An ultra-long crack-resistant wall and its construction method

Abstract

This invention relates to the field of wall construction technology in building engineering, and particularly to an ultra-long crack-resistant wall and its construction method. The ultra-long crack-resistant wall includes a base slab, multiple spaced reaction piers, and an intermediate wall. Horizontal reinforcement bars are provided between two adjacent reaction piers. The intermediate wall is poured and filled between two adjacent reaction piers to form an integral crack-resistant wall structure. The reaction piers are made of ordinary concrete, and the intermediate wall is made of expansive concrete. When the intermediate wall expands outward, it is compressed by the reaction piers, pre-establishing pre-compression stress. At the same time, horizontal reinforcement bars are arranged for tension, which can improve the compressive strength of the reaction piers and increase their compressive capacity. After the reaction piers are poured, the horizontal reinforcement bars are tightened. When the intermediate wall reaches 80% of its design strength, the horizontal reinforcement bars are released to form compressive stress. This compressive stress, together with the pre-compression stress established by the reaction piers, restricts the shrinkage and cold shrinkage deformation of the wall, offsets the tensile stress generated by the deformation of the concrete, and ensures that the wall has good crack resistance.

Description

Technical Field

[0001] This invention relates to the field of wall construction technology in building engineering, and in particular to an ultra-long crack-resistant wall and its construction method. Background Technology

[0002] In recent years, with the acceleration of urbanization in my country, the development and utilization of underground space has increased, resulting in many ultra-long, ultra-large, and ultra-deep basement structures. The concrete in these basement structures is prone to deformation and cracking during the pouring process. Therefore, crack control is an extremely important technical aspect in the construction of underground buildings. However, the material properties of concrete make the appearance of cracks in concrete structures unavoidable. When cracks exist in the exterior walls of underground structures, groundwater leakage can occur, affecting the durability and safety of the structure. Crack problems remain one of the challenges in the construction industry.

[0003] Many factors contribute to cracks in concrete structures, including changes in surface humidity, volumetric deformation, creep, and temperature. These factors account for approximately 90% of structural cracks. In the past, permanent expansion joints were commonly used to control structural cracks. However, permanent expansion joints are not only expensive and may affect the building's aesthetics after installation, but they can also cause noise and vibration during use due to joint movement. Furthermore, long-term use and aging of permanent expansion joints can lead to leaks and damage, requiring timely inspection and replacement. Currently, permanent expansion joints are rarely used in basement concrete structure designs, while the number of concrete structures with excessively long and large plan dimensions is constantly increasing.

[0004] Wall crack control technology involves multiple professional fields, including structure, materials, construction, design, and environment. Currently, there are no mature and effective crack control technologies or measures available domestically or internationally. For key projects involving ultra-large and ultra-long concrete structures, the main method for crack control is full-size concrete pouring and curing. However, this method requires a large amount of pouring formwork and has very high requirements for construction technology. It not only needs to complete concrete pouring within a short time but also requires the design of effective temperature change control schemes. It is extremely demanding in terms of construction site, schedule, and manpower, making it unsuitable for most projects. Furthermore, this method can only minimize crack formation to a certain extent, and the effect is not particularly ideal. Several other patent documents have also disclosed some wall crack control technologies. For example, patent application CN215564429U, entitled "A Device for Improving Shrinkage Cracks in Concrete Walls of Extra-Long Basements," employs a crack-prevention structure on a sealed template. This structure's special cross-section controls stress dispersion. However, this method affects the integrity of the concrete structure, resulting in poor wall load-bearing capacity. Another patent application CN115749049A, entitled "A Construction Method for Preventing Cracks in Extra-Long Shear Walls through Bidirectional Graded Induced Joints," discloses a method of controlling the formation of graded induced joints in the concrete structure by setting pre-embedded templates for induced joints. This creates pre-cracked areas, rationally guiding crack development, reducing stress concentration, and preventing disordered crack formation. However, this method is cumbersome to operate and severely impacts construction progress.

[0005] Therefore, preventing or reducing concrete shrinkage, avoiding cracks in the walls due to large deformation, and ensuring the safety and normal use of ultra-long basement concrete structures are major technical issues in the construction of building walls. At the same time, how to reduce construction costs, reduce construction procedures, and shorten construction period while ensuring that the wall structure does not crack, thus achieving better construction economy, is also a key issue that needs to be considered in controlling wall cracks. Summary of the Invention

[0006] One of the objectives of this invention is, at least, to address the problems of complex construction processes, high costs, and poor crack prevention effects when existing technologies mainly rely on external measures to constrain or improve walls. This invention provides an ultra-long crack-resistant wall and its construction method. The ultra-long crack-resistant wall, by setting reaction piers and arranging horizontal reinforcement between the reaction piers, can limit the shrinkage and cold-shrinkage deformation of the wall, offset the tensile stress generated by the deformation of the concrete, and ensure that the wall has good crack resistance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention includes the following aspects.

