A concrete face rockfill dam panel anti-cracking and anti-permeation structure, a design zoning determination method and a construction method thereof

Abstract

The application discloses a concrete face rockfill dam panel anti-cracking and anti-permeation structure, a design partition determination method and a construction method, and relates to the field of dam construction. The anti-cracking and anti-permeation structure comprises a concrete panel mixed with a self-repairing anti-permeation additive, and the outer side of the concrete panel is provided with a concrete anti-cracking layer, and the concrete of the concrete anti-cracking layer is super high performance concrete. During construction, the self-repairing anti-permeation additive is mixed in the concrete, and then the concrete panel is poured. After the pouring of the concrete panel is completed and the concrete is preliminarily solidified, super high performance concrete is proportioned, and a layer of the super high performance concrete is coated on the outer side of the concrete panel to form the concrete anti-cracking layer. The application can avoid the cracking of the panel to the maximum extent, and can self-repair and prevent permeation after cracking, thereby ensuring the safe operation of the dam. The application has the advantages of convenient construction, high construction efficiency, and good anti-permeation performance of the completed panel.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic structure engineering, and particularly relates to a concrete face slab anti-cracking and anti-permeation structure of a concrete face slab rock-fill dam, and a design zoning determination method and a construction method thereof. BACKGROUND

[0002] The concrete face slab rock-fill dam is a common dam type, and cracking of the face slab is the most common problem that plagues the dam field, and the cracking of the face slab seriously affects long-term safe operation of the dam. Cracks generated in the concrete face slab rock-fill dam are divided into two categories: 1) structural cracks caused by external force; and 2) non-structural cracks caused by too fast evaporation of water in the face slab and too large temperature difference of the face slab. Therefore, the method for preventing cracking of the face slab needs to be considered from two aspects of reducing deformation of the face slab and improving crack resistance of the face slab. At present, the repair methods of the concrete face slab are different due to different causes of the cracks, and the treatment of the cracks of the face slab is very complex. SUMMARY

[0003] In view of the above problems, the application aims to provide a concrete face slab rock-fill dam face slab anti-cracking and anti-permeation structure, which is stable in structure, can avoid cracking of the face slab to the greatest extent, and can self-heal and prevent permeation after cracking to ensure safe operation of the dam.

[0004] Another object of the application is to provide a design zoning determination method and a construction method of the concrete face slab rock-fill dam face slab anti-cracking and anti-permeation structure, which is convenient and efficient in construction and has good anti-permeation performance of the face slab after construction.

[0005] To achieve the above objects, the application adopts the following technical solutions.

[0006] A concrete face slab rock-fill dam face slab anti-cracking and anti-permeation structure comprises a concrete face slab mixed with a self-healing anti-permeation additive, and a concrete crack-resistant layer is arranged on the outer side of the concrete face slab, and the concrete of the concrete crack-resistant layer is ultra-high performance concrete; the content of the self-healing anti-permeation additive is 5% to 7% of the cementitious material in the concrete.

[0007] Further, the weight ratio of the ultra-high performance concrete is as follows: water 7% to 8%, cement 20% to 35%, quartz powder 0% to 4%, silicon powder 4% to 8%, high-efficiency water reducing agent 1% to 2%, fiber 4% to 6%, fly ash 0% to 13%, and quartz sand 40% to 50%.

[0008] The linear expansion coefficient of the ultra-high performance concrete is less than or equal to u , and u is calculated as follows:

[0009] Assuming that ΔT is the temperature difference of the whole concrete crack-resistant layer and the bottom concrete face slab, which is the difference between the average temperature of the concrete face slab and the lowest temperature, then

[0010] ΔT = ΔT y + ΔT d + ΔT c (1)

[0011] In the formula, ΔT y is half of the annual temperature change; ΔT d is half of the daily temperature change, which is half of the difference between the daily maximum temperature and the daily minimum temperature; ΔT c is the overall temperature reduction of the concrete crack-resistant layer and the bottom concrete panel, and ΔT c = 6℃;

[0012] The crack-resistant safety factor K of the ultra-high performance concrete is calculated according to the following formula:

[0013]

[0014] In the formula, ε g is the autogenous volume deformation of the ultra-high performance concrete; α u is the linear expansion coefficient of the ultra-high performance concrete; α d is the linear expansion coefficient of the lower concrete panel; R l is the tensile strength of the ultra-high performance concrete; ε ud is the allowable dry shrinkage strain of the surface ultra-high performance concrete, and ε u = 100uε; E u is the elastic modulus of the ultra-high performance concrete; and P is the action coefficient of the deformation of the lower concrete panel on the stress of the ultra-high performance concrete, and P = 0.6-0.8.

