Underpass tunnel lining concrete interface connecting structure and connecting method

Abstract

The present application relates to the technical field of tunnel concrete lining construction, and particularly relates to a lower-penetrating tunnel lining concrete interface connecting structure and a lower-penetrating tunnel lining concrete interface connecting method, which comprises an existing concrete structure and a newly-poured concrete structure arranged below the existing concrete structure, and a tenon structure protruding from the existing concrete structure to the newly-poured concrete structure is arranged at the interface between the existing concrete structure and the newly-poured concrete structure. The connecting structure adopts the tenon structure as the connecting mode of the new and old concrete interfaces, forms a lifting system of the newly-poured concrete structure to the existing concrete structure in the process of the lower-penetrating tunnel lining concrete construction, and particularly, the tenon structure comprises a prefabricated trapezoidal pad and a planted-steel-bar connecting piece. The planted-steel-bar connecting piece reliably transmits the axial force, the prefabricated trapezoidal pad reliably transmits the occlusion force and the shear force, and the bending resistance and the anti-deformation capacity of the joint under the axial force are strengthened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of tunnel engineering, and relates to the field of tunnel concrete lining construction technology, in particular to a lower-penetrating tunnel lining concrete interface connecting structure and a lower-penetrating tunnel lining concrete interface connecting method. BACKGROUND

[0002] The lower-penetrating tunnel arch top is connected into a whole by pouring concrete to make the new structure and the existing structure into a whole, so as to form the whole reliable connection of the new-poured concrete structure and the existing concrete structure of the lower-penetrating tunnel lining construction. The interface treatment mode of the new and old concrete must be optimized during construction to ensure the connection quality of the existing structure and the new structure. There is a performance difference between the new and old concrete, and the bonding interface is easy to crack under the action of load, which becomes a weak link of the reinforced structure. Therefore, improving the bonding performance of the lower-penetrating tunnel lining concrete interface is an important construction technical problem.

[0003] The common interface treatment modes of the new and old concrete in the prior art include drilling, brushing, sand blasting, slotting and setting connecting keys, and improper treatment easily leads to poor mechanical properties and connection reliability of the bonding interface. Therefore, whether the connection of the existing concrete structure and the new-poured concrete structure is firm is more important. SUMMARY

[0004] Based on the problems in the prior art, the present application provides a lower-penetrating tunnel lining concrete interface connecting structure and a lower-penetrating tunnel lining concrete interface connecting method, which comprises an existing concrete structure and further comprises:

[0005] a new-poured concrete structure arranged below the existing concrete structure,

[0006] The existing concrete structure and the new-poured concrete structure are provided with a tenon structure protruding to the new-poured concrete structure at the interface.

[0007] On the basis of the above-mentioned scheme, the tenon structure comprises a prefabricated trapezoidal pad, and a bottom surface of the prefabricated trapezoidal pad is fixedly connected with the existing concrete structure.

[0008] On the basis of the above-mentioned scheme, the prefabricated trapezoidal pad is made of UHPC.

[0009] On the basis of the above-mentioned scheme, the tenon structure further comprises a planted bar connecting piece for connecting the existing concrete structure, the prefabricated trapezoidal pad and the new-poured concrete structure, and the prefabricated trapezoidal pad is fixed on the existing concrete structure through the planted bar connecting piece.

[0010] On the basis of the above-mentioned scheme, the planted bar connecting piece comprises a planted bar and a nut for fastening the existing concrete structure and the prefabricated trapezoidal pad, and the prefabricated trapezoidal pad is provided with a through hole for passing through the planted bar along an axial direction thereof.

[0011] On the basis of the above scheme, the bottom surface area of the prefabricated trapezoidal cushion block connected with the existing concrete structure is larger than the bottom surface area connected with the newly poured concrete structure.

[0012] On the basis of the above scheme, the surface of the existing concrete structure is subjected to chiseling treatment.

[0013] A lower tunnel lining concrete interface connecting structure is used for connecting the lower tunnel lining concrete interface.

