Tunnel underground excavation reinforcing structure

Abstract

The utility model discloses a tunnel underground excavation reinforcing structure which comprises retaining structure pile foundations on the two sides, a pair of bearing platform structures and a pile foundation below a bearing platform arranged below the bearing platform structures, the retaining structure pile foundations are located on the outer side of the pile foundation below the bearing platform, and bridge end butt straps are arranged on the tops of the retaining structure pile foundations on the two sides. An arc-shaped pipe shed structure is arranged on the bridge end butt strap, a reinforcing layer structure is arranged between the bridge end butt straps on the two sides, and a cantilever bridge structure is arranged between the bearing platform structure and the reinforcing layer structure. The tunnel subsurface excavation reinforcing structure is reasonable in design, is supported by the vertically associated reinforcing structures and the arched cantilever bridge, is stable and reliable in reinforcement, can effectively control settlement, fully utilizes the existing main body and enclosure structure pile foundations, and is simple and convenient to construct and relatively low in construction cost.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel construction, in particular to a tunnel dark excavation reinforcement structure and an assembled construction after the reinforcement excavation. 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 fenced off and the roadside must be closed to relieve traffic. This is especially true 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 occupancy times.

[0003] Due to the influence of geology, tunnel excavation needs to be reinforced by reinforcement structures to control settlement; for example, when excavating a tunnel in a water-rich sandstone layer, 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 installed in the soil between the existing building and the shield tunnel, and the anchor cables are tensioned to the designed strength before the two ends of the anchor cables are fixed On the reinforcement piles, grouting is then 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 highway 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

[0004] In view of the deficiencies in the prior art, the utility model provides a tunnel dark excavation reinforcement structure to achieve the purpose of stable and reliable reinforcement and effective control of settlement.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0006] The tunnel excavation reinforcement structure includes retaining structure pile foundations on both sides, a pair of pedestal structures and pile foundations below the pedestal arranged below the pedestal structure. The retaining structure pile foundations are located on the outside of the pile foundations below the pedestal. Bridge end cladding is provided on the top of the retaining structure pile foundations on both sides, and arc-shaped pipe shed structures are provided on the bridge end cladding. A reinforcement layer structure is provided between the bridge end claddings on both sides, and a cantilever bridge structure is provided between the pedestal structure and the reinforcement layer structure.

[0007] Further:

[0008] The cap foundation structure comprises a cap foundation and a pentagonal pier arranged on the cap. The cantilever bridge box girder structure is tensioned and connected to the pentagonal pier through a main arch leg and a reinforced concrete pre-embedded anchor cable.

[0009] A ground connection wall outside the pedestal is provided between the pile foundation of the enclosure structure and the pile foundation below the pedestal.

[0010] The pile foundation below the pedestal includes a group of pile foundations arranged side by side, and a ground connection wall below the pedestal is arranged in the middle of the group of pile foundations.

[0011] The reinforcement layer structure comprises a reinforced concrete reinforcement layer and an anchor cable reinforcement layer which are connected up and down.

[0012] A connecting beam is provided between the two bridge piers of the pair of pier structures, and a connecting beam transverse anchor cable tensioning structure is provided on the connecting beam.

[0013] The cantilever bridge structure is a single-hole double-cantilever bridge, and the lower part of the single-hole double-cantilever bridge is provided with an arc-shaped grouting interlayer and an arc-shaped anchor cable reinforcement layer.

[0014] A main arch leg anchor cable reinforcement structure is provided in the main arch leg.

[0015] A bridge superstructure is arranged above the reinforced concrete reinforcement layer.

[0016] A group of bridge columns are arranged between the upper structure of the single-span double-cantilever bridge and the main arch leg and the side arch leg.

[0017] Compared with the prior art, the utility model has the following advantages:

[0018] The tunnel's dark excavation reinforcement structure is reasonably designed. Through the upper and lower related reinforcement structures and the arched cantilever bridge support, the reinforcement is stable and reliable, which can effectively control the settlement. It also makes full use of the existing main body and retaining structure pile base connecting wall, the construction is simple and the construction cost is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following is a brief description of the contents and symbols in the drawings of this specification:

[0020] Figure 1-1 This is a schematic diagram of the position relationship between the station and the passage openings on both sides of the entrance and exit of the utility model.

[0021] Figure 1-2 This is a schematic diagram of the location of the underground space within a subway station formed by the highway of the utility model passing through the subway station.

[0022] Figure 2 A schematic diagram of the positions of the protruding retaining structures and reinforced structural components added to the openings on both sides of the tunnel of the utility model.

[0023] Figure 3It is a schematic diagram of the reinforcement structure of the utility model.

[0024] Figure 4 This is a schematic diagram of the box-type structure of the utility model.

[0025] Figure 5 It is a schematic diagram of the arc-shaped anchor cable reinforcement layer of the utility model.

[0026] Figure 6 It is a schematic diagram of the arc-shaped grouting interlayer composed of reinforced concrete of the "lower portal ring beam" on both sides of the tunnel of the utility model.

[0027] Figure 7 This is a rendering of the utility model in which the pipe roof is composed of an arc-shaped pipe roof layer and the advance grouting pipe is composed of an arc-shaped advance grouting layer.

