Carbon fiber rope constrained minimally invasive reinforcement method for improving end-to-side pressure performance

Abstract

The application discloses a carbon fiber rope restraint minimally invasive reinforcement method for improving the bearing capacity of a concealed side column, and belongs to the technical field of building reinforcement. In view of the problem that a concealed side column is difficult to be directly reinforced due to the shielding of the connected wall body, and that a traditional method needs large-area demolition and reconstruction, leading to high cost and resource waste, the application drills holes on the wall body connected to the two ends of the side column, passes the carbon fiber rope through the holes, expands the two ends of the rope body to form a fan shape, and anchors the fan-shaped rope body on the surface of the column body, so that the bonding area and the anchoring force are significantly increased, and the reinforcement system is effectively prevented from slipping and failing. Meanwhile, based on test data fitting analysis, a bearing capacity calculation formula after reinforcement is established, and it is verified that the bearing capacity can be accurately predicted. The application does not need to demolish the wall body connected to the side column, and can realize minimally invasive reinforcement only by local drilling, so that the construction is efficient and quick, and the application has green low carbon and remarkable economic benefits.

Description

Technical Field

[0001] This invention relates to the field of building reinforcement technology, and in particular to a carbon fiber rope restraint minimally invasive reinforcement method for improving the bearing capacity of concealed end edges. Background Technology

[0002] A side column refers to a column that is connected to the wall at both ends in a certain direction within the building's structural plane, such as... Figure 4 As shown. Current methods for reinforcing edge columns in building structures typically involve wrapping the column perimeter with fiber-reinforced composite materials to improve its load-bearing capacity, such as... Figure 5 As shown. However, in existing building structures, the ends of edge columns are usually connected to the walls. If fiber-reinforced composite materials are to be wrapped around the column, it is necessary to partially or completely remove the original walls at both ends so that there are no walls obstructing the four sides of the column before normal construction can proceed. The process of removing and restoring the original walls will increase the workload and lead to significant economic losses; at the same time, it will generate a large amount of construction waste, resulting in resource waste, which is inconsistent with the green and low-carbon environmental protection concept. Summary of the Invention

[0003] The purpose of this invention is to provide a carbon fiber rope-constrained minimally invasive reinforcement method to improve the bearing capacity of concealed edge columns, thereby solving the technical problems of existing concealed edge column reinforcement methods that require the removal and restoration of the original wall, resulting in a large workload and low construction efficiency.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for minimally invasive reinforcement using carbon fiber rope confinement to improve the concealed end-edge bearing capacity, the method comprising the following steps: Step 1: Drill holes along the direction of the protective layer of the concealed surface of the experimental column to form a hole at the contact surface between the concealed surface and the shielding wall; Step 2: Clean and polish the drilled holes and conceal the experimental column to make the surface of the column flat and form a chamfer with a radius of 15-25mm at the corners; Step 3: Pass the FRP rope through the adjacent wall hole of the concealed experimental side column, so that the two ends of the FRP rope are placed on both sides of the wall. Pull the FRP rope taut to ensure that the FRP rope is tightly attached to the hole; unfold the end of the FRP rope into a fan shape and stick it to the concrete base surface of the two sides adjacent to the concealed surface. Step 4: Conduct a bearing capacity test on the reinforced concealed edge column, and generate stress and strain curves for the entire loading process based on the test data; Step 5: Apply stress-strain curves to determine the peak strength of the concealed edge column requiring reinforcement. Damaging stress Peak strain Destructive strain Maximum constraint lateral pressure Shape factor and shape factor Calculation, followed by failure mode discrimination analysis; Step 6: Based on the design requirements of the concealed edge column to be reinforced, verify by calculation whether the concrete compressive strength of the reinforced concealed edge column meets the engineering requirements. If the requirements are met, proceed with the construction of the concealed edge column using steps 1-4.

