Construction method for controlling integrity cracks of large-area basement building ground based on fractal theory

Abstract

The application discloses a large-area basement building ground integrity crack control construction method based on fractal theory, and is based on a self-similar construction method of fractal theory. First, the large-area basement building ground is regarded as the largest self-similar block, is greatly reduced, is subjected to multi-level fractal iteration design, is divided into a plurality of self-similar blocks with different proportions, is composed of a regular self-similar block set, and then each crack control structure is arranged in different fractal iteration nodes in an organized manner. The application takes the fractal theory as a theoretical basis, applies principles such as fractal iteration and fractal self-similarity, and performs fractal iteration of different levels on the large-area basement building ground, so that the large-area basement with super length and super width is greatly reduced and simplified, construction organization and management are optimized, and construction efficiency is improved. In addition, modular crack control structures are arranged in an organized manner, and a margin management is applied. Furthermore, multiple crack control measures are designed at key detail nodes, so that the purpose of crack control is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of building construction, and more specifically relates to a construction method for controlling overall cracks in the floor of a large-area basement building based on fractal theory. Background Technology

[0002] With the continuous development of my country's economy and the rapid progress of urban construction, the number of commercial, office, and educational public buildings is increasing, and the scale of underground space development is becoming larger and larger, with basements being excessively long and wide. Due to the inconsistency in rigidity between the structural floor slab of the basement and the building floor, cracks of varying depths and widths are prone to appear on the building floor due to uneven structural settlement, vehicle dynamic loads, and concrete shrinkage deformation, causing leakage.

[0003] Currently, crack control in basement floors is typically achieved through post-pouring strips, selection of superior raw materials, and construction management. While these methods can control cracks to some extent, they cannot fundamentally address the cracking problem in large-area basement floors. A comprehensive, organized, and systematic crack control method has not yet been developed, and new crack control methods are urgently needed. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the technical problem to be solved by this invention is to provide a construction method for controlling overall cracks in large-area basement building floors based on fractal theory. This method can effectively control cracks in large-area basement building floors, reduce leakage points, and ensure the durability and functionality of the basement building floors.

[0005] To address the above problems, this invention proposes a construction method for controlling overall cracks in the floor of large-area basement buildings based on fractal theory, comprising the following steps:

[0006] Step 1, Fractal Construction Design: Based on the self-similar construction method of fractal theory, the large-area basement floor is first divided into smaller self-similar blocks as the largest self-similar block. Multi-level fractal iterative design is carried out to divide it into several self-similar blocks of different proportions, forming a regular set of self-similar blocks. Then, the crack control structures are arranged in an organized manner at different fractal iteration nodes.

[0007] Step 2, Base Treatment: Drain the accumulated water in the local area of ​​the basement's structural floor slab, remove the concrete laitance layer and weak layer from the surface of the new and old concrete on the structural floor slab and the post-cast strip of the structural floor slab, cut off the remaining bolt heads on the structural floor slab, and remove the laitance, ash, and construction waste from the basement to pave the working surface for the construction of the building floor.

[0008] Step 3, Positioning and Laying Out: Based on the fractal construction design in Step 1, use measuring instruments to lay out the positioning control lines of each level of fractal iteration nodes, crack control structures, post-cast strips of the structural basement, slope ridge lines of the elevated unit modules, and key structures of the strip inverted beams on the basement structural base slab.

[0009] Step 4, Pre-embedded components and formwork: According to the positioning control lines in Step 3, construct the corresponding pre-embedded components at the crack control structure at each level of fractal iteration node, and fix the formwork and angle iron components.

[0010] Step 5: Slope finding and additional layer construction:

[0011] Within the self-similar block enclosed by the drainage ditch and the water retaining wall, refer to the 1m horizontal line on the basement wall to determine the maximum elevation of the building ground ridge and the minimum elevation of the drainage ditch. Then, draw horizontal lines at 1500mm to 2000mm intervals to carry out mortar patch construction in order to control the drainage slope.

[0012] Within the suspended unit module of the fourth self-similar block enclosed by the cut joint, the strip inverted beams are poured first. Then, along the drainage ditch direction between two adjacent strip inverted beams, cement mortar is used to smooth the bottom and create a slope from the middle to both sides. The drainage layer and filter layer are then constructed in sequence, extending to the drainage ditches on both sides.

