CN112878320A

CN112878320A - Construction method for reinforcing PHC tubular pile core in mucky soil layer area

Info

Publication number: CN112878320A
Application number: CN202110061025.2A
Authority: CN
Inventors: 朱道付; 张鸿羽; 崔世杰; 潘敬喜; 拓步胜
Original assignee: China MCC17 Group Co Ltd
Current assignee: China MCC17 Group Co Ltd
Priority date: 2021-01-18
Filing date: 2021-01-18
Publication date: 2021-06-01

Abstract

The invention discloses a construction method for reinforcing a pile core of a PHC (prestressed high-strength concrete) tubular pile in a mucky soil layer area, which is characterized in that according to a pile body quality report of low strain detection of the PHC tubular pile after excavation of a mucky soil body foundation, silt filled in an inner cavity of the PHC tubular pile judged to be of class II and class III quality grades is stirred and diluted by a high-pressure rotary jet drilling machine, then, high-pressure compressed air of the high-pressure rotary jet drilling machine is used for gradually extruding slurry formed by stirring and dilution out of the inner cavity of the PHC tubular pile, then, the crack position area of the joint weld of the PHC tubular pile is continued, reinforcing steel bars are arranged, and then, concrete is used for filling a pile core reinforcing space, so that the pile core reinforcing work at the crack position of the joint weld of the. The construction method of the invention can ensure the construction period of the project, thereby reducing the construction cost of the project increased by the subsequent pile repair.

Description

Construction method for reinforcing PHC tubular pile core in mucky soil layer area

Technical Field

The invention belongs to the technical field of building construction, relates to pile foundation construction, and particularly relates to a construction method for reinforcing a PHC (prestressed high-strength concrete) pipe pile core in a mucky soil layer area.

Background

The PHC tubular pile is one of common pile foundation design forms in pile foundation engineering, and has the advantages of low engineering cost, short construction period, high vertical bearing capacity, obvious soil squeezing effect and low horizontal shearing resistance of the tubular pile in the pile forming process. In the PHC tubular pile construction process, particularly the PHC tubular pile arranged in soil containing a shallow silt layer is low in horizontal shearing resistance if the PHC tubular pile is driven without reasonably arranging partitions and directions, so that the PHC tubular pile is easy to be driven due to lateral extrusion force formed by driving or lateral extrusion force formed by soil height difference during foundation excavation, the PHC tubular pile which is driven is subjected to lateral extrusion to cause joint welding line crack, silt in the silt layer is filled into an inner cavity of the PHC tubular pile along the crack gap of the PHC tubular pile joint welding line, and the pile core of the PHC tubular pile which is damaged by lateral force extrusion to be of the type II and type III quality grades cannot be reinforced due to the silt in the inner cavity of the PHC tubular pile.

Disclosure of Invention

Aiming at the technical problems in the background art, the invention provides a construction method for reinforcing a PHC tubular pile core in a mucky soil layer area, which solves the construction problem that the PHC tubular pile core in inner cavities of class II and class III quality grades cannot be reinforced due to the obstruction of silt, ensures the realization of a project construction node target, and reduces the project construction cost increased by the subsequent pile re-filling.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention relates to a construction method for reinforcing a PHC tubular pile core in a mucky soil layer area, which comprises the following steps:

step one, determining a PHC tubular pile needing pile core reinforcement;

step two, cleaning sludge in the inner cavity of the PHC pipe pile needing pile core reinforcement;

and step three, pile core reinforcement at the defect part of the PHC pipe pile needing pile core reinforcement.

The technical scheme of the invention is further improved, and the first step is as follows:

1.1, carrying out PHC pipe pile forming quality detection on PHC pipe piles in an excavated foundation area of a soil body one by adopting a low-strain detection method;

and 1.2, respectively marking the PHC tubular piles detected as class II, class III and class IV quality grades according to the low-strain detection report result, carrying out reinforcement treatment on the quality defects of the PHC tubular piles by adopting a pile core reinforcement mode for the class II and class III PHC tubular piles, and directly judging the class IV PHC tubular piles as waste piles and directly carrying out pile repair.