[0008] An ultra-long crack-resistant wall includes a base slab, multiple reaction piers spaced apart on the base slab, and an intermediate wall cast on the base slab. Horizontal reinforcement bars are provided between two adjacent reaction piers. The intermediate wall is cast and filled between two adjacent reaction piers, so that the base slab, reaction piers, and intermediate wall form an integral crack-resistant wall structure. The reaction piers are ordinary concrete structures, and the intermediate wall is an expansive concrete structure.

[0009] Preferably, the reaction piers have the same thickness as the overall crack-resistant wall structure, and the interval between two adjacent reaction piers is between 15m and 50m.

[0010] Preferably, when the interval between two adjacent reaction piers is 15m to 30m, the length of the reaction pier is 3m to 5m; when the interval between two adjacent reaction piers is 30m to 50m, the length of the reaction pier is 5m to 8m.

[0011] Preferably, a waterstop strip is provided at the connection between the reaction pier and the intermediate wall.

[0012] Preferably, the height of the reaction pier is more than 60% of the overall crack-resistant wall structure length.

[0013] Preferably, the crack-resistant wall is suitable for wall structures with a wall thickness of 0.2m or more and a length of 30m or more.

[0014] Correspondingly, this application also provides a construction method for an ultra-long crack-resistant wall, which includes the following construction steps when constructing the aforementioned ultra-long crack-resistant wall:

[0015] Step A: Construct the base slab;

[0016] Step B: Constructing the reaction pier, including tying the reaction pier reinforcement bars, arranging the horizontal reinforcement bars, and pouring the reaction pier concrete, wherein the horizontal reinforcement bars are fitted with corrugated pipes;

[0017] Step C: The intermediate wall is poured within 15 to 20 days after the reaction pier is poured. Before pouring, the horizontal reinforcement bars are tightened. Expansion concrete is used for pouring the intermediate wall. The force of tightening the horizontal reinforcement bars is calculated.

[0018] Step D: Construct the roof slab;

[0019] Step E: When the concrete strength of the intermediate wall reaches 80% of the design strength, place horizontal reinforcement bars and inject grout.

[0020] Preferably, in step C, the horizontal reinforcement bars are provided with connecting threads at both ends. Within 15-20 days after the completion of the reaction pier pouring, before pouring the intermediate wall, the horizontal reinforcement bars are connected and tightened using steel sleeves to generate tensile stress. The steel sleeves are arranged on the outside of the reaction piers at both ends of the intermediate wall to be poured. The calculation of the force exerted on the tightening of the horizontal reinforcement bars includes the following:

[0021] C1. Calculate the ultimate tensile strength parameter ε of expansive concrete. pa ε, the shrinkage parameter value d ε value of cold shrinkage parameter t Concrete expansion limit parameter value ε e ;

[0022] C2. Based on the concrete's restricted expansion parameter value ε e The preload stress ε´ established by the reaction pier is calculated. e =με e μ is the correction factor;

[0023] C3. Calculate the tightening force F=ε on the horizontal reinforcing bars. pa +ε d +ε t -ε´ e ;

[0024] C4. Then, based on the number of horizontal bars N, calculate the tightening force f=F / N for a single horizontal bar.

[0025] Preferably, in step B, when arranging the horizontal bars, multiple layers of horizontal bars are arranged, with each layer of horizontal bars spaced 200~400mm apart, and within each layer of horizontal bars, the interval between two adjacent horizontal bars is 50~100mm.

[0026] In summary, by adopting the above technical solution, the present invention has at least the following beneficial effects:

[0027] 1. The reaction pier is a concrete pier formed by intermittent casting. The reaction pier is first cast intermittently on the base slab. Since the reaction pier is an ordinary concrete structure, when it reaches a compressive strength of less than 2MPa, the shrinkage is small and the resulting internal stress is negligible. Moreover, the reaction pier is small in size compared to the length of the entire wall and has little temperature deformation. The compressive strength of the concrete pier before and after initial setting can reach more than 1.5MPa, which fully meets the requirements. The tensile stress generated in the later stage is less than its own tensile stress, so the reaction pier will not have the risk of cracking, thus ensuring that the reaction pier, as part of the wall, will not crack.

