Concrete diaphragm wall structure adapting to stress concentration of bedrock constraint area
By pouring high-tough concrete in the stress concentration section of the concrete anti-seepage wall and combining ordinary concrete, the crack problem caused by stress concentration in the bedrock constraint area is solved, the construction process is simplified, and the safety of the dam is ensured.
Patent Information
- Application Number
- CN202421624498.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-10
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2034-07-10
AI Technical Summary
In the construction of the reservoir, the concrete anti-seepage wall has a concentrated stress in the bedrock constraint area, causing the local tensile stress to exceed the concrete design tensile strength and trigger cracks. In the existing technology, the configuration of steel bars can only limit the development of cracks, and the occurrence of cracks cannot be avoided, and the construction is complicated.
High-tough concrete is poured in the stress concentration section of the anti-seepage wall casting area, combined with ordinary concrete, reduce the steel bar configuration steps, simplify construction, and reduce working stress through terrain excavation.
It effectively avoids cracking of anti-seepage wall structure, reduces construction complexity, and ensures the long-term safe operation of the dam.
Smart Images
Figure CN223003430U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of hydropower and water conservancy projects, in particular to a concrete cut-off wall structure adapted to stress concentration in the bedrock constraint area. Background Art
[0002] When building a dam to form a reservoir on a deep overburden layer of a riverbed, measures such as using a concrete cut-off wall to penetrate the overburden layer are often adopted to solve the reservoir seepage prevention problem. When the bottom of the cut-off wall extends into the bedrock, due to the constraint of the bedrock, stress concentration will occur, so there is generally an area where the local tensile stress of the cut-off wall exceeds the designed tensile strength of the concrete. Especially at the abrupt changes and sharp corners of the terrain on both banks, this phenomenon will be more obvious.
[0003] In engineering practice, generally, steel bars are arranged in the wall to limit the development and scale of cracks, but there are the following problems in doing so:
[0004] (1) Arranging steel bars in the wall can only limit the crack development of the cut-off wall and cannot fundamentally avoid the occurrence of cracks;
[0005] (2) Arranging steel bars in the wall requires making a steel cage, taking reinforcement measures to prevent the steel bars from deforming, and also requires hoisting and installing them in place. The overall structure is complex and the construction is troublesome;
[0006] (3) Due to the existence of the bedrock constraint area, it is almost inevitable for cracks to appear in the concrete cut-off wall. For the safe operation of the dam, the major potential safety hazard problem has not been fundamentally solved. Content of the Utility Model
[0007] The purpose of the utility model is to overcome the above-mentioned deficiencies of the prior art and provide a concrete cut-off wall structure adapted to stress concentration in the bedrock constraint area, which can solve the problems of complex structure of the wall with steel bars arranged and the inability to avoid cracks in the concrete cut-off wall.
[0008] To this end, the utility model adopts the following technical solutions:
[0009] A concrete cut-off wall structure adapted to stress concentration in the bedrock constraint area includes a cut-off wall pouring area. At the junction of the lower part of the cut-off wall pouring area and the bedrock surface, there is a stress concentration section, high-toughness concrete is poured in the stress concentration section, and ordinary concrete is poured in the cut-off wall pouring area outside the stress concentration section.
[0010] On the basis of adopting the above technical solutions, the utility model can also adopt the following further technical solutions, or use these further technical solutions in combination:
[0011] The cut-off wall pouring area includes a number of first-stage pouring areas and a number of second-stage pouring areas, and the first-stage pouring areas and the second-stage pouring areas are arranged at intervals.
[0012] The high-toughness concrete includes first-phase high-toughness concrete and second-phase high-toughness concrete. The first-phase high-toughness concrete is poured in the overlapping area between the first-phase pouring area and the stress concentration section, and the second-phase high-toughness concrete is poured in the overlapping area between the second-phase pouring area and the stress concentration section.
[0013] The ordinary concrete includes first-phase ordinary concrete located in the first-phase pouring area and second-phase ordinary concrete located in the second-phase pouring area.