[0013] At the post-cast strip of the structural base slab, along the direction of the drainage ditch, the drainage layer and the filter layer are constructed sequentially from the middle to both sides, extending to the drainage ditches on both sides.

[0014] Step Six: Reinforcement Construction:

[0015] Within the self-similar blocks enclosed by drainage ditches and water-retaining sills, and at the post-cast strips of the structural base slab, spacers are placed at intervals of 500mm to 800mm. Steel mesh is then arranged on the spacers, with lapped steel bars between two adjacent steel meshes to ensure the thickness of the steel protective layer.

[0016] Within the elevated unit module of the fourth self-similar block enclosed by the cut joint, place pads on the pre-laid filter layer, then tie the building floor slab reinforcement, and tie and fix the vertical reinforcement of the strip reverse beam with U-shaped stirrups to the building floor slab reinforcement.

[0017] Step 7: Pouring concrete: First, sprinkle water to wet the side formwork of the drainage ditch on the basement building floor, the strip inverted beam and the structural base plate, and remove debris. Then, according to the fractal self-similar blocks of the fractal construction design, pour concrete in a skip-pour manner. Ensure an interval of 7 to 10 days between skip-pours of two adjacent self-similar blocks.

[0018] Step 8, Curing: Moisturize and heat-insulate the concrete of the basement building floor for a period of more than 14 days, and ensure that the temperature drop or rise of the concrete does not exceed 10℃ / h.

[0019] Step Nine, Formwork Removal and Joint Cutting: When the concrete strength of the basement building floor reaches more than 75% of the design strength, remove the formwork on both sides of the drainage ditch; within 3 days after the concrete pouring is completed, according to the fractal construction design in Step One, use measuring instruments to mark the joint cutting positioning control line on the building floor, carry out joint cutting construction, and finally lay the ditch cover plate on the drainage ditch, and insert the pre-embedded reinforcing bars into the reserved holes at both ends of the ditch cover plate to ensure that it does not slip.

[0020] Furthermore, step one specifically includes the following steps:

[0021] S11, Level 1 Fractal Iteration: The entire basement floor is taken as the first self-similar block. Fractalization is performed according to the Sierpinski carpet model of fractal theory, that is, "nine compartments" are formed, resulting in 9 second self-similar blocks of equal area. The fractal nodes of two adjacent second self-similar blocks are designed with expansion joints.

[0022] S12, Second-level fractal iteration: The second self-similar block enclosed by the expansion joint is further fractalized according to the Sierpinski carpet model of fractal theory, resulting in 9 2 Three equal-area third self-similar blocks, with drainage ditches and water-retaining sills constructed at the fractal nodes of two adjacent third self-similar blocks;

[0023] S13, Third-level fractal iteration: The third self-similar block enclosed by the drainage ditch and the retaining wall is further fractalized according to the Sierpinski carpet model of fractal theory, resulting in 9 4 The construction of a slit is designed at the fractal node of two adjacent fourth self-similar blocks with equal area.

[0024] S14, Fourth-level fractal iteration: The fourth self-similar block enclosed by the slit is subjected to final fractal processing according to the Sierpinski carpet model of fractal theory, resulting in 9. 6 The construction of an overhead unit module is based on the fractal node design of two adjacent fourth self-similar blocks with equal areas.

[0025] Preferably, in step S11, the expansion joint is filled with a flexible joint filler board, and the top of the expansion joint is edged with an inverted L-shaped galvanized expansion joint angle iron with a width of 30mm. The two expansion joint angle irons are kept parallel in the length direction, and the expansion joint angle irons are welded and fixed by pre-embedded expansion joint angle iron support bars. The depth of embedding in the structural base plate is 120mm.

[0026] Preferably, in step S12, the drainage ditch and the water-retaining sill are arranged around the edge of the basement floor, with only the drainage ditch arranged in the middle area; the water-retaining sill is 100mm high and 80mm wide, with vertical reinforcing bars of 8mm diameter installed every 1000mm, and longitudinal reinforcing bars connected to the vertical reinforcing bars, embedded to a depth of 120mm in the structural base plate; the drainage ditch is 200mm deep and 300mm wide, with a 40mm wide L-shaped galvanized angle iron edging at its top, the two angle irons being parallel in the length direction, and the angle iron being welded and fixed by pre-embedded 10mm diameter ditch angle iron support bars, embedded to a depth of 120mm in the structural base plate.

