Underground excavation reinforcing structure for tunnel below crossing road

Abstract

The utility model discloses a tunnel underground excavation reinforcing structure below a street-crossing road, which is positioned below the street-crossing road and comprises an upper supporting bridge structure arranged close to a cushion layer of the street-crossing road and a lower supporting bridge structure positioned above an excavated tunnel, the lower supporting bridge structure is located under the upper supporting bridge structure, and a gap is formed between the upper supporting bridge structure and the lower supporting bridge structure. The settlement of the whole road can be well controlled and is not restricted by key time nodes of construction time; station and entrance and exit enclosure structures can be constructed synchronously, time node key lines of the subsurface tunnel are changed into non-key time node lines, the construction period is shortened, and the construction cost is relatively low.

Description

Technical Field

[0001] The utility model relates to the technical field of street tunnel construction, in particular to a tunnel dark excavation reinforcement structure under a street highway. Background Art

[0002] With the increasing number of subway constructions, it is inevitable that subway stations and entrances and exits are separated and blocked by roads to form street tunnels. Regardless of whether the tunnel is constructed by open-cut forward or open-cut reverse, the road must be enclosed and closed to relieve traffic, especially during the pile foundation construction of the tunnel retaining structure, which takes a long time to occupy the road. This often fails to meet the owners' requirements for long road occupation time.

[0003] like Figure 1 As shown, the subway station and the subway entrance and exit are separated by the highway to form a street tunnel. In order to reduce the impact on highway traffic, the street tunnel is often constructed by dark excavation. The traditional dark excavation method cannot be used for street tunnels, especially the excavation of long tunnels with water-rich sand and gravel layers. There are even cars shuttling back and forth above the tunnel. At present, the tunnel dark excavation is mostly constructed by jacking. When connecting the tunnel under the construction station and the entrance and exit highway, the traditional method is to reserve the street tunnel opening as the jacking receiving port after the main structure of the station is completed, and at the same time, the receiving well enclosure structure is constructed. The construction period is long, and the jacking construction costs about 160,000 per meter. Generally, a two-way eight-lane road plus a middle green belt and double-sided sidewalks are more than 60 meters long, and the jacking construction cost is huge. If the jacking construction accidentally encounters large isolated rocks and other adverse geological conditions, it cannot be constructed. It is restricted by geological strata and time nodes.

[0004] Due to the influence of geology, tunnel excavation needs to be reinforced by reinforcement structure to control the settlement of the entire highway; for example, when excavating a tunnel in a water-rich sandstone layer structure, the support above the tunnel and in all directions needs to be reinforced; especially the vehicle load support and the soil load support above the tunnel; for example, a reinforcement method for a shield tunnel passing under an existing building disclosed in Chinese patent CN109944593A; reinforcement piles are constructed on both sides of the existing building, anchor cables are inserted into the soil between the existing building and the shield tunnel, and the anchor cables are tensioned to the design strength before the two ends of the anchor cables are tightened. It is fixed on the reinforcement piles, and then grouting is injected into the soil below the existing building. The grouting wraps the anchor cable to form a reinforced concrete structure that supports the existing building. After the grouting reaches the designed strength, the reinforcement of the existing building is completed. This reinforcement method is only suitable for grouting into the soil below the existing building in a transversely shorter shield tunnel. Grouting can be done around the building before construction, but the longitudinal grouting of the road where vehicles travel cannot meet the needs of longitudinal traffic, and the pile foundation cannot be destroyed on both sides of the reinforcement. This reinforcement method cannot be used for tunnel excavation reinforcement and cannot solve the problem of longitudinal traffic. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a tunnel digging reinforcement structure under a street crossing highway, which can well control the settlement of the entire highway and has a relatively low construction cost.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] A tunnel excavation reinforcement structure under a street crossing, the reinforcement structure is located under the street crossing, the reinforcement structure comprises an upper supporting bridge structure arranged close to the cushion layer of the street crossing and a lower supporting bridge structure located above the excavated tunnel, the lower supporting bridge structure is located directly below the upper supporting bridge structure, and there is a spacing between the upper supporting bridge structure and the lower supporting bridge structure.

[0008] The lower supporting bridge structure is located 1.0-1.5 m above the excavated tunnel.

[0009] There is soil between the upper supporting bridge structure and the lower supporting bridge structure.

[0010] The upper supporting bridge structure and the lower supporting bridge structure are tensioned and consolidated with two bridge decks above and below the subway station and the tunnel excavation of the station entrance and exit through anchor cables.

[0011] The upper supporting bridge structure and the lower supporting bridge structure are connected via a group of suspension rods.

[0012] The upper supporting bridge structure is a single-span mid-bearing arch bridge structure, and the lower supporting bridge structure is a three-span top-bearing arch bridge structure or a continuous beam bridge structure.

[0013] The single-span half-through arch bridge structure comprises an arch rib and a bridge deck, and the arch rib and the bridge deck are connected via a half-through arch bridge hanger.

[0014] The three-hole top-supported arch bridge structure is arranged on the reinforced concrete pile foundation of the tunnel. The pile foundation uses the pile foundation of the station and entrance and exit retaining structure, and pile foundations are added on the outside of the retaining structure. A pedestal is provided on the top of the pile foundation. The upper mid-supported arch bridge has two pedestals, and the lower top-supported arch bridge has four pedestals. The gaps in the pile foundations under the four pedestals are used to apply a mixture of vertical anchor cables and steel grouting.

[0015] When constructing the upper pier of the mid-span arch bridge structure, the upper mid-span arch rib foot is pre-embedded, and when the arch foot passes upward through the crown beam of the bridge deck, it is tied together with the crown beam steel bars, and the crown beam steel bars are tied together with the exposed steel bars after the concrete of the pile foundation is broken. At the same time, transverse anchor cable sleeves and reinforced concrete grouting pipe sleeves and obliquely opposite lower bridge deck anchor cables are pre-embedded, as well as reserved hanger sleeves for the poured pile foundation, and mid-span hanger sleeves are pre-embedded.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] The underground tunnel reinforcement structure under the overpass is reasonably designed and can well control the settlement of the entire highway without being restricted by the critical time nodes of the construction period. The station and entrance and exit enclosure structures can be constructed simultaneously, so that the critical time node line of the underground tunnel becomes a non-critical time node line, shortening the construction period and making full use of the existing main body and maintenance structure pile foundation. The upper "bridge deck" uses resources such as crown beams, and the lower "bridge deck" uses the "portal ring beam" of traditional construction, cleverly utilizing traditional construction resources. If the internal steel frame and the secondary lining's own reinforcement system of the overpass tunnel are converted, the upper arch rib can be used multiple times to reduce costs, so the construction cost is relatively low. This solves the problem that first-tier cities do not allow long-term road closures on busy trunk roads. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following is a brief description of the contents and symbols in the drawings of this specification:

[0019] Figure 1 This is a schematic diagram of the locations of subway stations and station entrances and exits.