[0014] The bottom of the cutoff wall pouring area includes a cutoff wall bottom surface located in the middle area and cutoff wall bottom platforms located on both sides of the cutoff wall bottom surface. The cutoff wall bottom platforms are higher than the cutoff wall bottom surface. The cutoff wall bottom platforms are formed after the mutation and sharp corners in the bedrock are excavated. The depth of the cutoff wall bottom surface extending downward into the bedrock surface is greater than or equal to 1 m.
[0015] The width of the first-phase pouring area / the second-phase pouring area is 6 m to 8 m.
[0016] Compared with the prior art, the present utility model has the following advantages and beneficial effects: It reduces construction steps such as arranging steel bars in the cutoff wall body, simplifies the construction process; in the bedrock constraint area and terrain mutation parts, the terrain is first excavated and shaped to reduce the working stress of the cutoff wall; high-toughness concrete is poured in the parts where the stress in the cutoff wall pouring area exceeds the standard, making full use of its high tensile strength performance to avoid the problem of cutoff wall structure cracking and ensure the long-term safe operation of the dam. Description of the Drawings
[0017] Figure 1 It is a front elevation schematic diagram of the present utility model. Detailed Embodiments
[0018] In order to enable those skilled in the art to better understand the technical solutions of the present utility model, the preferred implementation schemes of the present utility model are described below in conjunction with specific embodiments. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar functional elements from beginning to end. However, it should be understood that the drawings are only for illustrative purposes and cannot be construed as a limitation to the present utility model; for better illustrating this embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as a limitation to the present utility model.
[0019] The present utility model will be further described below in conjunction with the drawings and embodiments, but it shall not be used as a basis for limiting the present utility model.
[0020] A concrete cut-off wall structure adapted to stress concentration in the bedrock constraint area provided by the utility model includes a cut-off wall pouring area 1. A stress concentration section 3 is provided at the junction of the lower part of the cut-off wall pouring area 1 and the bedrock surface 2. High-toughness concrete 4 is poured in the stress concentration section 3, and ordinary concrete 5 is poured in the cut-off wall pouring area 1 outside the stress concentration section 3.
[0021] The cut-off wall pouring area 1 includes a number of first-stage pouring areas 11 and a number of second-stage pouring areas 12, and the first-stage pouring areas 11 and the second-stage pouring areas 12 are arranged at intervals.
[0022] In this embodiment, the cut-off wall pouring area 1 is constructed in two stages. The width of the first-stage pouring area 11 / second-stage pouring area 12 is 6m to 8m, and it is formed by excavating with a drilling, digging (milling) groove machine in a loose pervious foundation or dam body with slurry-supported wall.
[0023] In this embodiment, the distribution area of the stress concentration section 3 is determined according to the calculation results in the following steps. Generally, tensile stress exceeding the tensile strength of ordinary concrete is likely to occur at the sudden change of the slope on both banks and the contact area between the bottom of the cut-off wall and the bedrock surface. Therefore, high-toughness concrete 4 is poured at the stress concentration section 3.
[0024] The high-toughness concrete 4 in this embodiment is an existing fiber-reinforced cement-based composite material that can be directly purchased, and is composed of raw materials such as cementitious materials, aggregates, admixtures, and synthetic fibers. After being stirred, formed, and cured with water in a certain proportion, the standard value of the cube compressive strength is not less than 50N / mm 2 and the equivalent flexural strength is not less than 9N / mm 2 .
[0025] The ordinary concrete 5 in this embodiment can also be directly purchased.
[0026] The high-toughness concrete 4 includes first-stage high-toughness concrete 41 and second-stage high-toughness concrete 42. The first-stage high-toughness concrete 41 is poured in the overlapping area of the first-stage pouring area 11 and the stress concentration section 3, and the second-stage high-toughness concrete 42 is poured in the overlapping area of the second-stage pouring area 12 and the stress concentration section 3.
[0027] The ordinary concrete 5 includes first-stage ordinary concrete 51 located in the first-stage pouring area 11 and second-stage ordinary concrete 52 located in the second-stage pouring area 12. Only the positions of one first-stage ordinary concrete 51 and one second-stage ordinary concrete 52 are schematically marked in the attachment of this embodiment. Figure 1 Among them, only the positions of one first-stage ordinary concrete 51 and one second-stage ordinary concrete 52 are schematically marked.
