Inclination disease reinforcing method for traffic bridge pile foundation

Abstract

The invention relates to an inclination disease reinforcing method for a traffic bridge pile foundation, which comprises the following steps: S1, preparing an inclined pile foundation, and manufacturing a bearing platform; s2, a lower pile section, a plurality of middle pile sections and an upper pile section are prepared; s3, at least two pile pressing reaction frames with center hole jacks are installed on the bearing platform, and pile pressing holes are dug in the bearing platform; s4, the lower pile section is hoisted in place and pressed into the preset pile hole through the pile pressing hole, then the middle pile section is hoisted in place, the pile splicing process is completed, hoisting and pile splicing of the remaining middle pile section and the upper pile section are completed in sequence, and a static pressure pile is obtained; and S5, the static pressure pile is pre-fixed through a wedge block, redundant pile head concrete is removed according to the designed elevation, then main reinforcements of the bearing platform and reserved main reinforcements of the upper pile section are welded, then a steel structure is fixed to the reserved main reinforcements to serve as a force transmission piece, pressure is applied to the static pressure pile through a center hole jack, and then concrete is poured to seal the pile. The inclined pile foundation has the advantages that the influence on traffic bridge operation is small, the safety of the inclined pile foundation is improved, and later maintenance work is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge pile foundation maintenance, and particularly to a reinforcement method for the inclination disease of pile foundations of bridges in service. Background Art

[0002] During the construction process of bridge construction, due to errors in the construction of bridge pile foundations, the pile foundations have an inclination phenomenon. Specifically, the pier columns and pile foundations are not accurately placed on the same axis, and this deviation causes the pile foundation to bear an additional bending moment. This additional bending moment has a negative impact on the bearing capacity of the pile foundation, thereby reducing its bearing capacity. The existence of this situation poses a potential threat to the safe use of bridges in service and may have an adverse impact on the structural safety and long-term stability of bridges. Due to the limitation of traffic and the close spacing of each pile foundation, it is difficult to implement large-scale pile replacement. Therefore, it is necessary to reinforce the inclination disease of the pile foundation to improve the safety of the inclined pile foundation.

[0003] A Chinese patent with the authorization announcement number CN103243745B discloses a method for correcting and resetting a pipe pile, comprising the following steps: (1) treating and repairing the damaged cushion layer around the pipe pile, so as to lay the foundation for the subsequent use of a jack to correct the pipe pile; (2) after the cushion layer around the pipe pile is repaired, using a high-pressure water gun and compressed air to flush and extract soil from the pipe pile that needs to be corrected, the depth of which exceeds the first section of the pipe pile and extends downward by 2 to 3 meters; for shallow concrete fragments, gravel, and construction waste in the pipe pile, the water is used to remove the soil; and Use a drilling rig to clean the hole and salvage tools to clean; (3) After the pipe piles are flushed and soil is taken, use the hanging hammer method to test the pipe pile deflection within a range of 3 to 5 meters to calculate the inclination; and use a tape measure or steel ruler to measure the deviation distance according to the axis of the pipe pile; (4) Use the calculated inclination and deviation distance to determine the corrected position of the pipe pile on the cushion layer, and dig a guide groove between the pipe pile and the corrected position, and dig out the head of the pipe pile to expose the cushion layer; (5) Use a drilling rig and a high-pressure water gun to flush and take soil on the side of the guide groove. The depth of the hole is determined according to the measured deviation distance. At the same time, the soil around the pile is drained to reduce the resistance generated during correction; (6) The pile to be corrected is supported by a jack, a steel pad is set at the tail end of the jack to support the cushion layer, and a circular support plate is set at the top to support the pile. The jack pushes the pile to reset it; in the process of pushing the pile to reset, 5-25mm gravel and fine sand are gradually poured into the holes around the pile until the pile is reset; for the parts that cannot be repaired, the jack can be used later to temporarily use the uncorrected pile as the reaction force or borrow a hand winch as the reaction force; ( 7) After the pile is reset, measure the inclination of the pile again using the hanging hammer method. If the reset is unsuccessful, repeat the above step (6) until the pile is successfully reset. (8) After the pile is successfully reset, fill the pile with core. Before filling the core, use a high-pressure water gun and a wire brush to clean the inside of the pile. Determine the length of the steel cage based on the actual pile body integrity and verticality combined with existing experience, and hoist the steel cage into the pile using a crane. (9) After the steel cage is hoisted into the pile and the position is determined, pour C35 micro-expansive concrete into the pile and wait for the concrete to dry.