[0020] Figure 2 The utility model is a schematic diagram of a reinforcement structure.

[0021] Figure 3-1 This is the elevation view of the station side reinforcement structure of the utility model.

[0022] Figure 3-2 This is a vertical view of the entrance and exit side reinforcement structure of the utility model.

[0023] Figure 4 It is a top view schematic diagram of the horizontal anchor cable arrangement of the reinforcement structure of the utility model.

[0024] Figure 5 It is a top view schematic diagram of the horizontal reinforced concrete interlayer of the reinforced structure of the utility model.

[0025] Figure 6 It is a cable-stayed cross-section diagram of the upper and lower "bridge decks" of the utility model.

[0026] Figure 7 It is a schematic cross-sectional view of the vertical portion below the reinforced structure highway of the utility model.

[0027] In the figure:

[0028] 1-Arch rib of mid-span arch bridge; 2-Horizontal anchor cable sleeve; 3-Horizontal reinforced concrete grouting pipe sleeve; 4-Cross support of mid-span arch bridge; 5-Hanging rod of mid-span arch bridge; 6-Hanging rod connecting the lower bridge deck; 7-Reinforced concrete interlayer; 8-Upper tension anchor cable layer (horizontal tension anchor cable layer for stations and entrances and exits); 9-Upper mid-span arch bridge pier; 10-Pile foundation; 11-Reinforced concrete interlayer (horizontal interlayer for stations and entrances and exits); 12-Lower Tension anchor cable layer (horizontal tension anchor cable layer for stations and entrances below); 13- Arch ribs of top-supported arch bridge; 14- Upper oblique anchor cable steel casing (used to apply anchor cables from the upper bridge deck to the lower bridge deck on the opposite side); 15- Lower oblique anchor cable steel casing (used to receive anchor cables from the upper bridge deck to the lower bridge deck on the opposite side); 16- Side span arch ribs; 17- Bottom top-supported three-arch bridge abutment; 19- Deck structure of mid-supported arch bridge (composed of deck interlayer and anchor cable of mid-supported bridge); 20- oblique anchor cable corrugated pipe; 21- reinforced concrete grouting pipe structure; 22- oblique prestressed anchor cable (anchor cable is applied from the upper bridge deck to the lower bridge deck on the opposite side); 23- lower three-arch bridge deck structure (or connecting beam bridge deck structure) (including interlayer and reinforcement layer three-arch bridge deck or connecting beam bridge deck); 24- transverse prestressed reinforcement layer (prestressed in the main view) Stress reinforcement layer); 25- transverse reinforced concrete grouting waterproof barrier (reinforced concrete grouting waterproof barrier in the main view); 26- transverse anchor cable; 27- overpass; 28- vertical anchor cable and reinforced concrete grouting mixed barrier (two vertical barriers on the left and right sides of the tunnel portal); 29- two pile foundations under the middle pier; 30- pile foundation under the pier (pile foundation under the left and right piers on the outside of the tunnel portal); 31- middle side vertical anchor cable and reinforced concrete grouting mixed barrier. 32- soil reinforcement in front of the entrance and exit side portal; 33- soil reinforcement in front of the station side portal; 34- continuous beam bridge deck; 35- bearing; 36- main arch leg, 37- column; 38- bridge head slab. DETAILED DESCRIPTION

[0029] The specific implementation of the utility model will be further explained in detail below through the description of embodiments with reference to the accompanying drawings.

[0030] like Figures 1 to 7 As shown, the tunnel excavation reinforcement structure under the overpass is located below the overpass 27, and its reinforcement structure includes an upper supporting bridge structure arranged near the cushion layer of the overpass and a lower supporting bridge structure located above the excavated tunnel, the lower supporting bridge structure is located directly below the upper supporting bridge structure, and there is a distance between the upper supporting bridge structure and the lower supporting bridge structure.

[0031] The lower supporting bridge structure is located 1.0-1.5m above the excavated tunnel, preferably 1.3m; there is soil between the upper supporting bridge structure and the lower supporting bridge structure. The upper supporting bridge structure supports vehicle loads and road and subgrade loads, and the lower supporting bridge structure supports the soil load between the upper supporting bridge structure and the lower supporting bridge structure in addition to supporting the remaining load supported by the upper supporting bridge structure. The lower supporting bridge deck is specially equipped with a double-layer reinforced concrete interlayer 11 and a double-layer horizontal reinforced concrete grouting pipe sleeve 3, which are arranged in a plum blossom shape to ensure that water leakage from the upper part is blocked during excavation below, and play the role of a "water-stop curtain" interlayer.

[0032] Both the upper supporting bridge structure and the lower supporting bridge structure are tensioned and consolidated with the two arch bridge decks above and below the excavation of the subway station and the tunnel ends of the station entrances and exits through anchor cables; the bridge deck of the upper supporting arch bridge structure and the bridge deck of the lower supporting bridge structure are connected by a set of hangers, and the structure is stable and reliable.

[0033] Preferred as Figure 2 and Figure 3-1 As shown, the upper supporting arch bridge structure is a single-hole mid-bearing arch bridge structure, and the lower supporting arch bridge structure is a three-hole top-bearing arch bridge structure. The three-hole top-bearing arch bridge structure is set on the reinforced concrete pile foundation of the tunnel enclosure structure. The pile foundation is based on the pile foundation of the station and entrance and exit enclosure structure, and pile foundations are added on the outside of the enclosure structure. A cap is provided on the top of the pile foundation. The upper mid-bearing arch bridge has two caps, and the lower top-bearing arch bridge has four caps. The gaps in the pile foundations under the four caps are used to apply a mixture of vertical anchor cables and steel grouting. The mixture of vertical anchor cables and steel grouting plays a role in blocking lateral water leakage and serves as a vertical "water-stopping curtain" interlayer. At the same time, it divides the excavation surface of the "street tunnel" into an excavation section of the "double-side wall guide pit" to reduce construction risks.

[0034] The upper single-span mid-span arch bridge structure includes arch ribs and bridge decks, which are connected by mid-span arch hangers. When the upper piers of the mid-span arch bridge structure are constructed, the upper mid-span arch rib feet are pre-embedded, and the arch feet are tied together with the crown beam steel bars when passing through the crown beam of the retaining structure upward. The steel bars of the crown beam are tied together with the exposed steel bars after the concrete is removed from the pile foundation. At the same time, transverse anchor cable sleeves and reinforced concrete grouting pipe sleeves and obliquely opposite lower bridge deck anchor cables are pre-embedded, as well as hanger sleeves reserved for the poured pile foundation and mid-span hanger sleeves are pre-embedded.