[0014] In addition, the application also provides a lower tunnel lining concrete interface connecting method, which specifically comprises the following steps:

[0015] S1: sequentially performing chiseling and cleaning treatment on the surface of the existing concrete structure;

[0016] S2: drilling holes on the existing concrete structure in the direction perpendicular to the interface;

[0017] S3: installing a planted bar in the hole;

[0018] S4: performing sand blasting treatment on the surface of the prefabricated trapezoidal cushion block;

[0019] S5: after installing the prefabricated trapezoidal cushion block on the planted bar, fixing the prefabricated trapezoidal cushion block on the existing concrete structure by using a nut;

[0020] S6: pouring a newly poured concrete structure below the existing concrete structure.

[0021] On the basis of the above scheme, in step S5, the large bottom surface of the prefabricated trapezoidal cushion block is connected with the existing concrete structure.

[0022] Compared with the prior art, the connecting structure adopts a mortise and tenon structure as the connecting mode of the new and old concrete interfaces, forms a lifting system of the newly poured concrete structure on the existing concrete structure in the construction process of the lower tunnel lining concrete, and in particular, the mortise structure comprises a prefabricated trapezoidal cushion block and a planted bar connecting piece, the planted bar connecting piece reliably transmits the axial force, the prefabricated trapezoidal cushion block reliably transmits the occlusal force and the shear force, and the bending resistance of the joint under the action of the axial force and the anti-deformation capacity are strengthened; in particular, the prefabricated trapezoidal cushion block is made of UHPC, and the mechanical properties and the durability of the UHPC (ultra-high performance concrete)-NC (normal concrete) bonding interface are obviously superior to those of the NC (normal concrete)-NC (normal concrete) interface, and the mechanical properties of the overall connection are the most superior. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a structural schematic view of the lower tunnel lining concrete interface connecting structure in Embodiment 1 of the application;

[0024] Figure 2 A sectional view of the prefabricated trapezoidal block (including a through hole) as described in Embodiment 1 of the present application;

[0025] Figure 3 A top view of the prefabricated trapezoidal block as described in Embodiment 1 of the present application;

[0026] Figure 4 A structural schematic diagram of the prefabricated trapezoidal block (arranged in an array between the existing concrete structure and the newly poured concrete structure) as described in Embodiment 1 of the present application;

[0027] Figure 5 A structural schematic diagram of the prefabricated trapezoidal block as described in Embodiment 1 of the present application;

[0028] Figure 6 A structural schematic diagram of the tenon structure as described in Embodiment 1 of the present application;

[0029] Figure 7 A structural schematic diagram of the anchor rod connecting piece as described in Embodiment 1 of the present application;

[0030] Figure 8 A structural schematic diagram of the interface chiseling treatment of the existing concrete structure in Step S1 of Embodiment 2 of the present application;

[0031] Figure 9 A structural schematic diagram of the hole drilling on the existing concrete structure in Step S2 of Embodiment 2 of the present application;

[0032] Figure 10 A structural schematic diagram of the installation of the anchor rod in Step S3 of Embodiment 2 of the present application;

[0033] Figure 11 A structural schematic diagram of the installation of the prefabricated trapezoidal block in Step S5 of Embodiment 2 of the present application;

[0034] Figure 12 A structural schematic diagram of the installation of the nut in Step S5 of Embodiment 2 of the present application. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with the drawings and embodiments, and it should be noted that the following embodiments are intended to facilitate the understanding of the present application and do not limit the present application in any way.

[0036] Embodiment 1

[0037] As shown in the drawings, Figure 1 the present application provides a through tunnel lining concrete interface connecting structure, comprising:

[0038] the existing concrete structure 1, further comprising:

[0039] A new cast concrete structure 2 is arranged below an existing concrete structure 1,

[0040] The existing concrete structure 1 and the new cast concrete structure 2 are provided with a tenon structure 3 protruding towards the new cast concrete structure 2 at the interface between the new and old concretes.

[0041] The above connecting structure of the present application adopts the tenon structure 3 as the connecting structure of the interface between the new and old concretes, forms a tenon and groove type connecting mode, forms an overall reliable connecting and lifting system of the new cast concrete structure 2 and the existing concrete structure 1 in the construction process of the lower tunnel lining concrete, reliably transmits the axial force and the biting force and the shear force, and strengthens the bending resistance and the anti-deformation ability of the joint under the action of the axial force.

[0042] As shown in Figure 2 As a specific embodiment, the tenon structure 3 includes a prefabricated trapezoidal pad 310, one bottom surface of which is fixedly connected with the existing concrete structure 1.

