Construction technology of novel anti-floating anchor rod

Abstract

The invention relates to the technical field of anti-floating anchor rod construction, in particular to a novel anti-floating anchor rod construction process which comprises the following steps: S1, material preparation: preparing anchor bars, anchor plates, positioning bars, steel pipe sleeves and water stop steel sheets; s2, anchor bar construction: drilling according to a design drawing, welding a plurality of positioning bars on anchor bars, hoisting the anchor bars into the drilling well, and backfilling a well pit with C30 concrete; s3, a waterproof layer is constructed, specifically, a gravel cushion layer, a concrete cushion layer and a waterproof roll are sequentially laid at the bottom of the foundation, and waterproof joint treatment is conducted on the roots of anchor bars; s4, anchor plate construction, wherein a water stop ring, a steel pipe sleeve and a water stop steel sheet are sequentially installed on the outer side of the anchor bar; according to the scheme, accurate centering and stable positioning of anchor bars in a drilling well are achieved through the spirally-arranged positioning bar system; the waterproof reliability and durability of the node are improved through a multi-layer composite waterproof structure; through the numerical simulation-based anchor plate-anchor bar connection optimization design, the balance of reasonable stress and economical applicability is realized.

Description

Technical Field

[0001] This invention relates to the field of anti-buoyancy anchor construction technology, and in particular to a novel construction process for anti-buoyancy anchors. Background Technology

[0002] Currently, basements are a popular and essential component in both residential and commercial buildings. According to relevant departments, water levels are high in most parts of Henan Province. In addition, the underground garages of most construction projects are buried at great depths and the water levels are also high. Therefore, the problem of buoyancy resistance has become a difficult and costly issue that needs to be addressed in the construction of these projects. New theoretical research and technological innovation are urgently needed to address the problem of buoyancy resistance.

[0003] In traditional construction processes, water leakage and seepage in the foundation slab are usually caused by the fact that the anti-buoyancy anchor rods are not designed to withstand the pressure, but actually bear the compressive stress given by the foundation. This leads to problems such as loosening and damage of the connection between the traditional anti-buoyancy anchor rod steel bars and the foundation, which in turn affects the quality of the entire underground project.

[0004] To address this, this invention proposes a novel construction process for anti-buoyancy anchors. It achieves precise alignment and stable positioning of the anchor bars during drilling through a spirally arranged positioning bar system; enhances the reliability and durability of joint waterproofing through a multi-layered composite waterproof structure; achieves a balance between reasonable stress distribution and economic applicability through numerical simulation-based optimized design of the anchor plate-anchor bar connection; and improves construction controllability and project quality consistency through process standardization and modularization. This systematically solves the shortcomings of traditional processes in positioning, waterproofing, connection design, and construction control, providing an efficient, reliable, and economical construction solution for anti-buoyancy engineering. Summary of the Invention

[0005] Technical problems solved: loosening and damage in the connection between traditional anti-buoyancy anchor bars and the foundation.

[0006] In view of the shortcomings of the prior art, the present invention provides a new construction process for anti-buoyancy anchor bolts, thereby solving the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A novel construction process for anti-buoyancy anchor bolts includes the following steps: S1. Material preparation: Prepare anchor bars, anchor plates, positioning bars, steel pipe sleeves, and water-stop steel plates; S2. Anchor bar construction: Drill wells according to the design drawings, weld multiple positioning bars on the anchor bars, hoist the anchor bars into the well, and backfill the well pit with C30 concrete. S3. Waterproofing layer construction: Lay a sand and gravel cushion layer, a concrete cushion layer and a waterproof membrane in sequence at the bottom of the foundation, and perform waterproofing joint treatment at the root of the anchor bar. S4. Anchor plate construction: Install the water-stop ring, steel pipe sleeve and water-stop steel plate in sequence on the outside of the anchor bar, and inject micro-expansion cement mortar between the steel pipe sleeve and the anchor bar to form a grouting layer. Finally, weld the anchor plate to the top of the anchor bar and carry out the construction of the protective layer and water-resistant plate.

