An adjustable load bearing fabricated spiral anchor foundation and method of design and installation thereof

Abstract

The utility model provides a kind of bearing capacity adjustable fabricated spiral anchor foundation and its design and installation method, including determining relevant parameters first, then determining soil body discriminant index by relevant parameters, then according to soil body discriminant index, the bearing capacity of soil body is evaluated, then when designing spiral anchor foundation, the area of bearing platform and the number of spiral anchor are designed according to evaluation result, the area of larger bearing platform and the number of more spiral anchor can increase the support force of spiral anchor foundation, adapt to soil body with poor bearing capacity, smaller bearing platform area and less spiral anchor can reduce the support force of spiral anchor foundation, adapt to soil body with good bearing capacity;Then according to the foregoing design, spiral anchor foundation is assembled, then spiral anchor foundation is installed in installation pit installation. Therefore, the support force of the design can be adjusted, and it is better matched with the application environment.

Description

Technical Field

[0001] This invention relates to a helical anchor foundation, belonging to the field of foundation component technology, and particularly to a prefabricated helical anchor foundation with adjustable bearing capacity, as well as its design and installation method. Background Technology

[0002] A spiral anchor is a foundation component that is embedded in the soil by rotation. Its core function is to provide stable support for various engineering structures, which can effectively reduce earthwork excavation, construction period and construction cost.

[0003] Chinese patent application number 202311477137.1, filed on November 7, 2023, discloses a prefabricated spiral anchor foundation for river network and swamp areas and its construction method. The prefabricated spiral anchor foundation for river network and swamp areas includes a reinforced concrete structure, a spiral anchor structure, a tension plate, a bearing plate, shear piles, and a retaining structure. The spiral anchor structure is positioned at a predetermined location within the river network and swamp area. The shear piles are arranged between the spiral anchor structures. The reinforced concrete structure includes anchor bolts, reinforced concrete main columns, and a reinforced concrete foundation. The bearing plate is located at the bottom of the reinforced concrete foundation. The tension plate is located on the upper part of the reinforced concrete foundation. The reinforced concrete foundation encloses the exposed portion of the shear piles. The reinforced concrete main columns are positioned above the reinforced concrete foundation. The anchor bolts are pre-embedded within the reinforced concrete main columns. Although the components of this design are prefabricated, it still has the following drawbacks:

[0004] In this design, the size of the foundation is fixed, meaning the support force it can provide is not adjustable. However, when using a helical anchor device in areas with good soil conditions, only the foundation of the helical anchor device needs to provide a small support force. In this case, the support force in this design is slightly wasted. Conversely, when using a helical anchor in areas with poor soil conditions, the foundation of the helical anchor device needs to provide a larger support force. In this case, the support force in this design may be insufficient. Therefore, this design is not well matched with the application environment.

[0005] The information disclosed in this background section is intended only to enhance understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects and problems of the existing technology, such as the inability to adjust the support force and poor matching with the application environment, and to provide a prefabricated helical anchor foundation with adjustable bearing capacity, which has adjustable support force and better matching with the application environment, as well as its design and installation method.

[0007] To achieve the above objectives, the technical solution of the present invention is:

[0008] A design method for a prefabricated helical anchor foundation with adjustable bearing capacity, the method comprising the following steps:

[0009] Step 1: First, determine the water content, elastic modulus, void ratio, and shear strength of the soil in the installation pit of the prefabricated spiral anchor foundation. Then, calculate the soil discrimination index based on the water content, elastic modulus, void ratio, and shear strength.

[0010] Step 2: Evaluate the soil bearing capacity based on the soil discrimination index;

[0011] Step 3: When designing prefabricated helical anchor foundations, adjust the area of ​​the foundation cap and the number of helical anchors based on the soil bearing capacity evaluation results.

[0012] The method for calculating the soil discrimination index is as follows:

[0013] S1. Normalize the water content, elastic modulus, void ratio and shear strength in sequence to obtain normalized water content, normalized elastic modulus, normalized void ratio and normalized shear strength.

[0014] S2. Assign weights to the normalized water content, normalized elastic modulus, normalized void ratio and normalized shear strength, and calculate the water content, elastic modulus, void ratio and shear strength results.

[0015] S3. The soil discrimination index is obtained by sequentially adding the water content result, elastic modulus result, void ratio result and shear strength result.

[0016] The evaluation of soil bearing capacity based on the soil discrimination index is as follows: if the soil discrimination index is greater than or equal to 0 and less than 0.5, the soil bearing capacity is poor; if the soil discrimination index is greater than or equal to 0.5 and less than 1, the soil bearing capacity is good.

[0017] The adjustment of the pile cap area and the number of helical anchors based on the soil bearing capacity evaluation results is as follows: if the soil bearing capacity is poor, the pile cap area and the number of helical anchors should be increased when designing the prefabricated helical anchor foundation; if the soil bearing capacity is good, the pile cap area and the number of helical anchors should be reduced when designing the prefabricated helical anchor foundation.