[0028] 2. The intermediate wall is made of expansive concrete. During the pouring process, when the expansive concrete is first poured and initially set, it releases a large amount of heat of hydration. At this time, the concrete expands and forms compressive stress on the outside. The surface temperature of the expansive concrete is low and the initial setting is fast, while the expansion in the center is greater and the heat of hydration is high, which will form a large outward compressive stress. This will cause the surface concrete to crack and form induced cracks. These induced cracks become the source of cracks in the wall later. Most of the cracks in the later stage continue to crack along the direction of the induced cracks. By setting reaction piers as a support structure, when the poured intermediate wall expands outward, it is squeezed after encountering the reaction piers and cannot form a continuous outward pressure on the surface concrete. Therefore, it can effectively avoid the induced cracks of the expansive concrete and ensure the safety of the wall structure.

[0029] 3. After the expansive concrete is poured, it gradually cools and sets. Due to temperature deformation, the concrete in the wall will generate tensile stress inward. At the same time, the shrinkage of the concrete in the later stage will also generate tensile stress inward. This will also cause cracks in the concrete due to deformation and stress. By setting concrete reaction piers, on the one hand, the induced cracks can be prevented. On the other hand, since the reaction piers that are poured first have already been formed and set, they have huge compressive strength. When the expansive concrete of the middle wall expands outward, it is squeezed when it encounters the reaction piers, and a large pre-compression stress is established in advance. This part of the pre-compression stress can offset part of the tensile stress generated by the shrinkage and temperature deformation of the middle wall concrete in the later stage, thus effectively preventing structural cracks.

[0030] 4. By arranging horizontal reinforcement bars for tension, the compressive strength of the reaction pier can be improved, and the compressive capacity can be increased. When the intermediate wall is cast with expansive concrete, the reaction pier can resist the expansion pressure of the intermediate wall, ensuring the structural safety of the reaction pier and avoiding induced cracks in the intermediate wall in the early stage.

[0031] 5. By tightening the horizontal reinforcement bars, when the intermediate wall is poured and reaches 80% of the design strength, the horizontal reinforcement bars are released to form compressive stress, which can largely limit the shrinkage and cold shrinkage deformation of the wall in the later stage, offset the tensile stress generated by the deformation of the concrete, and ensure that the wall has good crack resistance.

[0032] 6. By setting horizontal reinforcement bars, the size and number of reaction piers can be reduced. The size of the reaction piers can also reduce the amount of construction work (including the amount of rebar binding, waterstop installation and pouring work). This allows the reaction pier reinforcement bars to be tied in the shortest possible time after the bottom slab is poured, and subsequent pouring can be carried out. This avoids a large gradient deformation difference between the reaction piers and the bottom slab, effectively preventing cracks. Reducing the number of reaction piers not only reduces the amount of construction work, but also optimizes the construction process, making it easier to pour large volumes of intermediate walls in a whole.

[0033] 7. Setting horizontal reinforcement not only significantly improves the crack resistance of the wall, but also reduces the amount of steel reinforcement required for crack-resistant walls. Since increasing the amount of steel reinforcement in concrete does not have a significant effect on improving the crack resistance of the wall, only when the reinforcement ratio reaches more than 25% will there be a certain improvement effect. However, by setting horizontal reinforcement and tensioning it before pouring the intermediate wall, the horizontal reinforcement will form compressive stress on the intermediate wall concrete after subsequent tensioning. Compared with improving the crack resistance of concrete through reinforcement, its crack resistance effect is greatly enhanced (the crack resistance enhancement effect reaches more than 10 times), and the reinforcement cost is significantly reduced. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a conventional crack-resistant wall in Exemplary Example 1.

[0035] Figure 2 This is a structural schematic diagram of a conventional crack-resistant wall according to the second embodiment.

[0036] Figure 3 This is a structural schematic diagram of a conventional crack-resistant wall according to the third implementation method.

[0037] Figure 4 This is a structural schematic diagram of the ultra-long crack-resistant wall of the present invention.

[0038] The markings in the diagram are: 1-base plate, 2-reaction pier, 3-waterstop strip, 4-intermediate wall, 5-top plate, 6-horizontal reinforcement, 7-reinforcement sleeve, 8-corrugated pipe. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so that the objectives, technical solutions, and advantages of the present invention will be clearer. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Example 1

[0040] This embodiment provides a structure for a crack-resistant wall, such as... Figures 1-2As shown, the crack-resistant wall includes a base plate 1 and reaction piers 2 spaced apart on the base plate 1. The two reaction piers 2 are poured first to form a pouring space for pouring the intermediate wall 4. The intermediate wall 4 is then poured on the base plate 1 in the pouring space. During the pouring of the intermediate wall 4, the reaction piers 2 on both sides provide supporting reaction force to the intermediate wall 4. The base plate 1, reaction piers 2, and intermediate wall 4 form an integral crack-resistant wall structure. The top of the integral crack-resistant wall structure is a top plate 5. The reaction piers 2 are reinforced concrete structures formed by pouring ordinary concrete. The intermediate wall 2 is a reinforced concrete structure formed by pouring expansive concrete. The reaction piers 2 have the same thickness as the integral crack-resistant wall structure. The length of the reaction piers 2 is between 10% and 35% of the length of the integral crack-resistant wall structure. The height of the reaction piers 2 is 40% or more of the length of the integral crack-resistant wall structure.