[0005] Further, the specific process of step 1 is as follows: according to the pre-estimated interval distance required by the design, drill holes in the wall connected to the side columns. The diameter of the holes should be no less than 2 times the diameter of the FRP rope and no more than 3 times the diameter of the FRP rope. The verticality requirement is no more than 5°. When there is reinforcement in the wall, the position of the reinforcement should be found first using a reinforcement detector. The drilling position should be adjusted according to the position of the reinforcement, and the distance should not exceed 2cm to avoid damaging the original reinforcement during the drilling process. Furthermore, the specific process of step 2 is as follows: after drilling, clean the hole to ensure that there is no floating dust inside the hole. At the same time, grind the edges of the part of the side column to be reinforced to form a rounded corner with a uniform transition to avoid damage to the FRP material. Then clean the floating dust on the surface of the side column to ensure that its surface is clean and flat. Furthermore, in step 3, the two ends of the FRP rope are unfolded into a fan shape. The height should be equal to the distance between the two holes, and the width should be equal to the side length of the side post. An adhesive layer is evenly applied to the surface of the polished side post so that the fan shape at both ends of the FRP rope is tightly bonded to the base surface of the side post without air bubbles, thus completing the reinforcement. Furthermore, in step 4, the stress-strain curve includes an ascending segment and a descending segment. The ascending segment starts from the origin (0,0) and extends to the coordinate system (…). The peak value at () is the falling segment from the peak coordinate () Starting from ( ), extending to the coordinates of the failure point ( ) ),in, Let be the elastic modulus of the structure, and let be the slope of the curve at the origin (0,0). For peak strain, Peak stress, To disrupt the strain, To disrupt the strain; The stress-strain curve is described as shown in equation (1), with the rising segment being... The polynomial of the first order parabola has a second-order polynomial in the descending segment: Substituting (0,0) into the rising segment of equation (1), and equation (1) in The derivative at point is the elastic modulus. ,have: Will( Substituting into the descending segment of equation (1), we have: The elastic modulus is calculated using the standard formula. Get it, This refers to the compressive strength of the concrete material before reinforcement.

[0006] f c It is the dependent variable of the function in the constitutive relation, representing the ordinate of a point in the function, and also representing the independent variable (strain) to... The corresponding stress at that time. Similarly, , , These are also packaged parameters in equations that have no practical meaning; they only make the equations look simpler. Furthermore, in step 5, the peak intensity and destructive stress The specific calculation process is as follows: Peak intensity and destructive stress It can be calculated using equations (5) and (6), and compared with the effective mechanical constraint ratio in equation (7). The relationship is linear, where, It assumes the maximum confinement pressure of the concrete in the actual confined section, and the coefficient is... and It is a constant. The intercept is assumed to be 1, because when When it is 0 Considering that the stress during concrete crushing is approximately 85% of its peak strength, when When it is 0 ,therefore The intercept is 0.85. .

[0007] Furthermore, in step 5, the peak strain and destructive strain The calculation process is as follows: and The calculations are shown in equations (8) and (9), where the ultimate compressive strain of the concrete material before reinforcement is... Compared with the geometrically effective constraint ratio in equation (10) Linear correlation, coefficient and It is a constant. The intercept is 1 because when When the value is 0, unconfined concrete ; The intercept is 1.33, which is calculated from the experimental data; The failure mode is typically crushing of the concrete between the ropes, then the slope parameter... 、 、 and The value can be: , , , .

[0008] Furthermore, in step 5, the maximum constraint side pressure The calculation process is as follows: maximum constraint lateral pressure It is calculated by weighted average of the pressures applied by different constraint components, including FRP ropes ( ) and the sector ( In the reinforcement method of this patent, the opposite side is constrained by FRP rope, and the other two sides are constrained by the fan-shaped part of FRP rope, as shown in the figure. The maximum confining pressure is calculated by equation (11): Among them, FRP rope constraint force The constraint force of the sector section of the FRP rope is calculated using equation (12). The tension of the FRP rope Provided as shown in equation (13): The tensile strength of the fan-shaped section of the FRP rope and FRP rope tension The results are obtained from equations (14) and (15) respectively: in, The strain of half of the FRP rope sector is the FRP rope strain. The environmental reduction factor is calculated from equation (16). and efficiency coefficient It is determined by the standards: .