The technical scheme of the invention is further improved, and the second step is as follows:

2.1, measuring the filling depth of the sludge in the inner cavity of each PHC tubular pile needing pile core reinforcement by using a measuring rope according to the depth of the joint weld cracking position of each PHC tubular pile of the II-type and III-type quality grades in a low-strain detection report, wherein the defect position of each PHC tubular pile of the II-type and III-type quality grades is usually the position of the joint weld of the uppermost PHC tubular pile and is generally about 10-15 m in depth;

2.2, a high-pressure rotary spraying drilling machine is adopted to carry out rotary spraying and stirring of sludge in each cavity of each PHC tubular pile needing pile core reinforcement from the pile top while rotary spraying to a depth of 7m below the crack position of the joint weld of the PHC tubular pile in sequence through high-pressure water, so that the sludge in the range is converted into slurry through high-pressure rotary spraying and stirring;

and 2.3, spraying high-pressure compressed air into the inner cavity of each PHC tubular pile needing pile core reinforcement by using an air compressor configured by a high-pressure jet drilling machine, carrying out jet stirring on the sludge into slurry, extruding the inner cavity of each PHC tubular pile, measuring the depth of the sludge in the PHC tubular pile by using a measuring rope, and repeatedly using the stirring and extruding methods until the depth of the sludge in the inner cavity of each PHC tubular pile needing pile core reinforcement is reduced to a depth of 7m below the crack position of the joint welding seam of the PHC tubular pile.

The technical scheme of the invention is further improved, and the third step is as follows:

3.1, according to the specification of each PHC tubular pile needing pile core reinforcement, respectively manufacturing a circular tray with the diameter smaller than that of the inner cavity of the PHC tubular pile needing pile core reinforcement by using a steel plate, drawing a circumferential line on the upper surface of the circular tray by taking the circle center of the circular tray as the circle center, vertically welding a plurality of thread reinforcing steel bars for pile core reinforcement along the circumferential line at equal intervals, then vertically welding two round steel bars at two points outside the circumferential line of the circular tray at 180-degree intervals, and manufacturing the other end of each round steel bar into a hanging ring shape, wherein the length of each round steel bar exceeds the pile top of the PHC tubular pile needing pile core reinforcement to the position of the weld joint crack of the PHC tubular pile, so as to form a hanging rod for arranging the thread reinforcing steel bars in the inner cavity of the PHC tubular pile needing pile core reinforcement;

3.2, the circular tray faces downwards, the circular tray, the thread reinforcing steel bars and the hanging rods are vertically placed into an inner cavity of the PHC tubular pile needing pile core reinforcement, the crack position of the joint weld of the PHC tubular pile is taken as a central line, after the thread reinforcing steel bars are arranged on the upper portion and the lower portion of the thread reinforcing steel bars by half of the length, a cross arm made of short steel bars penetrates through hanging rings of the two hanging rods, the cross arm is placed on the pile top of the PHC tubular pile, and the arrangement of the thread reinforcing steel bars at the crack position of the joint weld of the PHC tubular pile is completed;

3.3, putting the PHC pipe pile into an inner cavity of the PHC pipe pile needing pile core reinforcement by using a well submersible pump, jacking the PHC pipe pile to a position depth range of 7m below a joint welding line of the PHC pipe pile, pumping out muddy water containing little slurry, then injecting C40 or concrete with higher strength grade into the inner cavity of the PHC pipe pile by using a concrete pump truck, wherein the pouring height is 6m upwards from the setting position height of the circular tray, and simultaneously keeping a poured concrete test block, after the concrete strength meets the design strength requirement, performing pile body quality low-strain detection on the PHC pipe pile reinforced by the pile core, and performing subsequent process construction after the PHC pipe pile quality low-strain detection is qualified.

According to the further improvement of the technical scheme, the circular tray is made of a steel plate with the thickness of 3mm, and the diameter of the circular tray is 10mm smaller than that of the PHC tubular pile; the diameter of the thread reinforcing steel bar is 14-20mm, and the length of the thread reinforcing steel bar is 6 m; the diameter of round steel bar is 6mm, and length is for being used for this PHC tubular pile top that needs the pile core reinforcement to this PHC tubular pile joint welding seam position 3m size down again.

Compared with the prior art, the construction method for reinforcing the pile core of the PHC tubular pile in the mucky soil layer area comprises the steps of according to a pile body quality report of low strain detection of the PHC tubular pile after excavation of a mucky soil body foundation, stirring and diluting silt filled in an inner cavity of the PHC tubular pile judged to be of class II and class III quality grades by using a high-pressure rotary jet drilling machine, then gradually extruding out the inner cavity of the PHC tubular pile by using high-pressure compressed air of the high-pressure rotary jet drilling machine, then continuously filling a pile core reinforcing space in a crack position area of a joint weld of the PHC tubular pile by using concrete after setting reinforcing steel bars, thereby completing pile core reinforcing work at the crack position of the joint weld of the PHC tubular pile, ensuring the construction period and reducing the engineering construction cost increased by subsequent pile refilling.