[0018] An adjustable bearing capacity prefabricated helical anchor foundation, the foundation comprising a pile cap, a concrete column and a helical anchor;

[0019] The foundation includes a long H-beam, a first short H-beam, a second short H-beam, and multiple precast concrete blocks. One side of the middle portion of the long H-beam is perpendicularly connected to one end of the first short H-beam, and the other side of the middle portion of the long H-beam is perpendicularly connected to one end of the second short H-beam. Precast concrete blocks are disposed between the long H-beam and the first and second short H-beams.

[0020] The top of the precast concrete block is connected to the bottom of the upper steel plate, and the bottom of the precast concrete block is connected to the top of the lower steel plate; the top of the upper steel plate is connected to the bottom surface of the top of the long H-beam, the first short H-beam, and the second short H-beam, and the top of the long H-beam is connected to the bottom of the concrete column; the bottom of the lower steel plate is connected to the top surface of the bottom of the long H-beam, the first short H-beam, and the second short H-beam; the top of the spiral anchor is detachably connected to the bottom of the long H-beam, the bottom of the first short H-beam, or the bottom of the second short H-beam.

[0021] The precast concrete block has a triangular structure and is composed of a large triangular block, multiple small triangular blocks, and multiple rectangular blocks.

[0022] Multiple small triangular blocks and multiple rectangular blocks are assembled to form multi-layered trapezoidal blocks, and multi-layered trapezoidal blocks are assembled with large triangular blocks to form the precast concrete blocks.

[0023] The small triangular block is a right triangle, and the trapezoidal block is composed of small triangular blocks at both ends and a rectangular block in the middle. The rectangular block is composed of multiple pairs of small triangular blocks and a rectangular block.

[0024] The top of the long I-beam is provided with an upper flange, which is connected to the lower flange at the bottom of the concrete column.

[0025] The first short I-beam has a first extended steel section on the side near the long I-beam, and one end of the first extended steel section is perpendicularly connected to the middle of the long I-beam.

[0026] The second short I-beam has a second extended steel section on the side near the long I-beam, and one end of the second extended steel section is perpendicularly connected to the middle of the long I-beam.

[0027] The spiral anchor includes an anchor body, the top of which is a spiral steel segment, which is detachably connected to the bottom of a long H-beam, a first short H-beam, or a second short H-beam. Spiral blades are evenly wound around the outer periphery of the anchor body, and the bottom of the anchor body is a conical head.

[0028] An installation method for a prefabricated helical anchor foundation with adjustable bearing capacity, the method comprising the following steps:

[0029] Step 1: Excavate the installation pit, level the ground of the installation pit, and then drill the reserved holes for the spiral anchor in the installation pit;

[0030] Step 2: First, screw the spiral anchors into the pre-drilled holes one by one, so that the top of the spiral anchor is higher than the ground, and then fix the spiral anchors. Next, splice and fix the middle of one side of the long I-beam to one end of the first short I-beam, and then splice and fix the middle of the other side of the long I-beam to one end of the second short I-beam to obtain the I-beam frame. Then fix the I-beam frame to the lower steel plate to obtain the overall frame. Then hoist the overall frame to the top of the spiral anchor, and then connect and fix the overall frame to the spiral anchor.

[0031] Step 3: First, use large triangular blocks, small triangular blocks and rectangular blocks to assemble multiple precast concrete blocks on the overall frame. Then, fix the precast concrete blocks to the overall frame in sequence. Next, fix the upper steel plate on the top of the precast concrete blocks and then fix the concrete column on the top of the long I-beam.

[0032] Step 4: Backfill the installation pit and compact the soil. At this point, the installation of the device is complete.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The present invention discloses an adjustable bearing capacity prefabricated helical anchor foundation and its design and installation method. The design method includes the following steps: First, determine the soil discrimination index based on the soil's water content, elastic modulus, void ratio, and shear strength. Second, evaluate the soil bearing capacity based on the soil discrimination index. Third, adjust the area of ​​the foundation cap and the number of helical anchors based on the soil bearing capacity evaluation results when designing the prefabricated helical anchor foundation. That is, when the soil bearing capacity is poor, increase the area of ​​the foundation cap and increase the number of helical anchors; when the soil bearing capacity is good, decrease the area of ​​the foundation cap and decrease the number of helical anchors. The advantages of the present invention also include:

[0035] Firstly, the area of ​​the foundation and the number of helical anchors are set based on the soil bearing capacity evaluation results, so the support force can be adjusted.

[0036] Secondly, the soil discrimination index is obtained based on the relevant parameters of the soil, and the soil discrimination index is referenced when designing the helical anchor, so it is well matched with the application environment.

[0037] Therefore, the supporting force of this invention is adjustable and better matched to the application environment.

