transversely arranged on the top end of the vertical walls 9; the length of the vertical wall 9 extends along the length direction of the bottom plate 10; and the bottom plate 10, the vertical wall 9 and the top plate 8 form at least one tunnel 30 therebetween, i.e. one tunnel 30 is formed between each two adjacent vertical walls 9, so that the cross section of the tunnel structure is a single-hole or multi-hole box type cross section; a road surface structure 16 and a tunnel pipe trench 19 are arranged in the tunnel 30; and a railway tunnel can also be formed by arranging rails in the tunnel; a seismic isolation structure is arranged between the tunnel structure and the bridge; the seismic isolation structure comprises a seismic isolation layer 7 arranged between the tunnel structure and the bridge, and a plurality of energy dissipation bars 4 arranged between the tunnel structure and the bridge; the bridge is arranged on the top plate of the tunnel structure and spans a river or an intersecting road; the bridge is characterized by being a small or medium span bridge; the bridge comprises two force transmission piers 3 arranged at the two ends of the seismic isolation layer 7, bridge piers 2 arranged on the force transmission piers 3, and a main beam 1 transversely arranged on the plurality of bridge piers 2; according to the width of the main beam, one or two bridge piers arranged on the left and right of each force transmission pier 3 can be arranged on each force transmission pier 3; the upper and lower ends of the energy dissipation bar 4 are respectively inserted into the force transmission pier 3 and the top plate 8; and a gap 31 for displacement is arranged between the energy dissipation bar 4 and the tunnel structure and / or the bridge, i.e. a gap 31 for displacement is arranged between the energy dissipation bar 4 and the force transmission pier 3 and / or the top plate 8.

[0041] In the above, when the gap 31 is arranged between the energy dissipation bar 4 and the force transmission pier 3, and no gap 31 is arranged between the energy dissipation bar 4 and the top plate 8, the energy dissipation bar 4 is fixed on the top plate 8 and remains stationary, and the bridge can slide and displace relative to the tunnel structure and the energy dissipation bar 4 within the range of the gap 31 to achieve the seismic isolation effect of the bridge; when no gap 31 is arranged between the energy dissipation bar 4 and the force transmission pier 3, and a gap 31 is arranged between the energy dissipation bar 4 and the top plate 8, the energy dissipation bar 4 is relatively fixed with the force transmission pier 3, i.e. the bridge and the energy dissipation bar are fixed and can slide and displace relative to the tunnel structure within the range of the gap 31 to achieve the seismic isolation effect of the bridge; and when gaps 31 are arranged between the energy dissipation bar 4 and the force transmission pier 3 and the top plate 8, the energy dissipation bar 4 can slide relative to the top plate within the range of the gap 31, and the bridge can also slide relative to the top plate and the energy dissipation bar 4 within the range of the gap 31, i.e. the maximum sliding distance of the bridge can be twice the size of the gap, which increases the sliding distance of the bridge to adapt to a larger earthquake intensity and improves the seismic isolation effect of the bridge.

[0042] Preferably, the main beam adopts a box section with good integrity and stability; a single box section or a multi-box section is selected according to the width of the bridge deck; and the bridge piers and the main beam are rigidly connected to form an integral whole, which ensures the structural rigidity and stability.

[0043] As preferred, the standing wall 9 is rigidly connected with the bottom plate 10, and the standing wall should have sufficient thickness to ensure that the load can be effectively transmitted to the bottom plate and dispersed in the foundation. The top plate 8 is rigidly connected with the standing wall 9, so that the tunnel section becomes a box section with good force and stability. The top plate 8 receives the load transmitted from the upper bridge and transmits the load downward through the standing wall.

[0044] In the embodiment, a plurality of hollow first sleeves 32 are embedded at the two ends of the top plate 8 and the isolation layer 7. The lower end of each energy dissipation rod 4 is inserted into the corresponding first sleeve 32. The number of the first sleeves 32 is the same as the number of the energy dissipation rods 4, and the inner diameter of the first sleeve 32 is larger than the outer diameter of the energy dissipation rod 4, so that a gap 31 for displacement is formed between the energy dissipation rod 4 and the top plate 8. Of course, in addition to embedding the sleeves, a plurality of first insertion holes can be directly provided at the two ends of the top plate 8 and the isolation layer 7 for the insertion of the energy dissipation rods 4. However, the direct insertion hole mode is prone to wear and tear when the energy dissipation rod contacts the hole wall, which affects the displacement and damages the structure of the top plate. The first sleeve is a rigid sleeve made of metal, which has sufficient bearing capacity and can avoid wear and tear.