[0028] In the figure:

[0029] 1-main arch leg, 2-anchor cable sleeve, 3-reinforced concrete grouting pipe sleeve, 4-single-hole double cantilever bridge, 5-window hole, 6-bridge column, 7-reinforced concrete reinforcement layer, 8-anchor cable reinforcement layer, 9-structure pile foundation under the slab, 10-bridge end slab, 11-arc grouting interlayer, 12-arc anchor cable reinforcement layer composed of lower anchor cable sleeve, 13-main arch leg anchor cable reinforcement layer, 14-bridge abutment, 15-bridge pier, 16-pile foundation under the abutment, 17-connecting beam between abutments, 18-connecting beam transverse anchor cable tensioning structure, 1 9-bridge deck upper structure, 20-ground connection wall outside the pedestal, 21-ground connection wall with reinforced pile foundation near the tunnel entrance, 22-the upper "partial tunnel gate ring beam" pipe shed forms an arc-shaped pipe shed layer, 23-the upper "partial tunnel gate ring beam" advance grouting pipe forms an arc-shaped advance grouting layer, 24-upper "partial tunnel gate ring beam", 25-pipe shed, 26-advance small guide tube, 27-ground connection wall below the pedestal (for laying vertical anchor cables and grouting pipe sleeves), 28-bridge box girder, 29-lower "partial tunnel gate ring beam"; 30-lower tunnel gate ring beam with corrugated pipe anchor cable;

[0030] 31-side arch leg, 32-connecting beam anchor cable reinforcement layer, 33-connecting beam reinforced concrete reinforcement layer, 34-soil reinforcement from top to bottom in front of the station tunnel end, 35-upper tunnel ring beam anchor cable reinforcement structure, 36-ground diaphragm on the soil side of the protruding part of the station tunnel, 37-ground diaphragm on the soil side of the protruding part of the ground diaphragm, 38-below Figure 2 Display the location of the combined reinforcement structure above the opening;

[0031] 39-enclosing structure of the protruding part of the entrance and exit, 40-soil reinforcement from top to bottom in front of the station tunnel end, 41-vertical steel pipe sleeve in the box structure of the ground-connected wall, 42-box structure, 43-main reinforcement of the entrance and exit ground-connected wall 37; 44-anchor sleeves reserved for assembled side walls; 45-anchor sleeves reserved for assembled top plates. DETAILED DESCRIPTION

[0032] 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.

[0033] like Figures 1-1 to 7 As shown, the tunnel excavation reinforcement structure includes structural pile foundations 9 under the slabs on both sides, a pair of pedestal structures and pile foundations 16 under the pedestal arranged under the pedestal structure; the pile foundations of the retaining structure are located on the outside of the pile foundations under the pedestal, and bridge end slabs 10 are provided on the tops of the structural pile foundations 9 under the slabs on both sides, and arc-shaped pipe shed structures are provided on the bridge end slabs, and a reinforcement layer structure 19 is provided between the bridge end slabs on both sides, and bridge piers and a cantilever bridge superstructure are provided between the pedestal structures and the reinforcement layer structures.

[0034] The abutment structure includes a bridge abutment 14 and a bridge pier 15 arranged above the bridge abutment. A pair of bridge piers are arranged opposite to each other, and the cantilever bridge structure is connected to the bridge piers through the main arch leg (side arch leg). The cantilever bridge structure is a single-hole double-cantilever bridge 4, and the lower part of the single-hole double-cantilever bridge is provided with an arc-shaped grouting interlayer 11 and an arc-shaped anchor cable reinforcement type reinforcement layer.

[0035] The bridge end slab 10 is arranged on the top of the added pile foundation 9; the arc-shaped pipe shed structure includes the upper "partial tunnel ring beam" pipe shed to form an arc-shaped pipe shed layer 22, the upper "partial tunnel ring beam" advance grouting pipe to form an arc-shaped advance grouting layer 23, the upper "partial tunnel ring beam" 24, the pipe shed 25 and the advance small guide tube 26; the arc-shaped pipe shed structure is located at the top of the entire reinforced structure.

[0036] An outer ground-connected wall 20 is provided between the pile foundation below the bridge deck and the reinforced pile foundation 21; an anchor cable sleeve 2 and a reinforced concrete grouting pipe sleeve 3 are provided in the outer ground-connected wall 20 of the pedestal, and the anchor cable and reinforced concrete composite structure are used for reinforcement; a ground-connected wall is provided between the outer ground-connected wall of the pedestal and the pile foundation 16 below the pedestal, and a pile foundation 21 is provided near the opening on the side of the opening; the reinforced pile foundation 21 mainly prevents the vertical inward soil pressure in the ground-connected wall 20, and the pile foundation below the pedestal includes a group of pile foundations arranged side by side, and a ground-connected wall 27 below the pedestal is provided in one group of pile foundations, and an anchor cable sleeve 2 and a reinforced concrete grouting pipe sleeve 3 are provided in the ground-connected wall 27, and a vertical anchor cable and reinforced concrete composite reinforcement layer is formed by anchor cable tensioning and grouting of the grouting pipe sleeve 3 provided in the double-sided ground-connected walls 27, and the structure is stable and reliable.

