Pipe concrete constraint type well wall and construction method thereof

Abstract

The invention discloses a pipe concrete constraint type well wall and a construction method thereof, and relates to the technical field of mine construction. Comprising a peripheral structure body and a lining, the peripheral structure body is made of high-strength concrete or steel fiber concrete, a reinforcement cage is arranged in the peripheral structure body, the lining comprises a plurality of annular pipes, the annular pipes are vertically arranged, the annular pipes are arranged on the inner edge of the peripheral structure body and abut against the peripheral structure body, and the annular pipes are filled with micro-expansion high-strength concrete to form a pipe concrete building body. The pipe concrete constraint type well wall structure can serve as the inner wall of a single-layer well wall or a double-layer well wall, the ultimate bearing capacity of the well wall is greatly improved, and the thickness of the well wall is effectively reduced on the premise that external loads can be resisted; the well wall structure is simple in construction process, good in overall water sealing performance and high in ultimate bearing capacity.

Description

Technical Field

[0001] The invention relates to the technical field of mine construction, and in particular to a pipe concrete restrained shaft wall and a construction method thereof. Background Art

[0002] With the long-term exploitation of shallow mineral resources and the growing demand for resources, the deepening of resource exploitation is an inevitable trend, and the depth of shaft construction will continue to increase. A considerable number of shafts will pass through strata as deep as 500 to 1000m. Under this condition, according to the current "Design Code for Coal Mine Shafts and Chambers", when a double-layer composite shaft wall structure is used in deep water-rich strata, even if C80 concrete support is used, the total thickness of the shaft wall will still exceed 3.0m, of which the inner wall thickness exceeds 2.5m, and the utilization rate of the shaft excavation section, that is, the ratio of the net cross-sectional area of ​​the shaft to the excavation cross-sectional area, is less than 30%. Therefore, the cost of shaft excavation and masonry construction is bound to be very high, which also greatly increases the cost of shaft freezing engineering and prolongs the construction period. In addition, due to the excessive thickness of the inner shaft wall, high-strength large-volume concrete will cause serious temperature cracking problems, which in turn leads to serious leakage of the shaft wall. With the increase of freezing depth, the double-layer composite shaft wall structure is becoming more and more unreasonable.

[0003] Therefore, in order to effectively reduce the thickness of the shaft wall, improve the utilization rate of the shaft excavation section, and reduce the project cost, it is urgent to develop new shaft wall structures and shaft wall construction methods. Summary of the invention

[0004] The main purpose of the present invention is to provide a pipe concrete constrained shaft wall and a construction method thereof to solve the above problems.

[0005] To achieve the above-mentioned purpose, the present invention provides a pipe-concrete constrained well wall, including an outer structure and an inner lining; the outer structure is made of high-strength concrete or steel fiber concrete, a steel cage is arranged in the outer structure, and the inner lining includes a plurality of annular tubes, the plurality of annular tubes are arranged vertically, the annular tubes are arranged at the inner edge of the outer structure and in conflict with the outer structure, and the annular tubes are filled with micro-expansion high-strength concrete to form a pipe-concrete structure.

[0006] Furthermore, the cross section of the annular tube is rectangular.

[0007] Furthermore, two adjacent annular tubes are fitted with each other, and the two adjacent annular tubes are fixedly connected.

[0008] Furthermore, two adjacent annular tubes are fixed by bonding carbon fiber braided tubes or welding steel tubes.

[0009] A construction method for a pipe-concrete constrained shaft wall adopts any one of the above-mentioned pipe-concrete constrained shaft walls, including a single-layer shaft wall construction method and a double-layer shaft wall construction method.

[0010] Further, it is applied to the single-layer well wall construction, including the following steps: S1, excavate a construction section from top to bottom; S2. Lower the blade angle template to the working surface and level the blade angle template; S3, lower the steel bars and complete the tying of the steel cage; S4, lowering the annular pipe to a predetermined position at the inner edge of the peripheral structure; S5, lowering the vertical mold and fixing it, wherein the inner edge of the annular tube contacts the vertical mold; S6, pouring concrete of the construction section; S7. Repeat steps S1-S6 until the construction reaches a predetermined depth.