[0008] In one possible implementation, in S1, there are 6 positioning bars, which are arranged at equal intervals along the length of the anchor bar. The bottom positioning bar is 20cm from the bottom of the anchor bar, and the top positioning bar is H+20cm from the top of the anchor bar downwards, where H is the total thickness of the base. Adjacent positioning bars are continuously offset by 30° in the circumferential direction, and the whole is distributed in a spiral upward distribution.

[0009] In one possible implementation, in step S4, a steel pipe sleeve with a water-stop ring is installed above the waterproof membrane, and the bottom of the steel pipe sleeve is squeezed to form a mechanical seal by the water-stop ring; a circular water-stop steel plate is welded in the middle of the steel pipe sleeve, and micro-expansion cement mortar is injected between the steel pipe sleeve and the anchor bar to form a rigid grouting layer.

[0010] In one possible implementation, the anchor plate is a square steel plate with a frustum-shaped weld in the middle. The anchor bar passes through the weld and is welded and fixed to the anchor plate. The lower surface of the anchor plate presses against the top of the steel pipe sleeve and is connected to the anchor bar through the weld.

[0011] In one possible implementation, the anchor bar is made of grade III threaded steel with a diameter of 25mm, the anchor plate is made of a circular steel plate of 300mm×300mm×8mm, the steel pipe sleeve is made of a steel pipe with an outer diameter of 48mm and a wall thickness of 3.5mm, and the water-stop steel plate is made of a circular steel plate with a diameter of 200mm and a thickness of 1.5mm with a 49mm circular through hole in the center.

[0012] Beneficial effects compared to existing technologies: 1. In this solution, the precise centering and stable positioning of the anchor bars in drilling is achieved through a spiral positioning rib system and refined welding technology, improving the integrity and load-bearing uniformity of the anti-buoyancy system. Traditional anti-buoyancy anchor bars often deviate during installation due to inaccurate positioning, affecting their cooperative stress-bearing performance with the surrounding concrete or soil, and even causing local stress concentration. In this process, six positioning ribs are spirally arranged around the anchor bar, with adjacent positioning ribs continuously offset by 30°, forming a three-dimensional spatial distribution of support points. This spiral upward layout allows the anchor bars to automatically adjust and remain in the center of the drilling during hoisting and concrete pouring, effectively avoiding the deviation problem caused by contact with the well wall on one side. 2. In this solution, the reliability and durability of the waterproofing system at the anchor root are achieved through a multi-layered waterproofing and joint sealing integrated structure, effectively preventing water seepage from eroding the structure. In anti-buoyancy projects, the point where the anchor passes through the foundation waterproofing layer often becomes a weak point for leakage. This process uses a multi-layered composite waterproofing system, including waterproof membranes and water-stop rings, to achieve comprehensive sealing of the anchor root joints. During construction, SBS modified bitumen waterproof membrane is meticulously wrapped around the anchor root and turned upwards to form the first layer of flexible waterproofing. Subsequently, a steel pipe sleeve with a water-stop ring is installed to compress the waterproofing layer and form a mechanical seal. A circular water-stop steel plate is welded in the middle of the steel pipe sleeve to enhance the water-blocking path. A higher grade of micro-expansion cement mortar is injected between the steel pipe sleeve and the anchor, which both fills the gaps and forms a rigid waterproofing layer. This multi-layered, progressive, and rigid-flexible waterproofing structure not only has a reasonable construction sequence and clear joints, but also effectively avoids joint leakage caused by material shrinkage, foundation deformation, or water pressure fluctuations. 3. In this scheme, the optimized connection design of anchor plates and anchor bars, along with numerical simulation verification, achieves the rationality and economic applicability of the connection node under high loads. In this process, the anchor plate is made of 300×300×8mm steel plate with a frustum-shaped weld at the center. The anchor bar is welded and fixed after penetration, forming a rigid connection node. Finite element numerical simulation was used to systematically analyze the stress-strain response of different anchor bar diameters and anchor plate thicknesses under loads of 100–400kN. Simulation results show that under the same load, increasing the anchor plate thickness can significantly reduce stress and deformation. However, considering both economy and load-bearing performance, the scheme of an 8mm thick anchor plate with a 25mm diameter anchor bar achieves the optimal balance between stress distribution, deformation control, and material usage. For example, under a 400kN load, the maximum stress of the 8mm anchor plate is 14139MPa, and the deformation is only 0.092mm, both meeting engineering safety requirements and demonstrating high material utilization. Attached Figure Description