[0041] In one preferred embodiment, the length of the reaction pier 2 is between 15% and 30% of the overall crack-resistant wall structure length, specifically determined according to the overall crack-resistant wall structure length. When the overall crack-resistant wall structure is between 10m and 20m, the length of the reaction pier is selected from the range of 35% closer to the endpoint. When the overall crack-resistant wall structure is between 20m and 30m, the length of the reaction pier is selected from the range of about 20% closer to the endpoint. When the overall crack-resistant wall structure is greater than 30m, the length of the reaction pier is selected from the range of about 10% closer to the endpoint. The ideal length of the reaction pier is between 3 and 8m, and can be selected based on both the overall crack-resistant wall structure length and the ideal length of the reaction pier.

[0042] In one preferred embodiment, the height of the reaction pier 2 is 40% or more of the overall crack-resistant wall structure length, and preferably 60% or more of the overall crack-resistant wall structure length.

[0043] The crack-resistant wall in this embodiment is suitable for wall structures with a thickness of 200mm or more and a length of 12m or more. When the overall crack-resistant wall structure is less than 10m in length, on the one hand, conventional crack control methods can be used to control the generation of cracks, such as proper pouring time and space, insulation measures, and curing measures. On the other hand, the crack-resistant wall structure and construction method using the gradient combination of this solution no longer have advantages.

[0044] In one preferred embodiment, a waterstop strip 3 is provided at the connection between the reaction pier 2 and the intermediate wall 4. The waterstop strip 3 is made of waterstop steel plate or waterstop rubber strip, etc. When the reaction pier 2 is poured, the waterstop strip 3 is pre-embedded to improve the anti-seepage performance of the crack-resistant wall after the intermediate wall 4 is poured and during the later operation and use of the crack-resistant wall, so as to avoid leakage.

[0045] This embodiment only applies to cases where the overall crack-resistant wall is less than 50m long. When the overall crack-resistant wall is longer than 50m, the length of the reaction piers is set between 3 and 8m, and multiple reaction piers are set at intervals of 15m to 40m. The intermediate wall is then poured between two adjacent reaction piers.

[0046] The reaction pier 2 is a concrete pier formed by intermittent pouring. The reaction pier 2 is first poured intermittently on the base slab 1. Since the reaction pier 2 is an ordinary concrete structure, when it reaches a compressive strength of less than 2MPa, the shrinkage it produces is small, and the resulting internal stress in the concrete is negligible. Moreover, the reaction pier 2 is smaller in size than the length of the entire wall, and the temperature deformation is small. The compressive strength of the concrete pier before and after initial setting can reach more than 1.5MPa, which fully meets the requirements. The tensile stress generated in the later stage is less than its own tensile stress, and the reaction pier will not have the risk of cracking.

[0047] The intermediate wall is made of expansive concrete. During the pouring process, when the expansive concrete is first poured and initially set, it releases a significant amount of heat of hydration. At this time, the concrete expands, creating outward compressive stress. Then, as it gradually cools and finally sets, the concrete deforms due to temperature changes, creating inward tensile stress. Simultaneously, the later shrinkage of the concrete itself also creates inward tensile stress. In both of these processes, the concrete will crack due to deformation and stress. In the first process, the surface temperature of the expansive concrete is low, and it sets quickly, while the central part expands more and releases more heat of hydration. High volume will create a large outward compressive stress, causing the surface concrete to crack and form induced cracks. By setting reaction piers as a support structure, when the poured intermediate wall expands outward, it will be squeezed after encountering the reaction piers, which can effectively prevent the expansion concrete from generating induced cracks. In the latter process, because the expansion concrete of the intermediate wall is squeezed after encountering the reaction piers, pre-compression stress is established in advance. This part of the pre-compression stress can offset part of the tensile stress generated by the expansion concrete of the intermediate wall in the later shrinkage and temperature deformation, thus effectively preventing the generation of structural cracks.