[0011] Further, in step S4, when two adjacent annular tubes are attached, a steel tube is welded to the two adjacent annular tubes or a carbon fiber braided tube is bonded to fix the two adjacent annular tubes.

[0012] Further, it is applied to the double-layer well wall construction, including the following steps: S1. The shaft is divided into sections from top to bottom to complete the outer wall construction; S2, tie the steel cage and place the annular pipe at the predetermined position on the inner edge of the inner well wall; S3, lift up the sliding template and fix it; wherein the inner edge of the annular tube is in direct contact with the sliding template; S4, pouring concrete of the construction section; S5. Repeat steps S2-S4 until the well wall construction is completed.

[0013] Further, in step S2, when two adjacent annular tubes are attached, a steel tube is welded to the two adjacent annular tubes or a carbon fiber braided tube is bonded to fix the two adjacent annular tubes.

[0014] The pipe concrete restrained well wall structure of the present invention can be used as the inner wall of a single-layer well wall or a double-layer well wall, greatly improving the ultimate bearing capacity of the well wall, and effectively reducing the thickness of the well wall while being able to resist external loads. The well wall structure has a simple construction process, good overall water sealing performance, and high ultimate bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a pipe concrete restrained shaft wall of the present invention Figure 1 .

[0016] Figure 2 A schematic diagram of a pipe concrete restrained shaft wall of the present invention Figure 2 .

[0017] Figure 3This is a comparison diagram of the annular strain evolution during the wellbore loading process between the present invention and the traditional wellbore loading process.

[0018] Among them, 1-annular tube; 2-micro-expansive high-strength concrete; 3-steel cage; 4-external structure. DETAILED DESCRIPTION

[0019] In order to achieve the above-mentioned purpose and effect, the technical means and structures adopted by the present invention are described in detail with reference to the accompanying drawings for the features and functions of the preferred embodiments of the present invention.

[0020] like Figure 1-Figure 2 As shown, the present invention provides a pipe-concrete constrained shaft wall, a peripheral structure 4 and an inner lining; the peripheral structure 4 as the shaft wall is made of high-strength concrete or steel fiber concrete, a steel cage 3 is arranged in the peripheral structure 4, and the inner lining includes a plurality of annular tubes 1, the plurality of annular tubes 1 are arranged vertically, the annular tubes 1 are arranged at the inner edge of the peripheral structure 4 and in contact with the peripheral structure 4, and the annular tubes 1 are filled with micro-expansion high-strength concrete 2 to form a pipe-concrete structure.

[0021] Specifically, according to the toughness and brittleness requirements, the annular tube 1 is made of a steel tube or a carbon fiber braided tube.

[0022] Specifically, grouting holes are provided on the annular pipe 1, and the cross section of the annular pipe 1 is rectangular, so as to facilitate construction.

[0023] Specifically, the arrangement density and position of the steel cages 3 in the outer structure 4 are arranged according to actual construction requirements.

[0024] During arrangement, two adjacent annular tubes 1 are fitted to each other, and the two adjacent annular tubes 1 are fixedly connected by bonding carbon fiber braided tubes or welding steel tubes.

[0025] The present invention forms a tube-concrete structure by arranging an annular tube 1 structure at the inner edge of the peripheral structure 4 and filling the annular tube 1 with micro-expansion high-strength concrete 2, and the tube-concrete structure and the peripheral structure jointly bear the external load. The annular tube 1 forms a constraint on the micro-expansion high-strength concrete 2 inside it, improving the compressive strength and plasticity of the concrete, and the concrete improves the stress conditions of the annular tube 1, increases the stability of the annular tube 1, and then comprehensively improves the compressive and shear bearing capacity of the tube-concrete structure, and the tube-concrete structure has a strong constraint effect on the outer peripheral structure 4.