[0015] The linear expansion coefficient α u of the ultra-high performance concrete is calculated according to the following formula:

[0016]

[0017] Further, an outer side of the concrete crack-resistant layer is provided with a viscoelastic surface anti-seepage coating, and the viscoelastic surface anti-seepage coating comprises a bonding bottom layer, a rough anti-seepage layer and a surface protection layer connected in sequence, and the bonding bottom layer is bonded to the outer side of the concrete crack-resistant layer.

[0018] Further, the viscoelastic surface anti-seepage coating is a polyfluorosilicon anti-seepage coating.

[0019] Further, the elastic modulus of the concrete crack-resistant layer is 40-60GPa, the tensile strength is 7-15MPa, the tensile strength and the elastic limit tensile strength are ≥1.1, and the ultimate tensile strain is ≥1500uε.

[0020] A kind of design zoning determination method of the concrete face rockfill dam panel anti-cracking impermeable structure, by determining the thickness of the concrete crack resistance layer, the thickness of the concrete crack resistance layer is greater than or equal to critical thickness b u , critical thickness b u Calculation process is as follows:

[0021] The structural force N1 of concrete panel under temperature drop, dry shrinkage and interaction with rockfill structure is calculated as follows:

[0022] N1=σ1A1 (4)

[0023]

[0024] D l =(L-L1) (6)

[0025]

[0026] In the formula: L is the axial length of concrete panel, σ1 is the maximum tensile stress of concrete panel caused by temperature drop and dry shrinkage, A1 is the cross-sectional area of concrete panel, b0 is the length of the top surface of concrete panel, L1 is the length of the fixed point of concrete panel from the bottom end of concrete panel, ξ is the slope angle of panel dam, α is the thickness variation rate of concrete panel, is the friction angle of concrete panel and rockfill body, C is the cohesion between concrete panel and rockfill body; ρ is the unit weight of concrete panel;

[0027] The calculation process of temperature force N2 in the concrete panel caused by temperature drop and dry shrinkage is as follows:

[0028] N2=σ2A1 (10)

[0029]

[0030] In the formula: σ2 is the temperature stress of concrete panel, which is obtained by finite element simulation calculation, E is the elastic modulus of concrete panel, α c is the linear expansion coefficient of concrete panel, T is the temperature of concrete panel, μ is the poisson's ratio of concrete panel;

[0031] The calculation process of the allowable bearing capacity N of concrete crack resistance layer is as follows:

[0032] N=σ t Lb u (12)

[0033] In the formula: σ t is the ultimate tensile strength of concrete crack resistance layer, b u is the critical thickness of concrete crack resistance layer;

[0034] Let N=N1+N2, then the critical thickness b of the concrete crack resistance layer satisfying the crack resistance requirement can be obtained u As shown in the following formula:

[0035]

[0036] A construction method of a concrete face slab rock-fill dam face slab crack resistance and impermeability structure, comprising the following steps:

[0037] A. After mixing a self-healing impermeability additive in the concrete, pouring the concrete face slab; the mixing amount of the self-healing impermeability additive is 5% to 7% of the cementitious material in the concrete, and the self-healing impermeability additive is mixed in the mixing tank together with the concrete during the mixing of the concrete;

[0038] B. After the pouring of the concrete face slab is completed and the preliminary solidification, the super high performance concrete is proportioned, and the weight proportioning of the super high performance concrete is as follows: water 7% to 8%, cement 20% to 35%, quartz powder 0% to 4%, silicon powder 4% to 8%, high efficiency water reducing agent 1% to 2%, fiber 4% to 6%, fly ash 0% to 13%, and quartz sand 40% to 50%;

[0039] The linear expansion coefficient of the proportioned super high performance concrete is less than or equal to α u , and the calculation process of α u is as follows:

[0040] Assuming that ΔT is the temperature difference of the overall temperature of the concrete crack resistance layer and the bottom concrete face slab, which is the difference between the average temperature of the concrete face slab and the lowest temperature, then

[0041] ΔT=ΔT y +ΔT d +ΔT c (1)

[0042] In the formula, ΔT y is half of the annual temperature change; ΔT d is half of the daily temperature change, which is half of the difference between the daily maximum temperature and the minimum temperature; and ΔT c is the overall temperature reduction amplitude of the concrete crack resistance layer and the bottom concrete face slab, and ΔT c =6℃.