[0043] As a specific embodiment, the prefabricated trapezoidal pad 310 is prefabricated by UHPC, which can improve the processing efficiency and batch manufacturing. The surface of the prefabricated trapezoidal pad 310 is treated by a sand blasting process, a high-pressure automatic sand blasting machine is used to spray sand on the surface of the UHPC prefabricated trapezoidal pad 310, and special sand blasting materials are uniformly sprayed on the surface of the prefabricated trapezoidal pad 310 to achieve the effect of spot-shaped concave-convex roughness and high-strength solidification adhesion. The purpose is to improve the bonding performance of the interface between the UHPC prefabricated trapezoidal pad 310 and the existing concrete structure 1 (NC lining concrete).

[0044] Among them, UHPC is ultra-high performance concrete, abbreviated as UHPC (Ultra-High Performance Concrete), the mechanical properties and durability of the bonding interface between UHPC (ultra-high performance concrete) and NC (ordinary concrete) are obviously better than those of the interface between NC (ordinary concrete) and NC (ordinary concrete), and the mechanical properties of the overall connection are the most superior.

[0045] As a preferred embodiment of the prefabricated trapezoidal cushion 310, the preparation method of the UHPC prefabricated trapezoidal cushion 310 preferably uses the preparation method provided in the patent application number 202011107738.X, patent name "A self-compacting C120 premixed dry concrete and its preparation method", "consisting of the following components by weight fraction: Portland cement 480-550 parts, coarse aggregate 40-55 parts, steel fiber 70-80 parts, fine aggregate 470-550 parts, admixture 11-15 parts, mineral admixture 145-190 parts; the coarse aggregate is fine stone with a particle size of 5-10 mm; the fine aggregate consists of 300-350 parts of quartz sand and 170-200 parts of artificial sand; the mineral admixture consists of 80-100 parts of mineral powder, 35-40 parts of fly ash and 30-40 parts of silica fume; the admixture consists of 8-10 parts of powder water reducer and 3-5 parts of defoaming agent; the water reducer is a polycarboxylic acid high-performance powder; the defoaming agent is a polyether defoaming agent; the steel fiber is coated with copper on the outer surface, with a diameter of 22 mm, a length of 12 mm, and a tensile strength greater than 2850 MPa.".

[0046] As a preferred embodiment, as shown in Figure 3 , the upper and lower bases of the prefabricated trapezoidal cushion 310 are square; the stability of the prefabricated trapezoidal cushion 310 under stress can be ensured; the prefabricated trapezoidal cushion 310 is a trapezoidal platform structure, and a plurality of prefabricated trapezoidal cushions 310 are regularly and uniformly arranged between the existing concrete structure 1 and the newly poured concrete structure 2, the distance between adjacent prefabricated trapezoidal cushions 310 is equal (as shown in Figure 4 ), ensuring the bonding stability between the existing concrete structure 1 and the newly poured concrete structure 2.

[0047] Based on the above scheme, as shown in Figure 5 , the prefabricated trapezoidal cushion 310 has a height H of 150 mm, the upper base of the prefabricated trapezoidal cushion 310 is a square with a side length of 300 mm, and the lower base is a square with a side length of 200 mm. The center points of the upper and lower bases coincide with the central axis of the prefabricated trapezoidal cushion 310, which can meet the requirement of uniform stress of the prefabricated trapezoidal cushion 310; the horizontal and vertical spacings between adjacent prefabricated trapezoidal cushions 310 are both 600 mm, which is the best choice for the prefabricated trapezoidal cushion 310 in the lower tunnel lining concrete interface.

[0048] As a specific embodiment, as shown in Figure 6 , the tenon structure 3 further comprises a planted steel connecting piece 320 for connecting the existing concrete structure 1, the prefabricated trapezoidal cushion 310 and the newly poured concrete structure 2, and the prefabricated trapezoidal cushion 310 is fixed on the existing concrete structure 1 through the planted steel connecting piece 320.

[0049] As a specific embodiment, asFigure 7 As shown, the anchor connecting piece 320 includes an anchor 321 and a nut 322 for fastening the existing concrete structure 1 and the prefabricated trapezoidal pad 310, which is provided with a through hole 311 for passing through the anchor 321 along the axial direction thereof (as shown). Figure 7 After the anchor 321 is inserted into the existing concrete structure 1, the prefabricated trapezoidal pad 310 is sleeved on the anchor 321 along the direction of the through hole 311, and the existing concrete structure 1 and the prefabricated trapezoidal pad 310 are fastened using the nut 322, thereby forming a tenon structure 3 by installing the UHPC prefabricated trapezoidal pad 310 at the interface of the existing concrete structure 1. Then, the pouring operation of the new poured concrete structure 2 (lining concrete) is performed, and the new poured concrete structure 2 serves as a groove structure matched with the tenon structure 3.