[0026] The pipe concrete restrained shaft wall structure can be used as the inner wall of a single-layer shaft wall or a double-layer shaft wall, greatly improving the ultimate bearing capacity of the shaft wall, and effectively reducing the thickness of the shaft wall while being able to resist external loads. This type of shaft wall structure has a simple construction process, good overall water sealing performance, and high ultimate bearing capacity.

[0027] The present invention also provides a construction method for a pipe-concrete constrained well wall, which uses the above-mentioned pipe-concrete constrained well wall, including a single-layer well wall construction method and a double-layer well wall construction method, wherein the outer walls of the single-layer well wall and the double-layer well wall are constructed from top to bottom, and the inner wall of the double-layer well wall is constructed from bottom to top.

[0028] In this embodiment, the single-layer well wall construction includes the following steps: S1. Dig a construction section from top to bottom.

[0029] S2. Lower the blade angle template to the work surface and level the blade angle template.

[0030] S3, lower the steel bars and complete the binding of the steel cage 3.

[0031] S4, lowering the annular tube 1 to the predetermined position on the inner edge of the peripheral structure 4 in sequence.

[0032] Specifically, the annular pipe 1 is prefabricated in advance on the well, and the material, size and vertical arrangement density of the annular pipe 1 are determined according to the well wall structure requirements and the hydrological and geological conditions of the strata through which the wellbore passes.

[0033] Preferably, during arrangement, two adjacent annular tubes 1 are fitted together, and after the annular tubes 1 are fitted together, the adjacent annular tubes 1 are fixed by welding a steel tube or bonding a carbon fiber braided tube between the two annular tubes 1 .

[0034] S5, lower the vertical mold and fix it, wherein the inner edge of the annular tube 1 contacts the vertical mold.

[0035] S6. Pour concrete for this construction section.

[0036] Specifically, high-strength concrete or steel fiber concrete is poured to form the outer structure 4, and the annular tube 1 is filled with slightly-expanding high-strength concrete 2 to form a tube concrete structure.

[0037] S7. Repeat steps S1-S6 until the construction reaches a predetermined depth.

[0038] In this embodiment, the double-layer well wall construction includes the following steps: S1. The shaft is divided into sections from top to bottom to complete the outer wall construction.

[0039] S2. Tie up the steel cage 3 and place the annular pipe 1 at a predetermined position on the inner edge of the inner well wall.

[0040] Specifically, the annular pipe 1 is prefabricated in advance on the well, and the material, size and vertical arrangement density of the annular pipe 1 are determined according to the well wall structure requirements and the hydrological and geological conditions of the strata through which the wellbore passes.

[0041] Preferably, during arrangement, two adjacent annular tubes 1 are fitted together, and after the annular tubes 1 are fitted together, the adjacent annular tubes 1 are fixed by welding a steel tube or bonding a carbon fiber braided tube between the two annular tubes 1 .

[0042] S3, lift up the sliding template and fix it; wherein the inner edge of the annular tube 1 is in direct contact with the sliding template.

[0043] S4. Pour concrete for this construction section.

[0044] S5. Repeat steps S2-S4 until the well wall construction is completed.

[0045] Preliminary tests have shown that the tube-concrete structure of the present invention combines the advantages of tube structure and concrete. The tube structure forms a rigid constraint on the concrete, thereby improving the compressive strength and plasticity of the concrete. The concrete in turn improves the stress conditions of the tube structure and increases the stability of the steel tube.

[0046] In order to compare the strength of the present invention with that of the traditional wellbore and to intuitively demonstrate the advantages of the present invention, scaled test models were established for the present invention and the traditional double-layer wellbore, respectively. The scaled test models were pressurized by a pressurizing system, and deformation and rupture simulation tests of the traditional double-layer wellbore and the pipe-concrete constrained wellbore under different confining pressures were completed. The variation law of the annular strain of the two scaled test models during the wellbore loading process was obtained.