[0038] 2. In the present invention, a prefabricated helical anchor foundation with adjustable bearing capacity and its design and installation method, the helical anchor foundation includes a foundation cap, a concrete column, and a helical anchor. The foundation cap includes a long H-beam, a first short H-beam, a second short H-beam, and multiple precast concrete blocks. The long H-beam is perpendicularly connected to the first and second short H-beams, and the three are connected by precast concrete blocks. The top and bottom of the precast concrete blocks are connected to an upper steel plate and a lower steel plate, respectively. The upper and lower steel plates are connected to the long H-beam, the first short H-beam, and the second short H-beam, respectively. The precast concrete blocks are assembled from multiple large triangular blocks, small triangular blocks, and rectangular blocks. In application, a foundation pit is first excavated, and then... The ground is leveled, and then the spiral anchor is driven into the reserved hole. Long H-beams are then spliced ​​with the first and second short H-beams to obtain an H-beam frame. Next, lower steel plates are spliced ​​onto the H-beam frame to obtain the overall frame. The overall frame is then hoisted and fixed to the spiral anchor. Multiple precast concrete blocks are then assembled using large triangular blocks, small triangular blocks, and rectangular blocks. The internal gaps are filled with cement mortar to form a whole. The cement mortar is matched to the size of the upper and lower steel plates. The precast concrete blocks are then fixed to the overall frame, and the upper steel plate is fixed. Finally, a concrete column is fixed to the top of the upper steel plate. The advantages of this invention also include:

[0039] Firstly, large triangular blocks, small triangular blocks, and rectangular blocks can be assembled into various sizes of precast concrete blocks. These different sizes of precast concrete blocks can provide different levels of support, thus matching various application environments that require different levels of support. Furthermore, it effectively saves the number of large triangular blocks, small triangular blocks, and rectangular blocks, thereby reducing project costs to some extent.

[0040] Secondly, the components of this invention are prefabricated in the factory and then assembled on-site in the foundation pit. The heavier foundation is divided into multiple smaller triangular blocks, small triangular blocks and rectangular blocks, which avoids the transportation difficulties caused by muddy roads in river network and swamp areas and saves transportation costs.

[0041] Therefore, the present invention has low cost and is relatively convenient to transport.

[0042] 3. In the present invention, a prefabricated helical anchor foundation with adjustable bearing capacity, and its design and installation method, the first and second short H-beams are provided with extended steel sections at their ends near the long H-beam. During application, the extended steel sections ensure a seamless connection between the first and second short H-beams and the long H-beam, resulting in better overall stability. Without the extended steel sections, cement mortar would easily flow into the gaps, leading to a decrease in strength. Therefore, the present invention has higher strength.

[0043] 4. In the present invention, a prefabricated helical anchor foundation with adjustable bearing capacity, and its design and installation method, the helical anchor includes an anchor body, a helical steel section, a helical blade, and a conical head. In application, the conical head makes it easier to press the helical anchor into the pre-drilled hole, the helical blade makes the connection between the helical anchor and the soil tighter, thereby improving the vertical bearing capacity of the helical anchor, and the helical steel section facilitates connection with long H-beams, first short H-beams, or second short H-beams. Therefore, the present invention has better vertical bearing capacity. Attached Figure Description

[0044] Figure 1 This is a flowchart of the design method in this invention.

[0045] Figure 2 This is a schematic diagram of the spiral anchor foundation in this invention.

[0046] Figure 3 yes Figure 2 A schematic diagram of the structure of the first short I-beam.

[0047] Figure 4 yes Figure 2 Top view.

[0048] Figure 5 yes Figure 2 Schematic diagram of the upper and middle steel plates.

[0049] Figure 6 yes Figure 2 Schematic diagram of the middle and lower steel plates.

[0050] Figure 7 It is a schematic diagram of the structure assembled into a large precast concrete block.

[0051] Figure 8 This is a schematic diagram of a structure assembled into smaller precast concrete blocks.

[0052] Figure 9 yes Figure 2 A schematic diagram of the structure of a medium-length I-beam.

[0053] Figure 10 yes Figure 2 A schematic diagram of the structure of the first short I-beam.

[0054] Figure 11 yes Figure 2 A schematic diagram of the structure of the second shortest I-beam.

[0055] Figure 12 yes Figure 2 A schematic diagram of the connecting steel sheet in the middle.

[0056] Figure 13 yes Figure 2 A structural schematic diagram of a concrete column.

[0057] Figure 14 yes Figure 2 A schematic diagram of the structure of a spiral anchor.

[0058] Figure 15 This is a schematic diagram of a small number of spiral anchors.

[0059] Figure 16 This is a schematic diagram of a large number of spiral anchors.

[0060] In the diagram: Foundation 1, Long I-beam 11, Long top surface 111, Long bottom surface 112, First connecting hole 113, First fixing hole 114, First short I-beam 12, First short bottom surface 121, Second connecting hole 122, Second fixing hole 124, First extension steel section 125, Upper steel plate 13, Upper steel plate hole 131, Lower steel plate 14, Lower steel plate hole 141, Second short I-beam 15, Second short bottom surface 151, Third connecting hole 15 2. No. 3 fixing hole 154, second extension steel section 155, concrete column 2, lower flange 21, lower flange hole 211, spiral anchor 3, anchor body 31, spiral steel section 32, spiral blade 33, conical head 34, connecting steel plate 6, upper flange 61, upper flange hole 611, flange fixing screw 612, precast concrete block 7, large triangular block 71, small triangular block 721, rectangular block 722, spliced ​​rectangular block 723, trapezoidal block 73. Detailed Implementation

[0061] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] In one embodiment of this application, see Figure 1 , Figure 2 , Figure 3 , Figure 4 , one A design method for a prefabricated helical anchor foundation with adjustable bearing capacity, the method comprising the following steps:

[0063] Step 1: First determine the moisture content of the soil in the installation pit for the prefabricated spiral anchor foundation. Elastic modulus Porosity With shear strength Then based on the moisture content Elastic modulus Porosity With shear strength Soil discrimination index was calculated. ;

[0064] Step 2: Based on the soil discriminant index Evaluation of soil bearing capacity;

[0065] Step 3: When designing the prefabricated helical anchor foundation, adjust the area of ​​the foundation cap 1 and the number of helical anchors 3 according to the soil bearing capacity evaluation results.