[0004] The above-mentioned prior art solutions have the following defects: although the method provides a specific step for correcting and resetting the pipe piles, in the actual operation process, its complexity and construction difficulty are still relatively high, especially the steps of flushing water to obtain soil and drilling rigs to clean holes, which are not only time-consuming, but also cause great interference to the surrounding environment and may affect the normal use of the bridge; in addition, the method requires repeated measurements and adjustments during the correction process. If the operation is improper, it may cause further damage to the pipe piles and even affect the structural safety of the entire bridge; therefore, it is particularly important to find a more efficient, safe and less impact-on-bridge structure tilt disease reinforcement method.

[0005] A Chinese patent with authorization announcement number CN108914999B discloses a correction and repair structure for a tilted pile foundation, including a positioning device, the positioning device including a front positioning plate, two side positioning plates slidably connected to the front positioning plate, and a locking mechanism is provided between the two side positioning plates and the front positioning plate; a straightening device is connected to one side of the positioning device, the straightening device includes a hydraulic jack connected to the front positioning plate, the hydraulic jack includes a cylinder body and a telescopic push rod, and a push plate is connected to the telescopic push rod; a drainage groove for slurry circulation is provided on the side of the push plate facing away from the telescopic push rod; a drainage pipe is embedded in the drainage groove, and both ends of the drainage pipe are divided into The two sides of the push plate are extended separately, the upward end of the drainage tube is connected with a quick connector, and the downward end of the drainage tube is connected with a plurality of shunt tubes; the bottom side of the push plate is rotatably connected with a vertical balance plate, and the side of the vertical balance plate facing the hydraulic jack is provided with a horizontal balance plate perpendicular to the vertical balance plate, and a first balance liquid capsule is provided on the horizontal balance plate, and the first balance liquid capsule contains liquid bubbles; a second balance liquid capsule is provided on the vertical balance plate, and the second balance liquid capsule contains liquid bubbles; an inner push block is slidably connected with the side of the vertical balance plate facing away from the hydraulic jack, and a distance measuring rod passing through the vertical balance plate is connected to the inner push block, and the distance measuring rod is marked with scales.

[0006] The above-mentioned existing technical solutions have the following defects: the above-mentioned correction and repair structure has a complex structure, cumbersome operation, and requires professional technicians to operate and maintain, which is costly; at the same time, when the correction and repair structure is used to reinforce the tilt disease of the pile foundation of a bridge that has been opened to traffic, it has a great impact on the traffic of the bridge, and requires a long period of closed construction, which brings inconvenience to traffic; in addition, during the use of the structure, due to its complex structure, it is easy to malfunction, the maintenance cost is high, and the maintenance time is long, which affects the construction progress. Therefore, it is necessary to propose a method for reinforcing the tilt disease of the pile foundation of a bridge that has been opened to traffic to solve the problems existing in the prior art. Summary of the invention

[0007] The problem to be solved by the present invention is to provide a method for reinforcing the inclination defects of pile foundations of bridges that have been opened to traffic in view of the above-mentioned deficiencies in the prior art. The method generates a reverse bending moment on the inclined pile foundation by adding a cap and a static pressure pile on the inclined pile foundation and applying permanent prestress on the static pressure pile, thereby offsetting the adverse bending moment caused by the inclination of the pile foundation and bearing part of the axial force of the pile. The method has the advantages of little impact on the operation of the bridge that has been opened to traffic, improving the safety of the inclined pile foundation and facilitating later maintenance work.

[0008] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0009] A method for reinforcing the pile foundation of a bridge that has been opened to traffic, comprising the following steps:

[0010] S1 prepares an inclined pile foundation, determines the location of the reinforcement according to the reinforcement arrangement of the inclined pile foundation, and then installs the cap reinforcement cage at the location of the reinforcement, and pours concrete to obtain the cap;

[0011] S2: prepare a lower pile segment, several middle pile segments, and an upper pile segment, wherein the bottom of the lower pile segment is in the shape of an inverted truncated cone, and a prestressed steel bar is inserted and anchored on the lower pile segment, and prestressed holes are respectively provided through the middle pile segment and the upper pile segment, and a plurality of reserved main bars are protruding from the top of the upper pile segment;

[0012] S3: installing at least two pile-pressing reaction frames with through-type jacks on the cap, the pile-pressing reaction frames are located on the inclined side of the inclined pile foundation, and a boss-shaped pile-pressing hole is dug on the cap according to the axis of the through-type jack;

[0013] S4: According to the axis line of the through-type jack, the lower pile section is first hoisted into place, and is pressed into the predetermined pile hole through the pile-pressing hole, and then the middle pile section is hoisted into place, and the connection end surface is coated with epoxy glue, the prestressed steel bars are installed in the prestressed channel, the through-type jack is used to tension the prestressed steel bars, the prestressed steel bars of the two adjacent pile sections are anchored, and the pile connection process is completed in sequence, and then the remaining middle pile sections and the upper pile section are hoisted and connected in sequence to obtain a static pile;