[0048] The post-cast intermediate wall can form an integral crack-resistant wall structure with the reaction pier, eliminating the need for casting formwork at the reaction pier location, thus improving construction efficiency. After the reaction pier and intermediate wall are connected as a whole, in addition to releasing pre-compression stress, they can also provide some tensile stress, resulting in a very significant crack resistance effect. Reinforcing bars are set in the reaction pier. The coefficients of thermal expansion of the concrete and reinforcing bars in the reaction pier are close, with the coefficient of thermal expansion of the reinforcing bars being about 1.2 times that of the concrete. At the same time, since the reinforcing bars are laterally constrained by the concrete, they share the load, and the slenderness ratio of the reinforcing bars under compression can be ignored. Therefore, the reaction pier plays a role in coordinating its own deformation, preventing the reinforcing bars from cracking the concrete during the concrete heating stage. The reaction pier makes full use of the tensile properties of the reinforcing bars and the compressive properties of the concrete. Under compression, it deforms into a cantilever structure bending deformation, adapting to the gradient distribution of crack-resistant stress between the old and new concrete. Example 2

[0049] This embodiment provides another structural form of crack-resistant wall structure, such as Figure 2 As shown, the height of the reaction pier 2 of the crack-resistant wall is the same as the height of the wall. After the reaction pier 2 is poured, the middle wall 4 is poured with expansive concrete in the middle pouring space, and finally the top plate 5 is poured. This structure also sets a waterstop strip 3 at the connection between the reaction pier 2 and the middle wall 4 to improve the anti-seepage performance of the basement wall structure.

[0050] It is worth noting that the reaction pier 2, which serves as a supporting structure, is different from ordinary formwork and its supporting structure. Ordinary formwork is only a component that provides positioning for pouring concrete. Ordinary formwork and supporting structure provide support for the poured concrete, but they do not have high compressive strength and cannot establish pre-compression stress during the later pouring of the intermediate wall 4. Example 3

[0051] This embodiment compares and discloses two lengths of crack-resistant wall structures. When the overall length of the crack-resistant wall is within 40m, such as Figures 1-2 As shown, the structural form of setting reaction piers 2 at both ends of the crack-resistant wall eliminates the need to increase the number of reaction piers 2. When the length of the crack-resistant wall is 60m or more, such as Figure 3 As shown, at this time, three or more reaction piers 2 can be set to ensure the crack resistance performance of the entire crack-resistant wall. When the wall length is between 40 and 60m, the number of reaction piers 2 can be designed as needed.

[0052] The reaction piers and crack-resistant walls described in this application are applicable not only to basement wall structures, but also to any concrete wall structure with a length greater than 12m in all engineering construction. Example 4

[0053] This embodiment provides an ultra-long crack-resistant wall structure, such as Figure 4 As shown, its structure is roughly the same as the crack-resistant wall structure in Example 1, except that:

[0054] A horizontal reinforcement bar 6 is set between two adjacent reaction piers 2. Within 15 to 20 days after the first reaction pier is poured, the horizontal reinforcement bar 6 is tightened, and then the intermediate wall 4 is poured. When the strength of the intermediate wall 4 reaches 80% of the design strength, the horizontal reinforcement bar is released and grouting is performed.

[0055] Within 15-20 days after the reaction piers are poured, they have reached their design strength. By setting horizontal reinforcement bars between two adjacent reaction piers 2, the following effects are achieved:

[0056] On the one hand, when the cross-sectional dimensions and compressive strength of the reaction pier do not meet the expansion force of the intermediate expansive concrete, the compressive strength of the reaction pier can be improved by arranging horizontal reinforcement bars for tension, thus increasing the compressive strength and compressive strength. This allows the reaction pier to resist the expansion pressure of the intermediate wall when using expansive concrete to pour the intermediate wall, ensuring the structural safety of the reaction pier and preventing the intermediate wall from developing induced cracks in the early stage.

[0057] On the other hand, by tightening the horizontal reinforcement bars, when the intermediate wall is poured and reaches 80% of the design strength, the horizontal reinforcement bars are released to form compressive stress, which can largely limit the shrinkage and cold shrinkage deformation of the wall in the later stage, offset the tensile stress generated by the deformation of the wall concrete, and ensure that the wall has good crack resistance.

[0058] On the other hand, by setting horizontal reinforcement bars, the size and number of reaction piers can be reduced. The size of the reaction piers can reduce the amount of construction work (including the amount of rebar binding, waterstop installation and pouring work). This allows the reaction pier reinforcement bars to be tied in the shortest possible time after the bottom slab is poured, and subsequent pouring can be carried out. This avoids a large gradient deformation difference between the reaction piers and the bottom slab, effectively preventing cracks. Reducing the number of reaction piers not only reduces the amount of construction work, but also optimizes the construction process, making it easier to pour large volumes of intermediate walls in a whole.

[0059] More importantly, setting horizontal reinforcement not only significantly improves the crack resistance of the wall, but also reduces the amount of steel reinforcement required for crack-resistant walls. Since increasing the amount of steel reinforcement in concrete does not have a significant effect on improving the crack resistance of the wall, only when the reinforcement ratio reaches more than 25% will there be a certain improvement effect. However, by setting horizontal reinforcement and tensioning it before pouring the intermediate wall, the horizontal reinforcement will form compressive stress on the intermediate wall concrete after subsequent tensioning. Compared with improving the crack resistance of concrete through reinforcement, its crack resistance effect is greatly enhanced (the crack resistance enhancement effect reaches more than 10 times), and the reinforcement cost is significantly reduced.