[0045] In the embodiment, a plurality of hollow second sleeves 33 are embedded at the lower end of the force transmission pile cap 3. The upper end of each energy dissipation rod 4 is inserted into the corresponding second sleeve 33. The number of the second sleeves 33 is the same as the number of the energy dissipation rods 4, and the position of the second sleeve 33 corresponds to the position of the first sleeve 32. The inner diameter of the second sleeve 33 is larger than the outer diameter of the energy dissipation rod 4, so that a gap 31 for displacement is formed between the energy dissipation rod 4 and the force transmission pile cap 3. Of course, in addition to embedding the sleeves, a plurality of second insertion holes can be directly provided on the force transmission pile cap for the insertion of the energy dissipation rods 4. However, the direct insertion hole mode is prone to wear and tear when the energy dissipation rod contacts the hole wall, which affects the displacement and damages the structure of the top plate. The first sleeve is a rigid sleeve made of metal, which has sufficient bearing capacity and can avoid wear and tear.

[0046] In the embodiment, in order to limit the excessive transverse or longitudinal displacement of the bridge, the displacement stroke of the bridge needs to be limited. Limiting baffle beams 5 are provided at the top end of the top plate 8 in the longitudinal and transverse directions and surround the outer periphery of the force transmission pile cap 3 at the two ends of the bridge. A certain gap is formed between the limiting baffle beam 5 and the force transmission pile cap 3. The gap between the limiting baffle beam 5 and the force transmission pile cap 3 is filled with elastic members 6 to prevent direct impact between the force transmission pile cap and the limiting baffle beam, which can cause damage.

[0047] In this embodiment, the force transmission platform 3 is arranged along the width of the top plate 8, that is, the length of the force transmission platform 3 is only slightly smaller than the width of the top plate 8, forming a large bridge foundation, and a plurality of energy dissipation bars 4 are arranged in the length direction of the force transmission platform 3, and two rows of energy dissipation bars 4 are arranged in the width direction of the force transmission platform 3; in this embodiment, the force transmission platform 3 (i.e. the bridge foundation) adopts an enlarged foundation, the force transmission platform 3 is rigidly connected with the pier 2, and the bridge foundation needs to ensure sufficient plan size and thickness to ensure that the foundation can well bear the load transmitted by the pier and uniformly disperse the load downward. Since the enlarged foundation is adopted, large pile driving machinery is not needed for construction during bridge construction, the construction has little impact on the safety of the tunnel, and special tunnel protection schemes are not needed, so compared with conventional bridge-tunnel construction, the cost of construction safety protection measures can be greatly saved.

[0048] In an embodiment, when the bottom of the tunnel is directly on a rock layer with high strength, but when the rock layer under the bottom plate is poor, the foundation needs to be reinforced, and methods such as reinforced piles and soft soil replacement can be used to improve the bearing capacity of the foundation to meet the design requirements, that is, the tunnel structure further includes a plurality of reinforced piles 20 arranged at the bottom of the bottom plate 10 and inserted into the foundation 21; of course, a cushion layer 11 is also arranged under the bottom plate 10, which is preferably made of concrete.

[0049] In an embodiment, a bridge deck structure 14 is arranged on the main beam 1, and a bridge head apron 25 is arranged between the ground and the two ends of the main beam 1, and a TST elastic expansion joint 26 is arranged between the two ends of the main beam 1 and the bridge head apron 25.

[0050] In an embodiment, a sidewalk 22 and a bridge railing 23 are further arranged on both sides of the main beam 1 to facilitate pedestrian traffic.

[0051] In an embodiment, when the bridge is under a river, a water isolation layer 12 is further arranged on the shock isolation layer 7, and a river hardening structure 15 is further arranged on the water isolation layer 12, and the river hardening structure 15 is surrounded by stone chips 13; when the bridge is under a road, a water isolation layer 12 is further arranged on the shock isolation layer 7, and a road surface structure is further arranged on the water isolation layer 12; in the above, the water isolation layer is preferably filled with cohesive soil waterproof geotextile.

[0052] In an embodiment, a drainage ditch 17 is arranged on both sides of the tunnel structure, and a drainage pipe 18 is arranged to connect the drainage ditch 17 and a tunnel pipe trench 19.

[0053] In an embodiment, a settlement joint 24 is arranged at both ends of the tunnel structure.

[0054] In an embodiment, the shock isolation layer is a high-strength graded gravel layer.

[0055] In one embodiment, the energy-consuming rod is a lead rod or a zinc rod.

[0056] In one embodiment, the elastic element is made of rubber.