[0037] A connecting beam 17 is provided between two bridge caps of a pair of cap structures, and a connecting beam transverse anchor cable tensioning structure 18 is provided on the connecting beam. Preferably, the connecting beam is arranged between a pair of bridge caps 14, and an anchor cable sleeve and a reinforced concrete grouting pipe sleeve are provided in the connecting beam, and the anchor cable and reinforced concrete composite structure are used for reinforcement.

[0038] A main arch leg anchor cable reinforcement structure is provided in the main arch leg 1, and a group of bridge columns 6 are provided between the upper structure of the single-span double-cantilever bridge and the main arch leg. The columns at the hollow position of the bridge support the upper box girder through the piers and the tensioned main and side arch legs, and a corresponding bridge box girder 28 is provided, and its structure is stable and reliable; the lower part of the single-span double-cantilever bridge is the lower "partial tunnel ring beam" 29, the middle position of the upper part is the main arch leg anchor cable reinforcement layer 13, and the upper part of the lower "partial tunnel ring beam" 29 is the lower anchor cable sleeve that constitutes a circular arc anchor cable reinforcement type reinforcement layer 12, and the corresponding reinforcement type reinforcement layer is provided with anchor cable sleeves and reinforced concrete grouting pipe sleeves, which are reinforced by the combined structure of anchor cables and reinforced concrete.

[0039] The upper reinforcement layer structure of the single-span double-cantilever bridge includes a reinforced concrete reinforcement layer 7 and an anchor reinforcement layer 8 which are connected in upper and lower connection; a bridge superstructure 19 is arranged above the reinforced concrete reinforcement layer, and in order to explain the bridge superstructure 19 separately, the anchor reinforcement layer and the reinforced concrete interlayer are collectively referred to; and a window hole 5 is arranged in the anchor reinforcement layer, and the window hole 5 is arranged in the box beam layer, and the space in the hole is used to anchor the main arch leg and the side arch leg to the box beam respectively.

[0040] The utility model has low construction cost, safe construction and firm reinforcement; construction safety: the whole Figure 4 Construction (reinforcement structure) is carried out after the upper "tunnel ring beam" is completed, and the entire station side on the departure side Figure 4 The overall reinforcement above the tunnel entrance is "protected" on the outside by the retaining structure of the soil-facing side 36 and the protruding parts on the left and right sides; the construction is safer and the reinforcement is firm: the combined structure on the tunnel entrance side: multiple groups of "triangle" and "inverted triangle" combinations of rigid reinforcement are cleverly combined together through anchor cables to form a solid rigid reinforcement, multi-layer anchor cables and reinforced concrete reinforcement layers, which provide sufficient guarantee for the passage of the entire double-sided rigid reinforcement.

[0041] The utility model has a reasonable design for the tunnel excavation reinforcement structure. Through the upper and lower related reinforcement structures and the arched cantilever bridge support, the reinforcement is stable and reliable, settlement can be effectively controlled, and the existing main body and surrounding structure pile foundations are fully utilized. The construction is simple and the construction cost is relatively low.

[0042] The preferred specific examples of the present utility model are:

[0043] The tunnel dark excavation reinforcement structure includes a part of the retaining structure space protruding outward from the retaining structures on both sides. It is safer to construct a new type of reinforced composite structure of the tunnel entrance within the protruding retaining structure space: the reinforcement structure includes a single-hole double-cantilever bridge-type structure of the rigid reinforcement structure at the end of the tunnel entrance, and the single-hole double-cantilever bridge-type structure includes: abutments and tensioning structure connecting beams, the tensioning structure connecting beams and the portal ring beam below the tensioning structure are tensioned and connected between the abutments and the bridge piers to form a closed "triangle-like" stable "reinforcement structure", the bridge piers and the bridge box girders are tensioned through the main arch legs and side arch legs to form two "inverted triangle" hollow single-hole double-cantilever bridge-type structure bridges, the columns at the hollow position of the bridge support the upper box girder through the supports and the main and side arch legs after tensioning, and the upper support of the bridge box girder is the "rigid reinforcement structure" of the bridge type above the tunnel excavation, namely the anchor cable reinforcement structure layer and the "bridge deck system", namely the reinforced concrete reinforcement structure layer. The box girder of the single-span double-cantilever bridge is firmly connected to the steel bars of the upper reinforcement layer (anchor cable reinforcement layer) to form the upper bridge deck structure of the single-span double-cantilever bridge.

[0044] First, construct the "portal ring beam structure" above the single-hole double-cantilever bridge to ensure the safety of the construction below. At the same time, add a "combined structure" with a part of the protruding retaining structure facing the soil side of the ground-connected wall pipe shed and grouting pipes. Transfer the pile foundation below the slab through the end slab, and it is safer to drill and remove the ground-connected wall below. Strengthen the "single-hole" position below the structural bridge and add a lower "partial portal ring beam". On the one hand, it supports the mid-span of the single-hole cantilever bridge. On the other hand, the lower "partial portal ring beam" is used to reinforce the "arched" anchor cable layer and reinforced concrete layer of the tunnel. Figure 4 , Figure 5 This reinforcement structure forms a horizontal connecting beam and a double-layer anchor cable and reinforced concrete composite structure for the upper bridge deck reinforcement, and a "lower portal ring beam" and "arch-shaped" anchor cable and reinforced concrete composite reinforcement layer below, and two groups of ground-connected wall anchor cables and concrete grouting composite reinforcement layers on both sides of the vertical opening.