[0066] Furthermore, the soil discrimination index The calculation method is as follows:

[0067] S1, regarding moisture content Elastic modulus Porosity With shear strength Normalization was performed sequentially to obtain the normalized water content. Normalized elastic modulus Normalized porosity With normalized shear strength ;

[0068] S2, normalized water content Normalized elastic modulus Normalized porosity With normalized shear strength Weights are assigned, and the water content is calculated. Elastic modulus results Porosity results With shear strength results ;

[0069] S3, Result of moisture content Elastic modulus results Porosity results With shear strength results The soil discrimination index is obtained by adding them in sequence. :

[0070]

[0071] In the formula: For moisture content results, For the elastic modulus results, The porosity result is... This is the shear strength result;

[0072] Furthermore, the evaluation of soil bearing capacity based on the soil discriminant index is as follows: if the soil discriminant index... A soil bearing capacity greater than or equal to 0 and less than 0.5 indicates poor soil bearing capacity. If the soil discrimination index... A value greater than or equal to 0.5 and less than 1 indicates good soil bearing capacity.

[0073] The adjustment of the area of ​​the foundation 1 and the number of spiral anchors 3 based on the soil bearing capacity evaluation results is as follows: if the soil bearing capacity is poor, the area of ​​the foundation 1 and the number of spiral anchors 3 will be increased when designing the prefabricated spiral anchor foundation; if the soil bearing capacity is good, the area of ​​the foundation 1 and the number of spiral anchors 3 will be reduced when designing the prefabricated spiral anchor foundation.

[0074] Furthermore, moisture content At higher elevations, the risk of soil liquefaction is high and the bearing capacity decreases, therefore the area of ​​the pile cap 1 needs to be increased, and the elastic modulus needs to be adjusted. At lower void ratios, the soil is weak and prone to settlement, requiring additional anchoring force through helical anchors 3 and increased stiffness of the foundation 1; At higher elevations, the soil becomes loose and has low shear strength, requiring an increase in the number of spiral anchors 3; shear strength When the resistance is low, the side friction of the helical anchor 3 is insufficient, and it is necessary to rely on the bearing platform 1 to diffuse the load. Therefore, a weighted comprehensive analysis is performed on the above four variables to dynamically adjust the area of ​​the bearing platform 1 and the number of helical anchors 3.

[0075] Furthermore, when performing weighted comprehensive analysis, the aforementioned four variables are first normalized, including the elastic modulus. With shear strength This is a positive indicator parameter, meaning that the higher the parameter, the more beneficial it is to the soil quality; water content. Compared with porosity As a negative indicator parameter, meaning the higher the parameter, the more detrimental the impact on soil quality, the measured values ​​of the aforementioned four variables are mapped to the 0-1 interval to eliminate dimensional differences:

[0076] ;

[0077] In the formula: For positive indicator parameter mapping; For the actual value of the parameter, This is the theoretical minimum value of the parameter in the area where the installation pit is located. This represents the theoretical maximum value of the parameter in the area where the installation pit is located;

[0078] ;

[0079] In the formula: Mapping for negative indicator parameters; For the actual value of the parameter, This is the theoretical minimum value of the parameter in the area where the installation pit is located; This represents the theoretical maximum value of the parameter in the area where the installation pit is located;

[0080] Furthermore, weights are allocated based on the sensitivity of various parameters in the river network marshland region. The marshland region experiences large fluctuations in water level and water content. The soil elastic modulus directly affects soil liquefaction and construction feasibility. Reflecting soil stiffness, which affects the settlement control of foundation 1, but marsh soil is generally soft, so its weight is slightly lower, and its void ratio is... Directly related to density and bearing capacity, it is a core characteristic of marsh soils, hence its slightly higher weight. Soil shear strength... The side friction resistance of the helical anchor is determined by a weighting similar to that of the water content. Therefore, the weights of each parameter are calculated based on the above. Allocation: Water Content Weight The weight of soil elastic modulus is 0.25. The porosity weight is 0.2. The soil shear strength weight is 0.3. It is 0.25;

[0081] Furthermore, based on the soil discrimination index The calculation results define the soil grade, and the area of ​​pile cap 1 and the number of spiral anchors 3 are dynamically adjusted: if the soil discrimination index is calculated... If the value is in the range of 0-0.5, it indicates that the soil is soft swamp soil, which can be considered a poor soil quality area with poor support capacity. Therefore, it is advisable to increase the area of ​​the foundation 1 and the number of spiral anchors 3. If the soil discrimination index is calculated... If the value is in the range of 0.5-1.0, it indicates that the soil is dense peat or medium to high quality swamp soil, which can be regarded as a good soil area with good support. Therefore, it is advisable to reduce the area of ​​the foundation 1 and appropriately reduce the number of spiral anchors 3.