[0027] Preferably, in step S13, the width of the cut is 8mm, the depth is 80mm, and it is cut around the structural column. The center line of the cut is 300mm away from the edge line of the structural column, and the cut is continuous in both the longitudinal and transverse directions.

[0028] Therefore, this invention proposes a construction method for controlling overall cracks in large-area basement building floors based on fractal theory, aiming to systematically control cracks in these floors. Using fractal theory as its foundation, the method employs principles such as fractal iteration and fractal self-similarity to perform different levels of fractal iteration on the large-area basement floor. Large self-similar fractal blocks and smaller self-similar fractal blocks form a regular set of self-similar blocks, ultimately simplifying the construction of ultra-long and ultra-wide basements, optimizing construction organization and management, and improving construction efficiency. This invention focuses on tackling technical challenges related to fractal nodes and detailed nodes of post-cast strips in large-area basement building floors. It systematically sets up modular crack control structures and utilizes redundancy management, designing multiple crack control measures at key detailed nodes to achieve the goal of crack control.

[0029] The construction method for controlling overall cracks in large-area basement building floors based on fractal theory provided by this invention has at least the following beneficial effects:

[0030] (1) Based on the fractal theory of the Sierpinski carpet model, the construction of large-area basement buildings can efficiently reduce the size of large-area basement buildings and simplify the complex by organizing the fractal, which is conducive to construction organization and management.

[0031] (2) Based on the principles of fractal self-similarity and fractal iteration in fractal theory, crack control structures are set up in an organized manner at fractal nodes to effectively absorb cracks caused by concrete shrinkage or expansion deformation or load vibration, thereby achieving the goal of "crack control crack".

[0032] (3) Using overhead unit modules, filter boards and non-woven fabrics are constructed from bottom to top to guide the water to the drainage ditch, then steel mesh is laid and concrete is poured. This pretreatment of potential leakage points effectively reduces the risk of leakage in the building floor later.

[0033] (4) By using the overhead unit module, strip inverted beams, mortar bottom slope layer, drainage layer and filter layer are regularly set up, and then steel bars are tied and concrete is poured as a whole. The residual water of the post-pouring strip and the leakage hazard points of the defect crack of the structural base plate is diverted to the drainage ditch on both sides, which effectively controls the leakage hazard of the weak parts of the building ground.

[0034] In summary, this invention can systematically prevent cracking and seepage in basement floors, effectively control cracks in the floor, reduce the risk of leakage, and ensure the functionality and durability of the basement floor.

[0035] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, the following detailed description is provided in conjunction with preferred embodiments and accompanying drawings. Attached Figure Description

[0036] To more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a first-order fractal iteration diagram of the ground surface of a large-area basement building;

[0038] Figure 2 This is a second-order fractal iteration diagram of the ground surface of a large-area basement building;

[0039] Figure 3 This is a three-level fractal iteration diagram of the ground surface of a large-area basement building;

[0040] Figure 4 This is a four-level fractal iteration diagram of the ground surface of a large-area basement building;

[0041] Figure 5 This is a fractal scale diagram of the ground surface of a large-area basement building;

[0042] Figure 6 It is a cross-sectional view of the concealed water-retaining sill and drainage ditch;

[0043] Figure 7 It is a cross-sectional view of an expansion joint;

[0044] Figure 8 It is a cross-sectional view of the cut;

[0045] Figure 9 This is a structural schematic diagram of the overhead unit module;

[0046] Figure 10 yes Figure 9 AA section view in the middle;

[0047] Figure 11 yes Figure 9 BB cross-section diagram in the middle;

[0048] Figure 12 This is a schematic diagram of the treatment of the post-cast strip in the structural base slab.