[0045] In short, this reinforcement structure consists of two (three) layers of closed reinforcement structures: the connecting beam between the two piers and the ground-connected wall below the pier are constructed through anchor cables and concrete interlayers on both sides of the tunnel to form the first (rigid) reinforcement and water and sand gushing barrier reinforcement structure; the lower "lower portal ring beam and the ground-connected walls on the left and right sides below the pier are constructed through anchor cables and concrete interlayers on both sides of the tunnel to form the first (second) reinforcement and water and sand gushing barrier reinforcement structure"; the upper single-hole double-cantilever bridge, the bridge deck anchor cables and reinforced concrete mixed reinforcement layer above the bridge and the ground-connected walls on the left and right sides of the pier are constructed through anchor cables and concrete interlayers on both sides of the tunnel to form the second (third) reinforcement and water and sand gushing barrier reinforcement structure.

[0046] like Figure 1-1As shown, traffic will be relieved at stations and entrances and exits, including fencing construction at the entrance and exit working surfaces, finding out the distribution of underground pipelines, and relocating pipelines within the reinforcement range of entrances and exits. For entrance and exit pile foundation retaining structures that run through the highway, a portion of the space must protrude outward, and the width and length of the space must meet the width and length of the bridge structure supporting the opening.

[0047] like Figure 1-2 As shown, the dark-cut tunnel that needs to be excavated may also be under the highway across the station. The subway station has a large space and there is no shield and jacking work surface equipment large enough to solve the problem of dark-cut tunnels under the highway. On the other hand, the highway does not allow long-term occupation of the road. For the excavation of the subway station, this new type of reinforcement will come into being. After the successful reinforcement of this new type, excavation is carried out. Although the dark excavation is carried out after reinforcement, the station space is large, and the excavator can still carry out normal excavation, and the excavation can be carried out through the two ends of the station. After the excavation is completed, the standard section of the station (between AB and CD) is assembled. The station prefabricated components can be hoisted under the station through the station end well AB or CD end, and the prefabricated subway prefabricated components are pushed into the station "standard section" (between AB and CD) after the reinforcement excavation is completed.

[0048] Construction description: The station and the entrance and exit are built with the protruding part of the enclosure structure. The protruding part of the station entrance faces the soil surface 36 ground-connected wall, and the protruding part of the entrance has the side enclosure structure 39. The pile foundation 9 under the slab is close to the side enclosure structure 39. The inner side of the hole of the sheet-pile combination foundation is the ground-connected wall 20, and the inner side of the ground-connected wall 20 is the reinforced pile foundation 21. The protruding part of the entrance and exit faces the soil surface ground-connected wall 37. The elevation of the pile foundation 9 under the slab, the ground-connected wall 20 and the reinforced pile foundation 21 is the same as the bottom of the upper bridge deck. The ground-connected wall 20 is arranged as follows: Figure 2 The anchor cable and grouting pipe sleeve shown in the figure have the anchor cable sleeve close to the inner side of the hole and the grouting pipe sleeve arranged on the outer side in a plum blossom shape.