[0082] Furthermore, the specific dimensions of the prefabricated helical anchor foundation with adjustable bearing capacity are designed based on the load combination of the transmission tower (including dead load, live load, wind load, seismic load, etc.) and the bearing capacity of the foundation.

[0083] In one embodiment of this application, see Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11An adjustable-load-bearing prefabricated helical anchor foundation is disclosed. The device includes a foundation 1, a concrete column 2, and a helical anchor 3. The foundation 1 includes a long H-beam 11, a first short H-beam 12, a second short H-beam 15, and multiple precast concrete blocks 7. One side of the middle portion of the long H-beam 11 is perpendicularly connected to one end of the first short H-beam 12, and the other side of the middle portion of the long H-beam 11 is perpendicularly connected to one end of the second short H-beam 15. Precast concrete blocks 7 are disposed between the long H-beam 11 and the first and second short H-beams 12 and 15. The top of the precast concrete blocks 7 is connected to the bottom of an upper steel plate 13, and the bottom of the precast concrete blocks 7 is connected to a lower steel plate. The top of the upper steel plate 13 is connected to the bottom surface of the top of the long H-beam 11, the first short H-beam 12, and the second short H-beam 15; the top of the long H-beam 11 is connected to the bottom of the concrete column 2; the bottom of the lower steel plate 14 is connected to the top surface of the bottom of the long H-beam 11, the first short H-beam 12, and the second short H-beam 15; the top of the spiral anchor 3 is detachably connected to the bottom of the long H-beam 11, the bottom of the first short H-beam 12, or the bottom of the second short H-beam 15; the precast concrete block 7 has a triangular structure and is composed of a large triangular block 71, multiple small triangular blocks 721, and multiple rectangular blocks 722.

[0084] An installation method for a prefabricated helical anchor foundation with adjustable bearing capacity, the method comprising the following steps:

[0085] Step 1: Excavate the installation pit, level the ground of the installation pit, and then drill the reserved holes for the spiral anchor 3 in the installation pit;

[0086] Step 2: First, screw the spiral anchors 3 into the pre-drilled holes one by one, so that the top of the spiral anchors 3 is higher than the ground, and then fix the spiral anchors 3; then, splice and fix the middle of one side of the long I-beam 11 to one end of the first short I-beam 12, and then splice and fix the middle of the other side of the long I-beam 11 to one end of the second short I-beam 15 to obtain the I-beam frame; then fix the I-beam frame to the lower steel plate 14 to obtain the overall frame; then hoist the overall frame above the spiral anchors 3, and then connect and fix the overall frame to the spiral anchors 3.

[0087] Step 3: First, use large triangular blocks 71, small triangular blocks 721 and rectangular blocks 722 to splice multiple precast concrete blocks 7 on the overall frame. Then, fix the precast concrete blocks 7 to the overall frame in sequence. Then, fix the upper steel plate 13 on the top of the precast concrete blocks 7. Then, fix the concrete column 2 on the top of the long I-beam 11.

[0088] Step 4: Backfill the installation pit and compact the soil. At this point, the installation of the device is complete.

[0089] Further, see Figure 6 , Figure 7 Multiple small triangular blocks 721 and multiple rectangular blocks 722 are spliced ​​together to form multi-layer trapezoidal blocks 73, and multi-layer trapezoidal blocks 73 are spliced ​​together with large triangular blocks 71 to form the precast concrete block 7.

[0090] Further, see Figure 6 , Figure 7 The small triangular block 721 is a right triangle, and the trapezoidal block 73 is composed of small triangular blocks 721 at both ends and a rectangular block 723 in the middle. The rectangular block 723 is composed of multiple pairs of small triangular blocks 721 and a rectangular block 722.

[0091] When applied in river network and marshland areas, if the soil discrimination index... If the value is within the range of 0.5-1.0, a relatively good evaluation result for land bearing capacity can be obtained. In this case, smaller precast concrete blocks 7 can be assembled: first, assemble the large triangle 71, then assemble multiple small triangles 721 into a rectangular block 723. Next, assemble multiple rectangular blocks 723 and rectangles 722 in the middle of the trapezoidal block 73. Then, assemble two small triangles 721 at both ends of the trapezoidal block 73, ensuring that the hypotenuses of the two small triangles 721 connect to the two right-angled sides of the large triangle 71, with the hypotenuses and right-angled sides lying in the same plane. Finally, fix the trapezoidal block 73 and the large triangle 71 with cement mortar to form a smaller precast concrete block 7. If the soil discrimination index... If the value is within the range of 0-0.5, a poor land bearing capacity assessment result can be obtained. In this case, it is necessary to splice together a larger precast concrete block 7: first splice together a smaller precast concrete block 7, then use splicing rectangles 723 and 722 to splice together the middle of trapezoidal block 73, then use two small triangular blocks 721 to splice together the two ends of trapezoidal block 73, then connect the upper base of trapezoidal block 73 to the hypotenuse of the smaller precast concrete block 7, and the hypotenuse and the right angle side of small triangular block 721 are in the same plane, and then fix it into a larger precast concrete block 7 with cement mortar; the large triangle 71 can be directly clipped at the connection between the long I-beam 11 and the first short I-beam 12 and the second short I-beam 15, which is convenient for on-site construction splicing, and the size of the large triangle 71 is also suitable for this purpose. With slightly larger dimensions, fewer small triangular blocks 721 and rectangular blocks 722 need to be assembled, saving manpower. During assembly, most of the small triangular blocks 721 are identical, and the gaps are filled with rectangular blocks 722. Only large triangular blocks 71, small triangular blocks 721, and rectangular blocks 722 need to be prefabricated to complete the assembly of smaller or larger precast concrete blocks 7. The mold cost of precast concrete blocks 7 is lower, and the water-cement ratio can be uniformly controlled during the production of precast concrete blocks 7, so that the precast concrete blocks 7 have higher compressive strength, resulting in higher overall foundation bearing capacity and improved construction quality. In the existing technology, precast concrete blocks 7 are often manufactured on-site in river network and swampy areas, so it is difficult to control the water-cement ratio, resulting in lower compressive strength of precast concrete blocks 7 in the existing technology.