[0057] Example 2

[0058] This embodiment illustrates a construction method for a bridge-tunnel combined structure, used to construct the bridge-tunnel combined structure described in Embodiment 1, and specifically includes the following steps:

[0059] S1. The foundation pit is excavated using the open-cut method, and foundation pit support construction is carried out to avoid landslides during construction in the foundation pit;

[0060] S2. Treat the bearing foundation in the foundation pit. If the bearing capacity of the foundation does not meet the design requirements, the foundation must be reinforced first. Reinforcement can be carried out by means of reinforcement piles or replacement of weak layers. That is, drive a number of reinforcement piles into the foundation and level the surface of the ground layer at the design elevation.

[0061] S3. Pour concrete on the bearing foundation to form a cushion layer and perform leveling and slope adjustment.

[0062] S4. Tie the bottom slab and vertical wall reinforcement on the foundation layer, and then pour concrete on the foundation layer to form the bottom slab and vertical wall. Tie the top slab and limiting beam reinforcement, and pre-embed the first sleeve, drainage ditch and drainage pipe at the designed location. Then pour concrete on the top of the vertical wall to form the top slab and limiting beam to form a tunnel structure, and enclose at least one tunnel between the bottom slab, vertical wall and top slab. Of course, in addition to pre-embedding the first sleeve, several first insertion holes can be reserved on the top slab when pouring the top slab for the energy dissipation rod to be inserted one by one; wherein, the inner diameter of the first insertion hole or the first sleeve is greater than the outer diameter of the energy dissipation rod.

[0063] S5. After the tunnel structure has reached the preset strength, the foundation pit support components are removed, and the construction of functional ancillary structures such as pipe trenches, road surfaces, or tracks inside the tunnel is carried out; at this time, the construction of bridge structures on the tunnel structure can be carried out simultaneously.

[0064] S6. Construct a seismic isolation layer on the top slab;

[0065] S7, first insert energy consumption rod in the first jack or the first sleeve, construct the force transmission platform and the pier on the shock absorption layer, and a plurality of second jacks or a plurality of second sleeves corresponding to the energy consumption rod are arranged on the force transmission platform, the inner diameter of the second jack or the second sleeve is greater than the outer diameter of the energy consumption rod; this step can be divided into two cases, when the pier and the force transmission platform are prefabricated, the shock absorption layer can be appropriately thinned, the shock absorption layer is paved and leveled, the energy consumption rod is inserted into the first sleeve, the integrated component composed of the pier and the force transmission platform is transported to the site, and then is hoisted and installed to the designed position by the crane, the upper end of the energy consumption rod is inserted into the second sleeve, and the process needs to be paid attention to, the second jack or the second sleeve is reserved or embedded at the position where the energy consumption rod is embedded when the prefabricated construction is carried out, and at the same time, in order to ensure the smooth hoisting and installation, the first sleeve is embedded to form the socket hole of the energy consumption rod and ensure the embedding precision when the top plate of the tunnel is poured; when the pier and the force transmission platform are cast in situ, the thickness of the shock absorption layer is appropriately thickened, a layer of sand is laid on the shock absorption layer to separate the shock absorption layer and the force transmission platform, and then the force transmission platform and the pier are successively cast by binding the steel bars on the sand layer;

[0066] S8, the hardening structure of the bridge under road or river is constructed; if it is a river, the river water needs to be drained first, then a water isolation layer is laid on the shock absorption layer on the tunnel structure, and then the hardening pavement structure at the bottom of the river and the soil retaining wall structure on both sides of the river bank are successively constructed to form the hardening structure of the river, and then the hardening structure of the river is backfilled with stone chips; if it is a bridge under road, the water isolation layer is directly laid and compacted, and then the soil retaining wall structure on both sides and the pavement structure are successively constructed.

[0067] S9, the main beam of the bridge is constructed by pouring and embedding the support;

[0068] S10, the construction of the bridge deck pavement and the bridge rail and other auxiliary facilities is completed.

[0069] In the above, the settlement joint needs to be arranged between the two ends of the tunnel structure under the bridge and the adjacent section of the tunnel, that is, the tunnel structure under the bridge is not rigidly connected with the adjacent end of the tunnel to meet the settlement requirement of the bridge in the use process.

[0070] The technical scheme provided by the embodiment of the application is described in detail above, specific examples are applied in this paper to describe the principle and implementation mode of the embodiment of the application, and the description of the above embodiments is only applicable to help understand the principle of the embodiment of the application; meanwhile, for those skilled in the art, the embodiment of the application will have changes in the specific implementation mode and application range, and the above description should not be understood as the limitation of the application.