[0009] Furthermore, in step 5, the shape factor and calculate The process is as follows: aspect ratio coefficient and aspect ratio coefficient It is calculated from equations (17) and (18): FRP rope effective restraint area ratio It is calculated from equation (19): lateral effective constraint domain area ratio and the proportion of the effective constraint domain area in the longitudinal direction It is calculated from equations (20) and (21): Lateral effective constraint area and vertical effective constraint domain area It is calculated from equations (22) and (23): .

[0010] Furthermore, in step 5, the specific process of failure mode discrimination analysis is as follows: First, it is necessary to prevent the carbon fiber rope from peeling off from the side column and ensure the adhesion between the side column concrete base and the rope. Greater than the ultimate tensile strength of carbon fiber rope fan As shown in equation (24), where The tensile strength of the epoxy resin adhesive is obtained from the product instructions or laboratory tests. This represents the bonding area of ​​the carbon fiber cloth. Calculate according to formula (14), Take as To ensure mechanically prevent the carbon fiber rope from peeling off, the system differentiates between two failure modes based on the preset constraint configuration: tensile failure of the fan-shaped portion of the carbon fiber rope and crushing of the concrete between the ropes. Damage mode discrimination index It can be calculated from equation (25), where, For the borehole clearance, when When the calculated value is greater than the critical value of 0.25 kN·m, the failure mode is concrete crushing; otherwise, the failure mode is the fan-shaped section of the FRP rope breaking. .

[0011] The present invention, by adopting the above-described technical solution, has the following beneficial effects: The reinforcement method of this invention does not require the demolition of the wall connected to the edge column. The reinforcement construction can be completed by drilling holes at specific locations. This avoids the increased costs and waste of resources caused by the demolition and reconstruction of the wall around the edge column. It is an efficient, fast, green and low-carbon reinforcement method. A complete set of calculation procedures has been established, the stress mechanism is clear, and each parameter has a corresponding formula. The accuracy and operability have been verified by experiments and actual engineering. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the minimally invasive reinforced concealed side column structure of the present invention; Figure 2 This is the stress-strain curve diagram of the concealed edge column minimally invasive reinforcement method of this invention; Figure 3 This is the force analysis diagram of the maximum constraint side pressure of the present invention; Figure 4 This is a schematic diagram of the side pillar of the present invention; Figure 5 This is an existing edge column reinforcement method of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are merely to provide the reader with a thorough understanding of one or more aspects of the present invention, and these aspects of the invention can be implemented even without these specific details.

[0014] like Figure 1 As shown, a minimally invasive reinforcement method using carbon fiber rope confinement to improve the bearing capacity of concealed edge bearing structures is presented. This method, employing FRP rope confinement to enhance the bearing capacity of edge columns, involves drilling holes in the walls connected to both ends of the edge column. The FRP rope is then passed through these holes, and its ends are unfolded into a fan shape to increase the contact area between the rope and the column base, thereby increasing adhesion and preventing detachment that could lead to reinforcement system failure. Furthermore, based on scaled-down test data, a formula for calculating the bearing capacity of this reinforcement method is proposed using data fitting. Experimental verification demonstrates its good applicability and ability to accurately predict the bearing capacity after reinforcement. Figure 1 As shown.

[0015] The method includes the following steps: Step 1: Drill holes in the wall adjacent to the experimental side column. Drill holes in the wall connected to the side column according to the design requirements. The hole diameter should be no less than twice the diameter of the FRP rope and no more than three times the diameter of the FRP rope. The verticality requirement is no greater than 5°. Note that when there is reinforcement in the wall, a rebar detector should be used to locate the rebar first. The drilling position can be adjusted according to the rebar location, with a distance not exceeding 2cm, to avoid damaging the original rebar during drilling.

[0016] Step 2: Hole cleaning and column grinding. After drilling, clean the holes to ensure there is no dust inside. At the same time, grind the edges of the parts of the column to be reinforced to form a uniformly rounded corner to avoid damage to the FRP material. Then clean the dust off the surface of the column to ensure that the surface is clean and flat.