[0014] S5 first uses a wedge block to pre-fix the static pressure pile, and removes excess pile head concrete according to the design elevation, then welds the main reinforcement of the foundation and the reserved main reinforcement of the upper pile section, and then fixes a steel structure on the reserved main reinforcement as a force transmission member to apply a pressure of 100~150kN to the static pressure pile through the through-type jack, and controls the center distance between the inclined pile foundation and the static pressure pile to be 1.2~1.8m, then pours concrete to seal the pile, and after the concrete strength reaches 90% of the design strength, the through-type jack relieves the pressure and removes the pile pressure reaction frame.

[0015] Furthermore, in said S1, the inclined pile foundation is roughened in advance. When roughening the concrete, the concrete surface slurry is first removed until the aggregate is exposed, and then the roughening is started. The number of chiseling points exceeds 8000 points / ㎡. The roughening method is flat chiseling, and the dust is removed with compressed air or rinsed with clean water.

[0016] Furthermore, in said S1, the cap steel cage is implanted into the colloid outflow hole at the rebar planting position in a continuously rotating manner, the rebars can be implanted or adjusted before gelation, and the rebars cannot be disturbed during the period from gelation to the start of solidification; when the cap steel cage collides with the pile hole, the rebars should be cut off.

[0017] Furthermore, in the above S1, a layer of interface agent with a thickness of 1-2 mm is applied to the surface of the inclined pile foundation in advance.

[0018] Further, in the step S2, steel pipes with outer diameters of 34 mm and 57 mm respectively and connected sequentially from top to bottom are used as prestressed ducts.

[0019] Further, in the step S4, after the pressing of the previous pile segment is completed, the next pile segment is hoisted to a height of 10 cm, and then the end faces of two adjacent pile segments are dried, blown clean, and cleaned with acetone. Then, an epoxy glue layer with a thickness of 2 - 4 mm is applied to both ends, and the next pile segment is vertically lowered. After the epoxy glue is cured, the prestressed steel bars are tensioned.

[0020] Further, in the step S4, the tensioning tonnage of the prestressed steel bars by the hole - through jack is 250 kN. It is required to hold the pressure for 2 minutes, and then anchor after stabilizing the pressure for another 2 minutes.

[0021] Further, in the step S4, wooden boards with a thickness of 3 - 4 cm or multiple layers of gunny bags are padded on the top of the pile segment, and then a steel cap is put on for pile pressing.

[0022] Further, in the step S5, single - sided welding is used for steel bar welding, and the weld length is not less than 10d.

[0023] Further, in the step S5, a steel plate with a thickness of 2 cm and a diameter of 15 cm is pasted on the reserved main steel bar with epoxy glue, and 3 steel bars with a diameter of 5 cm are welded on the steel plate as force - transmitting members to complete the process of the hole - through jack applying pressure to the jacked pile through the force - transmitting members.

[0024] In summary, the beneficial technical effects of the present invention are as follows: By adding a bearing platform and jacked piles on the inclined pile foundation and applying permanent prestress to the jacked piles, the jacked piles are in a compressed state. The main steel bars of the bearing platform and the reserved main steel bars on the jacked piles are connected synchronously, and then concrete is poured to fill the pile - pressing holes, making the structure integral. By applying force to the jacked piles, a reverse bending moment can be provided to offset the adverse bending moment generated by the inclination of the pile foundation, and at the same time, part of the axial force of the pile is borne to balance the bending moment generated by the inclination of the inclined pile foundation, having the advantages of little impact on the operation of the opened - to - traffic bridge, improving the safety of the inclined pile foundation, and being convenient for later maintenance work. Brief Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of the pile foundation of the opened - to - traffic bridge in Embodiment 1 of the present invention.

[0026] Figure 2 is a schematic connection diagram between the inclined pile foundation, the bearing platform and the jacked piles in Embodiment 1 of the present invention.

[0027] Figure 3 is a schematic structural diagram of the bearing platform in Embodiment 2 of the present invention.

[0028] Figure 4 It is a schematic structural diagram of the upper pile section of Example 3 of the present invention.

[0029] Figure 5 It is a schematic diagram of the connection relationship between the upper pile section and the prestressed steel bars in Example 3 of the present invention.

[0030] Figure 6 It is a schematic structural diagram of the middle pile section and the lower pile section of Example 3 of the present invention.

[0031] Figure 7 It is a schematic diagram of the connection relationship between the cap, the pile pressure reaction frame and the static pressure pile in Example 4 of the present invention.

[0032] Figure 8 It is a schematic diagram of the connection relationship between the prestressed duct, prestressed steel bars and connecting sleeves of two adjacent pile sections in Example 5 of the present invention.