[0049] In the diagram: 1-First self-similar block, 2-Second self-similar block, 3-Building ground edge, 4-Expansion joint, 5-Drainage ditch and water-retaining sill, 6-Third self-similar block, 7-Cut joint, 8-Fourth self-similar block, 9-Elevated unit module, 10-Fifth self-similar block, 11-Structural base plate, 12-Building ground, 13-Vertical reinforcement of water-retaining sill, 14-Longitudinal reinforcement of water-retaining sill, 15-Water-retaining sill, 16-Drainage ditch, 17-R-angle of ditch bottom. 18-Ditch cover, 19-Reserved hole, 20-Ditch angle iron support bar, 21-Angle iron, 22-Expansion joint angle iron support bar, 23-Expansion joint angle iron, 24-Sealer board, 25-Structural column, 26-Strip inverted beam, 27-Slope layer, 28-Drainage layer, 29-Filter layer, 30-Padded block, 31-U-shaped stirrup, 32-Building floor slab reinforcement, 33-Vertical reinforcement of inverted beam, 34-Steel mesh, 35-Post-cast strip of structural base slab. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example:

[0052] The basement floor of a certain construction project has a length of am, a width of am, and a thickness of 200mm. The present invention is used for construction using a 4-level fractal iteration.

[0053] like Figure 1-12 As shown, the construction method for controlling overall cracks in large-area basement building floors based on fractal theory of the present invention includes the following steps:

[0054] (1) Fractal construction design: Based on the self-similar construction method of fractal theory, the large-area basement overall building ground 12 is first reduced to the largest self-similar block and multi-level fractal iteration design is carried out to divide it into several self-similar blocks of different proportions, forming a regular self-similar block set. Then, each crack control structure is arranged in an organized manner at different fractal iteration nodes to achieve the purpose of "crack control crack".

[0055] 1) First-level fractal iteration: The entire basement floor (with the building floor edge 3 as the boundary) is taken as the first self-similar block 1 (self-similar block ①) (side length am). According to the fractal theory Sierpinsky carpet model, fractal is performed to form "nine compartments", resulting in 9 equal-area second self-similar blocks 2 (self-similar blocks ②) (side length a / 3m). The fractal nodes of two adjacent second self-similar blocks 2 are designed to construct the expansion joint 4. At the structural column 25, a flexible joint filler 24 is filled around the structural column 25 in both longitudinal and transverse directions. The top of the expansion joint 4 is edged with an inverted L-shaped galvanized expansion joint angle iron 23 with a width of 30mm. The two expansion joint angle irons 23 are parallel in the length direction. The expansion joint angle iron 23 is welded and fixed by the pre-embedded expansion joint angle iron support rib 22, and the depth of embedding in the structural base plate is 120mm.

[0056] 2) Second-level fractal iteration: The second self-similar block 2 enclosed by the expansion joint 4 is further fractalized according to the Sierpinski carpet model of fractal theory, resulting in 9. 2 Each of the three self-similar blocks 6 (self-similar block ③) with equal area (side length a / 9m) has a drainage ditch and a water-retaining sill 5 at the fractal nodes of two adjacent self-similar blocks 6. The drainage ditch and water-retaining sill 5 are arranged around the edge of the basement floor 12, with only the drainage ditch 16 arranged in the middle area. The water-retaining sill 15 is concealed, with a height of 100mm, a width of 80mm, and a diameter of 8mm. Vertical reinforcing bars 13 are installed every 1000mm, and longitudinal reinforcing bars 14 are connected to the vertical reinforcing bars 13. The depth of the water-retaining sill 15 embedded in the structural base plate 11 is 120mm. The drainage ditch 16 has a depth of 200mm and a width of 300mm. Its top is edged with a 40mm wide L-shaped galvanized angle iron 21. The two angle irons 21 are parallel in the length direction. The angle irons 21 are welded and fixed by pre-embedded ditch angle iron support bars 20 with a diameter of 10mm. The depth of the water-retaining sill 16 embedded in the structural base plate 11 is 120mm.

[0057] 3) Third-level fractal iteration: The third self-similar block 6, enclosed by the drainage ditch and the retaining wall 5, is further fractalized according to the Sierpinski carpet model of fractal theory, resulting in 9. 4Each of the four self-similar blocks 8 (the fourth self-similar block) has an equal area (side length a / 27m). The fractal node design of the cut slit 7 between two adjacent fourth self-similar blocks 8 is constructed. The cut slit 7 is 8mm wide and 80mm deep. It is located at the structural column 25 and wraps around the structural column 25. The centerline of the cut slit 7 is 300mm away from the edge of the structural column 25. It maintains continuity in both the longitudinal and transverse directions.