[0017] Step 3: FRP rope installation. Pass the FRP rope through the holes, placing both ends on either side of the wall. Tighten the FRP rope, ensuring it is tightly fitted to the holes. Spread the two ends of the FRP rope into a fan shape; the height should equal the distance between the two holes, and the width should equal the side length of the support column. Apply epoxy resin evenly to the sanded surface of the support column, ensuring the fan-shaped ends of the FRP rope adhere tightly to the column base without air bubbles. The reinforcement is now complete.

[0018] Step 4: A concealed bearing capacity test was conducted on the reinforced edge column using this reinforcement method. The bearing capacity test followed the existing conventional bearing capacity test procedure. Multiple stress changes were recorded, and all data were then fitted into a curve. Based on the test data, a stress-strain curve for the entire loading process was formed, as shown below. Figure 2 As shown, the curve includes an ascending segment and a descending segment. The ascending segment starts from the origin (0,0) and extends to (…). The peak at ( ); the falling segment from the peak ( Starting from the point of failure, extending to the point of failure ( ).in, Let be the elastic modulus of the structure, and let be the slope of the curve at the origin (0,0); Peak strain; This represents the peak stress. To disrupt the strain; To prevent damage and strain.

[0019] The stress-strain curve is described as shown in equation (1), with the rising segment being... The polynomial of the first order parabola has a second-order polynomial in the descending segment: Substituting (0,0) into the rising segment of equation (1), and equation (1) in The derivative at point is the elastic modulus. ,have: Will( Substituting into the descending segment of equation (1), we have: The elastic modulus is calculated using the standard formula. Get it, This refers to the compressive strength of the concrete material before reinforcement.

[0020] Step 5: Peak Intensity and destructive stress Calculate peak intensity and destructive stress It can be calculated using equations (5) and (6), and compared with the effective mechanical constraint ratio in equation (7). The relationship is linear, where, It assumes the maximum confinement pressure of the concrete in the actual confined section, and the coefficient is... and It is a constant. The intercept is assumed to be 1, because when When it is 0 Considering that the stress during concrete crushing is approximately 85% of its peak strength, when When it is 0 ,therefore The intercept is 0.85. .

[0021] Step 6: Peak Strain and destructive strain calculate: and The calculations are shown in equations (8) and (9), where the ultimate compressive strain of the concrete material before reinforcement is... Compared with the geometrically effective constraint ratio in equation (10) Linear correlation, coefficient and It is a constant. The intercept is 1 because when When the value is 0, unconfined concrete ; The intercept is 1.33, which is calculated from the experimental data; The failure mode is typically crushing of the concrete between the ropes, then the slope parameter... 、 、 and The value can be: , , , .

[0022] In step 7: maximum constraint side pressure Calculate:, such as Figure 3 As shown, the maximum constraint side pressure It is calculated by weighted average of the pressures applied by different constraint components, including FRP ropes ( ) and the sector ( In the reinforcement method of this patent, the opposite side is constrained by FRP rope, and the other two sides are constrained by the fan-shaped part of FRP rope, as shown in the figure. The maximum confining pressure is calculated by equation (11): Among them, FRP rope constraint force The constraint force of the sector section of the FRP rope is calculated using equation (12). The tension of the FRP rope Provided as shown in equation (13): The tensile strength of the fan-shaped section of the FRP rope and FRP rope tension The results are obtained from equations (14) and (15) respectively: in, The strain of half of the FRP rope sector is the FRP rope strain. The environmental reduction factor is calculated from equation (16). and efficiency coefficient It is determined by the standards: .

[0023] Step 8: Shape Factor and Calculate the aspect ratio coefficient. and aspect ratio coefficient It is calculated from equations (17) and (18): FRP rope effective restraint area ratio It is calculated from equation (19): lateral effective constraint domain area ratio and the proportion of the effective constraint domain area in the longitudinal direction It is calculated from equations (20) and (21): Lateral effective constraint area and vertical effective constraint domain area It is calculated from equations (22) and (23): .