[0028] In this embodiment, the thickness of the cut-off wall is 50 to 100 cm, and the larger value is taken for projects with high importance and large cut-off wall height.
[0029] The bottom of the cutoff wall pouring area 1 includes the cutoff wall bottom surface 6 in the middle area and the cutoff wall bottom platforms 7 on both sides of the cutoff wall bottom surface 6. The cutoff wall bottom platforms 7 are higher than the cutoff wall bottom surface 6. The cutoff wall bottom platforms 7 are formed after the mutation and sharp corners in the bedrock are excavated. The depth that the cutoff wall bottom surface 6 extends downward into the bedrock surface 2 is greater than or equal to 1 m, and the cutoff wall bottom platforms 7 are smoothly connected to the cutoff wall bottom surface 6.
[0030] As Figure 1 shown, Figure 1 the dotted line in
[0031] shows the position of its bottom bedrock surface 2 (the hard rock surface below the riverbed overburden layer), as well as the mutations and sharp corners in the bedrock.
[0032] A concrete cutoff wall structure adapted to stress concentration in the bedrock constraint area provided by the present utility model has the following construction process:
[0033] 1. According to the two-dimensional or three-dimensional finite element calculation results, preliminarily determine the area where the tensile stress of the cutoff wall in the bedrock constraint area exceeds the standard (stress concentration section 3) and the maximum stress value.
[0034] 2. The area where the tensile stress of the cutoff wall exceeds the standard generally occurs at the sudden changes and sharp corners of the terrain on both banks. Excavate such terrain, remove the mutated terrain to form the cutoff wall bottom platforms 7, and then re-conduct two-dimensional or three-dimensional finite element calculations.
[0035] 3. Initially propose multiple terrain excavation schemes. According to the two-dimensional or three-dimensional finite element calculation results, determine the area where the tensile stress of the concrete cutoff wall in the bedrock constraint area exceeds the standard and the maximum value for each excavation scheme. Generally, the area where the tensile stress exceeds the standard at this time is smaller than the first calculation area. Considering various factors such as project investment and technical feasibility, comprehensively compare and select to determine the terrain excavation scheme.
[0036] 4. In this embodiment, first excavate the first-stage pouring area 11, pour the first-stage high-toughness concrete 41 in the overlapping area between the first-stage pouring area 11 and the stress concentration section 3, and pour the first-stage ordinary concrete 51 after the first-stage high-toughness concrete 41 solidifies.
[0037] 5. Excavate the second-stage pouring area 12, pour the second-stage high-toughness concrete 42 in the overlapping area between the second-stage pouring area 12 and the stress concentration section 3, and pour the second-stage ordinary concrete 52 after the second-stage high-toughness concrete 42 solidifies.
[0038] The design value of the tensile strength ft of the high-toughness concrete can reach 3.8 - 4 MPa, which is about 3.5 times the design value of the tensile strength of C20 concrete, 1.1 MPa.
[0039] Before construction, it is also necessary to note:
[0040] It is necessary to compare the maximum tensile stress of the cutoff wall from the secondary calculation results of two-dimensional or three-dimensional finite elements with the designed tensile strength ft of the high-toughness concrete: If the maximum value is less than ft, then the high-toughness concrete is poured in two phases at the stress concentration section 3.
[0041] If the calculated maximum tensile stress of the cutoff wall is greater than ft, then appropriately thicken the thickness of the cutoff wall until the maximum tensile stress of the cutoff wall is less than the designed tensile strength ft of the high-toughness concrete. At the parts where the tensile stress of the concrete cutoff wall in the bedrock constraint area exceeds the standard, pour the high-toughness concrete. Engineering practice shows that it is very rare for the calculated maximum tensile stress of the cutoff wall to be greater than 4 MPa.