[0035] The utility model discloses a method for reinforcing a tunnel under a street crossing road, comprising the following steps:

[0036] 1) Determine the elevation of the deck cap of the upper mid-through arch bridge structure: According to the road structure, determine the elevation and position of the reinforcement layer below the highway cushion layer, so as to determine the additional reinforcement pile foundation (required pile foundation elevation) when making the main structure and entrance and exit enclosure structure to meet the reinforcement load-bearing requirements;

[0037] 2) Construction of station and entrance and exit enclosure structure: The enclosure method adopts underground continuous wall / bored cast-in-place piles + jet grouting piles + internal support; the enclosure structure on the side of the street tunnel, especially near the tunnel gate, uses bored cast-in-place piles + jet grouting piles + internal support. There is no underground continuous wall + internal support for the "street tunnel" enclosure structure on the same side of the station and the entrance and exit; by pre-embedding sleeve hangers with sealed ends during pile foundation construction, increase the pile foundation under each pedestal; increase pile foundations on the outside of the station and entrance and exit;

[0038] 3) Excavation: Before excavation, the soil in front of the tunnel opening must be reinforced from the ground to 2 meters below the lower cap. The width of the lower cap is 2 meters outside, and the width of the upper cap is 2 meters outside. The depth is also 2 meters below the cap. Use three-axis concrete mixing to mix the soil. The strength must meet the requirements of self-stabilization of the cap construction before excavation can be carried out and excavation construction can be carried out smoothly. Figure 1 As shown, the soil reinforcement 32 in front of the tunnel door on the entrance and exit side and the soil reinforcement 33 in front of the tunnel door on the station side; the station and the entrance and exit are excavated, and the excavation is supported at the same time. When the excavation reaches the pedestal of the arch bridge structure above, the pedestal and the crown beam position are then constructed, and the crown beam is constructed. When constructing the panel of the crown beam, it is necessary to pay attention to pre-embed various transverse, vertical, and oblique sleeves required to pass through all prestressed anchor cables for tensioning;

[0039] 4) Excavate the station or entrance and exit to the bottom, construct the bottom cushion and floor, set up temporary supports, and remove the retaining structure bridge deck. It is necessary to construct part of the retaining structure pile foundation concrete. Before removal, advance grouting is performed from the piles to the inner side of the removal surface of the road (excavation surface). Only after the heading face is stabilized can the overlapping part of the bridge deck below the retaining structure pile foundation be removed. The pile foundation steel bars are retained, and the hanging rods used to seal the pre-embedded steel casing during the construction of the pre-embedded pile foundation are retained to implant the newly added steel bars to make the lower bridge deck. Similarly, all the horizontal, oblique and upper hanging rods passing through the lower bridge deck need to be added with sleeves. The double-deck bridge reinforcement structure on the station side is earlier than that on the entrance and exit side. The anchor cables are applied from the station side through the guide holes from the bridge deck to the entrance and exit side.

[0040] Furthermore, step 3) of the reinforcement method is specifically as follows:

[0041] Before excavation, the soil at the entrance of the tunnel must be reinforced; the depth, range and strength of the reinforcement meet the need for self-stabilization of the soil when the pile foundations of the subsequent abutments and double-deck bridge decks are removed. At the same time, the soil reinforcement strength must also meet the requirements for smooth excavation. The station and entrances and exits are excavated and supported while excavating. According to the highway structure, the "reinforced concrete interlayer" is applied from the station side to the entrance and exit side in close proximity to the plain soil layer below the highway cushion. Grouting of the grouting pipe is carried out according to the existing tunnel construction pipeline grouting device and grouting construction method, and it can be constructed efficiently and stably in combination with other reinforcement methods; the tunnel construction pipeline grouting device includes a grouting pipe and a thread hole anchor pipe, an inlet and outlet pipe and a piston structure. A group of thread holes are provided on the pipe wall of the thread hole anchor pipe. The grouting pipe, the inlet and outlet pipe and the piston structure are all arranged in the thread hole anchor pipe. One end of the grouting pipe and the inlet and outlet pipe extends through the piston structure. The grouting construction method utilizes air inlet and outlet pipes to inflate the enclosed space with grouting pressure, and grouting is performed on the grouting pipe under high pressure in a relatively closed space. The high-pressure grouting presses the slurry into the loose soil through the hollow grouting pipe, forming a "plate-shaped" reinforced concrete and soil barrier, forming a "water-stop curtain" barrier.

[0042] That is, through the grouting construction method, the reinforced concrete "bridge deck" of the tunnel above the street tunnel is formed to form a reinforced concrete "water-stop curtain interlayer". The station side reinforced concrete grouting is first constructed, and the remaining steel bars are effectively connected with the mid-span bridge deck (i.e., the crown beam of the enclosure structure). When excavating to the pedestal of the arch bridge structure above, the pedestal and the crown beam are then constructed. When constructing the crown beam, i.e., the mid-span bridge deck, it is necessary to pay attention to pre-embedding various transverse, vertical, and oblique sleeves required to pass through all prestressed anchor cables. This includes the effective connection between the steel bars in the "reinforced concrete interlayer" and the "crown beam" steel bars from the station side to the entrance and exit side in advance, as well as the effective connection of the steel bars at the top of the pile foundation. The excavation of the main structure of the station and the construction of the crown beam are slightly earlier than those on the entrance and exit side. The anchor cables are constructed from the station side through the guide drilling holes from the station bridge deck to the entrance and exit side. According to the fact that the excavation of the main structure of the station and the construction of the crown beam are ahead of the entrance and exit side, the concrete strength of the "reinforced concrete interlayer" constructed in advance on the upper side reaches the strength required for tensioning. The navigation guide is used from the station side to drill holes on the entrance and exit side to apply anchor cables with corrugated tubes to the equipment. The anchor cables with corrugated tubes at the starting end of the station are also laid through sleeves in the mid-span bridge deck structure (i.e. in the crown beam of the enclosure structure). The entrance and exit side of the station accepts the anchor cables with corrugated tubes, which are laid in the mid-span bridge deck on the entrance and exit side (i.e. in the crown beam of the enclosure structure), and accept the reinforced concrete interlayer constructed from the station side. After breaking the concrete of the overlapping part of the reinforced concrete interlayer and the bridge deck, the steel bars are left to be effectively connected with the "bridge deck" above the entrance and exit side. The entrance and exit side mid-span bridge deck is constructed in the same way as the station side. When the concrete strength of the mid-span "reinforced concrete bridge deck" on both sides of the station and the entrance and exit reaches the required tensioning, and the concrete strength of the reinforced concrete interlayer above the anchor cable reaches the required tensioning, the horizontal anchor cables of the bridge deck above the station and the entrance and exit are tensioned to complete the first horizontal "prestressed tensioned anchor cable bridge" above the station and the entrance and exit. The rigid reinforcement is the anchor cable, and the "bridge deck pavement" is the "reinforced concrete structure interlayer" above the anchor cable. The "reinforced concrete structure interlayer" allows the ground vehicle load and the road's own load to act evenly on the tensioned anchor cable.