[0024] Step 9: The specific process of failure mode discrimination analysis is as follows: First, it is necessary to prevent the carbon fiber rope from peeling off from the side column and ensure the adhesion between the side column concrete base and the rope. Greater than the ultimate tensile strength of carbon fiber rope fan As shown in equation (24), where The tensile strength of the epoxy resin adhesive is obtained from the product instructions or laboratory tests. This represents the bonding area of ​​the carbon fiber cloth. Calculate according to formula (14), Take as To ensure mechanically prevent the carbon fiber rope from peeling off, the system differentiates between two failure modes based on the preset constraint configuration: tensile failure of the fan-shaped portion of the carbon fiber rope and crushing of the concrete between the ropes. Damage mode discrimination index It can be calculated from equation (25), where, For the borehole clearance, when When the calculated value is greater than the critical value of 0.25 kN·m, the failure mode is concrete crushing; otherwise, the failure mode is the fan-shaped section of the FRP rope breaking. .

[0025] Step 10: Based on the design requirements of the concealed edge column to be reinforced, verify by calculation whether the concrete compressive strength of the reinforced concealed edge column meets the engineering requirements. If the requirements are met, proceed with the construction of the concealed edge column using steps 1-4.

[0026] The following example calculation demonstrates this: A side column connected to a wall on one side of a building needs to be reinforced to increase its load-bearing capacity by at least 20%. The column has a cross-sectional dimension of 610mm × 610mm, the original concrete strength is 45MPa, and it contains 12 identical longitudinal steel bars with a diameter of 32mm and a yield strength of 400MPa. The FRP rope used has an elastic modulus of 236.4GPa and an ultimate tensile strain of 0.00118; the epoxy resin has a tensile strength of 50.6MPa.

[0027] The original structure had rounded corners with a radius of 25mm, and the cross-sectional areas of the concrete and reinforcing steel were 371600mm² and 980mm², respectively. The column's bearing capacity before reinforcement was 9281kN, and it is required to increase to 11138kN after reinforcement. Therefore, the concrete's bearing capacity needs to be increased to 56.4MPa. To be conservative, the effect of the reinforcing steel in the structure is ignored, and the following reinforcement scheme is proposed: Using FRP rope cross-sectional area Drill hole diameter is 35mm; rope spacing Then the net distance of the rope Fan length ( ) and fan width ( The diameters are 585mm and 120mm respectively.

[0028] ① Determine the damage mode Assumption = From equation (14), the ultimate tensile stress of the FRP rope fan can be obtained: The bond strength between the FRP rope and the concrete substrate, calculated by equation (24), is greater than the ultimate tensile stress of the FRP rope fan. To determine the failure mode, the ultimate tensile stress of the FRP rope fan is recalculated using equations (15) and (18): According to equation (28), the failure mode is concrete crushing between ropes: ② Calculate the maximum constraint lateral pressure ③ Calculate the compressive strength of the reinforced concrete From equations (5) and (7), we can obtain: Therefore, the reinforcement solution met the engineering requirements.

[0029] FRP ropes can be replaced by composite structures of steel bars and steel plates, etc., with the aim of providing lateral restraint to the side column to be reinforced through minimally invasive methods such as drilling and slotting, under the condition of constraint on one side of the side column. However, this method does not have the construction convenience of the method proposed in this patent, and has relatively heavy self-weight and easy corrosion, etc., which have long-term negative effects. Therefore, it can only be used as a lower-level alternative to this patent.

[0030] Only epoxy resin is listed as an adhesive material in this patent. Other similar materials that can provide adhesion between the concrete substrate and the reinforcing material, and between the reinforcing materials, can be used as alternatives to this patent.

[0031] Comparative example: The reinforcement method in this application is different from existing methods. Figure 5 The reinforcement methods shown are compared. Figure 5 Existing reinforcement methods require the removal of walls on both sides before reinforcement can begin, and the walls must be restored afterward. This involves a large workload, a long construction period, and low reinforcement efficiency. The reinforcement method proposed in this application only requires drilling holes to complete the reinforcement. Figure 1 As shown, the reinforcement is more efficient and faster, meeting the stress requirements of relevant reinforcement.