Claims

1. A bridge-tunnel combined structure, comprising a frame-type tunnel structure and a bridge located at the upper end of the tunnel structure, characterized in that, A seismic isolation structure is provided between the tunnel structure and the bridge. The seismic isolation structure includes a seismic isolation layer between the tunnel structure and the bridge, and several energy dissipation bars between the tunnel structure and the bridge. The bridge includes at least two force transmission bearings spaced apart on the seismic isolation layer, piers on the force transmission bearings, and a main beam spanning multiple piers. Each force transmission bearing has two piers arranged on the left and right. The upper and lower ends of the energy dissipation bars are respectively inserted into the upper end of the tunnel structure and the lower end of the force transmission bearing, and a gap for displacement is provided between the energy dissipation bars and the tunnel structure and / or the force transmission bearings. The top of the tunnel structure has a protruding limiting beam surrounding the force transmission bearings at both ends of the bridge, and an elastic element is provided between the limiting beam and the force transmission bearing.

2. The bridge-tunnel combined structure according to claim 1, characterized in that, The upper end of the tunnel structure and the seismic isolation layer are provided with a number of first insertion holes or a number of hollow first sleeves. The lower end of the energy dissipation rod is inserted into the first insertion hole or the first sleeve in a corresponding manner, and the inner diameter of the first insertion hole or the first sleeve is larger than the outer diameter of the energy dissipation rod, so as to form a gap for displacement between the energy dissipation rod and the tunnel structure.

3. The bridge-tunnel combined structure according to claim 2, characterized in that, The lower end of the bridge is provided with a number of second insertion holes or a number of hollow second sleeves. The upper end of the energy dissipation rod is inserted into the second insertion hole or the second sleeve in a corresponding manner. The inner diameter of the second insertion hole or the second sleeve is larger than the outer diameter of the energy dissipation rod, so as to form a gap for displacement between the energy dissipation rod and the bridge.

4. The bridge-tunnel combined structure according to any one of claims 1-3, characterized in that, The force transmission support extends along the width of the tunnel structure, and a plurality of energy dissipation bars are spaced apart along the length of the force transmission support, and at least one row of energy dissipation bars is arranged along the width of the force transmission support.

5. The bridge-tunnel combined structure according to claim 4, characterized in that, The tunnel structure includes a base slab on the foundation, at least two vertical walls spaced apart on the base slab along the width direction, and a top slab at the top of the vertical walls. The base slab, vertical walls, and top slab enclose at least one tunnel, so that the cross-section of the tunnel structure is a single-hole or multi-hole box-shaped cross-section.

6. The bridge-tunnel combined structure according to claim 5, characterized in that, The tunnel structure also includes several reinforcing piles located at the bottom of the base plate and inserted into the foundation.

7. A construction method for a bridge-tunnel combined structure, characterized in that, Includes the following steps: S1. Excavate the foundation pit and carry out foundation pit support construction; S2. Treat the bearing foundation. If the bearing capacity of the foundation does not meet the design requirements, the foundation must be reinforced first, and the surface of the ground layer at the design elevation must be leveled. S3. Pour a cushion layer on the bearing foundation and perform leveling and slope adjustment treatment; S4. Reinforced concrete is poured sequentially on the foundation to form a base slab, vertical walls and a top slab, so that at least one tunnel is formed between the base slab, vertical walls and top slab, and several first insertion holes for energy dissipation bars to be inserted one-to-one are reserved on the top slab or several first sleeves for energy dissipation bars to be inserted one-to-one are pre-embedded, the inner diameter of the first insertion hole or the first sleeve is greater than the outer diameter of the energy dissipation bar. S5. Carry out road surface or track construction inside the tunnel; S6. Construct a seismic isolation layer on the top slab; S7. First, insert the energy dissipation rod into the first insertion hole or the first sleeve. Then, construct the force transmission bearing platform and the bridge pier on the seismic isolation layer. On the force transmission bearing platform, there are several second insertion holes for the energy dissipation rod to be inserted one by one, or several second sleeves for the energy dissipation rod to be inserted one by one are pre-embedded. The inner diameter of the second insertion hole or the second sleeve is greater than the outer diameter of the energy dissipation rod. S8. Construct the road or river paving structure under the bridge; if it is a river, the river water must first be diverted, then a water-proof layer is laid on the seismic isolation layer above the tunnel structure, and then the riverbed hardening paving structure and the retaining wall structure on both sides of the river are constructed in sequence; if it is a road under the bridge, the water-proof layer is laid and compacted directly, and then the retaining wall structure on both sides and the road surface structure are constructed in sequence. S9. Erect scaffolding and pour the main beams of the bridge. S10. Complete the construction of bridge deck paving and railings.

8. The construction method for the bridge-tunnel combined structure according to claim 7, characterized in that, In step S7, when the piers and load-bearing caps are prefabricated in the factory, the prefabricated integrated components consisting of the piers and load-bearing caps are transported to the site and then lifted and installed in the design position by a crane; when the piers and load-bearing caps are cast in place, a layer of sand is laid on the seismic isolation layer, and then steel bars are tied on the sand layer to cast the load-bearing caps and piers in sequence.

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