[0092] In another embodiment of this application, see Figure 8 , Figure 9 , Figure 10 The bottom of the long I-beam 11 is a long bottom surface 112, on which a plurality of first connecting holes 113 are evenly distributed, and the first connecting holes 113 are detachably connected to the top of the spiral anchor 3; the bottom of the first short I-beam 12 is a first short bottom surface 121, on which a plurality of second connecting holes 122 are evenly distributed, and the second connecting holes 122 are detachably connected to the top of the spiral anchor 3; the bottom of the second short I-beam 15 is a second short bottom surface 151, on which a plurality of third connecting holes 152 are evenly distributed, and the third connecting holes 152 are detachably connected to the top of the spiral anchor 3.

[0093] In application, the spiral anchors 3 can be spliced ​​according to the actual support requirements. For example, when the soil bearing capacity is good, spiral anchors 3 can be connected at intervals on the first connecting hole 113, the second connecting hole 122, and the third connecting hole 152 to meet the support requirements and save spiral anchors 3. When the soil bearing capacity is poor, spiral anchors 3 can be connected on all the first connecting holes 113, the second connecting hole 122, and the third connecting hole 152 to meet the support requirements.

[0094] In another embodiment of this application, see Figure 9 , Figure 12 , Figure 13 The top of the long I-beam 11 is connected to the bottom of the connecting steel plate 6. An upper flange 61 is provided on the top of the connecting steel plate 6, and the top of the upper flange 61 is connected to the bottom of the lower flange 21 at the bottom of the concrete column 2. Upper flange holes 611 are evenly distributed on the upper flange 61, and lower flange holes 211 are provided on the lower flange 21 at positions corresponding to the upper flange holes 611. Flange fixing bolts 612 are inserted into both the lower flange holes 211 and the upper flange holes 611.

[0095] In application, first connect the long I-beam 11 to the connecting steel plate 6, which can be fixed with screws. Then align the upper flange hole 611 with the lower flange hole 211, and then screw the flange fixing screws 612 into the upper flange hole 611 and the lower flange hole 211 in sequence. This completes the fixing of the upper flange 61 and the lower flange 21, thus completing the fixing of the long I-beam 11 to the concrete column 2.

[0096] In another embodiment of this application, see Figure 8 , Figure 9 , Figure 10 The first short I-beam 12 has a first extension steel section 125 on the side near the long I-beam 11, and one end of the first extension steel section 125 is perpendicularly connected to the middle of the long I-beam 11; the second short I-beam 15 has a second extension steel section 155 on the side near the long I-beam 11, and one end of the second extension steel section 155 is perpendicularly connected to the middle of the long I-beam 11.

[0097] In application, when connecting the first short I-beam 12 to the long I-beam 11, the first extended steel segment 125 is connected to the middle of the long I-beam 11 to prevent gaps from appearing between the first short I-beam 12 and the long I-beam 11. Such gaps would cause cement mortar to flow, resulting in a decrease in overall strength. Similarly, when connecting the second short I-beam 15 to the long I-beam 11, the second extended steel segment 155 is connected to the middle of the long I-beam 11 to prevent gaps from appearing between the second short I-beam 15 and the long I-beam 11. Such gaps would cause cement mortar to flow, resulting in a decrease in overall strength.

[0098] In another embodiment of this application, see Figure 4 , Figure 5 , Figure 6 , Figure 9 , Figure 10 , Figure 11The upper steel plate 13 has evenly distributed upper steel plate holes 131 along its edge. The upper steel plate holes 131 correspond to the first fixing hole 114 on the top of the long I-beam 11, the second fixing hole 124 on the top of the first short I-beam 12, or the third fixing hole 154 on the top of the second short I-beam 15. Fixing screws are inserted into the upper steel plate holes 131 and the first fixing hole 114, the second fixing hole 124, or the third fixing hole 154.

[0099] Furthermore, the lower steel plate 14 has uniformly distributed lower steel plate holes 141, which correspond to the threaded holes at the bottom of the long I-beam 11, the first short I-beam 12, or the second short I-beam 15, and fixing screws are inserted into the lower steel plate holes and the threaded holes.