[0032] Matters not covered in this invention are common knowledge.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for minimally invasive reinforcement using carbon fiber rope confinement to improve the concealed end-edge bearing capacity, characterized in that, The method includes the following steps: Step 1: Drill holes along the direction of the protective layer of the concealed surface of the experimental column to form a hole at the contact surface between the concealed surface and the shielding wall; Step 2: Clean and polish the drilled holes and conceal the experimental column to make the surface of the column flat and form a chamfer with a radius of 15-25mm at the corners; Step 3: Pass the FRP rope through the adjacent wall hole of the concealed experimental side column, so that the two ends of the FRP rope are placed on both sides of the wall. Pull the FRP rope taut to ensure that the FRP rope is tightly attached to the hole. Spread the end of the FRP rope into a fan shape and stick it to the concrete base surface of the two sides adjacent to the concealed surface. Step 4: Conduct a bearing capacity test on the reinforced concealed edge column, and generate stress and strain curves for the entire loading process based on the test data; Step 5: Apply stress-strain curves to determine the peak strength of the concealed edge column requiring reinforcement. Damaging stress Peak strain Destructive strain Maximum constraint lateral pressure Shape factor and shape factor Calculation, followed by failure mode discrimination analysis; Step 6: Based on the design requirements of the concealed edge column to be reinforced, verify by calculation whether the concrete compressive strength of the reinforced concealed edge column meets the engineering requirements. If the requirements are met, proceed with the construction of the concealed edge column using steps 1-4.

2. The carbon fiber rope restraint minimally invasive reinforcement method for improving concealed end-edge pressure bearing performance according to claim 1, characterized in that, The specific process of step 1 is as follows: based on the pre-estimated interval distance required by the design, drill holes in the wall connected to the edge column. The diameter of the hole should be no less than 2 times the diameter of the FRP rope and no more than 3 times the diameter of the FRP rope. The verticality requirement is no more than 5°. When there is reinforcement in the wall, the position of the reinforcement should be found first using a reinforcement detector. Adjust the drilling position according to the position of the reinforcement, and the distance should not exceed 2cm to avoid damaging the original reinforcement during the drilling process.

3. The method for minimally invasive reinforcement using carbon fiber rope restraint to improve the concealed end-edge bearing capacity according to claim 1, characterized in that, Step 2 involves cleaning the hole after drilling to ensure there is no dust inside. At the same time, the edges of the part of the side post to be reinforced are ground to form a rounded corner with a uniform transition to avoid damage to the FRP material. Then, the dust on the surface of the side post is cleaned to ensure that the surface is clean and flat.

4. The carbon fiber rope restraint minimally invasive reinforcement method for improving concealed end-edge pressure bearing performance according to claim 1, characterized in that, In step 3, unfold both ends of the FRP rope into a fan shape. The height should be equal to the distance between the two holes, and the width should be equal to the side length of the side post. Apply an adhesive layer evenly to the polished side post surface so that the fan shape at both ends of the FRP rope is tightly bonded to the base surface of the side post without air bubbles, and the reinforcement is completed.

5. The method for minimally invasive reinforcement using carbon fiber rope restraint to improve concealed end-edge bearing capacity according to claim 1, characterized in that, In step 4, the stress-strain curve includes an ascending segment and a descending segment. The ascending segment starts from the origin (0,0) and extends to the coordinate system (…). The peak value at () is the falling segment from the peak coordinate () Starting from ( ), extending to the coordinates of the failure point ( ) ),in, Let be the elastic modulus of the structure, and let be the slope of the curve at the origin (0,0). For peak strain, Peak stress, To disrupt the strain, To disrupt the strain; The stress-strain curve is described as shown in equation (1), with the rising segment being... The polynomial of the first order parabola has a second-order polynomial in the descending segment: Substituting (0,0) into the rising segment of equation (1), and equation (1) in The derivative at point is the elastic modulus. ,have: Will( Substituting into the descending segment of equation (1), we have: The elastic modulus is calculated using the standard formula. Get it, To strengthen the compressive strength of the concrete material before reinforcement, f c It is the dependent variable of a function in a relation, representing the y-coordinate of a point in the function. , , All of these are packaged parameters in the equation.