[0047] The annular pipe is a rectangular cross-section pipe with a thickness of 2 mm, a pipe section of 8 cm × 12 cm, and a total wall thickness of 25 cm. Figure 3 As shown in the figure, the test results show that when the confining pressure varies in the range of 0~6MPa, the strain of the wellbore is basically the same. When the confining pressure exceeds 7.5MPa, the strain difference between the two modes of wellbore gradually increases with the increase of confining pressure, increasing step by step from 33με~85με, and the average load difference per level increases by about 48με. When the confining pressure reaches 13MPa, the maximum strain difference between the two wellbore is 174με, the minimum difference is 56με, and the average strain difference is 107με. On the other hand, the traditional double-layer wellbore ruptures locally when the confining pressure reaches 16MPa, while the pipe-concrete constrained wellbore finally ruptures at a confining pressure of 23.5MPa, and the structural strength is increased by 47%.

[0048] The above descriptions are only preferred embodiments of the present invention, not all embodiments. Anyone should be aware that any structural changes made under the inspiration of the present invention, and any technical solutions that are the same or similar to the present invention, belong to the protection scope of the present invention.

Claims

1. A pipe-concrete restrained shaft wall, characterized in that: It includes an outer structure and an inner lining; the outer structure is made of high-strength concrete or steel fiber concrete, a steel cage is arranged in the outer structure, and the inner lining includes a plurality of annular tubes, which are arranged vertically, and the annular tubes are arranged at the inner edge of the outer structure and in contact with the outer structure, and the annular tubes are filled with micro-expansion high-strength concrete to form a pipe concrete structure.

2. A pipe-concrete restrained shaft wall as claimed in claim 1, characterized in that: The cross section of the annular tube is rectangular.

3. A pipe-concrete restrained shaft wall as claimed in claim 2, characterized in that: The two adjacent annular tubes are fitted with each other and are fixedly connected to each other.

4. A pipe-concrete restrained shaft wall as claimed in claim 3, characterized in that: Two adjacent annular tubes are fixed by bonding carbon fiber braided tubes or welding steel tubes.

5. A method for constructing a pipe-concrete-constrained shaft wall, using the pipe-concrete-constrained shaft wall according to any one of claims 1 to 4, characterized in that: It includes single-layer well wall construction method and double-layer well wall construction method.

6. A method for constructing a pipe-concrete restrained shaft wall as claimed in claim 5, characterized in that: Applied to single-layer well wall construction, including the following steps: S1, excavate a construction section from top to bottom; S2. Lower the blade angle template to the working surface and level the blade angle template; S3, lower the steel bars and complete the tying of the steel cage; S4, lowering the annular pipe to a predetermined position at the inner edge of the peripheral structure; S5, lowering the vertical mold and fixing it, wherein the inner edge of the annular tube contacts the vertical mold; S6, pouring concrete of the construction section; S7. Repeat steps S1-S6 until the construction reaches a predetermined depth.

7. A method for constructing a pipe-concrete restrained shaft wall as claimed in claim 6, characterized in that: In step S4, when two adjacent annular tubes are attached, a steel tube is welded to the two adjacent annular tubes or a carbon fiber braided tube is bonded to fix the two adjacent annular tubes.

8. A method for constructing a pipe-concrete restrained shaft wall as claimed in claim 5, characterized in that: Applied to double-layer well wall construction, including the following steps: S1. The shaft is divided into sections from top to bottom to complete the outer wall construction; S2, tie the steel cage and place the annular pipe at the predetermined position on the inner edge of the inner well wall; S3, lift up the sliding template and fix it; wherein the inner edge of the annular tube is in direct contact with the sliding template; S4, pouring concrete of the construction section; S5. Repeat steps S2-S4 until the well wall construction is completed.

9. A method for constructing a pipe-concrete restrained shaft wall as claimed in claim 8, characterized in that: In step S2, when two adjacent annular tubes are attached, a steel tube is welded to the two adjacent annular tubes or a carbon fiber braided tube is bonded to fix the two adjacent annular tubes.

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