[0058] 4) Fourth-level fractal iteration: The fourth self-similar block 8 enclosed by the slit 7 is subjected to final fractal analysis according to the Sierpinski carpet model of fractal theory, resulting in 9. 6 The structure of the overhead unit module 9 is designed with fractal nodes of two adjacent fifth self-similar blocks 10 (self-similar block ⑤) of equal area (side length a / 81m).

[0059] (2) Grassroots treatment:

[0060] Construction preparation work includes pumping out water from local areas of the basement's structural slab 11, removing the concrete laitance layer from the surface of the structural slab 11, and cutting off any remaining bolt heads from the structural slab 11. Construction waste such as laitance, ash, and waste materials are then removed from the basement to prepare the working surface for the construction of the building floor 12.

[0061] (3) Positioning and layout: According to the fractal construction design in step (1), on the structural base slab 11 of the basement, use measuring instruments to lay out the positioning control lines of key structures such as fractal iteration nodes of each level, crack control structure, post-cast strip 35 of structural base slab, slope ridge line of overhead unit module 9 and strip inverted beam 26.

[0062] (4) Pre-embedding and formwork: According to the positioning control line in step (3), construct the vertical reinforcement and support reinforcement of the expansion joint 4, drainage ditch and water retaining wall 5 and strip inverted beam 26 at the crack control construction of each level fractal iteration node, and fix the expansion joint 4, T-shaped sluice board 24, drainage ditch template, angle iron and other components.

[0063] (5) Slope finding and additional layer construction:

[0064] 1) Within the third self-similar block 6 (side length a / 9m) enclosed by the drainage ditch and the water retaining wall 5, refer to the 1m horizontal line on the basement wall to determine the maximum elevation of the ridge line of the building ground 12 and the minimum elevation of the drainage ditch 16. Then, draw horizontal lines with a longitudinal and transverse spacing of 1500mm to 2000mm and carry out mortar patch construction to control the drainage slope.

[0065] 2) Within the fourth self-similar block 8 (side length a / 27m) of the overhead unit module 9 enclosed by the cut 7, the strip inverted beam 26 is first poured. Between the two adjacent strip inverted beams 26, along the direction of the drainage ditch 16, a slope-finding layer 27 is set up with cement mortar from the middle to both sides. Then, the drainage plate of the drainage layer 28 and the non-woven fabric of the filter layer 29 are constructed in sequence, extending to the drainage ditches 16 on both sides.

[0066] 3) At the post-cast strip 35 of the structural base slab, along the direction of the drainage ditch 16, the non-woven fabric of the drainage board and filter layer 29 are constructed sequentially from the middle to both sides, extending to the drainage ditch 16 on both sides.

[0067] (6) Reinforcement construction:

[0068] 1) Place spacers 30 at intervals of 500mm to 800mm within the third self-similar block 6 enclosed by the drainage ditch and the water retaining wall 5 and at the post-cast strip 35 of the structural base plate. Arrange the steel mesh 34 on the spacers 30 and arrange lapped steel bars between two adjacent steel meshes 34 to ensure the thickness of the steel protective layer.

[0069] 2) In the elevated unit module 9 of the fourth self-similar block 8 enclosed by the cut slit 7, place the pad block 30 on the pre-laid filter layer 29, then tie the building floor panel reinforcement 32, and tie and fix the vertical reinforcement 33 of the strip reverse beam 26 to the building floor panel reinforcement 32 with U-shaped stirrups 31.

[0070] (7) Concrete pouring: First, sprinkle water to wet the side formwork of the drainage ditch 16 of the basement building floor 12, the strip beam 26 and the structural base plate 11, and remove debris. Then, according to the third self-similar block 6 of the fractal construction design, the concrete is poured in a skip-pour manner. The skip-pour time between two adjacent self-similar blocks should be 7d to 10d.