[0033] Figure 9 It is a schematic diagram of the connection relationship between the cap, the pile hole and the static pile in Example 6 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the technical means, creative features, objectives and functions achieved by the present invention clearer and easier to understand, the present invention is further explained below in conjunction with the accompanying drawings and specific implementation methods.

[0035] Example 1: Reference Figure 1 and Figure 2 , which is a method for reinforcing the inclined damage of the pile foundation of a bridge that has been opened to traffic disclosed by the present invention, comprising the following steps:

[0036] S1 prepares an inclined pile foundation, determines the location of the reinforcement according to the reinforcement arrangement of the inclined pile foundation, and then installs the cap reinforcement cage at the location of the reinforcement, and pours concrete to obtain the cap;

[0037] S2 prepares a lower pile segment, several middle pile segments, and an upper pile segment, the bottom of the lower pile segment is in the shape of an inverted truncated cone, and prestressed steel bars are inserted and anchored on the lower pile segment, prestressed holes are respectively provided through the middle pile segment and the upper pile segment, and a plurality of reserved main bars are protruding from the top of the upper pile segment;

[0038] S3: at least two pile pressure reaction frames with through-type jacks are installed on the cap, the pile pressure reaction frames are located on the inclined side of the inclined pile foundation, and pile pressure holes are dug on the cap according to the axis of the through-type jacks;

[0039] S4 According to the axis line of the through-type jack, first hoist the lower pile section in place, press it into the predetermined pile hole through the pile pressing hole, then hoist the middle pile section in place, and successively complete the process of brushing epoxy glue on the connecting end face, installing prestressed steel bars in the prestressed duct, tensioning the prestressed steel bars by the through-type jack, anchoring the prestressed steel bars of adjacent two pile sections, and pile pressing for pile connection. Then successively complete the hoisting and pile connection of the remaining middle pile sections and the upper pile section to obtain the jacked pile;

[0040] S5 First, pre-fix the jacked pile with wedge blocks, remove the redundant pile head concrete according to the design elevation, then weld the main reinforcement of the bearing platform and the reserved main reinforcement of the upper pile section, and then fix the steel structure on the reserved main reinforcement as a force transfer member to apply a pressure of 120 kN to the jacked pile through the through-type jack, and control the center distance between the inclined pile foundation and the jacked pile to be 1.5 m. Then pour concrete to seal the pile until the concrete strength reaches 90% of the design strength, and then the through-type jack is depressurized and the pile pressing reaction frame is removed.

[0041] Example 2: Refer to Figure 3 , a method for strengthening the inclination disease of the pile foundation of an already opened-to-traffic bridge disclosed by the present invention. The difference from Example 1 is that the specific implementation manner of S1 is

[0042] 1) Surface treatment of chiseling the inclined pile foundation concrete:

[0043] When chiseling the concrete, first remove the floating slurry on the concrete surface until the aggregate is exposed, and then start chiseling. The number of chiseling points exceeds 8000 points / m², the chiseling method is flat chiseling, and use compressed air to remove the dust or rinse it clean with clean water;

[0044] 2) Drilling:

[0045] (1) Detection: Before implanting the steel bars, detect the steel bars in the structure body of the inclined pile foundation to avoid damaging the steel bars as much as possible;

[0046] (2) Hole cleaning: Use a special steel brush to clean the hole before implanting the steel bars;

[0047] (3) Dust removal: Blow out the dust and accumulated water;

[0048] (4) Pre-injection: Use a special mixing nozzle. The first 4 guns of adhesive flowing out of the mixing nozzle must be discarded and cannot be used;

[0049] (5) Glue injection: Start glue injection after inserting the mixing nozzle into the bottom of the hole, slowly move the mixing nozzle outwards to ensure that there are no bubbles or voids in the hole, and inject glue to 2 / 3 of the hole depth;

[0050] (6) Steel bar implantation: Insert the steel cage of the bearing platform into the position of the implanted steel bar in a continuously rotating manner until the colloid flows out of the hole opening. The steel bar can be implanted or adjusted before gelation, and the steel bar cannot be disturbed during the period from gelation to solidification start; when the steel cage of the bearing platform conflicts with the pile pressing hole, the steel bar should be cut off;

[0051] 3) Binding of steel bars

[0052] When the steel bars conflict with the pile pressing holes, the steel bars should be cut off. After the pile pressing is completed and before the pile is sealed, single-sided welding should be used for the steel bar welding, and the weld length should not be less than 10d;

[0053] 4) Pouring of concrete

[0054] Apply a layer of interface agent with a thickness of 1 - 2 mm on the surface of the original concrete to enhance the connection between the new and old concretes; the surface of the base layer is required to be firm, clean, without weathering, sanding, peeling and other phenomena, and the sundries on the surface and the conveyed concrete should be removed in advance; when the surface of the pier body of the pile cap is particularly dry and has strong water absorption, the surface of the pier body should be moistened with clean water first.