[0100] In application, first align the upper steel plate hole 131 with the first fixing hole 114, the second fixing hole 124, or the third fixing hole 154. Then, screw the fixing screws into the upper steel plate hole 131 and the first fixing hole 114, the second fixing hole 124, or the third fixing hole 154 in sequence to complete the fixing of the upper steel plate 13 with the long H-beam 11, the first short H-beam 12, or the second short H-beam 15. After aligning the lower steel plate hole 141 with the threaded hole at the bottom of the long H-beam 11, the first short H-beam 12, or the second short H-beam 15, screw in the fixing screws to complete the fixing of the lower steel plate 14 with the long H-beam 11, the first short H-beam 12, or the second short H-beam 15.

[0101] In another embodiment of this application, see Figure 2 , Figure 3 , Figure 13 The spiral anchor 3 includes an anchor body 31, the top of which is a spiral steel section 32. The spiral steel section 32 is detachably connected to the bottom of a long I-beam 11, a first short I-beam 12, or a second short I-beam 15. Spiral plates 33 are evenly wound around the outer periphery of the anchor body 31, and the bottom of the anchor body 31 is a conical head 34.

[0102] When applied, the conical head 34 allows the spiral anchor 3 to be easily pressed into the reserved hole. When the spiral blade 33 is screwed into the soil, it generates shear resistance, thereby improving the vertical bearing capacity and pull-out resistance of the spiral anchor 3. The spiral steel section 32 is provided with threads to facilitate connection with the bottom of the long I-beam 11, the first short I-beam 12, or the second short I-beam 15.

[0103] In another embodiment of this application, see Figure 2 , Figure 3 All metal parts are coated with anti-corrosion materials. The spiral anchor 3 is made of fiberglass. All bolts are high-strength bolts, which ensures sufficient tensile strength compared to concrete foundations. This avoids the risk of tensile damage to the foundation caused by settlement due to poor geology and high groundwater levels in river network and swamp areas.

[0104] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A design method for a prefabricated helical anchor foundation with adjustable bearing capacity, characterized in that: The method includes the following steps: Step 1: First, determine the water content, elastic modulus, void ratio, and shear strength of the soil in the installation pit of the prefabricated spiral anchor foundation. Then, calculate the soil discrimination index based on the water content, elastic modulus, void ratio, and shear strength. Step 2: Evaluate the soil bearing capacity based on the soil discrimination index; Step 3: When designing the prefabricated helical anchor foundation, adjust the area of ​​the pile cap (1) and the number of helical anchors (3) according to the soil bearing capacity evaluation results; The method for calculating the soil discrimination index is as follows: S1, regarding moisture content Elastic modulus Porosity With shear strength Normalization was performed sequentially to obtain the normalized water content. Normalized elastic modulus Normalized porosity With normalized shear strength ; S2, normalized water content Normalized elastic modulus Normalized porosity With normalized shear strength Weights are assigned, and the water content is calculated. Elastic modulus results Porosity results With shear strength results ; S3, Result of moisture content Elastic modulus results Porosity results With shear strength results The soil discrimination index is obtained by adding them in sequence. : ； In the formula: For moisture content results, For the elastic modulus results, The porosity result is... This is the shear strength result; The evaluation of soil bearing capacity based on the soil discriminant index is as follows: if the soil discriminant index... A soil bearing capacity greater than or equal to 0 and less than 0.5 indicates poor soil bearing capacity. If the soil discrimination index... A value greater than or equal to 0.5 and less than 1 indicates good soil bearing capacity. The adjustment of the area of ​​the foundation (1) and the number of spiral anchors (3) based on the soil bearing capacity evaluation results is as follows: if the soil bearing capacity is poor, the area of ​​the foundation (1) and the number of spiral anchors (3) are increased when designing the prefabricated spiral anchor foundation; if the soil bearing capacity is good, the area of ​​the foundation (1) and the number of spiral anchors (3) are reduced when designing the prefabricated spiral anchor foundation. The normalization process is as follows: elastic modulus With shear strength This is a positive indicator parameter, meaning that the higher the parameter, the more beneficial it is to the soil quality; water content. Compared with porosity As a negative indicator parameter, meaning the higher the parameter, the more detrimental the impact on soil quality, the measured values ​​of the aforementioned four variables are mapped to the 0-1 interval to eliminate dimensional differences: ； In the formula: For positive indicator parameter mapping; The actual value of the parameter. This is the theoretical minimum value of the parameter in the area where the installation pit is located. This represents the theoretical maximum value of the parameter in the area where the installation pit is located; ； In the formula: Mapping for negative indicator parameters; The actual value of the parameter. This is the theoretical minimum value of the parameter in the area where the installation pit is located; This represents the theoretical maximum value of the parameter in the area where the installation pit is located; Weights are assigned based on the sensitivity of various parameters in river network marshland areas, where water levels fluctuate greatly and water content is high. The soil elastic modulus directly affects soil liquefaction and construction feasibility. Reflecting the soil stiffness, it affects the settlement control of the foundation (1), but marsh soil is generally soft, so the weight is slightly lower and the void ratio is lower. Directly related to density and bearing capacity, it is a core characteristic of marsh soils, hence its slightly higher weight. Soil shear strength... The side friction resistance of the helical anchor is determined by a weighting similar to that of the water content. Therefore, the weights of each parameter are calculated based on the above. Allocation: Water Content Weight The weight of soil elastic modulus is 0.