[0060] The basic principle that reinforcement has very little impact on improving the crack resistance of walls is as follows: Cracks in concrete are directly related to concrete drying shrinkage and thermal shrinkage. Concrete thermal shrinkage can be mitigated by improving pouring and curing processes. Factors affecting concrete drying shrinkage include: cement type, cement fineness, aggregate type, water-cement ratio, cement paste volume, initial curing time, ambient humidity, reinforcement ratio, and vibration method. According to the concrete drying shrinkage calculation formula: As can be seen in the formula, εd is the concrete drying shrinkage value. For the limiting contraction under standard conditions, take 3.24 × 10⁻⁶. -4 M1, M2, ... M n Here are the correction coefficients for the above influencing factors, b is an empirical coefficient, generally taken as 0.01, and 0.03 when the curing is poor, and t is the concrete age in days (d). The correction coefficients for the influence of reinforcement ratio on drying shrinkage are shown in the table below:

[0061] Reinforcement ratio Correction parameter Mn 0.00 1.00 0.05 0.86 0.10 0.76 0.15 0.68 0.20 0.61 0.25 0.55

[0062] As can be seen from the table, increasing the reinforcement ratio of the wall from 0 to 25% has little impact on the drying shrinkage value of the concrete, but the cost increases significantly. Usually, the cross-sectional reinforcement ratio of the transverse reinforcement of most walls is less than 5%, and only the longitudinal reinforcement of columns can reach a reinforcement ratio of 5%. By arranging horizontal bars, the steel bars generate a large compressive stress on the concrete under tension, thereby offsetting the tensile stress on the concrete.

[0063] The ultra-long crack-resistant wall in this embodiment is suitable for applications where the wall length is greater than 20m. When the length of the crack-resistant wall is between 20m and 50m, two reaction piers are arranged. Compared with the crack-resistant wall structure in Embodiment 1, the reaction piers in this ultra-long crack-resistant wall can be shorter, and the pouring length of the middle wall can be longer, ensuring that the reaction piers have sufficient compressive strength. The middle wall will not produce induced cracks in the early stage and shrinkage cracks in the later stage. The size of the reaction piers is mainly set according to the arrangement interval of two adjacent reaction piers. When the interval between two adjacent reaction piers is 15m to 30m, the length of the second reaction pier is set to 3m to 5m. When the interval between two adjacent reaction piers is 30m to 50m, the length of the second reaction pier is set to 5m to 8m, thereby reducing the size and number of reaction piers. Example 5

[0064] This embodiment provides a construction method for ultra-long crack-resistant walls, such as... Figure 4 As shown, the construction process for the ultra-long crack-resistant wall in Example 4 includes the following steps:

[0065] Step A: Constructing the base slab 1, including tying the base slab reinforcement bars and pouring the base slab concrete;

[0066] Step B: Constructing the reaction pier 2, including tying the reaction pier reinforcement bars, arranging the horizontal reinforcement bars 6, and pouring the reaction pier concrete, wherein the horizontal reinforcement bars 6 are fitted with corrugated pipes 8;

[0067] Step C: Within 15 to 20 days after the reaction pier 2 is poured, pour the intermediate wall 4. Before pouring, tighten the horizontal reinforcement 6. The intermediate wall 4 is made of expansive concrete. The force of tightening the horizontal reinforcement 6 is calculated.

[0068] Step D: Construct the top slab 5;

[0069] Step E: When the concrete strength of the intermediate wall 4 reaches 80% of the design strength, place the horizontal reinforcement 6 and inject grout;

[0070] The term "ultra-long crack-resistant wall" refers to a wall with an overall length of more than 20m.

[0071] In one preferred embodiment, in step C, the horizontal reinforcement 6 is provided with connecting threads at both ends. Within 15-20 days after the completion of the reaction pier 2 and before the pouring of the intermediate wall 4, the horizontal reinforcement 6 is connected and tightened using steel sleeves 7, thereby generating tensile stress. The steel sleeves 7 are arranged on the outside of the reaction piers 2 at both ends of the intermediate wall 4 to be poured. The calculation of the force required to tighten the horizontal reinforcement 6 includes the following:

[0072] C1. Calculate the ultimate tensile strength parameter ε of expansive concrete. pa ε, the shrinkage parameter value d ε value of cold shrinkage parameter t Concrete expansion limit parameter value ε e ;

[0073] C2. Based on the concrete's limited expansion parameter value ε e The preload stress ε´ established by the reaction pier is calculated. e =με e μ is the correction factor;

[0074] C3. Calculate the tightening force F=ε on the horizontal reinforcing bars. pa +ε d +ε t -ε´ e ;

[0075] C4. Then, based on the number of horizontal bars N, calculate the tightening force f=F / N for a single horizontal bar.