[0055] Example 3: Refer to Figures 4 to 6 , which is a method for strengthening the inclination disease of the pile foundation of an already opened - to - traffic bridge disclosed by the present invention. The difference from Example 2 is that the specific implementation method of S2 is to pre - fabricate the pile segments in the factory or on - site, that is, prepare a lower pile segment, an intermediate pile segment, and an upper pile segment. The pile body should not be distorted, and the joint surface of the pile segments should be flat and smooth; when pre - fabricating the pile segments, steel pipes with outer diameters of 34 mm and 57 mm and connected sequentially from top to bottom are used as the prestressed duct.

[0056] Example 4: Refer to Figure 7 , which is a method for strengthening the inclination disease of the pile foundation of an already opened - to - traffic bridge disclosed by the present invention. The difference from Example 3 is that the specific implementation method of S3 is to install two pile - pressing reaction frames with through - hole jacks on the pile cap. The pile - pressing reaction frames should be kept vertical, and the pile - pressing reaction frames are located on the inclined side of the inclined pile foundation. According to the axis line of the through - hole jack, dig pile - pressing holes on the pile cap.

[0057] Example 5: Refer to Figure 8 , which is a method for strengthening the inclination disease of the pile foundation of an already opened - to - traffic bridge disclosed by the present invention. The difference from Example 4 is that the specific implementation method of S4 is that when the pile segment is hoisted in place, it must be kept vertical, so that the through - hole jack and the axis line of the pile segment are on the same vertical line, and there should be no eccentric pressing; when pressing the pile, place a 3 - 4 cm thick wooden board or multiple layers of gunny bags on the top of the pile segment, put on the steel cap and then press the pile.

[0058] 1) Pile - pressing construction steps: Locate the position of the jacked pile, dig a pile hole with a depth of 0.5 m and a diameter of 30 cm under the pile cap to facilitate the positioning of the jacked pile. After the lower pile segment is pressed in place, install the connecting sleeve, hoist the next pile segment in place, apply epoxy glue, install the prestressed steel bars, tension the prestressed steel bars after the epoxy glue is cured, press the pile, and then hoist the next pile segment and repeat the above steps;

[0059] 2) Epoxy glued pile arrangement: After the previous pile segment is driven, the next pile segment is hoisted to a height of 10 cm, and then the end faces of the two adjacent pile segments are dried, blown clean, and cleaned with acetone. Then a layer of epoxy glue with a thickness of 2-4 mm is applied on both ends, and the next pile segment is kept vertically lowered. After the epoxy glue is cured, the prestressed steel bars are tensioned;

[0060] 3) For pile sections with uneven and smooth sides of pile joints, they should be chiseled flat to ensure that the upper and lower surfaces are fully bonded. After solidification, the prestressed steel bars are tensioned to the control force and then anchored after stabilizing the pressure for 2 minutes, and then the pressing construction can begin. After the pressing bearing capacity meets the design requirements, after constant pressure for 1 hour, when the settlement is <0.2mm, the pile pressing can be stopped;

[0061] The tensioning tonnage of the through-type jack for tensioning prestressed steel bars is 250kN, and the pressure is required to be maintained for 2 minutes, and then anchored after stabilizing the pressure for another 2 minutes;

[0062] 4) Pile foundation construction should not be stopped midway and should be completed in one go. If a pause is required, the tip should stay in the soft soil layer and the pause time should not exceed 24 hours;

[0063] 5) During the pile driving process, careful records should be kept of each stage of the pile driving construction;

[0064] 6) The final pile driving force should be used as the control standard for pile driving construction, and the depth of pile driving should be used as an auxiliary control;

[0065] 7) The plane deviation between the driven pile hole and the designed position shall not exceed ±20mm; when driving the pile, the vertical deviation of the pile section shall not exceed 1.5% of the pile length.