25. The porosity weight is 0.

2. The soil shear strength weight is 0.

3. It is 0.

25.

2. A helical anchor foundation obtained by applying the design method of the prefabricated helical anchor foundation with adjustable bearing capacity as described in claim 1, characterized in that: The foundation includes a pile cap (1), a concrete column (2), and a spiral anchor (3). The foundation (1) includes a long H-beam (11), a first short H-beam (12), a second short H-beam (15), and a plurality of precast concrete blocks (7). One side of the middle of the long H-beam (11) is perpendicularly connected to one end of the first short H-beam (12), and the other side of the middle of the long H-beam (11) is perpendicularly connected to one end of the second short H-beam (15). Precast concrete blocks (7) are arranged between the long H-beam (11), the first short H-beam (12), and the second short H-beam (15). The top of the precast concrete block (7) is connected to the bottom of the upper steel plate (13), and the bottom of the precast concrete block (7) is connected to the top of the lower steel plate (14); the top of the upper steel plate (13) is connected to the bottom surface of the top of the long I-beam (11), the first short I-beam (12), and the second short I-beam (15), and the top of the long I-beam (11) is connected to the bottom of the concrete column (2); the bottom of the lower steel plate (14) is connected to the top surface of the bottom of the long I-beam (11), the first short I-beam (12), and the second short I-beam (15); the top of the spiral anchor (3) is detachably connected to the bottom of the long I-beam (11), the bottom of the first short I-beam (12), or the bottom of the second short I-beam (15). The precast concrete block (7) has a triangular structure and is composed of a large triangular block (71), multiple small triangular blocks (721) and multiple rectangular blocks (722).

3. The helical anchor foundation obtained by the design method of the prefabricated helical anchor foundation with adjustable bearing capacity according to claim 2, characterized in that: Multiple small triangular blocks (721) and multiple rectangular blocks (722) are spliced ​​together to form a multi-layer trapezoidal block (73), and the multi-layer trapezoidal block (73) and the large triangular block (71) are spliced ​​together to form the precast concrete block (7).

4. The helical anchor foundation obtained by the design method of the prefabricated helical anchor foundation with adjustable bearing capacity according to claim 3, characterized in that: The small triangular block (721) is a right triangle, and the trapezoidal block (73) is composed of small triangular blocks (721) at both ends and a rectangular block (723) in the middle. The rectangular block (723) is composed of multiple pairs of small triangular blocks (721) and a rectangular block (722).

5. The helical anchor foundation obtained by the design method of the prefabricated helical anchor foundation with adjustable bearing capacity according to claim 2, characterized in that: The top of the long I-beam (11) is provided with an upper flange (61), which is connected to the lower flange (21) at the bottom of the concrete column (2).

6. The helical anchor foundation obtained by the design method of the prefabricated helical anchor foundation with adjustable bearing capacity according to claim 2, characterized in that: The first short I-beam (12) is provided with a first extension steel section (125) on the side near the long I-beam (11), and one end of the first extension steel section (125) is perpendicularly connected to the middle of the long I-beam (11). The second short I-beam (15) has a second extension steel section (155) on the side near the long I-beam (11), and one end of the second extension steel section (155) is perpendicularly connected to the middle of the long I-beam (11).

7. The helical anchor foundation obtained by the design method of the prefabricated helical anchor foundation with adjustable bearing capacity according to claim 2, characterized in that: The spiral anchor (3) includes an anchor body (31), the top of which is a spiral steel segment (32), the spiral steel segment (32) is detachably connected to the bottom of a long I-beam (11), a first short I-beam (12) or a second short I-beam (15), the outer periphery of which is uniformly wound with spiral plates (33), and the bottom of which is a conical head (34).

8. An installation method for a helical anchor foundation obtained by the design method of the prefabricated helical anchor foundation with adjustable bearing capacity as described in claim 2, characterized in that: The method includes the following steps: Step 1: Excavate the installation pit, level the ground of the installation pit, and then drill the reserved holes for the spiral anchor (3) on the installation pit; Step 2: First, screw the spiral anchor (3) into the reserved hole in sequence so that the top of the spiral anchor (3) is higher than the ground, and then fix the spiral anchor (3); then splice and fix the middle of one side of the long I-beam (11) to one end of the first short I-beam (12), and then splice and fix the middle of the other side of the long I-beam (11) to one end of the second short I-beam (15) to obtain the I-beam frame; then fix the I-beam frame to the lower steel plate (14) to obtain the overall frame; then hoist the overall frame to the top of the spiral anchor (3), and then connect and fix the overall frame to the spiral anchor (3); Step 3: First, use large triangular blocks (71), small triangular blocks (721) and rectangular blocks (722) to splice multiple precast concrete blocks (7) on the overall frame. Then, fix the precast concrete blocks (7) to the overall frame in sequence. Then, fix the upper steel plate (13) on the top of the precast concrete blocks (7). Then, fix the concrete column (2) on the top of the long I-beam (11). Step 4: Backfill the installation pit and compact the soil. At this point, the installation of the device is complete.

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