[0043] The utility model has a reasonable design of the tunnel under the street crossing highway and the reinforcement method, which can well control the settlement of the entire highway and is not restricted by the critical time nodes of the construction time; the station and the entrance and exit enclosure structure can be constructed synchronously, so that the critical time node line of the dark excavation tunnel becomes a non-critical time node line, shortening the construction period, making full use of the existing main body and maintenance structure pile foundation, the upper "bridge deck" uses resources such as crown beams, and the lower "bridge deck" uses the "tunnel ring beam" of traditional construction. If the internal steel support of the street crossing tunnel and the secondary lining's own reinforcement system are converted, the upper arch rib can be used multiple times to reduce costs, so the construction cost is relatively low. Solve the problem that first-tier cities do not allow long-term road closures on busy trunk roads.

[0044] This utility model not only saves a lot of construction costs, but also requires the completion of the main structure of the station as a prerequisite for the construction of the pipe jacking. The utility model can be constructed synchronously during the construction of the station and the entrance and exit enclosure structure. The utility model turns the key time node line of the dark excavation tunnel into a non-key time node line. It can not only meet the owner's requirements for urban road construction, but also save a lot of construction costs compared to traditional methods, and is safer and can better control the construction quality of the new reinforcement structure and reinforcement method; this method can well control the settlement of the entire highway and is not restricted by the key time node of the construction time.

[0045] The utility model can save huge construction costs, and can provide technical support for cost quotations with great competitive advantages in fierce subway bidding; it can highlight the huge economic value, reduce or even eliminate the need for road occupation during construction bidding, and demonstrate the competitive social value.

[0046] The utility model can effectively solve the problems of the prior art dark-digging tunnels, such as long road occupation time, high construction cost, and insurmountable water and sand gushing from gravel-rich layers. What was previously impossible to accomplish with conventional dark-digging can now be accomplished quickly, safely, with high quality and efficiency.

[0047] The utility model solves the problem of supporting the top and all directions of the dark excavation of the "street crossing tunnel". The subway station is located on one side of the highway. The subway station and entrances and exits A and E are separated by the street crossing highway. The reinforced structure of the utility model mainly supports the vehicle load and its own soil load above the dark excavation tunnel. It is proposed to build two bridges under the street crossing highway, one is under the highway close to the cushion position, aiming to support the vehicle load and the road surface and roadbed load, and the other is to build a "bridge" about one and a half meters above the excavated tunnel. In addition to supporting the remaining load of the first "bridge" above, it also supports the soil load between the first bridge and the second bridge. The two "bridges" are tensioned and consolidated with the "bridge decks" of two "single-hole mid-span" arch bridges and two "three-hole top-span arch bridges" above and below the tunnel excavation of the subway station and the station entrance and exit through anchor cables. The tension force of the two bridges under the cross-street highway is "transmitted" to each pile foundation through four "arch bridges" to complete the reinforcement above the excavated tunnel. At the same time, the reinforced concrete structure interlayer is constructed by guiding drilling above the anchor cables to form a horizontal reinforced concrete "water-stop curtain" interlayer. When the concrete strength of the reinforced concrete "water-stop curtain" interlayer above the anchor cables reaches the tensioning strength, the double-deck arch bridge deck structure concrete strength reaches the tensioning strength before tensioning can be carried out. The arch bridge pile foundation makes full use of the pile foundation of the station and station entrance and exit enclosure structure. The pile foundation is reinforced concrete. If necessary, pile foundations are added on the outside of the enclosure structure to meet the support force of the arch bridge and the bridge under the road surface. The arch rib of the upper single-hole "mid-span arch bridge" is consolidated with the "bridge deck" by the mid-span arch bridge hanger 5. The arch rib of the "mid-span arch bridge" and the hanger 6 are consolidated with the upper structure of the three-hole arch bridge below through two "mid-span bridge upper structure reserved holes", excluding the arch rib. If the lower part is a continuous beam bridge (single-hole double cantilever beam bridge), Figure 3-1 , Figure 3-2 ) can be consolidated and tensioned with the box girder (bridge deck structure consolidation or bridge hollow belly) passing through it. The foundation under the three-arch bridge below is a reinforced concrete pile foundation. The pile foundation is based on the pile foundation of the station and entrance and exit retaining structure. According to the foundation and load requirements, additional pile foundations are determined near the outer side of the retaining structure to form a cap. There are two caps for the upper mid-span arch bridge and four caps for the lower top-span arch bridge. The gap between the pile foundation under the four caps and the pile foundation of the retaining structure is used to construct a "water-stop curtain wall" made of a mixture of vertical anchor cables and steel grouting. The four vertical "water-stop curtain walls", three arch ribs and the lower top-span "bridge deck" form a "double-side wall guide pit" interface, so that the "double-side wall guide pit method excavation" can be carried out after the overall reinforcement in the later stage.

[0048] The preferred specific examples of the present utility model are:

[0049] like Figures 2 to 7As shown, the reinforcement structure of the utility model comprises a mid-span arch bridge arch rib 1; a horizontal anchor cable sleeve 2; a horizontal reinforced concrete grouting pipe sleeve 3; a mid-span arch bridge cross support 4; a mid-span arch bridge hanger 5; a hanger 6 connecting the lower bridge deck; a reinforced concrete interlayer 7; an upper tensioned anchor cable layer 8; an upper mid-span arch bridge abutment 9; a pile foundation 10; a reinforced concrete interlayer 11; a lower tensioned anchor cable layer 12; an upper-bearing arch bridge arch rib 13; an upper oblique anchor cable steel casing 14; a lower oblique anchor cable steel casing 15; a side span arch rib 16; a lower upper-bearing three-arch bridge abutment 17; a mid-span arch bridge rib 13; a horizontal anchor cable sleeve 24; a horizontal reinforced concrete grouting pipe sleeve 35; a side span arch rib 16; a lower upper-bearing three-arch bridge abutment 17; a mid-span arch bridge rib 13; a horizontal anchor cable sleeve 25; a horizontal reinforced concrete grouting pipe sleeve 36; a horizontal reinforced concrete grouting pipe sleeve 37; a horizontal reinforced concrete grouting pipe sleeve 38; a horizontal reinforced concrete grouting pipe sleeve 39; a horizontal reinforced concrete grouting pipe sleeve 40; a horizontal reinforced concrete grouting pipe sleeve 41; a horizontal reinforced concrete grouting pipe sleeve 42; a horizontal reinforced concrete grouting pipe sleeve 43; a horizontal reinforced concrete grouting pipe sleeve 44; a horizontal reinforced concrete grouting pipe sleeve 45; a horizontal reinforced concrete grouting pipe sleeve 46; a horizontal reinforced concrete grouting pipe sleeve 47; a horizontal reinforced concrete grouting pipe sleeve 48; a horizontal reinforced concrete grouting pipe sleeve 49; a horizontal reinforced concrete The supported bridge deck structure 19; the oblique anchor cable sleeve 20; the reinforced concrete grouting pipe structure 21; the oblique prestressed anchor cable 22; the three-arch bridge deck structure below 23; the transverse prestressed reinforcement layer 24; the reinforced concrete grouting water-stop barrier 25; the transverse anchor cable 26; the vertical anchor cable and the reinforced concrete grouting mixed barrier 28; the pile foundation below the middle pedestal 29; the pile foundation below the side pedestal of the opening 30; the middle vertical anchor cable and the reinforced concrete grouting mixed barrier 31; the soil reinforcement in front of the entrance and exit side portal 32; and the soil reinforcement in front of the station side portal 33 and the continuous beam bridge box girder 34.

[0050] like Figure 2 It is the "main view of the reinforcement structure above the excavation face opening" with two identical structures at both ends of the highway tunnel. Both ends are "mid-span arch bridges" above, and directly below the main span of the "mid-span arch bridge" (about 1.5 meters above the top of the highway tunnel excavation), three-arch "upper-bearing arch bridge". In addition to its own suspenders, the arch ribs of the upper mid-span main span cleverly pass through the sleeves through the mid-span "bridge deck" and the "bridge deck" of the upper three-arch bridge. In addition to the support of the three arch ribs and pile foundation below, the lower bridge deck also has the tension of the upper mid-span arch ribs, which plays a double role of protection.

[0051] Combination Figure 2 , Figure 3-1 , Figure 3-2 , Figure 4 as well as Figure 5 illustrate:

[0052] Combination Figure 1 To explain: First, fence off the construction site to be constructed, conduct pipeline surveys on the two ends MN and GH of the station and the entrance and exit, and above the dark-cut tunnels through which they pass, so as to prepare for the subsequent installation of anchor cables and grouting interlayers between the two ends and the excavated tunnels. Avoid existing pipelines below as much as possible, and relocate pipelines in advance in case a small number of them cannot be avoided. Reinforce the soil in front of the opening above the excavated street tunnel, from the ground down to 2 meters below the lower pedestal, 2 meters wide to the outside of the lower pedestal, 2 meters wide to the outside of the upper pedestal, and 2 meters deep to the same pedestal. Use three-axis concrete mixing to mix the soil, and the strength must meet the requirements of self-stabilization of the soil for pedestal construction and excavation construction before excavation can begin. Figure 1 33 on the station side and 32 on the entrance and exit side.

[0053] according to Figure 2 For highway structures, select the elevation position of the transverse anchor cable and the concrete reinforcement grouting interlayer 7 above the anchor cable and the position of the tension anchor cable 8, and then determine the elevation of the reinforced concrete pile foundation casting below the mid-bearing pier of the station and entrance and exit junction enclosure structure. In addition, a certain number of pile foundations 10 are added at the pier position to meet the needs of pier construction. Similarly, it is determined that the pile foundations of the four piers of the three-hole upper bearing type below are also increased. The required pile foundations are added on the outside of the enclosure structure, and the pile foundations are arranged in parallel with the pile foundations of the enclosure structure, making full use of the existing pile foundations of the enclosure structure and reducing construction costs. When constructing the pile foundation, a vertical hanger 6 with a sleeve is pre-inserted during the pouring of the pile foundation in the upper mid-bearing main span. The bottom of the hanger 6 is sealed to prevent concrete from being introduced into the sleeve, corresponding to the cross support 4 of the mid-bearing arch bridge. A part of the hanger 5 is connected to the upper "bridge deck", and a part of the hanger 6 is connected to the lower "bridge deck". The hanger 6 with a sleeve is pre-buried in the pile foundation in advance when constructing the pile foundation of the maintenance structure. The pile foundation construction of the station enclosure structure is completed, and the top floating concrete is removed to allow the anchor cable to be inserted. When constructing the upper mid-span arch bridge abutment 9 and the side span arch rib 16, the upper mid-span arch rib foot is pre-embedded. When the arch foot passes through the crown beam upward, it is tied together with the crown beam steel bar. The steel bar of the mid-span bridge deck 19 is tied together with the exposed steel bar after the concrete is removed from the pile foundation. At the same time, the horizontal anchor cable sleeve 2 is pre-embedded, as well as the oblique steel sleeve 14 on the opposite side, and the sleeves of the reserved hanger 6 for the pouring pile foundation are pre-embedded, and the 5 sets of the mid-span hanger are pre-embedded. After checking the horizontal, oblique sleeves and vertical hangers and the reserved hanger 6 with sleeves, the steel bars at the crown beam are tied and the crown beam is poured. The arch rib 1 of the arch bridge above the bridge deck is constructed through the mid-span arch rib of the crown beam. The left and right sides of the arch rib are connected with the cross support 4. The reserved hanger 6 and the mid-span arch bridge hanger 5 inserted into the crown beam sleeve are connected with the upper arch rib. A steel plate pad is added above the arch rib at the connection to prepare for the subsequent tensioning of the hanger.