[0066] Example 6: Reference Figure 9 , is a method for reinforcing the pile foundation of a bridge that has been opened to traffic disclosed in the present invention, which is different from Example 5 in that the specific implementation of S5 is as follows:

[0067] 1) After the pile is driven, when the pile top reaches the designed elevation, the exposed pile head shall be cut off; before cutting, the pile shall be fixed with a wedge, and then a 3-5 cm deep groove shall be opened to remove the pile head concrete. Only the prefabricated pile reinforcement shall be retained, penetrated into the cap, and welded to the main reinforcement of the cap. It is strictly forbidden to cut the pile head randomly in the cantilever situation;

[0068] 2) Sealing pile:

[0069] (1) Roughen the inner wall of the pile hole, weld and cut off the main reinforcement and reserved reinforcement (i.e. No. 7 reinforcement in the figure);

[0070] (2) Before sealing the pile, clean up the debris in the hole, drain the accumulated water, chisel the pore wall and remove the floating slurry on the pile surface to increase the bonding force;

[0071] (3)When sealing the pile, paste a steel plate with a thickness of 2 cm and a diameter of 15 cm on the reserved main reinforcement with epoxy glue, weld 3 steel bars with a diameter of 5 cm on the steel plate as force transfer members, and apply a preload to the pile foundation with a through-hole jack;

[0072] (3)Finally, pour the slightly expanding early-strength C30 concrete, tamp it and cure it; after the concrete strength reaches 90% of the design strength, the pressure can be released to ensure the permanent prestress;

[0073] (4)Remove the through-hole jack and cut off the excess steel bars flush with the surface of the pile cap.

[0074] Example 7: A method for strengthening the inclination disease of the pile foundation of an already opened-to-traffic bridge disclosed by the present invention is different from Example 6 in that the structural forces of the inclined pile foundation before and after the inclination disease strengthening are calculated.

[0075] I. Calculation by the "m" method:

[0076] According to Appendix P of the "Code for Design of Highway Bridge and Culvert Foundations and Substructures" (JTGD63-2007):

[0077] 1. Calculation width of the pile: When d≥1.0; b 1 =k×kf(d + 1)=1×0.9×(1.2 + 1)=1.98;

[0078] 2. Calculation of the pile foundation deformation coefficient:

[0079] I = πR 4 / 64 = 3.1415926×(1.2 4 ) / 64 = 0.101788;

[0080] EI = 0.8EcI = 0.8×2.8E + 07×0.1017876 - 2280042.7

[0081] a = ((m*b 1 ) / EI) 0.2 = (5000×1.98 / 2280042.7) 0.2 = 0.3369291;

[0082] 3. ah = 6.739

[0083] ah>2.5, it is an elastic pile, kh = 0;

[0084] 1 / (a 3 ×EI)-1.146678E - 05,

[0085] 1 / (α 2 )×EI = 3.863493E - 06,

[0086] 1 / (a×EI) = 1.301723E-06,

[0087] a 2 ×EI = 258833.1501,

[0088] a 3 ×EI = 87208.4082,

[0089] Combined with the bending moment correction coefficient (JTG D63-2007), the calculation shows that the point with the maximum bending moment is at 0.8 meters underground, M = 1260 (KN·m).

[0090] II. Pile foundation reinforcement calculation:

[0091] 1. The ratio of the radius rs of the circle where the longitudinal reinforcement is located to the radius r of the circular cross-section: g = rs / r = 1.06 / 1.2 = 0.8833;

[0092] 2. Eccentricity of the axial force: e 0 = Md / Nd = 1260 / 1800 = 0.7000m;

[0093] 3. Influence coefficient of load eccentricity on cross-section curvature: ξ 1 = 0.2 + 2.7×e 0 / ho = 0.2 + 2.7×(0.7000 / 1.13) = 1.8726 > 1.0, ξ 1 = 1.0;

[0094] 4. Influence coefficient of member slenderness ratio on cross-section curvature: ξ 2 = 1.15 - 0.01×lo / h = 1.15 - 0.01×(15.9 / 1.2) = 1.0, ξ 2 = 1.0;

[0095] 5. Eccentricity amplification coefficient: n = 1.3857;

[0096] 6. Eccentricity of the axial force: eo- = eo×n = 0.9700×1.3857 = 1.3441m;

[0097] 7. Cross-section radius: r = 0.6m;

[0098] 8. Select reasonable calculated values (as follows): ξ = 0.310; A = 0.6073; B = 0.4295; C = -0.9080; D = 1.7637;

[0099] 9. p = (fcd / fsd) × (B × r - A × eo) / (C × eo - D × g × r) = (11500 / 280000) × (0.4295 × 0.6 - 0.6073 × 0.9700) / (-0.9080 × 0.9700 - 1.7637 × 0.8833 × 0.6) = 0.00750;

[0100] 10. Design value of axial force: Ndu = A × r 2 × fcd + C × p × r 2 × fsd' = 0.6073 × (0.6000 2 ) × 11500 + -0.9080 × 0.00750 × (0.6 2 ) × 280000 = 1828.07 (KN);

[0101] 11. Required cross - sectional area of steel bars is: 0.00750 × 3.1415926 × 0.3600 × 1000000 = 8476.85 mm 2 , Required steel bars are: 23 bars of HRB335 grade 22 steel bars;

[0102] 12. Actual reinforcement ratio is: 0.00778.