[0050] Specifically, the anchor 321 is selected from high-strength short steel bars, so that the new poured concrete structure 2 (lining concrete structure) to be poured and the existing concrete structure 1 are integrated into a whole. The type and length of the material of the anchor 321 must meet the requirements of the design document, and the anchor 321 must be subjected to a pull-out test according to the specification after completion.

[0051] As a specific embodiment, the bottom surface area of the prefabricated trapezoidal pad 310 connected with the existing concrete structure 1 is smaller than the bottom surface area connected with the new poured concrete structure 2. In this scheme, the contact area of the prefabricated trapezoidal pad 310 with the existing concrete structure 1 is small, although it is also a tenon and groove type connecting structure, but in the tunnel, the new poured concrete structure 2 is located below the existing concrete structure 1, and the new poured concrete structure 2 is greatly affected by gravity. Therefore, a smaller contact area will result in relatively smaller bite force and shear force of the existing concrete structure 1 and the prefabricated trapezoidal pad 310. Based on this, another specific embodiment is proposed, as shown in Figure 1 As shown, the bottom surface area of the prefabricated trapezoidal pad 310 connected with the existing concrete structure 1 is greater than the bottom surface area connected with the new poured concrete structure 2. Since the upper bottom surface has a large contact area with the existing concrete structure 1, it is beneficial to increase the bonding force with the existing concrete structure 1 and improve the connection stability, thereby increasing the bite force and shear force.

[0052] Based on the above structure, as a specific embodiment, as shown in Figure 8As shown, the surface of the existing concrete structure 1 is subjected to chiseling treatment. The purpose is to firmly bond the construction surfaces of the two construction stages. A special concrete chiseling machine is used to chisel the surface of the existing concrete structure 1, and the surface layer concrete of the existing concrete structure 1 is chiseled off. A cleaning device is used to clean the surface of the existing concrete structure 1 to ensure that there are no loose blocks and dust on the surface. The interface between the existing concrete structure and the newly poured concrete structure can be firmly bonded, and the bonding performance between the tenon structure 3 and the existing concrete structure 1 is enhanced, so that the tenon structure 3 is not easy to displace.

[0053] The above connecting structure of the present application can be used for the interface treatment of new and old concrete. The stability of the bonding interface is maintained under the action of load, and the interface is not easy to crack, thereby forming a stable reinforcing structure.

[0054] Embodiment 2

[0055] Based on the connecting structure of embodiment 1, the present embodiment provides a method for connecting the interface of a tunnel lining concrete, and the specific steps include:

[0056] As shown in Figure 8 S1: treating the surface of the existing concrete structure 1: sequentially chiseling and cleaning the surface of the existing concrete structure 1;

[0057] A special concrete chiseling machine is used to chisel the surface of the existing concrete structure 1, and the surface layer concrete is chiseled off. A cleaning device is used to clean the surface of the concrete to ensure that there are no loose blocks and dust on the surface. Next, a high-pressure automatic sand blasting machine is used to sand blast the interface of the existing concrete structure 1 to achieve a spot-like rough and uneven state.

[0058] Specifically, this method can improve the effect of high-strength solidification adhesion.

[0059] As shown in Figure 9 S2: drilling holes in the existing concrete structure 1, the drilling direction being perpendicular to the surface of the existing concrete structure 1:

[0060] As shown in Figure 10 S3: installing the reinforcing bar: inserting the reinforcing bar into the existing concrete structure 1 along a direction perpendicular to the surface of the existing concrete structure 1; and filling the hole gap by injecting special MT500 chemical injection type reinforcing bar glue.

[0061] S4: treating the surface of the prefabricated trapezoidal cushion block 310: sand blasting the surface of the prefabricated trapezoidal cushion block 310;

[0062] The surface of the precast trapezoidal pad 310 is sandblasted using a high-pressure automatic sandblasting machine. This method can improve the bonding performance between the UHPC precast trapezoidal pad 310 and the newly poured concrete structure 2.