[0043] The crack resistance safety factor K of the super high performance concrete is calculated according to the following formula:

[0044]

[0045] In the formula, ε g is the autogenous volume deformation of the super high performance concrete; α u is the linear expansion coefficient of the super high performance concrete; and α dis the linear expansion coefficient of the lower concrete panel; R l is the tensile strength of the ultra-high performance concrete; ε ud is the allowable dry shrinkage strain of the surface ultra-high performance concrete, taken as 100με; E u is the elastic modulus of the ultra-high performance concrete; P is the action coefficient of the deformation of the lower concrete panel on the stress of the ultra-high performance concrete, taken as P = 0.6-0.8;

[0046] The linear expansion coefficient α u of the ultra-high performance concrete is then obtained.

[0047]

[0048] When all limestone aggregates are used and the value of α u calculated by formula (3) cannot be less than or equal to, the mix ratio of the ultra-high performance concrete is modified to increase R l , so that the linear expansion coefficient of the ultra-high performance concrete after the mix ratio is completed is less than or equal to α u .

[0049] C. A layer of the ultra-high performance concrete is applied to the outer side of the concrete panel to form a concrete anti-cracking layer.

[0050] Further, the thickness of the concrete anti-cracking layer is greater than or equal to the critical thickness b u , and the critical thickness b u is calculated as follows:

[0051] The calculation process of the structural force N1 generated by the interaction of the concrete panel with the rockfill structure under temperature drop and dry shrinkage is as follows:

[0052] N1 = σ1A1 (4)

[0053]

[0054] In the formula, L is the axial length of the concrete panel, σ1 is the maximum tensile stress of the concrete panel generated by temperature drop and dry shrinkage, A1 is the cross-sectional area of the concrete panel, b0 is the length of the top surface of the concrete panel, L1 is the length of the fixed point of the concrete panel from the bottom end of the concrete panel, ξ is the dam slope angle of the panel, α is the thickness variation rate of the concrete panel, is the friction angle of the concrete panel and the rockfill structure, C is the cohesion between the concrete panel and the rockfill structure; and ρ is the unit weight of the concrete panel.

[0055] The calculation process of the temperature force N2 inside the concrete panel caused by temperature drop and dry shrinkage is as follows:

[0056] N2 = σ2A1 (10)

[0057]

[0058] wherein: σ2 is the temperature stress of the concrete panel, which is calculated by finite element simulation, E is the elastic modulus of the concrete panel, α c is the linear expansion coefficient of the concrete panel, T is the temperature of the concrete panel, and μ is the Poisson's ratio of the concrete panel;

[0059] The calculation process of the allowable bearing capacity N of the concrete anti-cracking layer is as follows:

[0060] N = σ t Lb u (12)

[0061] wherein: σ t is the ultimate tensile strength of the concrete anti-cracking layer, b u is the critical thickness of the concrete anti-cracking layer;

[0062] N = N1 + N2, the critical thickness b u of the concrete anti-cracking layer that meets the anti-cracking requirement can be obtained, as shown in the following formula:

[0063]

[0064] Further, after the ultra-high performance concrete is initially solidified, a layer of viscoelastic surface anti-seepage coating is coated on the surface of the concrete anti-cracking layer; the viscoelastic surface anti-seepage coating comprises, in sequence, a bonding bottom layer, a rough anti-seepage layer and a surface protection layer, the bonding bottom layer is bonded to the outer side of the concrete anti-cracking layer and penetrates into the concrete anti-cracking layer.

[0065] Further, the viscoelastic surface anti-seepage coating is a polyfluorosilicon anti-seepage coating.

[0066] The concrete panel anti-cracking and anti-seepage structure of the concrete face rockfill dam, the partition determination method and the construction method have the advantages that the structure is stable, has better anti-cracking property and smaller panel deformation, can avoid panel cracking to the greatest extent, and after cracking, the concrete can be chemically reacted again to automatically heal the concrete cracks, ensure the safe operation of the dam, the construction is convenient, the construction efficiency is high, and the constructed panel has good anti-seepage performance. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 is a structural schematic view of the concrete panel anti-cracking and anti-seepage structure of the concrete face rockfill dam. DETAILED DESCRIPTION

[0068] The structure and the technical effects to be achieved of the present application will be described below in combination with specific embodiments and the drawings, but the selected embodiments are only used for description and explanation, and are not used to limit the scope of the present application.

[0069] As shown in Figure 1 , the present application provides a concrete face rockfill dam panel anti-cracking and anti-permeation structure, comprising a concrete panel 1 mixed with a self-repairing anti-permeation additive, and a concrete anti-cracking layer 2 provided on the outer side of the concrete panel 1, wherein the concrete of the concrete anti-cracking layer 2 is ultra-high performance concrete (UHPC).

[0070] Specifically, the concrete panel mixed with the self-repairing anti-permeation additive has an additive content of 5% to 7% of cementitious materials, and the additive is mixed into the mixing tank together with the concrete during the mixing of the concrete.