[0103] III. Bearing capacity check:

[0104] 1. ξ close to the actual reinforcement is 0.315; A = 0.6211; B = 0.4365; C = -0.8828; D = 1.7738;

[0105] 2. e 0 (cal) = (B × fcd + D × p × g × fsd') / (A × fcd + C × p × fsd') × = (0.4365 × 11500 + 1.7738 × 0.00778 × 0.8833 × 280000) / (0.6211223 × 11500 + -0.8828 × 0.00778 × 280000) × 0.6 = 0.9691 m 3 ;

[0106] 3. e 0 '(cal) / e 0 '(actual) = 0.9691 / 0.9700 = 0.9990 > 0.98; Requirements are met. ξ = 0.315 is what we want.

[0107] 4. Design value of axial force: Ndu = A × r 2 × fcd + C × p × r 2 × fsd' = 1879.36 KN > yo × Nd = 1800 KN; The result shows that the cross - sectional compressive bearing capacity is sufficient.

[0108] 5. Design value of bending moment: Ndu × e 0 = B × r 3 × fcd + D × p × r 3 × fsd' = 1821.5 kN·m > γo × Nd × e 0 = 1746 kN·m. The results show that the compressive bearing capacity of the 22nd section is sufficient among 23 HRB335 bars, and the structure is safe. Considering that the actual reinforcement is 40 HRB335 Ф 2 2, and the superstructure is constant = N 1 800 kn; Calculation of flexural bearing capacity: ξ = 0.340; A = 0.6915; B = 0.4699; C = -0.7585; D = 1.8187;

[0109] 6. e 0 ' (calculated) (B × fcd + D × p × g × fsd') / (A × fcd + C × p × fsd') × r = (0.4764 × 11500 + 1.8266 × 0.01361 × 0.8833 × 280000) / (0.7057424 × 11500 + -0.7340 × 0.01361 × 280000) × 0.6 = 1.3118 m;

[0110] 7. Design value of bending moment: Ndu × e 0 = B × r 3 × fed + D × p × r 3 × fsd- = 2494 kN·m > γo × Nd × e 0 = 1746 kN·m.

[0111] After calculation, when the pier is inclined, the reinforcement of the pile foundation meets the bearing capacity requirements. However, compared with other pile foundations, the safety reserve has decreased significantly. In this case, it is considered to add a bearing platform on the inclined pile foundation and arrange 2 static pressure piles that are pressed in section by section. The allowable bearing capacity of a single pile is controlled at 150 kN. The center distance between the newly pressed pile and the original pile is 1.5 m. When sealing the pile, a force of 120 kN is applied to the pile foundation, and then C30 slightly expanded early-strength concrete is poured. Through the above method, a bending moment of 2×120×1.5 = 360 kN·m can be provided, which just balances the bending moment generated due to the inclination of the pile foundation. The diameter of the static pressure pile is 30 cm, the length of each pile section is 1.5 m, and 1 prestressed steel bar with a diameter of 25 mm is arranged in each pile section. The pile sections are bonded with epoxy mortar. The pile length is temporarily considered as the penetration depth of 15 m. After the bearing capacity of the pressed pile meets the design requirements, keep the constant pressure for 1 hour. If the settlement < 0.2 mm, the pile pressing can be ended. The prestressed steel bar between the pile sections uses 1 precision rolled threaded steel bar with a diameter of 25 mm. The design strength of this steel bar is 450 MPa, and the tension control force is 250 kN. After the epoxy glue bonding between the pile sections is cured, it is tensioned to the tension control force, kept stable for 2 minutes and then anchored, and pressed in section by section.

[0112] For the anchoring adhesive used in the present invention, Class A adhesive must be used, and its safety performance must meet the relevant requirements for the anchoring adhesive in the "Code for Strengthening Design of Highway Bridges" (JTG / T J22 - 2008).

[0113] The new and old concrete section agents must meet the requirements of the "Concrete Interface Treatment Agent" (JCT 907 - 2002).

[0114] The safety performance of the epoxy glue should meet the requirements of the "Code for Strengthening Design of Concrete Structures" (GB 50367 - 2013).