[0013] 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, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the construction process of the present invention; Figure 2 This is a schematic diagram showing the positioning rib spacing setting of the present invention; Figure 3 This is a schematic diagram of the misalignment angle of the positioning ribs in this invention; Figure 4 This is a schematic diagram of the welding of the positioning ribs according to the present invention; Figure 5 This is a schematic diagram of the connection between the anti-buoyancy anchor bar and the foundation according to the present invention; Figure 6 for Figure 5Enlarged view of point A in the middle; Figure 7 for Figure 5 Enlarged view at point B in the middle; Figure 8 for Figure 5 Enlarged view at point C; Figure 9 The stress trend diagrams under different loads are shown in Table 3. Figure 10 The stress trend diagrams under different loads are shown in Table 4. Figure 11 The stress trend diagrams under different loads are shown in Table 5. Figure 12 The stress trend diagram is shown in Table 6 under different loads. Detailed Implementation

[0015] Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can also be implemented in various different forms, and therefore the present invention is not limited to the embodiments described below. In addition, for the purpose of more clearly describing the present invention, parts not connected to the invention will be omitted from the drawings. The technical solution in this application embodiment is to solve the problems mentioned in the background art, and the overall idea is as follows: Example:

[0016] Please refer to Figures 1 to 8 As shown in the figure, this embodiment introduces a new type of anti-buoyancy anchor construction process, which includes the following steps: S1. Material preparation, including anchor bars, anchor plates, positioning bars, steel pipe sleeves, and water-stop steel plates, as detailed below: The anchor bars are made of 25mm diameter grade III threaded steel, and their length is determined according to the drilling depth. Figure 2 As shown, the preset drilling design depth is Then the length of the anchor bar Based on the thickness, such as Figure 5 As shown, the foundation includes a 10cm gravel cushion layer, a 10cm concrete cushion layer, a 0.8cm double-layer waterproof layer, a 5cm protective layer, and a 60cm waterproof slab. ; The anchor plate is made of 300×300×8mm steel plate, such as Figure 8 As shown, located at the top of the anchor bar, the anchor bar passes through the weld seam in the center, and the weld seam is designed as a frustum with an upper diameter of 35mm and a lower diameter of 28mm. Positioning ribs are mainly used to assist in positioning anchor ribs at the center of the drilling site, such as... Figures 2 to 4 As shown, a single anchor bar requires 6 positioning bars, which are cut from grade III threaded steel with a diameter of 25mm, and their length... , To allow for better movement of the anchor bars within the drilling rig during installation, a semi-circular welding groove with a diameter of 30mm is cut at the center of the positioning bar. The welding position of the lowermost positioning bar on the anchor bar is located 20cm above the bottom of the anchor bar, and the welding position of the uppermost positioning bar on the anchor bar is located at the top of the anchor bar. Right now The spacing between the four anchor bars in the middle and the adjacent anchor bars at the top and bottom ends is [missing information]. ; The steel pipe sleeve, made of 48mm outer diameter and 3.5mm wall thickness, is positioned between the waterproofing plate and the protective layer, below the anchor plate, and has a water-stop ring at its bottom end. ; The water-stop steel sheet is a round steel sheet with a diameter of 200mm and a thickness of 1.5mm. A 49mm round through hole is opened in the center. It is fitted into the middle of the steel pipe through the through hole and connected and fixed by welding. S2, Anchor bar construction S2.1 Drilling: Determine the drilling location, diameter, and depth based on the design drawings. The specific values ​​are determined based on the engineering geological conditions and anti-buoyancy design requirements.