[0071] The ultra-high performance concrete has a ratio of 7% to 8% of water, 20% to 35% of cement, 0% to 4% of quartz powder, 4% to 8% of silica powder, 1% to 2% of high-efficiency water-reducing agent, 4% to 6% of fiber, 0% to 13% of fly ash, and 40% to 50% of quartz sand, and the high-efficiency water-reducing agent can be polyhydroxy acid water-reducing agent, and the fiber can be organic fiber and / or steel fiber.

[0072] The linear expansion coefficient of the ultra-high performance concrete is less than or equal to α u , and the calculation process of α u is as follows:

[0073] Assuming that ΔT is the temperature difference of the overall temperature of the concrete anti-cracking layer and the bottom concrete panel, which is the difference between the average temperature of the concrete panel and the lowest temperature, then

[0074] ΔT = ΔT y + ΔT d + ΔT c (1)

[0075] In the formula, ΔT y is half of the annual temperature change. ΔT d is half of the daily temperature change, which is half of the difference between the highest temperature and the lowest temperature in a day. ΔT c is the overall temperature reduction range of the concrete anti-cracking layer and the bottom concrete panel, and ΔT c = 6℃.

[0076] The anti-cracking safety factor K of the ultra-high performance concrete is calculated according to the following formula:

[0077]

[0078] In the formula, ε g is the self-generated volume deformation of the ultra-high performance concrete. α u is the linear expansion coefficient of the ultra-high performance concrete. α d is the linear expansion coefficient of the concrete panel below. R l is the tensile strength of the ultra-high performance concrete. ε udE represents the allowable drying shrinkage strain of the ultra-high performance concrete surface, taken as 100uε. u P is the elastic modulus of ultra-high performance concrete. P is the coefficient of influence of the deformation of the lower concrete panel on the stress of the ultra-high performance concrete, taken as P = 0.6 to 0.8.

[0079] Then calculate the linear expansion coefficient α of ultra-high performance concrete. u :

[0080]

[0081] Furthermore, the present invention also provides a method for determining the design zoning of the anti-crack and anti-seepage structure of a concrete-faced rockfill dam panel. Zoning is performed by determining the thickness of the concrete anti-crack layer 2, separating the concrete panel 1 and the concrete anti-crack layer 2, wherein the thickness of the concrete anti-crack layer 2 is greater than or equal to the critical thickness b. u The elastic modulus is 40-60 GPa, the tensile strength is 7-15 MPa, the tensile strength and elastic limit tensile strength are ≥1.1, and the ultimate tensile strain is ≥1500 uε. The ultimate tensile strain of ordinary concrete is usually about 100 uε, while the ultimate tensile strain of the ultra-high performance concrete of this invention is ≥1500 uε, and the crack resistance of ultra-high performance concrete is significantly improved compared with ordinary concrete.

[0082] Critical thickness b u The calculation process is as follows:

[0083] The concrete crack-resistant layer mainly bears two types of forces to limit the formation of cracks: one is the structural force N1 generated by the interaction between the concrete panel and the riprap structure under temperature drop and drying shrinkage conditions; the other is the temperature force N2 inside the concrete panel caused by temperature drop and drying shrinkage.

[0084] When the allowable bearing capacity N of the concrete crack-resistant layer is greater than or equal to N1+N2, the concrete crack-resistant layer meets the crack resistance requirements.

[0085] The calculation process for the structural force N1 generated by the concrete panel interacting with the riprap structure under conditions of temperature drop and drying shrinkage is as follows:

[0086] N1=σ1A1 (4)

[0087]

[0088] In the formula: L is the axial length of the concrete panel, σ1 is the maximum tensile stress of the structure caused by temperature drop and drying shrinkage of the concrete panel, A1 is the cross-sectional area of ​​the concrete panel, b0 is the length of the top surface of the concrete panel, L1 is the length from the fixed point of the concrete panel to the bottom of the concrete panel, ξ is the slope angle of the panel dam, and α is the thickness variation rate of the concrete panel. Wherein, f is the friction angle of the concrete face slab and the rockfill body, C is the cohesion between the concrete face slab and the rockfill body, and p is the unit weight of the concrete face slab.