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for reinforcing the inclined damage of the pile foundation of a bridge that has been opened to traffic, characterized in that: The following steps are included: S1 prepares an inclined pile foundation, determines the location of the reinforcement according to the reinforcement arrangement of the inclined pile foundation, and then installs the cap reinforcement cage at the location of the reinforcement, and pours concrete to obtain the cap; S2: prepare a lower pile segment, several middle pile segments, and an upper pile segment, wherein the bottom of the lower pile segment is in the shape of an inverted truncated cone, and a prestressed steel bar is inserted and anchored on the lower pile segment, and prestressed holes are respectively provided through the middle pile segment and the upper pile segment, and a plurality of reserved main bars are protruding from the top of the upper pile segment; S3: installing at least two pile-pressing reaction frames with through-type jacks on the cap, the pile-pressing reaction frames are located on the inclined side of the inclined pile foundation, and pile-pressing holes are dug on the cap according to the axis of the through-type jacks; S4: According to the axis line of the through-type jack, the lower pile section is first hoisted into place, and is pressed into the predetermined pile hole through the pile-pressing hole, and then the middle pile section is hoisted into place, and the connection end surface is coated with epoxy glue, the prestressed steel bars are installed in the prestressed channel, the through-type jack is used to tension the prestressed steel bars, the prestressed steel bars of the two adjacent pile sections are anchored, and the pile connection process is completed in sequence, and then the remaining middle pile sections and the upper pile section are hoisted and connected in sequence to obtain a static pile; S5 first uses a wedge block to pre-fix the static pressure pile, and removes excess pile head concrete according to the design elevation, then welds the main reinforcement of the foundation and the reserved main reinforcement of the upper pile section, and then fixes a steel structure on the reserved main reinforcement as a force transmission member to apply a pressure of 100~150kN to the static pressure pile through the through-type jack, and controls the center distance between the inclined pile foundation and the static pressure pile to be 1.2~1.8m, then pours concrete to seal the pile, and after the concrete strength reaches 90% of the design strength, the through-type jack relieves the pressure and removes the pile pressure reaction frame.

2. A method for reinforcing the inclined damage of pile foundations of bridges that have been opened to traffic according to claim 1, characterized in that: In S1, the inclined pile foundation is roughened in advance. When roughening concrete, the concrete surface slurry is first removed until the aggregate is exposed, and then roughening begins. The number of chiseling points exceeds 8,000 points / ㎡. The roughening method is flat chiseling, and dust is removed with compressed air or rinsed with clean water.

3. The method for reinforcing the inclined damage of the pile foundation of a bridge that has been opened to traffic according to claim 1 is characterized in that: In S1, the cap steel cage is implanted into the colloid outflow hole at the reinforcement planting position in a continuously rotating manner. The reinforcement can be implanted or adjusted before gelation, and the reinforcement should not be disturbed during the period from gelation to the beginning of solidification. When the cap steel cage collides with the pile hole, the reinforcement should be cut off.

4. A method for reinforcing the inclined damage of pile foundations of bridges that have been opened to traffic according to claim 1, characterized in that: In the above-mentioned S1, a layer of interface agent with a thickness of 1-2 mm is applied to the surface of the inclined pile foundation in advance.

5. The method for reinforcing the inclined pile foundation of a bridge that has been opened to traffic according to claim 1 is characterized in that: In S2, steel pipes with outer diameters of 34 mm and 57 mm respectively and connected sequentially from top to bottom are used as prestressed channels.

6. The method for reinforcing the inclined pile foundation of a bridge that has been opened to traffic according to claim 1, characterized in that: In S4, after the pile driving of the previous pile segment is completed, the next pile segment is hoisted to a height of 10 cm, and then the end faces of the two adjacent pile segments are dried, blown clean, and cleaned with acetone, and then a layer of epoxy glue with a thickness of 2-4 mm is applied to both ends, and the next pile segment is kept vertically lowered, and the prestressed steel bars are tensioned after the epoxy glue is cured.

7. The method for reinforcing the inclined pile foundation of a bridge that has been opened to traffic according to claim 1, characterized in that: In S4, the tensioning tonnage of the through-type jack for tensioning the prestressed steel bars is 250 kN, and the pressure is required to be maintained for 2 minutes, and then anchored after stabilizing the pressure for 2 minutes.

8. The method for reinforcing the inclined pile foundation of a bridge that has been opened to traffic according to claim 1 is characterized in that: In S4, a 3-4 cm thick wooden board or multiple layers of sacks are placed on the top of the pile segment, and a steel cap is put on before the pile is pressed.

9. The method for reinforcing the inclined pile foundation of a bridge that has been opened to traffic according to claim 1, characterized in that: In the above S5, the steel bar is welded using single-sided welding, and the weld length is not less than 10d.

10. The method for reinforcing the inclined pile foundation of a bridge that has been opened to traffic according to claim 1, characterized in that: In S5, a steel plate with a thickness of 2 cm and a diameter of 15 cm is glued to the reserved main reinforcement with epoxy glue, and three steel rods with a diameter of 5 cm are welded to the steel plate as force transmission parts to complete the process of the through-type jack applying pressure to the static pressure pile through the force transmission parts.

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