[0049] 38 is the location of the reinforcement structure of the tunnel bridge on the station side; 34-type soil reinforcement in front of the tunnel on the station side; 35-soil reinforcement in front of the tunnel on the entrance and exit side 40; the ground-connected wall 36 on the station side and the ground-connected wall 37 on the entrance and exit side are made of glass fiber reinforcement to make the ground-connected wall "reinforcement skeleton", and on both sides (station and entrance and exit sides), except for the vertical ground-connected wall 20 facing the earth and the vertical ground-connected wall 27 under the vertical pedestal, the anchor cables and grouting pipe sleeves are directly arranged in the ground-connected wall 20 facing the earth and the vertical ground-connected wall 27 respectively. Figure 2 All other sleeves that need to pass through the bridge reinforcement structure, the departure side station side ( Figure 2The middle end reinforcement assembly (which needs to be laid with sleeves and grouting pipes) is laid in the corresponding position of the earth-facing ground-connected wall 36, and should be as consistent as possible with the position where the sleeves are laid in the bridge reinforcement structure; the "sleeves" of the 24-position pipe shed and the advanced small guide tube on the upper portal ring beam of the earth-facing ground-connected wall 37 at the receiving side entrance and exit are directly laid in the "reinforcement skeleton" of the upper portal ring beam of the earth-facing ground-connected wall 37, mainly to reduce the construction of drilling and removing the ground-connected wall. The space position of the connecting beam 17 and the bridge deck 19 above the bridge that need to pass through the sleeve, as well as the "portal ring beam" below the bridge, do not need to lay sleeves, because the receiving side must drill and remove the ground-connected wall construction to receive the corresponding reinforcement components. After drilling and removing the ground-connected wall and 37, the receiving components are laid in the corresponding reinforcement structure of the new receiving side. In order to allow the receiving side to smoothly receive the opposite side's corrugated pipe anchor cable, if both sides are constructed at the same time or the time interval is short, there is no need to lay out a "box structure". If both sides are not constructed at the same time or the time interval between the two sides is long, it is necessary to add a "box structure" such as Figure 3 , add a "box-type structure" at the position where the anchor cable or grouting pipe with corrugated pipe needs to be accepted. The box-type is made of iron sheet. The box-type cut hole passes through the steel sleeve 41 with the main reinforcement 43 of the ground connection wall 37. The other parts of the steel sleeve are filled with environmentally friendly lightweight solid foam to prevent excessive filling of concrete during the pouring process, which is beneficial to the opposite side drilling conveyor belt corrugated pipe anchor cable. The steel sleeve vertically implanted in the box-type structure is smaller than the corrugated pipe with anchor cable, and is larger than the spacing between the corrugated pipes with 2 times the anchor cable. It is convenient to accept the anchor cable of the corrugated pipe through the side wall 37, and the main reinforcement in the steel sleeve is connected with a thread head sleeve up and down; the remaining space of the box-type structure steel sleeve is enough for the concrete above the box beam to pass into the ground connection wall below the "box-type structure". The ground connection wall 20 on the receiving side and the ground connection wall 27 under the pedestal need to be specially made. The vertical main reinforcement of the steel skeleton only needs to meet the requirements of post-tensioning after acceptance, and a few horizontal connecting steel bars are needed. The insufficient part is drilled out and supplemented. The poured concrete grade meets the support requirements, which is convenient for the opposite side drilling to pass through;

[0050] When the excavation reaches the bridge upper portal ring beam 24 on both sides, the surface concrete on the back side of the bridge upper portal ring beam 24 is broken until the pre-buried pipe shed sleeve and grouting pipe sleeve are exposed, and the floating soil of the pile heads of the 9 pile foundations below the slab is broken; (remove the semicolon in front) the slab is constructed, the slab is a slab with holes, and the slab is used as the support point on the left and right sides of the upper portal ring beam. The upper portal ring beam 24 steel bars are firmly connected with the slab steel bars, and the two ends of the corrugated pipe anchor cable 35 in the upper portal ring beam are arranged in the slab hole to reserve 40cm for subsequent tensioning; the lower part of the corrugated pipe anchor cable 35 is supported by the horizontal steel bars of the upper portal ring beam 24. First, the pipe shed and the advanced small conduit are constructed, and the length of the pipe shed is 5 meters. Then, the ends of the pipe shed and the advanced small conduit are firmly connected to the upper portal ring beam 24. For a small number of pipe sheds and advanced small conduit sleeves of the pre-buried pre-ground connection wall 36 that are misplaced or missing, the drilling is supplemented and then filled.

[0051] When the excavation reaches the position of the upper portal ring beam 24 on the receiving side entrance and exit side, the bridge carries out the end slab construction, and the pipe shed and the advanced small duct construction are carried out in the same way as the station side, leaving the tail end firmly connected with the upper portal ring beam 24. The upper portal ring beam 24 steel bars and the left and right sections of the sleeve anchor cable are laid in the left and right side slabs.

[0052] Four ground connection walls are added in advance on the protruding part according to the reinforcement requirements. Figure 3 The ground-connected wall 20 outside the middle pedestal and the ground-connected wall 27 below the pedestal are pre-arranged with anchor cable sleeves 2 and reinforced concrete grouting pipe sleeves 3 when the ground-connected wall is manufactured. The anchor cable sleeves 2 are close to the inside of the hole, and the anchor cable sleeves 2 and reinforced concrete grouting pipe sleeves 3 are arranged in a cross-plum blossom shape. The receiving side does not need to be arranged with a sleeve, which is convenient for receiving receiving components such as corrugated pipe anchor cables on the opposite side, and the sleeve is arranged after receiving. Ground-connected wall Figure 2 The ground connection wall 20 outside the middle cap and the ground connection wall 27 below the cap, the length of the ground connection wall is the width of the protruding part in the north-south direction, such as Figure 3 Position layout, one set of ground diaphragm walls is laid out in the gap between the piles below the bridge cap, with a height up to the cap and the same elevation as the cap pile foundation, and another set of ground diaphragm walls is laid out on the outside of the cap, with a height up to the bridge superstructure, and an east-west ground diaphragm wall is constructed between the two outer ground diaphragm walls on the outside of the protruding part ( Figure 1-1 The ground diaphragm wall 36 and the ground diaphragm wall 37 on the soil side of the convex part of the ground diaphragm opening are made of fiberglass. It is convenient for excavation after reinforcement and for laying out the missing casing in advance. The other ground diaphragm walls 20 outside the pedestal and the ground diaphragm wall 27 below the pedestal are made of steel bars. In the manufacturing process, all the casings on the departure side that need to pass through the sleeves are prefabricated in accordance with the prefabrication method when making the ground diaphragm wall 20. Figure 3 The display requires the sleeve to be arranged according to Figure 3 The marked connecting beam 17, the upper and lower opening ring beams, and the corresponding positions of the ground connecting wall 20 in the bridge superstructure 19 where the sleeves need to be laid are laid "sleeves" so that after the sleeve anchors and grouting pipes are constructed on the opposite side, the tail sleeve anchor cable, the tail small pipe shed, etc. can be laid through the "sleeve laying" Figure 2 The corresponding position in the soil can be saved to break up the ground-connected wall 20, thus saving construction costs. For a few casings that have been offset from the corresponding position in the soil due to the production of the ground-connected wall sleeve or according to the production method, a wash drill is used to drill holes to supplement the "sleeves". The ground-connected wall 37 on the receiving side of the entrance and exit of the anchor cable and the grouting pipe is made of glass fiber reinforcement to make the ground-connected wall "skeleton" in order to accept the installation of the anchor cable and the grouting pipe with sleeve. Except for the upper "portal ring beam" pipe shed and the advance small guide tube sleeve, the other receiving measuring points do not need to be laid with sleeves, because the receiving side needs to drill out the ground-connected wall to receive the required components and then lay them. Figure 4 Reinforcement structure.