[0089] The calculation process of the temperature force N2 in the concrete face slab caused by temperature drop and dry shrinkage is as follows:

[0090] N2 = σ2A1 (10)

[0091]

[0092] Wherein, σ2 is the temperature stress of the concrete face slab, which can also be calculated by finite element simulation, E is the elastic modulus of the concrete face slab, α is the linear expansion coefficient of the concrete face slab, T is the temperature of the concrete face slab, and μ is the Poisson's ratio of the concrete face slab. c

[0093] The calculation process of the allowable bearing capacity N of the concrete anti-cracking layer is as follows:

[0094] N = σ t Lb u (12)

[0095] Wherein, σ t is the ultimate tensile strength of the concrete anti-cracking layer, b u is the critical thickness of the concrete anti-cracking layer.

[0096] The critical thickness b of the concrete anti-cracking layer satisfying the anti-cracking requirement can be obtained by making N = N1 + N2, and is shown in the following formula: u

[0097]

[0098] In order to improve the anti-seepage performance of the concrete face slab 1, an elastoviscous surface anti-seepage coating 3, such as a polyfluorosilicon anti-seepage coating, is arranged outside the concrete anti-cracking layer 2. Further, the elastoviscous surface anti-seepage coating 3 comprises a bonding bottom layer, a rough anti-seepage layer and a surface protection layer connected in sequence, and the bonding bottom layer is bonded to the outer surface of the concrete anti-cracking layer 2. The limit tensile strain of the three-layer structure of the panel anti-cracking and anti-seepage structure of the application is ranked as follows: elastoviscous surface anti-seepage coating > concrete anti-cracking layer > concrete face slab.

[0099] The application further provides a construction method of the panel anti-cracking and anti-seepage structure of the concrete face slab rockfill dam, which comprises the following steps:

[0100] A. After mixing a self-healing anti-seepage additive in the concrete, the concrete face slab 1 is poured; the mixing amount of the self-healing anti-seepage additive is 5% to 7% of the cementitious material, and the self-healing anti-seepage additive is mixed in the mixing tank together with the concrete when the concrete is stirred;

[0101] ​​B.After the concrete panel 1 is poured and initially solidified, the super high performance concrete is prepared, and the super high performance concrete is prepared as follows: water 7% to 8%, cement 20% to 35%, quartz powder 0% to 4%, silicon powder 4% to 8%, high efficiency water reducing agent 1% to 2%, fiber 4% to 6%, fly ash 0% to 13%, and quartz sand 40% to 50%. The high efficiency water reducing agent can be polyhydroxy acid water reducing agent, and the fiber can be organic fiber and / or steel fiber.

[0102] The linear expansion coefficient of the prepared super high performance concrete is less than or equal to α u , and α u is calculated as follows:

[0103] The deformation of the concrete crack resistant layer is synchronized with the deformation of the lower concrete panel after the humidity changes. Assuming that ΔT is the temperature difference of the concrete crack resistant layer and the lower concrete panel, which is the difference between the average temperature of the concrete panel and the minimum temperature, then

[0104] ΔT = ΔT y + ΔT d + ΔT c (1)

[0105] In the formula, ΔT y is half of the annual temperature change; ΔT d is half of the daily temperature change, which is half of the difference between the daily maximum temperature and the minimum temperature; ΔT c is the temperature reduction of the concrete crack resistant layer and the lower concrete panel, and ΔT c = 6℃.

[0106] The crack safety factor K of the super high performance concrete is calculated as follows:

[0107]

[0108] In the formula, ε g is the autogenous volume deformation of the super high performance concrete; α u is the linear expansion coefficient of the super high performance concrete; α d is the linear expansion coefficient of the lower concrete panel; R l is the tensile strength of the super high performance concrete; ε ud is the allowable dry shrinkage strain of the surface super high performance concrete, and ε u = 100uε; E u is the elastic modulus of the super high performance concrete; and P is the stress action coefficient of the deformation of the lower concrete panel on the super high performance concrete, and P = 0.6 to 0.8.

[0109] Then the linear expansion coefficient α u of the super high performance concrete is obtained.

[0110]

[0111] When designing the mix proportion of the ultra-high performance concrete, the linear expansion coefficient calculated according to the formula (3) is taken as the target, the proportion of the limestone aggregate in the mix proportion is adjusted so that the linear expansion coefficient is less than or equal to α u When all the limestone aggregate is used and the value of α u calculated according to the formula (3) cannot be met, the mix proportion of the ultra-high performance concrete is modified, the R l is increased, so that the linear expansion coefficient of the ultra-high performance concrete after the mix proportion is completed is less than or equal to α u .

[0112] C. A layer of the ultra-high performance concrete is applied to the outer side of the concrete panel to form the concrete anti-cracking layer 2, and the manual flat scraping method can be used for construction.