6. The carbon fiber rope restraint minimally invasive reinforcement method for improving concealed end-edge pressure bearing performance according to claim 1, characterized in that, In step 5, peak intensity and destructive stress The specific calculation process is as follows: Peak intensity and destructive stress It can be calculated using equations (5) and (6), and compared with the effective mechanical constraint ratio in equation (7). The relationship is linear, where, It assumes the maximum confinement pressure of the concrete in the actual confined section, and the coefficient is... and It is a constant. The intercept is assumed to be 1, because when When it is 0 Considering that the stress during concrete crushing is approximately 85% of its peak strength, when When it is 0 ,therefore The intercept is 0.

85. 。 7. The method for minimally invasive reinforcement using carbon fiber rope restraint to improve concealed end-edge bearing capacity according to claim 1, characterized in that, In step 5, peak strain and destructive strain The calculation process is as follows: and The calculations are shown in equations (8) and (9), where the ultimate compressive strain of the concrete material before reinforcement is... Compared with the geometrically effective constraint ratio in equation (10) Linear correlation, coefficient and It is a constant. The intercept is 1, because when When the value is 0, unconfined concrete ; The intercept is 1.33, which is calculated from the experimental data; The failure mode is typically crushing of the concrete between the ropes, then the slope parameter... 、 、 and The value can be: ， ， ， 。 8. The method for minimally invasive reinforcement using carbon fiber rope restraint to improve the concealed end-edge bearing capacity according to claim 1, characterized in that, In step 5, the maximum constraint lateral pressure The calculation process is as follows: maximum constraint lateral pressure It is calculated by weighted average of the pressures applied by different constraint components, including FRP ropes ( ) and the sector ( In the reinforcement method of this patent, the opposite side is constrained by FRP rope, and the other two sides are constrained by the fan-shaped part of FRP rope, as shown in the figure. The maximum confining pressure is calculated by equation (11): Among them, FRP rope constraint force The constraint force of the sector section of the FRP rope is calculated using equation (12). The tension of the FRP rope Provided as shown in equation (13): The tensile strength of the fan-shaped section of the FRP rope and FRP rope tension The results are obtained from equations (14) and (15) respectively: in, The strain of half of the FRP rope sector is the FRP rope strain. The environmental reduction factor is calculated from equation (16). and efficiency coefficient It is determined by the standards: 。 9. A method for minimally invasive reinforcement using carbon fiber rope confinement to improve the concealed end-edge bearing capacity according to claim 1, characterized in that, In step 5, the shape factor and calculate The process is as follows: aspect ratio coefficient and aspect ratio coefficient It is calculated from equations (17) and (18): FRP rope effective restraint area ratio It is calculated from equation (19): lateral effective constraint domain area ratio and the proportion of the effective constraint domain area in the longitudinal direction It is calculated from equations (20) and (21): Lateral effective constraint area and vertical effective constraint domain area It is calculated from equations (22) and (23): 。 10. A method for minimally invasive reinforcement using carbon fiber rope confinement to improve concealed end-edge bearing capacity according to claim 1, characterized in that, In step 5, the specific process of failure mode discrimination analysis is as follows: First, it is necessary to prevent the carbon fiber rope from peeling off from the side column and ensure the adhesion between the side column concrete base and the rope. Greater than the ultimate tensile strength of carbon fiber rope fan As shown in equation (24), where The tensile strength of the epoxy resin adhesive is obtained from the product instructions or laboratory tests. This represents the bonding area of ​​the carbon fiber cloth. Calculate according to formula (14), Take as To ensure mechanically prevent the carbon fiber rope from peeling off, the system differentiates between two failure modes based on the preset constraint configuration: tensile failure of the fan-shaped portion of the carbon fiber rope and crushing of the concrete between the ropes. Damage mode discrimination index It can be calculated from equation (25), where, For the borehole clearance, when When the calculated value is greater than the critical value of 0.25 kN·m, the failure mode is concrete crushing; otherwise, the failure mode is the fan-shaped section of the FRP rope breaking. 。

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