[0053] Add reinforced pile foundation 21 between the cap and the ground-connected wall to increase the soil pressure of the outer soil pressure on the vertical anchor cables and the soil side pressure of the concrete mixed structure layer. Add pile foundation under the cap to meet the support structure needs, and add pile foundation under the bridge end slab to meet the support needs of the upper "partial portal ring beam". The soil is reinforced from top to bottom 34 in front of the station portal end above the outer side of the protruding part, and the upper portal ring beam anchor cable reinforcement structure 35 is reinforced downward. The reinforcement height is 2 meters above the bottom plate to the upper portal ring beam, and 3 meters to the left and right.

[0054] Figure 3 Note: According to the above, when constructing the enclosure structure, the structures required for the additional support structure will be constructed together with the enclosure structures of the station and entrances and exits;

[0055] Preparation work before excavation of stations and entrances and exits: Figure 2 Soil reinforcement is done in front of the outer side of the protruding part on the middle entrance and exit side 32 and the station side 33. The height of the reinforcement is 3m from the bottom plate to the top of the ring beam 24 above the upper opening, and the width is 2m at the outer end of the bridge. A three-axis mixer is used to mix the concrete and soil mixture for reinforcement. The enhanced strength is prepared to be suitable for the construction of the reinforced bridge structure below and to meet the requirements of post-excavation of the pile foundation when breaking the opening below the bridge after the bridge reinforcement structure is completed.

[0056] The pile foundations and openings of the station and retaining structures need to be constructed at the same time as the pile foundations. After the additional bridge reinforcement structure is completed, earthwork excavation should be carried out, and support should be adopted while digging. Pay attention to the integrity of the pre-added pile foundation and ground-connected wall structure under the protruding part to avoid accidentally digging the pile foundation and ground-connected wall structures required for the bridge structure below;

[0057] The bridge end 10 position is straightened while digging and supporting, the single-hole double-cantilever bridge end slab 10 is constructed, and the bracket is set up to complete the upper ring beam 24 of the opening. Pay attention to the bundle of arc-shaped glass corrugated tube 35 with anchor cable, and the horizontal steel bar support under the corrugated tube is 30cm apart. The bridge end 10 position is straightened while digging and supporting, the single-hole double-cantilever bridge end slab 10 is constructed, and the bracket is set up to complete the upper ring beam 24 of the opening. Pay attention to the bundle of arc-shaped glass corrugated tube 35 with anchor cable. The corrugated anchor cable is implanted in the slab 10 with hole in the middle, and the arc-shaped main steel bar of the upper portal ring beam 24 of the opening is implanted in the slab 10 with hole.

[0058] The width of the upper "partial portal ring beam" covers the protruding part of the entrance and exit, and a large sleeve for a pipe rack 25 is arranged in the steel bar, and a small advance guide tube 26 with an inclination of 20 degrees is reserved; after the upper portal ring beam steel bar is tied, the supporting formwork is poured; the corrugated anchor cable is implanted in the middle slab 10 with a hole, and the arc-shaped main steel bar of the upper portal ring beam 24 of the portal is implanted in the slab 10 with a hole, and enters the hole of the slab 10 through the sleeve; after the concrete strength of the upper portal ring beam 24 and the slab at the end of the bridge meets the tensioning requirements, the corrugated pipe anchor cable 35 in the upper portal ring beam 24 is tensioned to complete the construction of the upper portal ring beam 24.