[0113] Specifically, the thickness of the concrete anti-cracking layer is greater than or equal to the critical thickness b u , and the critical thickness b u is calculated as follows:

[0114] The calculation process of the structural force N1 generated by the interaction between the concrete panel and the rockfill structure under the temperature drop and dry shrinkage is as follows:

[0115]

[0116] In the formula, L is the axial length of the concrete panel, σ1 is the maximum tensile stress of the concrete panel generated by the temperature drop and dry shrinkage, A1 is the cross-sectional area of the concrete panel, b0 is the length of the top surface of the concrete panel, L1 is the length of the fixed point of the concrete panel from the bottom end of the concrete panel, ξ is the dam slope angle of the panel, α is the thickness variation rate of the concrete panel, is the friction angle of the concrete panel and the rockfill body, C is the cohesion between the concrete panel and the rockfill body, and ρ is the unit weight of the concrete panel.

[0117] The calculation process of the temperature force N2 inside the concrete panel caused by the temperature drop and dry shrinkage is as follows:

[0118] N2 = σ2A1 (10)

[0119]

[0120] In the formula, σ2 is the temperature stress of the concrete panel, which is calculated by finite element simulation, E is the elastic modulus of the concrete panel, α c is the linear expansion coefficient of the concrete panel, T is the temperature of the concrete panel, and μ is the Poisson's ratio of the concrete panel.

[0121] The calculation process of the allowable bearing capacity N of the concrete anti-cracking layer is as follows:

[0122] N = σ t Lb u (12)

[0123] In the formula, σ t is the ultimate tensile strength of the concrete anti-cracking layer, b u is the critical thickness of the concrete anti-cracking layer;

[0124] N = N1 + N2, the critical thickness b u of the concrete anti-cracking layer meeting the anti-cracking requirement can be obtained, as shown in the following formula:

[0125]

[0126] In order to improve the anti-seepage performance, after the ultra-high performance concrete is initially solidified, a layer of viscoelastic surface anti-seepage coating 3, such as a polyfluorosilicon anti-seepage coating, is coated on the surface of the concrete anti-cracking layer 2. Further, the viscoelastic surface anti-seepage coating 3 comprises a bonding bottom layer, a rough anti-seepage layer and a surface protection layer connected in sequence. The bonding bottom layer is bonded to the outer side of the concrete anti-cracking layer and penetrates into the concrete anti-cracking layer 2 to strengthen the bonding with the concrete anti-cracking layer 2. The rough anti-seepage layer has excellent anti-seepage function and mainly plays a role of anti-seepage. The surface protection layer has high ultraviolet resistance to prevent aging of the anti-seepage coating. The limit tensile strain of the three-layer structure of the panel anti-cracking and anti-seepage structure of the application is in the order of: viscoelastic surface anti-seepage coating > concrete anti-cracking layer > concrete panel.

[0127] The self-healing type anti-seepage additive in the application plays a role that, when the concrete panel 1 appears seepage due to cracks and the like, free Ca(OH)2 in the concrete is precipitated and reacts with active silicon dioxide in the self-healing type anti-seepage additive to generate tricalcium silicate crystals to block the seepage channel, that is,

[0128] Ca(OH)2 + SiO2 → CaSiO3 + H2O

[0129] The concrete panel anti-cracking and anti-seepage structure of the concrete panel rock-fill dam of the application, the design zoning determination method and the construction method can not only increase the anti-cracking capacity of the concrete panel, but also enable the concrete to spontaneously generate a self-healing chemical reaction after cracks occur in the concrete panel, so as to achieve the effect of self-healing of the cracks. The application not only controls the generation of cracks, but also limits the development of cracks through self-healing of the concrete, thus providing an effective and feasible method for prevention and treatment of cracking of the concrete panel and improving the operation life of the concrete panel rock-fill dam.

[0130] The present application is defined by the claims. However, based on the disclosure given herein, those skilled in the art can make obvious or obvious variations or modifications of the application, which are also within the scope of the present application.