[0017] S2.2 Anchor bar preparation: 25mm diameter Grade III threaded steel bars are selected for the anchor bars. The length calculation formula is as follows: Six positioning bars are welded to the anchor bar. The positioning bars are made of threaded steel of the same specification, and their length is determined according to the drilling diameter. The welding positions are evenly spaced on the anchor bar, with a spacing of [missing information]. The bottommost positioning bar is 20cm from the bottom of the anchor bar, and the topmost positioning bar is H+20cm down from the top of the anchor bar; a semi-circular welding groove with a diameter of 30mm is opened in the center of the positioning bar to facilitate welding and fixing with the anchor bar. During welding, the upper and lower positioning ribs are as follows: Figure 3 The anchor bars are all continuously offset by 30°, and the overall trend is spiral upward. The spiral arrangement makes the contact points between the positioning bars and the well wall in three-dimensional space, avoiding all positioning bars from contacting the well wall on the same circumferential surface, thereby preventing the anchor bars from deviating to one side in the well and ensuring that the anchor bars are always located in the center of the well.

[0018] S2.3 Backfilling: Hoist the anchor bars with welded positioning bars to the center of the well, and pour C30 concrete to the design elevation to ensure that the anchor bars form an integral load-bearing system with the surrounding soil or rock.

[0019] S3, Waterproofing layer construction S3.1. Laying of sand and gravel cushion layer and concrete cushion layer: First, lay a 10cm thick sand and gravel cushion layer at the bottom of the foundation, level and compact it; then lay a 10cm thick concrete cushion layer as the base layer of the waterproof layer.

[0020] S3.2 Waterproofing layer installation: Lay two layers of 0.4cm thick SBS modified bitumen waterproofing membrane on the concrete subbase. During construction, ensure that the membrane is laid flat and without voids, the overlap width meets the specifications, and the perimeter is properly finished. When the SBS waterproofing layer is laid to the anchor bar position, a fine treatment is carried out at the root of the anchor bar. The SBS roll is tightly wrapped around the anchor bar and turned up to a certain height to use its adhesiveness for initial sealing.

[0021] S4, Anchor Plate Construction S4.1 Installation of the waterstop layer, such as Figure 6 As shown, first, the water-stop ring is placed on the outside of the anchor bar and moved down to the intersection with the waterproof layer. Then, the welded steel pipe sleeve and water-stop steel plate are placed on the outside of the anchor bar, so that the bottom end of the steel pipe sleeve squeezes the water-stop ring. Because there is a gap between the steel pipe sleeve and the anchor bar, a grouting layer is formed. The grouting layer is filled with micro-expansion cement mortar with a grade one higher than that of the water-resistant board.

[0022] S4.2 Anchor plate welding: After the grouting layer is filled, the anchor plate is fitted onto the top of the anchor bar through the weld, as shown below. Figure 8 As shown, the bottom end of the anchor plate is pressed against the top end of the steel pipe sleeve. While applying a certain pressure to the anchor plate, welding is performed at the weld seam to fix the anchor plate to the top of the anchor bar.

[0023] S4.3, Construction of Protective Layer and Waterproof Board: After completing the joint waterproofing system, lay a 5cm thick fine stone concrete protective layer on the surface of the waterproof layer, and finally pour a 60cm thick waterproof board structural concrete to enclose the entire waterproofing system and form permanent protection.

[0024] The tensile strength and strain of anchor bolt connectors of different sizes and specifications under different load conditions were determined using numerical simulation software. Data analysis was then used to further determine the quantitative relationship between the tensile strength of the connectors and the dimensions of the components. The experiment is as follows: 1. Based on the actual stress conditions of the engineering project, the component size schemes were divided into two categories. The width and length of the anchor plate of the connector were both 300mm. The load was applied in increments of 100kN to 400kN, as shown in Tables 1 and 2 respectively. Table 1: Dimensions of Components with Anchor Bar Diameter of 28mm