[0076] Concrete cracking is mainly caused by excessive tensile stress generated by shrinkage. When the tensile stress is less than the ultimate tensile strength of the concrete, the concrete will not crack. When expansive concrete is used to pour the intermediate wall, the presence of the reaction pier causes the expansive concrete to be compressed and establish pre-compression stress. This pre-compression stress can resist some of the tensile stress generated by the later shrinkage and temperature deformation of the concrete. At the same time, horizontal reinforcement is arranged and tightened to form tension stress. The pre-compression stress of the reaction pier and the pre-compression stress formed by the tension of the horizontal reinforcement together offset the tensile stress generated by the shrinkage of the concrete, thereby effectively preventing the generation of structural cracks.

[0077] When calculating the finishing force F of tightening the horizontal reinforcement bars, in reality, as long as the tensile stress on the concrete is less than the ultimate tensile strength parameter of the concrete, cracking can be guaranteed. However, the ideal state is that the concrete is neither subjected to tensile nor compressive stress, ensuring that the concrete is in a "free" state. Therefore, the finishing force F of tightening the horizontal reinforcement bars is ε. pa +ε d +ε t -ε´ e ε´ in the formula e During the pouring process of expansive concrete, the prestress established by the reaction pier under pressure determines the limiting expansion parameter ε of the concrete. e Part of the strain is converted into prestress, therefore a correction factor μ is introduced, which is usually between 0.2 and 0.35, ε´ e =με e In actual construction, because concrete has strong compressive strength, the tightening force can be increased when tightening horizontal bars.

[0078] In one preferred embodiment, when arranging the horizontal ribs 6 in step B, multiple layers of horizontal ribs 6 are arranged, with each layer of horizontal ribs 6 spaced 200~400mm apart, and within each layer of horizontal ribs 6, the interval between two adjacent horizontal ribs 6 is 50~100mm.

[0079] Combination Figure 4As shown, after the pouring of the base slab 1 and guide wall is completed, when proceeding to step B to construct the reaction pier 2, the steel bars of the reaction pier 2 are first tied. After the tying is completed, horizontal bars 6 are arranged. Corrugated pipes 8 are sleeved on the horizontal bars 6 along the length of the reaction pier. The ends of the horizontal bars 6 are provided with connecting threads. When constructing the reaction pier, since the volume of the reaction pier 2 is much smaller than the volume of the entire crack-resistant wall structure, and also smaller than the volume of the reaction pier without horizontal bars 6, the steel bar tying cycle of the reaction pier 2 can be greatly shortened. At the same time, the concrete pouring of the reaction pier 2 can be completed in a very short time. The steel bar tying and concrete pouring can be completed within 2 to 3 days, thereby reducing the constraint changes on the entire crack-resistant wall structure caused by the temperature rise and fall of the base slab 1 with the reaction pier 2. Through fitting calculation, all of these are included in the range of plastic deformation that occurs after the intermediate wall 4 is poured in the later stage, further improving the crack resistance performance of the crack-resistant wall.

[0080] The intermediate wall 4 is poured 15-20 days after the reaction pier is poured. Before pouring, the horizontal reinforcement 6 is tightened by the steel sleeves 7 arranged at the ends of the reaction pier 2, thereby forming tensile stress. It is worth noting that the process of tightening the horizontal reinforcement 6 is different from conventional prestressing tensioning. Conventional prestressing tensioning requires the use of tensioning beams, jacks and other devices, and the tensioning prestress is also larger. However, in this technical solution, only a torque wrench is needed to tighten the horizontal reinforcement. The torque wrench controls the magnitude of the force, which is simple, easy and convenient. Moreover, in the parts where horizontal reinforcement is arranged, the reinforcement can be reduced or even eliminated, reducing the amount of steel reinforcement in the reinforced concrete.

[0081] When constructing the intermediate wall, you can first construct the intermediate wall 4 in the middle part of the reaction pier 2, and then construct the top part of the reaction pier 2 and the top plate 5. Alternatively, you can first construct the intermediate wall 4 in the middle part of the reaction pier 2 and the top part of the reaction pier 2, and then construct the top plate 5. When the intermediate wall 4 reaches 80% of the design strength, place the horizontal reinforcement 6 and grout the corrugated pipe 8.