[0071] (8) Curing: Moisturize and heat-insulate the concrete of the basement building floor 12, and ensure that the curing time is more than 14 days. The temperature drop and rise of the concrete should not exceed 10℃ / h.

[0072] (9) Formwork removal and joint cutting: When the concrete strength of the basement building floor 12 reaches more than 75% of the design strength, the formwork on both sides of the drainage ditch 16 is removed; within 3 days after the concrete is poured, according to the fractal construction design in step (1), the positioning control line of the joint cutting 7 is laid out on the building floor 12 using a measuring instrument, and the joint cutting 7 is constructed. Finally, the ditch cover plate 18 is laid on the drainage ditch 16. The bottom of the drainage ditch 16 is provided with a bottom R angle 17, and the pre-embedded reinforcing bars are inserted into the reserved holes 19 at both ends of the ditch cover plate 18 to ensure that it does not slip.

[0073] In this invention, the basement floor is constructed based on the fractal theory Sierpinski carpet model, featuring multi-level fractal iteration. At the fractal iteration nodes of two adjacent fractal self-similar blocks, there are corresponding structures for organized crack control. The large-area basement floor is organically divided into several regular fractal self-similar blocks, so that the local self-similar blocks and the overall building floor self-similar blocks form a part-whole relationship, and the concrete shrinkage deformation is most balanced.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any transformations or substitutions that can be understood by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of the present invention.

Claims

1. A construction method for controlling overall cracks in the floor of a large-area basement building based on fractal theory, characterized in that, Includes the following steps: Step 1, Fractal Construction Design: Based on the self-similar construction method of fractal theory, the large-area basement floor is first divided into smaller self-similar blocks as the largest self-similar block. Multi-level fractal iterative design is carried out to divide it into several self-similar blocks of different proportions, forming a regular set of self-similar blocks. Then, the crack control structures are arranged in an organized manner at different fractal iteration nodes. Step 2, Base Treatment: Drain the accumulated water in the local area of ​​the basement's structural floor slab, remove the concrete laitance layer and weak layer from the surface of the new and old concrete on the structural floor slab and the post-cast strip of the structural floor slab, cut off the remaining bolt heads on the structural floor slab, and remove the laitance, ash, and construction waste from the basement to pave the working surface for the construction of the building floor. Step 3, Positioning and Laying Out: Based on the fractal construction design in Step 1, use measuring instruments to lay out the positioning control lines of each level of fractal iteration nodes, crack control structures, post-cast strips of the structural basement, slope ridge lines of the elevated unit modules, and key structures of the strip inverted beams on the basement structural base slab. Step 4, Pre-embedded components and formwork: According to the positioning control lines in Step 3, construct the corresponding pre-embedded components at the crack control structure at each level of fractal iteration node, and fix the formwork and angle iron components. Step 5: Slope finding and additional layer construction: Within the self-similar block enclosed by the drainage ditch and the water retaining wall, refer to the 1m horizontal line on the basement wall to determine the maximum elevation of the building ground ridge and the minimum elevation of the drainage ditch. Then, draw horizontal lines at 1500mm to 2000mm intervals to carry out mortar patch construction in order to control the drainage slope. Within the suspended unit module of the fourth self-similar block enclosed by the cut joint, the strip inverted beams are poured first. Then, along the drainage ditch direction between two adjacent strip inverted beams, cement mortar is used to smooth the bottom and create a slope from the middle to both sides. The drainage layer and filter layer are then constructed in sequence, extending to the drainage ditches on both sides. At the post-cast strip of the structural base slab, along the direction of the drainage ditch, the drainage layer and the filter layer are constructed sequentially from the middle to both sides, extending to the drainage ditches on both sides. Step Six: Reinforcement Construction: Within the self-similar blocks enclosed by drainage ditches and water-retaining sills, and at the post-cast strips of the structural base slab, spacers are placed at intervals of 500mm to 800mm. Steel mesh is then arranged on the spacers, with lapped steel bars between two adjacent steel meshes to ensure the thickness of the steel protective layer. Within the elevated unit module of the fourth self-similar block enclosed by the cut joint, place pads on the pre-laid filter layer, then tie the building floor slab reinforcement, and tie and fix the vertical reinforcement of the strip reverse beam with U-shaped stirrups to the building floor slab reinforcement. Step 7: Pouring concrete: First, sprinkle water to wet the side formwork of the drainage ditch on the basement building floor, the strip inverted beam and the structural base plate, and remove debris. Then, according to the fractal self-similar blocks of the fractal construction design, pour concrete in a skip-pour manner. Ensure an interval of 7 to 10 days between skip-pours of two adjacent self-similar blocks. Step 8, Curing: Moisturize and heat-insulate the concrete of the basement building floor for a period of more than 14 days, and ensure that the temperature drop or rise of the concrete does not exceed 10℃ / h. Step Nine, Formwork Removal and Joint Cutting: When the concrete strength of the basement building floor reaches more than 75% of the design strength, remove the formwork on both sides of the drainage ditch; within 3 days after the concrete pouring is completed, according to the fractal construction design in Step One, use measuring instruments to mark the joint cutting positioning control line on the building floor, carry out joint cutting construction, and finally lay the ditch cover plate on the drainage ditch, and insert the pre-embedded reinforcing bars into the reserved holes at both ends of the ditch cover plate to ensure that it does not slip.