[0025] Table 2: Dimensions of Components with Different Reinforcing Bar Diameters

[0026] 2. Component boundary conditions First, the anchor plate of the connector is a fixed boundary because in practical applications, the steel plate is cast-in-place with the foundation concrete, and the concrete constraint on the anchor plate can be approximated as a fixed boundary condition. Second, the connection between the anti-buoyancy anchor bar and the anchor plate is considered to be a welded connection, which can also be approximated as a fixed boundary condition. All boundary conditions are set as fixed boundaries, and then different loads are applied until the bar is pulled out of the connector. The bar is HRB400 grade, with an elastic modulus of 2.0 x 10⁵ MPa.

[0027] The finite element simulation does not consider the influence of concrete on the anchor plate of the connector. The deformation and stress diameter of the steel plate are provided by the reinforcing steel. Therefore, the system has theoretical redundancy in calculation, which can ensure the reliability of the connection between the anti-buoyancy anchor reinforcement and the anchor plate to the greatest extent, and ensure that there will be no detachment or insufficient anchorage length under actual water pressure. During the simulation, loads were applied in levels of 100KN, 200KN, 300KN, and 400KN, and the corresponding stress and strain were recorded. The load setting principle is to consider that the pull-out force borne by anti-buoyancy anchor reinforcements of different lengths and diameters will vary in actual applications. Therefore, the simulation can consider the influence of different loads on the anchor plate, making the research more standardized and universally applicable.

[0028] 3. Analysis of Numerical Simulation Results The strain of connectors of different sizes was obtained through finite element numerical simulation. Analyzing the strain and deformation can help select appropriate size specifications in practical engineering. The following results were obtained by summarizing the stress and strain data from the finite element numerical simulation: (1) When the anti-buoyancy anchor bar is 25mm thick and the anchor plate thickness of the connector is inconsistent, the maximum stress values ​​obtained by applying different loads are shown in Table 3: Table 3: Statistical Table of Anchor Bar Stress under Different Loads By using data analysis methods to summarize and generalize the data, the stress variation trend of the connection system under different loads was obtained, and the linear relationship was derived as follows: When the anchor plate is under 6mm stress, the stress-load relationship is as follows: When the anchor plate is under 8mm stress, the stress-load relationship is as follows: When the anchor plate is under 10mm stress, the stress-load relationship is as follows: When the anchor plate is under 12mm stress, the stress-load relationship is as follows: The stress trend fed back by the above-mentioned sexual relationship is as follows: Figure 9 As shown.

[0029] (2) When the anti-buoyancy anchor bar is 25mm thick and the thickness of the anchor plate of the connector is inconsistent, the maximum strain values ​​obtained by applying different loads are shown in Table 4: Table 4: Statistics on Anchor Bar Deformation under Different Loads By using data analysis methods to summarize and generalize the data, the strain variation trend of the connection system under different loads was obtained, and the linear relationship was derived as follows: When the anchor plate is under 6mm stress, the relationship between strain and load is as follows: When the anchor plate is under 8mm stress, the relationship between strain and load is as follows: When the anchor plate is under 10mm stress, the relationship between strain and load is as follows: When the anchor plate is under 12mm stress, the relationship between strain and load is as follows: The stress trend fed back by the above-mentioned sexual relationship is as follows: Figure 10 As shown.

[0030] (3) When analyzing the connection anchor plate with a thickness of 8mm and the anti-buoyancy anchor bar with diameters of 22mm, 25mm, 28mm, and 32mm, the maximum strain values ​​obtained by applying different loads are shown in Table 5: Table 5: Statistics of Anchor Bar Deformation under Different Loads By using data analysis methods to summarize and generalize the data, the strain variation trend of the connection system under different loads was obtained, and the linear relationship was derived as follows: When the anchor bar diameter is 22mm, the relationship between strain and load is as follows: When the anchor bar diameter is 25mm, the relationship between strain and load is as follows: When the anchor bar diameter is 28mm, the relationship between strain and load is as follows: When the anchor bar diameter is 32mm, the relationship between strain and load is as follows: The stress trend fed back by the above-mentioned sexual relationship is as follows: Figure 11 As shown.