[0042] The high-toughness concrete extends into the bedrock surface 2 by no less than 1.0 m. The actual pouring range should be slightly larger than the area of the calculation results, generally preferably greater than 1 m. The top elevation of the high-toughness concrete is a horizontal plane, and the bottom is a topographic platform or gentle slope, with a thickness of 50 - 100 cm. Calculate the engineering quantity of the high-toughness concrete for each cutoff wall section according to the thickness of the cutoff wall, the bottom and top elevations; when constructing each wall section, pour the corresponding volume.
[0043] Other parts of the cutoff wall are implemented according to the standard design.
[0044] Based on the description and drawings of the present utility model, those skilled in the art can easily manufacture or use a concrete cutoff wall structure adapted to stress concentration in the bedrock constraint area of the present utility model and can achieve the positive effects recorded in the present utility model.
[0045] It should be noted that the terms "comprising" and "having" and any variations thereof in the description, claims and above-mentioned drawings of the present utility model are intended to cover non-exclusive inclusion. The terms "installed", "set", "provided with", "connected", "linked", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two mechanisms, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0046] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by terms such as "one end", "the other end", "outer side", "inner side", "horizontal", "end portion", "length", "outer end", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the indicated mechanism or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. The terms "first" and "second" are also used only for the sake of brevity in description and do not indicate or imply relative importance.
[0047] In addition, when practicing the claims of the present utility model, those skilled in the art can understand and influence the variations of the disclosed embodiments through the study of the drawings, the disclosure, and the appended claims. In addition, in the claims and the specification, words such as "comprising", "containing", etc. do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.
[0048] The above are only the preferred embodiments of the present utility model and are not used to limit the scope of implementation of the present utility model. That is, all equal changes and modifications made in accordance with the present utility model are covered by the scope of the claims of the present utility model, and no further examples will be given here.
Claims
1. A concrete anti-seepage wall structure adapted to stress concentration in bedrock constraint zone, characterized in that: The invention comprises an anti-seepage wall casting area (1), wherein a stress concentration section (3) is provided at the intersection of the lower part of the anti-seepage wall casting area (1) and the bedrock surface (2), the stress concentration section (3) is cast with high-toughness concrete (4), and ordinary concrete (5) is cast in the anti-seepage wall casting area (1) outside the stress concentration section (3).
2. A concrete anti-seepage wall structure adapted to stress concentration in bedrock constraint zone as claimed in claim 1, characterized in that: The anti-seepage wall casting area (1) comprises a plurality of first-phase casting areas (11) and a plurality of second-phase casting areas (12), wherein the first-phase casting areas (11) and the second-phase casting areas (12) are arranged at intervals.
3. A concrete anti-seepage wall structure adapted to stress concentration in bedrock constraint zone as claimed in claim 2, characterized in that: The high-toughness concrete (4) comprises a first-stage high-toughness concrete (41) and a second-stage high-toughness concrete (42); the first-stage high-toughness concrete (41) is cast in an overlapping area between the first-stage casting area (11) and the stress concentration section (3); and the second-stage high-toughness concrete (42) is cast in an overlapping area between the second-stage casting area (12) and the stress concentration section (3).
4. A concrete anti-seepage wall structure adapted to stress concentration in bedrock constraint zone as claimed in claim 2, characterized in that: The ordinary concrete (5) comprises first-phase ordinary concrete (51) located in the first-phase pouring area (11) and second-phase ordinary concrete (52) located in the second-phase pouring area (12).
5. A concrete anti-seepage wall structure adapted to stress concentration in bedrock constraint zone as claimed in claim 1, characterized in that: The bottom of the anti-seepage wall casting area (1) comprises an anti-seepage wall bottom surface (6) located in the middle area and an anti-seepage wall bottom platform (7) located on both sides of the anti-seepage wall bottom surface (6), the anti-seepage wall bottom platform (7) is higher than the anti-seepage wall bottom surface (6), and the anti-seepage wall bottom platform (7) is formed by removing abrupt changes and sharp corners in the bedrock, and the depth of the anti-seepage wall bottom surface (6) extending downward into the bedrock surface (2) is greater than or equal to 1m.
6. A concrete anti-seepage wall structure adapted to stress concentration in bedrock constraint zone as claimed in claim 2, characterized in that: The width of the first-phase pouring area (11) / the second-phase pouring area (12) is 6m to 8m.