[0059] After the concrete strength of the upper "partial portal ring beam" reaches 180% of the design value, the soil below the upper portal ring beam is excavated and the bridge cap is constructed after the excavation to the bottom of the bridge cap. The pile foundation added below the bridge pier and the cap is broken to remove the loose soil at the pile head, and the copper reinforcement slurry concrete remaining in the ground-connected wall extending into the bridge pier and the cap is implanted into the bearing and cap steel bars, completing the binding of the cap and bearing steel bars;

[0060] After excavation to the bottom elevation of the cap, first construct the corresponding part of the ground-connected wall 36 with casing anchor cable and grouting pipe. The anchor cable (through the casing) and the grouting pipe steel bar are laid in the connecting beam 17. The height below the connecting beam meets the required height above the hole. Anchor cable sleeve 45 is laid below the connecting beam. The height of the reserved hole of the assembled tunnel top plate after the tunnel excavation should be considered. The absolute elevation of the assembled tunnel top plate and the elevation of the reserved hole of the assembled top plate should be fully considered. One or two more layers can be left to avoid the misalignment of the elevation with the reserved hole of the assembled tunnel top plate. The height above the connecting beam meets the needs of convenient layout of the pre-buried anchor cable and grouting pipe casing for the construction of the ground-connected wall. If necessary, the height of the connecting beam can be increased to meet the needs of the pre-buried pipe of the ground-connected wall. At the same time, the cap height is adjusted accordingly to meet the needs of the connecting beam and the pre-buried casing of the connecting beam. First, the horizontal reinforced concrete interlayer 33 is constructed according to the elevation position of the reinforced concrete arranged in the cap layer, and the corrugated pipe anchor cable layer 32 is constructed close to the bottom. Like the upper structure 7 and 8 of the upper bridge deck, the corrugated pipe anchor cable extends 40cm from the back of the soil to facilitate the opposite side to accept the same construction. When the concrete strength meets the tensioning requirements, the remaining tail steel bars of the reinforced cage concrete interlayer are implanted in the connecting beam and firmly connected with the connecting steel bars. The horizontal corrugated pipe anchor cable 18 of the connecting beam is arranged horizontally in the connecting beam, and the two ends extend 40cm outside the cap to prepare for tensioning when the cap meets the tensioning conditions. The cap 14 and the connecting beam 17 are reinforced with steel bars at the same time, including the horizontal corrugated pipe anchor cable 18. The oblique pre-buried pipe is pre-buried on the outside of the left and right caps, which is used for a small amount of anchor cables of the lower opening ring beam 30 to pass through the cap. A small part is consolidated and tensioned with the cap, and the other part is consolidated and tensioned with the bridge pier.

[0061] Pier construction:

[0062] First, the cap formwork is constructed, and steel bars for the upper "pentagonal bridge pier" are reserved. The cap is cast first, and the upper bridge pier is cast after the cap concrete strength meets the casting requirements of the upper support. When tying the steel bars of the upper bridge pier, pay attention to the layout of the main arch leg and the side arch leg with corrugated pipe anchor cable 13, one end of which extends out of the regular pentagon outside the 40cm long anchor cable, and the other end extends out of the bridge deck hole 40cm for subsequent tensioning;

[0063] The vertical main reinforcement of the pile foundation is used to make part of the reinforcement of the bridge column, and some other reinforcement is added to meet the requirements of the vertical and transverse stirrups of the column. The reinforcement above the column is implanted into the bridge deck, and the column formwork is cast to reserve the reinforcement that extends into the bridge deck and effectively and firmly connect it with the bridge deck reinforcement.

[0064] Bridge deck construction:

[0065] By increasing the pile foundation reinforcement, increasing the bridge deck reinforcement, and reserving copper (steel) bars in the columns for effective binding holes, holes 5 are added at the extended reinforcement and the pre-embedded corrugated pipe anchor cable openings during the construction of the main side arch legs to facilitate subsequent anchor cable tensioning of the main side arch.

[0066] The bridge deck construction is divided into two parts. One part is the bridge deck box girder 28 which mainly supports the superstructure. The box girder at the bottom of the bridge deck is connected to the support through the tensioning of the main and side legs to form a rigid reinforcement support body. The columns are the vertical support structure, and the vertical ground connection walls on the left and right sides of the pedestal form a comprehensive support structure.

[0067] The other part is composed of reinforced concrete reinforcement layer 7 and anchor cable reinforcement layer 8. After the construction of the box beam at the bottom of the bridge is completed, the box beam platform is used to construct the staggered cable with casing and reinforced concrete interlayer at the same position on the opposite side by using navigation directional drilling equipment. The casing anchor cable passes through the bridge deck superstructure 19 through the casing. Similarly, the remaining steel bars at the tail of the reinforced concrete interlayer are implanted into the steel bars of the bridge superstructure 19 for effective and firm connection. The bridge superstructure mainly runs through the anchor cables and reinforced concrete interlayers on both sides of the channel. It is the tensioning reinforcement of the anchor cables on both sides of the channel and the reinforcement of the reinforced concrete water-stopping interlayer above. The upper and lower slabs can be connected through the vertical steel bars reserved in the pile foundation of the lower bridge deck.

[0068] After excavation to the bottom elevation of the pedestal, firstly carry out the horizontal reinforced concrete interlayer construction according to the elevation position of the reinforced concrete arranged in the pedestal layer, and then carry out the construction of the corrugated pipe anchor cable layer close to the bottom. Similar to the upper structure of the upper bridge deck, the corrugated pipe anchor cable extends 40cm from the back of the soil to facilitate the opposite side to accept the same construction. When the concrete strength meets the tensioning requirements, the remaining tail steel bars of the reinforced cage concrete interlayer are embedded in the connecting beam and firmly connected with the connecting steel bars. The connecting beam is horizontally arranged with the corrugated pipe anchor cable in the connecting beam, and the two ends extend 40cm from the pedestal to prepare for tensioning when the pedestal meets the tensioning conditions. The connecting beam 17 between the two pedestals is constructed on the upper side, and the reinforcement steel is pre-embedded in the steel bar binding of the connecting beam.