[0031] (4) When analyzing the connection anchor plate with a thickness of 8mm and the anti-buoyancy anchor bar with diameters of 22mm, 25mm, 28mm, and 32mm, the maximum stress values ​​obtained by applying different loads are shown in Table 6: Table 6: Statistical Table of Anchor Bar Stress under Different Loads By using data analysis methods to summarize and generalize the data, the stress variation trend of the connection system under different loads was obtained, and the linear relationship was derived as follows: When the anchor bar diameter is 22mm, the stress-load relationship is as follows: When the anchor bar diameter is 25mm, the stress-load relationship is as follows: When the anchor bar diameter is 28mm, the stress-load relationship is as follows: When the anchor bar diameter is 32mm, the stress-load relationship is as follows: The stress trend fed back by the above-mentioned sexual relationship is as follows: Figure 12 As shown.

[0032] Data analysis reveals that under different load conditions, stress and strain change linearly with increasing load. However, this increase slows down as the anchor plate thickness increases. Based on the trend line, a design with an anti-buoyancy anchor bar diameter of 25mm and an anchor plate size of 300×300×8mm is theoretically more suitable.

[0033] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A novel construction process for anti-buoyancy anchors, characterized in that, Includes the following steps: S1. Material preparation: Prepare anchor bars, anchor plates, positioning bars, steel pipe sleeves, and water-stop steel plates; S2. Anchor bar construction: Drill wells according to the design drawings, weld multiple positioning bars on the anchor bars, hoist the anchor bars into the well, and backfill the well pit with C30 concrete. S3. Waterproofing layer construction: Lay a sand and gravel cushion layer, a concrete cushion layer and a waterproof membrane in sequence at the bottom of the foundation, and perform waterproofing joint treatment at the root of the anchor bar. S4. Anchor plate construction: Install the water-stop ring, steel pipe sleeve and water-stop steel plate in sequence on the outside of the anchor bar, and inject micro-expansion cement mortar between the steel pipe sleeve and the anchor bar to form a grouting layer. Finally, weld the anchor plate to the top of the anchor bar and carry out the construction of the protective layer and water-resistant plate.

2. The construction process of a novel anti-buoyancy anchor as described in claim 1, characterized in that, In S1, there are 6 positioning bars, which are arranged at equal intervals along the length of the anchor bar. The bottom positioning bar is 20cm from the bottom of the anchor bar, and the top positioning bar is H+20cm from the top of the anchor bar downwards. H is the total thickness of the base. Adjacent positioning bars are continuously offset by 30° in the circumferential direction, and the whole is distributed in a spiral upward distribution.

3. The construction process of a novel anti-buoyancy anchor as described in claim 2, characterized in that, In step S4, a steel pipe sleeve with a water-stop ring is installed above the waterproof membrane, and the bottom of the steel pipe sleeve is squeezed to form a mechanical seal by the water-stop ring; a circular water-stop steel plate is welded in the middle of the steel pipe sleeve, and micro-expansion cement mortar is injected between the steel pipe sleeve and the anchor bar to form a rigid grouting layer.

4. The construction process of a novel anti-buoyancy anchor as described in claim 1, characterized in that, The anchor plate is a square steel plate with a frustum-shaped weld in the middle. The anchor bar passes through the weld and is welded and fixed to the anchor plate. The lower surface of the anchor plate presses against the top of the steel pipe sleeve and is connected to the anchor bar through the weld.

5. The construction process of a novel anti-buoyancy anchor as described in claim 1, characterized in that, The anchor bar is made of grade III threaded steel with a diameter of 25mm, the anchor plate is made of round steel plate with a diameter of 300mm×300mm×8mm, the steel pipe sleeve is made of steel pipe with an outer diameter of 48mm and a wall thickness of 3.5mm, and the water-stop steel plate is made of round steel plate with a diameter of 200mm and a thickness of 1.5mm with a 49mm round through hole in the center.

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