[0054] When excavation reaches the position of the three-hole upper-bearing arch bridge below, the part from the connecting beam 23 (i.e., the bridge deck) to the pier position of the lower structure of the bridge is broken, and the pile foundation concrete at this position is broken. The concrete strength of the pile foundation at this position is checked to see if the concrete strength of the upper bridge deck 19 reaches the design value, and whether the hanger 5 between the upper bridge deck 19 and the arch rib 1 is effectively connected and tensioned, because the breaking process of the lower pile foundation connected to it requires that the upper bridge deck 19 has sufficient tension on the lower pile foundation, and at the same time, the soil at the soil position facing the soil surface on the outside of the pile foundation should be checked. Advance small pipe grouting, grouting reinforcement of the exposed surface is performed according to the soil position and soil stability to ensure the stability of the soil after the pile foundation is broken. According to the self-stabilization of the soil, consider conducting advance small pipe grouting above the excavation surface (the upper arc-shaped small "small pipe shed"), "small pipe shed", or using the retained pile foundation steel bars to increase the steel bars. The left and right sides of the upper "small semi-arc-shaped tunnel ring beam" are respectively set on the pile foundation of the outer retaining structure of the pedestal on the left and right sides of the tunnel opening, with a width greater than the width of the bridge deck below. At the same time, the sleeve is used to allow the hanger 6 to pass through the upper reinforcement layer. In short, by breaking the pile foundation from above, not only the safety of the upper pile foundation is guaranteed, but also the upper safety structure is constructed by breaking the pile foundation steel bars to ensure the safety of the construction below the bridge deck. Figure 1 Before excavation, the soil reinforcement in front of the tunnel gate on the middle entrance and exit side 32 and the soil reinforcement in front of the tunnel gate on the station side 33 must be carried out with three-axis mixing pile soil reinforcement in front of the tunnel gate. The reinforcement range and depth are described in the "Earthwork Excavation" section. Ensure that the pile foundation section is self-stabilized and safe after the concrete is removed.

[0055] After the pile foundation at the upper-supported arch bridge position below is broken, the hanger 6 inserted during the pile foundation construction is exposed through the sleeve through the upper reinforcement. The hanger 6 is effectively tied with the steel bars for the construction of piers, arch ribs and the three-arch bridge deck structure 23 below, as well as the steel cage steel bars after the concrete is broken, and exposed below the three-arch bridge deck structure. Clear the concrete from the closed grouting pipe on the other side, including the sleeve with anchor cable on this side through the inclined sleeve 14 from the upper supported arch bridge on the opposite side, including the inclined sleeve bundled from the upper side of the opposite side. These sleeves with anchor cables (due to the distance, the slope is slightly deviated, passing through the back side of the lower bridge deck 23, and receiving the inclined steel sleeve 15 below; including the closed grouting pipe at the anchor cable 12, the reinforced concrete soil barrier 11 on the opposite side, after overlapping with the barrier on this side, break the concrete in the reinforced concrete at the overlapping part, leaving the steel bars tied with the steel bars on this side, check the grouting pipes at the same position on the opposite side, and the steel bars after the concrete barrier and the corresponding components on this side. Whether the prestressed end seal is intact, if there is damage, the sleeve needs to be supplemented to penetrate the corresponding component for subsequent tensioning.

[0056] During the construction of the connecting beam part 23, in order to reduce the elevation excavation surface of the lower deck three-arch bridge, the lower arch rib and the connecting beam (bridge deck) are partially overlapped; or Figure 3-1 The medium continuous beam bridge replaces the "three-arch arch bridge" in the figure. The continuous beam bridge has a shorter elevation and reduces the need to destroy the pile foundation of the retaining structure.

[0057] like Figure 3-1 As shown in the figure, the elevation view of the station side reinforcement structure; there is a mid-through arch bridge above the station side where construction begins, and no pier is set in the middle of the excavation surface below. Figure 3-2 As shown, the elevation view of the reinforced structure on the entrance and exit side; no mid-bearing arch bridge is used on the upper side of the corresponding receiving side, and no cap and supporting pile foundation are set in the middle of the lower excavation surface; and Figure 3-1 The station and the entrance and exit are constructed correspondingly; the upper and lower parts are superimposed with single-hole double-cantilever beam bridges, with additional bearings 35; main arch legs 36, columns 37; bridgehead slabs 38; no abutments are set on the bridgehead slabs 38 at both ends of the bridgehead, and only slabs 38 are set on the upper part, and the concrete is broken and the steel bars are connected and cast after the top of the pile foundation is removed; the lower slabs 38 are also connected and cast after the concrete is broken through the steel cage.

[0058] When the station and the entrance and exit are respectively making the pile foundation of the retaining structure, the position and elevation of the upper mid-bearing bridge deck 19 are taken into consideration, and the suspender 6 is arranged from the upper arch rib 1 to the lower bridge deck position when necessary. When constructing the upper mid-bearing supply bridge upper structure, priority is given to constructing from the station side of the main structure first, and the horizontal anchor cable sleeve 2 and the horizontal grouting pipe sleeve 3 are pre-installed in the interlayer 7 and the anchor cable reinforcement layer 8 of the bridge deck 19 on the station side. The anchor cable and the grouting pipe are horizontally applied in the horizontal anchor cable sleeve 2 and the horizontal grouting pipe sleeve 3 from the station side, and then the anchor cable and the grouting pipe are applied by the other party from the entrance and exit side. The anchor cable and the concrete grouting pipe are broken at the exit side, and the remaining grouting steel bar is effectively connected with the receiving side's entrance and exit inverted bridge deck steel bar, and the receiving anchor cable is connected with the entrance and exit side bridge deck steel bar with the horizontal anchor cable sleeve 2, and the sleeve extends out about 40cm for later tensioning. Similarly, the anchor cables and grouting pipes from the bridge deck below the station side are constructed in the same way as from the bridge deck above the station to the bridge deck at the opposite entrance and exit. When the large anchor cables are obliquely applied from the bridge deck above the station to the bridge deck below the opposite entrance and exit, the oblique sleeves are also pre-buried. In particular, the slope should be calculated according to the distance and elevation between the upper and lower bridge decks, and the navigation impact drill should be used. Note that the tensioning of the anchor cables in the crown beam of the reinforcement layer should not be carried out until the concrete strength in the interlayer grouting reinforced concrete layer meets the tensioning conditions, including the concrete "interlayer" of the vertical anchor cables and the grouting reinforced cage concrete. It is necessary to wait until the strength of the grouting concrete meets the tensioning conditions before tensioning all the horizontal, vertical and oblique anchor cables can be tensioned. After tensioning, when the construction reaches the lower bridge deck 23, the concrete around the sleeve hanger sealed at the lower bridge deck in the pre-buried pile foundation reinforcement cage needs to be broken to allow the sleeve hanger to pass through the lower bridge deck or the lower bridge deck structure. After the various parts of the upper and lower bridges on the station side and the entrances and exits are completed, including the vertical string rods and hangers, from the upper arch rib to the upper bridge deck and to the lower bridge deck or under the lower arch rib, all the horizontal and vertical anchor cables are tensioned and then grouting is injected into the anchor cable sleeve.

[0059] After the completion of the various parts of the upper and lower bridges on the station side and the entrance and exit, including all the transverse bridge decks and the bridge decks of the connecting beams, the reinforced concrete interlayer grouting is first carried out, and the anchor cables are tensioned after the strength reaches the required level. After tensioning, the anchor cable outer sleeve is grouted. The vertical string rods and hangers are completed from the upper arch rib to the upper bridge deck and to the lower bridge deck or under the lower arch rib. The vertical anchor cables and reinforced concrete mixed interlayer form a "double-side guide pit excavation interface" with the upper bridge deck.