[0082] The number and structural form of the reaction piers 2 do not affect the setting of the horizontal reinforcement 6. For example, in the wall structure of embodiments 2 and 3, horizontal reinforcement can also be set on the reaction piers. When the number of reaction piers is 3 or more, the horizontal reinforcement on both sides of the reaction pier in the middle part passes through the reaction pier and is staggered. They are tightened and stretched. After the middle wall on one side reaches 80% of the design strength, the horizontal reinforcement is released and grouting is completed.

[0083] The above description is merely a detailed illustration of specific embodiments of the present invention and is not intended to limit the invention. Various substitutions, modifications, and improvements made by those skilled in the art without departing from the principles and scope of the present invention should be included within the protection scope of the present invention.

Claims

1. An ultra-long crack-resistant wall, characterized in that, The ultra-long crack-resistant wall includes a base plate (1), multiple reaction piers (2) spaced apart on the base plate (1), and an intermediate wall (4) cast on the base plate (1). Horizontal reinforcement bars (6) are set between two adjacent reaction piers. The intermediate wall (4) is cast and filled between two adjacent reaction piers (2) and simultaneously covers the top of the reaction piers (2), so that the base plate (1), reaction piers (2) and intermediate wall (4) form an integral crack-resistant wall structure. The top of the integral crack-resistant wall structure is a top plate (5). Waterstop strips (3) are set at the connection between the reaction piers (2) and the intermediate wall (4). The reaction piers (2) are reinforced concrete structures formed by casting ordinary concrete, and the intermediate wall (4) is reinforced concrete structures formed by casting expansive concrete. The length of the reaction piers (2) is between 10% and 35% of the length of the integral crack-resistant wall structure, and the height of the reaction piers (2) is 60% or more of the height of the integral crack-resistant wall structure.

2. The ultra-long crack-resistant wall according to claim 1, characterized in that, The reaction pier (2) has the same thickness as the overall crack-resistant wall structure.

3. The ultra-long crack-resistant wall according to claim 2, characterized in that, The interval between two adjacent reaction piers (2) is between 15m and 50m.

4. The ultra-long crack-resistant wall according to claim 3, characterized in that, When the interval between two adjacent reaction piers (2) is 15m to 30m, the length of the reaction pier (2) is 3m to 5m. When the interval between two adjacent reaction piers (2) is 30m to 50m, the length of the reaction pier (2) is 5m to 8m.

5. The ultra-long crack-resistant wall according to any one of claims 1 to 4, characterized in that, This ultra-long crack-resistant wall is suitable for wall structures with a thickness of 0.2m or more and a length of 30m or more.

6. A construction method for an ultra-long crack-resistant wall, comprising the following construction steps when constructing the ultra-long crack-resistant wall as described in any one of claims 1 to 5: Step A: Construction of the base slab (1); Step B: Construction of the reaction pier (2), including binding the reaction pier reinforcement, arranging the horizontal reinforcement (6) and pouring the reaction pier concrete, wherein the horizontal reinforcement (6) is fitted with a corrugated pipe (8). Step C: Within 15 to 20 days after the reaction pier (2) is poured, pour the intermediate wall (4). Before pouring, tighten the horizontal reinforcement (6). The intermediate wall (4) is poured with expansive concrete. The force of tightening the horizontal reinforcement is calculated. Step D: Construct the roof slab (5); Step E: When the concrete strength of the intermediate wall reaches 80% of the design strength, place horizontal reinforcement bars (6) and grout.

7. The construction method for the ultra-long crack-resistant wall according to claim 6, characterized in that, In step C, the horizontal reinforcement (6) is provided with connecting threads at both ends. Within 15 to 20 days after the completion of the reaction pier (2) and before the pouring of the intermediate wall (4), the horizontal reinforcement (6) is connected and tightened with steel sleeves (7) to form tensile stress. The steel sleeves (7) are arranged on the outside of the reaction piers (2) at both ends of the intermediate wall (4) to be poured. When calculating the force of tightening the horizontal reinforcement (6), the following is included: C1. Calculate the ultimate tensile strength parameter ε of expansive concrete. pa ε, the shrinkage parameter value d ε value of cold shrinkage parameter t Concrete expansion limit parameter value ε e ; C2. Based on the concrete's limited expansion parameter value ε e The preload stress ε´ established by the reaction pier is calculated. e =με e μ is the correction factor; C3. Calculate the overall force F=ε when tightening the horizontal reinforcing bar. pa +ε d +ε t -ε´ e ; C4. Then, based on the number of horizontal bars N, calculate the tightening force f=F / N for a single horizontal bar.

8. The construction method for the ultra-long crack-resistant wall according to claim 6, characterized in that, In step B, when arranging the horizontal bars, multiple layers of horizontal bars are arranged, with each layer of horizontal bars spaced 200~400mm apart, and within each layer of horizontal bars, the interval between two adjacent horizontal bars is 50~100mm.

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