[0069] Figure 2 The protruding part of the ground connection wall 36 on the middle station side is made of steel bars, which are embedded in the ground connection wall. Figure 3 The upper structure 19 of the middle bridge, the reinforced concrete reinforcement layer 7 and the anchor cable reinforcement layer 8 of the bridge connecting beam, the anchor cable reinforcement layer 32 of the connecting beam, and the reinforced concrete reinforcement layer 33 of the connecting beam are horizontally provided with anchor cable sleeves 2 and steel bar concrete grouting pipe sleeves 3. Similarly, the elevation positions of the upper "partial tunnel ring beam" 24 and the lower "partial tunnel ring beam" 29 are pre-embedded with 26 pipe shed sleeves, grouting pipe sleeves, as well as anchor cable sleeves and grouting pipe 3 sleeves at the corresponding elevation positions of the continuous wall, so that the tails of the subsequent anchor cables and reinforced concrete can be merged into the upper "partial tunnel ring beam" 24 and the lower "partial tunnel ring beam" 29 through sleeves after the subsequent construction; Figure 1-1 The ground-connected wall is made of glass fiber in the middle and lower part of the middle entrance and exit, which is convenient for breaking the ground-connected wall to receive the anchor cables with sleeves and reinforced concrete components from the corresponding position on the station side; the ground-connected wall outside the opening is pre-buried with anchor cables with sleeves and reinforced concrete grouting pipes, and the anchor cable sleeve 2 is arranged near the inside of the opening, and the grouting pipe sleeve 3 is arranged outside, in a plum blossom shape, with both ends sealed;

[0070] When the casting strength of the connecting beam 29 meets the requirements for setting up the scaffold, the scaffold is set up to carry out the construction of the lower portal ring beam 29 and the main and side arch legs. Considering the construction of the main side arch legs 1 and 31 of the bridge and the lower portal ring beam 29, the main side arch legs 1 and 31 and the lower portal ring beam steel bars and the corrugated pipe anchor cables are arranged in the supports. The support with corrugated pipe anchor cable of the lower portal ring beam is extended 40cm, and the other anchor cable is passed through the reserved sleeve of the pedestal and bundled with the pedestal.

[0071] 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.

[0072] 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 dark excavation reinforcement structure, comprising a retaining structure pile foundation connecting wall on both sides, a pair of cap structures and a cap below the cap structure, wherein the retaining structure pile foundation is located outside the cap below the cap, and is characterized in that: The tops of the pile foundations of the retaining structures on both sides are provided with bridge end scaffoldings, arc-shaped pipe shed structures are arranged on the bridge end scaffoldings, reinforcement layer structures are arranged between the bridge end scaffoldings on both sides, and a cantilever bridge structure is arranged between the pedestal structure and the reinforcement layer structure.

2. The tunnel reinforcement structure according to claim 1, characterized in that: The abutment structure comprises a bridge abutment and bridge piers arranged on the bridge abutment, and the upper structure of the cantilever bridge is connected with the bridge piers through main arch legs and side arch legs.

3. The tunnel reinforcement structure according to claim 1, characterized in that: A ground connection wall outside the pedestal is provided between the pile foundation of the enclosure structure and the pile foundation below the pedestal.

4. The tunnel reinforcement structure according to claim 1, characterized in that: The pile foundation below the pedestal includes a group of pile foundations arranged side by side, and a ground connection wall below the pedestal is arranged in the middle of the group of pile foundations.

5. The tunnel dark excavation reinforcement structure according to claim 1, characterized in that: The reinforcement layer structure comprises a reinforced concrete reinforcement layer and an anchor cable reinforcement layer which are connected up and down.

6. The tunnel dark excavation reinforcement structure as claimed in claim 2, characterized in that: A connecting beam is provided between the two bridge abutments of the pair of abutment structures, and a connecting beam transverse anchor cable tensioning structure is provided on the connecting beam.

7. The tunnel reinforcement structure according to claim 2, characterized in that: The cantilever bridge structure is a single-hole double-cantilever bridge, and the lower part of the single-hole double-cantilever bridge is provided with an arc-shaped grouting interlayer and an arc-shaped anchor cable reinforcement layer.

8. The tunnel reinforcement structure according to claim 2, characterized in that: The main arch legs and the side arch legs are provided with main arch leg and side arch leg anchor cable reinforcement structures.

9. The tunnel dark excavation reinforcement structure as claimed in claim 5, characterized in that: A bridge superstructure is arranged above the reinforced concrete reinforcement layer.

10. The tunnel reinforcement structure according to claim 7, characterized in that: A group of bridge columns are arranged between the upper structure of the single-span double-cantilever bridge and the main arch legs and the side arch legs.

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