[0063] like Figures 11-12 As shown, S5: Install and tighten the precast trapezoidal pad 310: Add the precast trapezoidal pad 310 to the rebar 321 that has been inserted into the existing concrete structure 1, and tighten it with the nut 322. By installing the UHPC precast trapezoidal pad 310 at the interface of the existing concrete structure 1, a tenon-groove connection is formed at the interface between the new and old concrete. Before tightening the nut 322, the gaps in the rebar holes are filled by injecting special MT500 chemical injection rebar adhesive.

[0064] Specifically, high-strength short steel bars are used as anchor bars 321 for connection, so that the newly poured concrete structure 2 (lining concrete structure) to be poured is connected to the existing concrete structure 1 as a whole. The type and length of the anchor bar 321 material must meet the requirements of the design documents. After the anchor bar 321 is completed, a pull-out test must be carried out on the anchor bar according to the specifications. Only after passing the test can the next process be carried out.

[0065] like Figure 1 As shown, S6: Pouring new concrete structure 2: Performing the pouring operation of the lower new concrete structure 2 (lining concrete).

[0066] Using the structure and method of this embodiment, a tenon-and-groove connection structure is formed by installing UHPC precast trapezoidal pads 310 on the concrete interface of the existing concrete structure 1, thereby forming a support system for the existing concrete structure 1 by the newly poured concrete structure 2 during the construction of the underpass tunnel lining concrete; through the convex and concave tenon-and-groove joint, axial force, interlocking force and shear force are reliably transmitted, and the bending resistance and deformation resistance of the joint under the action of axial force are strengthened, effectively improving the connection quality between the existing concrete structure 1 and the newly poured concrete structure 2.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A concrete interface connection structure for a lower tunnel lining, comprising an existing concrete structure (1), characterized in that, Also included are: a new cast concrete structure (2) arranged below the existing concrete structure (1); the existing concrete structure (1) and the new cast concrete structure (2) are provided with a tenon structure (3) protruding towards the new cast concrete structure (2) at the interface; the tenon structure (3) includes a prefabricated trapezoidal pad (310), one bottom surface of which is fixedly connected with the existing concrete structure (1); the tenon structure (3) further includes a rebar connecting piece (320) for connecting the existing concrete structure (1), the prefabricated trapezoidal pad (310) and the new cast concrete structure (2), the prefabricated trapezoidal pad (310) being fixed on the existing concrete structure (1) through the rebar connecting piece (320); the rebar connecting piece (320) includes a rebar (321) and a nut (322) for fastening the existing concrete structure (1) and the prefabricated trapezoidal pad (310), the prefabricated trapezoidal pad (310) being provided with a through hole (311) along an axis direction thereof for passing through the rebar (321).

2. The underpass tunnel lining concrete interface connection structure according to claim 1, characterized by, The prefabricated trapezoidal pad (310) is prefabricated from UHPC.

3. The underpass tunnel lining concrete interface connection structure according to claim 1, characterized by, The bottom surface area of the prefabricated trapezoidal pad (310) connected with the existing concrete structure (1) is greater than that connected with the new cast concrete structure (2).

4. The underpass tunnel lining concrete interface connection structure according to claim 1, characterized by, The surface of the existing concrete structure (1) is subjected to chiseling treatment.

5. The connecting structure according to any one of claims 1-4 for connecting the interface of a tunnel lining concrete.

6. A method of connecting the interface of a lower tunnel lining concrete characterized by, Using the connecting structure according to any one of claims 1-4, specifically, the following steps are included: S1: sequentially chiseling and cleaning the surface of the existing concrete structure (1); S2: drilling holes in the existing concrete structure (1) along a direction perpendicular to the surface thereof; S3: installing a rebar (321) in the hole; S4: sandblasting the surface of the prefabricated trapezoidal pad (310); S5: installing the prefabricated trapezoidal pad (310) on the rebar (321) and then fixing the prefabricated trapezoidal pad (310) on the existing concrete structure (1) with a nut (322); S6: casting a new cast concrete structure (2) below the existing concrete structure (1).

7. The underpass tunnel lining concrete interface connection method according to claim 6, characterized by, In step S5, the large bottom surface of the prefabricated trapezoidal pad (310) is connected with the existing concrete structure (1).

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