[0060] Figure 4 It is the top view of the horizontal anchor reinforcement layer and the main view Figure 2 , Figure 3-1 , Figure 3-2 The soil reinforcement 8 in front of the station side tunnel door or the tension anchor cable layer 12 below is Figure 7 The upper tensioned anchor cable layer 8 or the lower tensioned anchor cable layer 12 in the cross-sectional view, the transverse prestressed reinforcement layer 24; the horizontal anchor cable reinforcement layer; Figure 5 It is a top view of the reinforced concrete interlayer and a main view. Figure 2 , Figure 3-1 , Figure 3-2 The inner reinforced concrete interlayer 7 or the reinforced concrete interlayer 11 is Figure 7 The horizontal reinforced concrete grouting water-stopping barrier 25 in the cross-section diagram; the horizontal reinforced concrete barrier is above the horizontal anchor cable reinforcement layer, and the reinforced concrete barrier 7 mainly evenly supports the road cushion layer, so that the anchor cable layer 8 can be fully stressed. The horizontal reinforced concrete barrier 11 is above the horizontal anchor cable reinforcement layer 12, and the reinforced concrete barrier 11 mainly prevents water and sand gushing from the barrier layer, so that the anchor cable layer 12 can be fully stressed (evenly distributed).

[0061] Figure 6 It is the oblique anchor cable tensioning between the upper upper-supported arch bridge deck 19 and the lower bridge deck 23 on the opposite side. Before constructing the upper bridge deck 19, use the guide drilling equipment to drill holes in the lower bridge deck 23 on the opposite side, taking into full consideration that the length of the receiving side is not less than the tensioning length. The distance from the two bridge decks, calculate the slope and guide the drilling to the lower bridge deck on the opposite side. Note that the anchor cable is with a closed sleeve. The starting station with a sleeve anchor cable and the upper bridge deck are laid through the sleeve 14 and the upper bridge deck. The receiving side is constructed to the lower bridge deck 23 for laying, and the strength of the upper and lower bridge decks meets the tensioning strength, while taking into account the concrete strength of the water surface to the reinforced concrete interlayer to meet the tensioning strength. According to the geological conditions, generally only three thicker oblique anchor cables are needed to be laid. If the geological conditions are well developed, the oblique anchor cables can be reduced as appropriate.

[0062] other Figure 4 , Figure 5 A full row of casing anchor cables and reinforced concrete barriers must be laid. Figure 4 The size and spacing of anchor cables must also take into account road loads and other deadweight loads. Figure 5It is also necessary to consider the soil structure of the tunnel and the leakage of the soil layer beside the tunnel. The reinforced concrete structure interlayer 7 of the upper bridge deck is mainly used to fully stress the anchor cable below and completely support the ground cushion layer. The sand layer with poor geological conditions and easy leakage is increased in the reinforced concrete water-stop curtain interlayer 11 in the lower bridge deck 23. The grouting pipe layers are arranged in a plum blossom shape, and the grouting pipes are constructed as continuously as possible. The purpose is to form an overall water-stop interlayer between the upper grouting pipes.

[0063] All kinds of transverse, oblique anchor cables and transverse reinforced concrete grouting pipes are first laid out on the starting side of construction using guide holes so that the retained anchor cables with casings are laid out together with the horizontal sleeve 2 and the exposed grouting pipe steel bars and the bridge deck steel bars at the starting end. The receiving side accepts the anchor cables with casings and the exposed steel bars in the reinforced concrete are removed together with the receiving side bridge deck to form a closed water-stopping effect.

[0064] The deck structure 19 of a mid-span arch bridge is the upper part of the "bridge deck", that is, the reinforced concrete interlayer 7 or the reinforced concrete interlayer 11 (a combination of the reinforced concrete interlayer 7 and the upper tensioned anchor cable layer 8) in the main view of the reinforced concrete interlayer; the lower three-arch deck structure 23 is the lower anchor cable reinforcement layer of the "bridge deck", the upper tensioned anchor cable layer 8 or the lower tensioned anchor cable layer 12 (a combination of the reinforced concrete interlayer 11 and the lower tensioned anchor cable layer 12) in the main view; the oblique anchor cable corrugated pipe 20 is the oblique prestressed anchor cable (referring to the anchor cable of the lower bridge deck 23 obliquely extending from the upper bridge deck of the station through the sleeve 14 to the opposite entrance and exit); the transverse reinforcement is through the transverse prestressed reinforcement layer 8, the reinforced concrete grouting water-stop interlayer 7, the transverse steel casing 2 and the transverse anchor cable 26.

[0065] The three arch bridges below are 1.3 meters higher than the top of the tunnel excavation, and the vertical interlayers on the left and right sides are also 1.3 meters outward, which is convenient for the construction of the small guide tube and the tunnel steel arch frame during tunnel excavation. The "double side wall pilot pit excavation method" can be used for excavation: the left and right sides are excavated separately, and the upper step excavation and the lower step excavation are carried out in the middle. The four steel arch frames are only constructed when the steel arch frame and the invert pass through the vertical anchor cable and the reinforced concrete grouting mixed interlayer 28, and the interlayer concrete is broken to avoid the grouting anchor cable as much as possible. According to the geological conditions and the reinforcement effect of the horizontal and vertical concrete interlayers, the waterproof invert is backfilled and the secondary lining is carried out to realize the transformation from temporary reinforcement to permanent reinforcement of the tunnel steel arch frame with the advance anchor secondary lining. After the tunnel is connected, the upper arch rib temporarily exposed on the ground can be cut off and reused next time. The pile foundation 29 and vertical anchor cables and the middle side vertical anchor cables and reinforced concrete grouting mixed interlayer 31 of the lower three-arch bridge and the lower middle pier can be removed to facilitate tunnel excavation and passage and complete the temporary reinforcement task. The pile foundation 30 and the vertical anchor cables and reinforced concrete mixed interlayer 28 under the left and right piers are retained. The reinforced concrete mixed interlayer 28 resists the lateral pressure of the tunnel side wall and prevents leakage of the side wall. The pile foundation 30 under the left and right piers is retained to support the three-arch bridge or continuous beam ((single-hole double cantilever beam bridge). Because the tunnel construction is completed through the arch frame of the street tunnel, the main support has been converted to the steel arch frame structure and the secondary lining structure of the street tunnel structure system as the main support. The pile foundations and vertical anchor cables and reinforced concrete mixed structure under the left and right piers are retained. The vertical anchor cables and reinforced concrete mixed reinforcement layer 28 are used to support auxiliary reinforcement support and strengthen the anti-seepage effect of the side wall.