Claims

1. A crack-resistant and seepage-proof structure for concrete-faced rockfill dam panels, characterized in that, The concrete panel includes a self-healing anti-seepage admixture, and the outer surface of the concrete panel is provided with a concrete crack-resistant layer. The concrete in the crack-resistant layer is ultra-high performance concrete. The dosage of the self-healing anti-seepage admixture is 5% to 7% of the cementitious material in the concrete. The weight proportions of the ultra-high performance concrete are as follows: water 7%–8%, cement 20%–35%, quartz powder 0%–4%, silica fume 4%–8%, high-efficiency water-reducing agent 1%–2%, fiber 4%–6%, fly ash 0%–13%, and quartz sand 40%–50%. The coefficient of linear expansion of the ultra-high performance concrete is less than or equal to α. u α u The calculation process is as follows: Assuming ΔT is the temperature difference between the concrete crack-resistant layer and the bottom concrete panel, which is the difference from the average temperature of the concrete panel to its lowest temperature, then... ΔT=ΔT y +ΔT d +ΔT c (1) In the formula, ΔT y It is half of the annual temperature variation; ΔT d It is half of the daily temperature variation, which is half the difference between the daily maximum and minimum temperatures; ΔT c The overall temperature reduction of the concrete crack-resistant layer and the bottom concrete panel is represented by ΔT. c =6℃; The crack resistance safety factor K of the ultra-high performance concrete is calculated using the following formula: In the formula, ε g For the autogenous volume deformation of ultra-high performance concrete; α u α is the coefficient of linear expansion of ultra-high performance concrete. d R is the coefficient of linear expansion of the lower concrete panel; l The tensile strength of ultra-high performance concrete; ε ud E represents the allowable drying shrinkage strain of the ultra-high performance concrete surface, taken as 100uε; u P is the elastic modulus of ultra-high performance concrete; P is the coefficient of influence of the deformation of the lower concrete panel on the stress of ultra-high performance concrete, with P = 0.6 to 0.

8. Then calculate the linear expansion coefficient α of ultra-high performance concrete. u :

2. The anti-crack and seepage-resistant structure for concrete-faced rockfill dam panels according to claim 1, characterized in that: The outer side of the concrete crack-resistant layer is provided with a viscoelastic surface anti-seepage coating, which includes an adhesive underlayer, a rough anti-seepage layer, and a surface protective layer connected in sequence. The adhesive underlayer is bonded to the outer side of the concrete crack-resistant layer.

3. The anti-crack and anti-seepage structure for concrete-faced rockfill dam panels according to claim 2, characterized in that: The viscoelastic surface waterproofing coating is a polyfluorosilicone waterproofing coating.

4. The anti-crack and seepage-resistant structure for concrete-faced rockfill dam panels according to claim 1, characterized in that: The elastic modulus of the concrete crack-resistant layer is 40-60 GPa, the tensile strength is 7-15 MPa, the tensile strength and elastic limit tensile strength are ≥1.1, and the ultimate tensile strain is ≥1500 uε.

5. A method for determining the design zoning of the concrete-faced rockfill dam panel anti-crack and anti-seepage structure according to any one of claims 1-4, characterized in that: The concrete crack-resistant layer is divided into zones based on its thickness, which is greater than or equal to the critical thickness b. u Critical thickness b u The calculation process is as follows: The calculation process for the structural force N1 generated by the concrete panel interacting with the riprap structure under conditions of temperature drop and drying shrinkage is as follows: N1=σ1A1 (4) D l =(L-L1) (6) In the formula: L is the axial length of the concrete panel, σ1 is the maximum tensile stress of the structure caused by temperature drop and drying shrinkage of the concrete panel, A1 is the cross-sectional area of ​​the concrete panel, b0 is the length of the top surface of the concrete panel, L1 is the length from the fixed point of the concrete panel to the bottom of the concrete panel, ξ is the slope angle of the panel dam, and α is the thickness variation rate of the concrete panel. ρ is the friction angle between the concrete panel and the riprap, C is the cohesion between the concrete panel and the riprap, and ρ is the unit weight of the concrete panel. The calculation process for the temperature-induced force N2 inside the concrete panel caused by temperature drop and drying shrinkage is as follows: N2=σ2A1 (10) In the formula: σ2 is the temperature stress of the concrete panel, which is obtained through finite element simulation calculation; E is the elastic modulus of the concrete panel; α c denoted as the coefficient of linear expansion of the concrete panel, T as the temperature of the concrete panel, and μ as the Poisson's ratio of the concrete panel. The calculation process for the allowable bearing capacity N of the concrete crack-resistant layer is as follows: N=σ t Lb u (12) In the formula: σ t b is the ultimate tensile strength of the concrete crack-resistant layer. u This represents the critical thickness of the concrete crack-resistant layer. If N = N1 + N2, then the critical thickness b of the concrete crack-resistant layer that satisfies the crack resistance requirement can be obtained. u As shown in the following formula:

6. A construction method for a concrete-faced rockfill dam panel anti-crack and anti-seepage structure, characterized in that, Includes the following steps: A. After adding a self-healing anti-seepage admixture to the concrete, pour the concrete panel; the dosage of the self-healing anti-seepage admixture is 5% to 7% of the cementitious material in the concrete, and it is added to the mixing tank and mixed with the concrete during the concrete mixing process; B. After the concrete panel is poured and initially solidified, prepare ultra-high performance concrete. The weight ratio of ultra-high performance concrete is: water 7% to 8%, cement 20% to 35%, quartz powder 0% to 4%, silica fume 4% to 8%, high-efficiency water-reducing agent 1% to 2%, fiber 4% to 6%, fly ash 0% to 13%, and quartz sand 40% to 50%. The coefficient of linear expansion of the ultra-high performance concrete after the mix design is completed is less than or equal to α. u α u The calculation process is as follows: Assuming ΔT is the temperature difference between the concrete crack-resistant layer and the bottom concrete panel, which is the difference from the average temperature of the concrete panel to its lowest temperature, then... ΔT=ΔT y +ΔT d +ΔT c (1) In the formula, ΔT y It is half of the annual temperature variation; ΔT d It is half of the daily temperature variation, which is half the difference between the daily maximum and minimum temperatures; ΔT c The overall temperature reduction of the concrete crack-resistant layer and the bottom concrete panel is represented by ΔT. c =6℃; The crack resistance safety factor K of the ultra-high performance concrete is calculated using the following formula: In the formula, ε g For the autogenous volume deformation of ultra-high performance concrete; α u α is the coefficient of linear expansion of ultra-high performance concrete. d R is the coefficient of linear expansion of the lower concrete panel; l The tensile strength of ultra-high performance concrete; ε ud E represents the allowable drying shrinkage strain of the ultra-high performance concrete surface, taken as 100uε; u P is the elastic modulus of ultra-high performance concrete; P is the coefficient of influence of the deformation of the lower concrete panel on the stress of ultra-high performance concrete, with P = 0.6 to 0.

8. Then calculate the linear expansion coefficient α of ultra-high performance concrete. u : When all materials used are limestone aggregate and the α calculated by equation (3) is not less than or equal to α, u When the value is reached, the mix proportion of ultra-high performance concrete is modified to increase R. l This ensures that the coefficient of linear expansion of the ultra-high performance concrete after mix design is less than or equal to α. u ; C. Apply a layer of this ultra-high performance concrete to the outer surface of the concrete panel to form a crack-resistant concrete layer.

7. The construction method of the concrete-faced rockfill dam panel anti-crack and anti-seepage structure according to claim 6, characterized in that: The thickness of the concrete crack-resistant layer is greater than or equal to the critical thickness b. u Critical thickness b u The calculation process is as follows: The calculation process for the structural force N1 generated by the concrete panel interacting with the riprap structure under conditions of temperature drop and drying shrinkage is as follows: N1=σ1A1 (4) D l =(L-L1) (6) In the formula: L is the axial length of the concrete panel, σ1 is the maximum tensile stress of the structure caused by temperature drop and drying shrinkage of the concrete panel, A1 is the cross-sectional area of ​​the concrete panel, b0 is the length of the top surface of the concrete panel, L1 is the length from the fixed point of the concrete panel to the bottom of the concrete panel, ξ is the slope angle of the panel dam, and α is the thickness variation rate of the concrete panel. ρ is the friction angle between the concrete panel and the riprap, C is the cohesion between the concrete panel and the riprap, and ρ is the unit weight of the concrete panel. The calculation process for the temperature-induced force N2 inside the concrete panel caused by temperature drop and drying shrinkage is as follows: N2=σ2A1 (10) In the formula: σ2 is the temperature stress of the concrete panel, which is obtained through finite element simulation calculation; E is the elastic modulus of the concrete panel; α c denoted as the coefficient of linear expansion of the concrete panel, T as the temperature of the concrete panel, and μ as the Poisson's ratio of the concrete panel. The calculation process for the allowable bearing capacity N of the concrete crack-resistant layer is as follows: N=σ t Lb u (12) In the formula: σ t b is the ultimate tensile strength of the concrete crack-resistant layer. u This represents the critical thickness of the concrete crack-resistant layer. If N = N1 + N2, then the critical thickness b of the concrete crack-resistant layer that satisfies the crack resistance requirement can be obtained. u As shown in the following formula:

8. The construction method of the concrete-faced rockfill dam panel anti-crack and anti-seepage structure according to claim 6 or 7, characterized in that: After the ultra-high performance concrete has initially solidified, a viscoelastic surface anti-seepage coating is applied to the surface of the concrete crack-resistant layer; the viscoelastic surface anti-seepage coating includes an adhesive underlayer, a rough anti-seepage layer, and a surface protective layer connected in sequence, the adhesive underlayer being bonded to the outer side of the concrete crack-resistant layer and penetrating into the concrete crack-resistant layer.

9. The construction method of the concrete-faced rockfill dam panel anti-crack and anti-seepage structure according to claim 8, characterized in that: The viscoelastic surface waterproofing coating is a polyfluorosilicone waterproofing coating.

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