2. The construction method for controlling overall cracks in the floor of a large-area basement building based on fractal theory according to claim 1, characterized in that: Step one specifically includes the following steps: S11, Level 1 Fractal Iteration: The entire basement floor is taken as the first self-similar block. Fractalization is performed according to the Sierpinski carpet model of fractal theory, that is, "nine compartments" are formed, resulting in 9 second self-similar blocks of equal area. The fractal nodes of two adjacent second self-similar blocks are designed with expansion joints. S12, Second-level fractal iteration: The second self-similar block enclosed by the expansion joint is further fractalized according to the Sierpinski carpet model of fractal theory, resulting in 9 2 Three equal-area third self-similar blocks, with drainage ditches and water-retaining sills constructed at the fractal nodes of two adjacent third self-similar blocks; S13, Third-level fractal iteration: The third self-similar block enclosed by the drainage ditch and the retaining wall is further fractalized according to the Sierpinski carpet model of fractal theory, resulting in 9 4 The construction of a slit is designed at the fractal node of two adjacent fourth self-similar blocks with equal area. S14, Fourth-level fractal iteration: The fourth self-similar block enclosed by the slit is subjected to final fractal processing according to the Sierpinski carpet model of fractal theory, resulting in 9. 6 The construction of an overhead unit module is based on the fractal node design of two adjacent fourth self-similar blocks with equal areas.

3. The construction method for controlling overall cracks in the floor of a large-area basement building based on fractal theory according to claim 2, characterized in that: In step S11, the expansion joint is filled with a flexible joint filler board, and the top of the expansion joint is edged with an inverted L-shaped galvanized expansion joint angle iron with a width of 30mm. The two expansion joint angle irons are kept parallel in the length direction. The expansion joint angle irons are welded and fixed by pre-embedded expansion joint angle iron support bars, and the depth of embedding in the structural base plate is 120mm.

4. The construction method for controlling overall cracks in the floor of a large-area basement building based on fractal theory according to claim 2, characterized in that: In step S12, the drainage ditch and the water retaining wall are arranged around the edge of the basement floor, with only the drainage ditch arranged in the middle area; the water retaining wall is 100mm high, 80mm wide, and 8mm in diameter. Vertical reinforcing bars are installed every 1000mm, and longitudinal reinforcing bars are connected to the vertical reinforcing bars. The depth of embedding into the structural base plate is 120mm. The drainage ditch is 200mm deep and 300mm wide. Its top is edged with 40mm wide L-shaped galvanized angle iron. The two angle irons are parallel in the length direction. The angle irons are welded and fixed by pre-embedded ditch angle iron support bars with a diameter of 10mm. The depth of embedding into the structural base plate is 120mm.

5. A construction method for controlling overall cracks in the floor of a large-area basement building based on fractal theory, as described in claim 2, is characterized in that: In step S13, the width of the cut is 8mm and the depth is 80mm. At the structural column, the cut is made around the structural column, with the center line of the cut 300mm away from the edge line of the structural column, and the cut is continuous in both the longitudinal and transverse directions.

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