[0066] In the utility model, there are two prestressed tensioned "bridges" below the "street tunnel". The prestressed tensioning points act on the four arch bridge deck structures at the entrance of the "street tunnel". The two upper mid-bearing arch ribs mainly bear the downward gravity decomposed by the tensioning force through the hangers. In addition, the width of the upper bridge deck is increased to the outside to resist the partial tensioning "negative bending moment" to resist the tensioning force. The arch ribs transmit the pile foundation below through the pedestal. The "bridge deck pavement" is a reinforced concrete structure. Another part of the hangers of the arch ribs of the mid-bearing arch bridge are consolidated with the three arch bridge decks below, and also bear the downward gravity decomposed by the tensioning force of the lower bridge deck. At the same time, the three arches support the upper part of the lower bridge deck through the pedestal pile foundation. In addition, the reinforced concrete immediately above reaches the strength and then tensions, which can also resist part of the tensioning force. The width of the lower bridge deck is appropriately increased, which is also used to resist the partial tensioning "negative bending moment" to resist the tensioning force.

[0067] The utility model has two horizontal tensioned reinforcement "bridges" upward and downward. Together with the station and the entrance and exit, the double "triangle" is formed by the tension of the upper and lower cross anchor cables. The road vehicles travel longitudinally above the "stable triangle" reinforcement. All loads are decomposed from the horizontal tension force into gravity acting on the pile foundation through the reinforcement structure of the utility model, which ingeniously and perfectly completes the reinforcement before excavation.

[0068] Quality and safety guarantee of this reinforcement method: The biggest risk in tunnel excavation is the risk of water and sand gushing. The utility model has done a very good job in addressing the risk of water and sand gushing. This is particularly evident in that two layers of "reinforced concrete water-stop curtain official interlayers" have been laid above the excavation before excavation. It also highlights the vertical water-stop curtain interlayers mixed with four vertical anchor cables and reinforced concrete interlayers, and separates the excavation interface into a "double-side wall pilot pit method" to increase safety. Form an upper and left closed safe working interface. Nevertheless, for greater safety and infallibility, it is recommended to have a quick rescue grouting material on standby during the excavation process, and use "non-water-reactive polymer materials" (a mixture of cyanate and polyols, which can be proportioned according to strength requirements) for quick rescue water-stop reinforcement.

[0069] 1. Drill holes for film bag placement. Drill holes for film bag placement at a spacing of 0.3-0.4m. The hole diameter is about 5-12cm and the hole depth is about 20-40cm. 2. Place the film bag: Put the grouting pipe into the open end of the film bag and fix the open end of the film bag on the grouting pipe with a hoop. The length of the film bag should be greater than the hole depth. Generally, the diameter is 10-40cm and the length is 30-60cm. Put the bundled film bag into the hole. 3. Inject polymer material into the membrane bag: inject two-component expansive polymer material into each membrane bag in turn through the grouting pipe. The polymer material first reacts in a gelatinous state and then solidifies quickly. The curing strength is adjusted according to the ratio of the two-component expansive polymer material as needed. In order to achieve basic stability of the face, a grouting material with a strength of 1-3MaP after curing of the two-component expansive polymer material is selected. Let the grouting wrap around the face, and let the two-component expansive polymer grouting material with a strength of 1-3MaP seal the leakage point, and perform reverse high-pressure grouting. Meet the reinforcement needs for sufficient sudden dangerous situations. Be foolproof, escort this reinforcement structure and reinforcement method, and be more conducive to the safer promotion of the utility model.

[0070] The above is only an explanation of the preferred embodiments of the present invention. The above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0071] The utility model is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the utility model is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the utility model, or the concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. A tunnel reinforcement structure under a street road, the reinforcement structure is located under the street road, and is characterized by: The reinforcement structure includes an upper supporting bridge structure arranged near the cushion layer of the overpass and a lower supporting bridge structure located above the excavated tunnel. The lower supporting bridge structure is located directly below the upper supporting bridge structure, and there is a distance between the upper supporting bridge structure and the lower supporting bridge structure.

2. The tunnel reinforcement structure under the street crossing highway as claimed in claim 1, characterized in that: The lower supporting bridge structure is located 1.0-1.5 m above the excavated tunnel.

3. The tunnel reinforcement structure under the street crossing road as claimed in claim 1, characterized in that: There is soil between the upper supporting bridge structure and the lower supporting bridge structure.

4. The tunnel reinforcement structure under the street crossing road as claimed in claim 1, characterized in that: The upper supporting bridge structure and the lower supporting bridge structure are tensioned and consolidated with two bridge decks above and below the subway station and the tunnel excavation of the station entrance and exit through anchor cables.

5. The tunnel reinforcement structure under the street crossing road as claimed in claim 1, characterized in that: The arch rib of the upper supporting bridge structure and the lower supporting bridge deck structure of the lower supporting bridge structure are connected via a portion of hangers.

6. The tunnel reinforcement structure under the street crossing road as claimed in claim 1, characterized in that: The upper supporting bridge structure is a single-span mid-bearing arch bridge structure, and the lower supporting bridge structure is a three-span top-bearing arch bridge structure.

7. The tunnel reinforcement structure under the street crossing road as claimed in claim 6, characterized in that: The single-span half-through arch bridge structure comprises an arch rib and a bridge deck, and the arch rib and the bridge deck are connected via a half-through arch bridge hanger.

8. The tunnel reinforcement structure under the street crossing road as claimed in claim 6, characterized in that: The three-hole top-supported arch bridge structure is arranged on the reinforced concrete pile foundation of the tunnel. The pile foundation uses the pile foundation of the station and entrance and exit retaining structure, and pile foundations are added on the outside of the retaining structure. A pedestal is provided on the top of the pile foundation. The upper mid-supported arch bridge has two pedestals, and the lower top-supported arch bridge has four pedestals. The gaps in the pile foundations under the four pedestals are used to apply a mixture of vertical anchor cables and steel grouting.

9. The tunnel reinforcement structure under the street crossing road as claimed in claim 7, characterized in that: When constructing the upper pier of the mid-span arch bridge structure, the upper mid-span arch rib foot is pre-embedded, and when the arch foot passes upward through the crown beam of the bridge deck, it is tied together with the crown beam steel bars, and the crown beam steel bars are tied together with the exposed steel bars after the concrete of the pile foundation is broken. At the same time, transverse anchor cable sleeves and reinforced concrete grouting pipe sleeves and obliquely opposite lower bridge deck anchor cables are pre-embedded, as well as reserved hanger sleeves for the poured pile foundation, and mid-span hanger sleeves are pre-embedded.

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