Drawings

FIG. 1 is a schematic view of a PHC pile in a soil body according to the present invention;

FIG. 2 is a schematic diagram illustrating measurement of sludge in an inner cavity of a PHC pipe pile according to the present invention;

FIG. 3 is a schematic diagram illustrating the cleaning of sludge in the inner cavity of the PHC tubular pile;

FIG. 4 is a schematic view of the arrangement of the thread reinforcing steel bars at the welding seam position of the PHC pipe pile extension in the invention;

in the figure: 1. a soil body; 2. PHC tubular pile; 3. a joint weld; 4. sludge; 5. a high-pressure rotary jet drilling machine; 6. an air compressor; 7. a circular tray; 8. reinforcing steel bars with threads; 9. a boom; 10. a cross arm; 11. measuring a rope; 12. and (5) round steel bars.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The construction method for reinforcing the PHC tubular pile core in the mucky soil layer area is adopted to finish the work of reinforcing the PHC tubular pile core of partial II-type and III-type quality grades in the mucky layer by taking an example of moving a certain 150t converter of a certain steel to a new project.

The project is summarized in that the engineering pile foundations all adopt pretensioned prestressed high-strength concrete pipe piles, the types of the pile foundations are PHC550-AB125, PHC500-AB125 and PHC600-AB130, the pile length is 50-65 m, and the number of the pile foundations is 9000 excess sleeves.

The invention relates to a construction method for reinforcing a pile core of a PHC (prestressed high-strength concrete) pipe pile in a mucky soil layer area, which is characterized in that silt filled in an inner cavity of the PHC pipe pile judged to be of class II and class III quality grades is stirred and diluted by high-pressure water of a high-pressure rotary jet drilling machine according to a pile body quality detection report of low strain detection of the PHC pipe pile after excavation of a mucky soil body foundation, the stirring depth is from the pile top of the PHC pipe pile to the depth position required by pile core reinforcement, then, high-pressure compressed air of a high-pressure jet grouting drilling machine is used, muddy water formed by stirring and diluting the silt through jet grouting is gradually extruded out of an inner cavity of the PHC tubular pile, silt cleaning work required by pile core reinforcement at the crack position of the joint welding line of the PHC tubular pile is completed, then, the filling of a pile core reinforcement space is carried out by concrete at the crack position area of the joint welding line of the PHC tubular pile after reinforcing steel bars are arranged, and therefore the pile core reinforcement work at the crack position of the joint welding line of the PHC tubular pile is completed.

The construction method for reinforcing the pile core of the PHC tubular pile in the mucky soil layer area according to the present invention will be described in detail with reference to fig. 1 to 4.

The construction steps of the invention are as follows:

the method comprises the following steps: determining a PHC tubular pile needing pile core reinforcement;

1. and (3) carrying out pile-forming quality detection on the PHC pipe piles 2 in the excavated foundation area of the soil body 1 one by adopting a low-strain detection method.

2. According to the low-strain detection report result, the PHC tubular piles 2 detected as the II-type, III-type and IV-type quality grades are respectively marked, the PHC tubular piles 2 of the II-type and III-type carry out reinforcement treatment on the quality defects of the PHC tubular piles 2 in a pile core reinforcement mode, the PHC tubular piles 2 of the IV-type are directly judged as waste piles, and pile repair work of the PHC tubular piles 2 of the IV-type is carried out according to a pile repair diagram after the PHC tubular piles are confirmed by a contact design unit.

Step two: cleaning sludge in the inner cavity of the PHC pipe pile needing pile core reinforcement;

1. according to the depth of the crack position of the joint welding seam 3 of the PHC tubular pile 2 with the quality grades of II and III in the low strain detection report, the filling depth of the sludge 4 in the inner cavity of each PHC tubular pile 2 needing pile core reinforcement is measured by using the measuring rope 11.

2. The defect position of the PHC tubular pile 2 in the shallow sludge layer is usually about 10-15 m deep at the position of the joint welding line 3 of the PHC tubular pile 2 at the top, and high-pressure water of a high-pressure rotary spraying drilling machine 5 is adopted to stir sludge 4 from the pile top of the PHC tubular pile 2 while rotary spraying to the position 7m deep below the cracking position of the joint welding line 3 of the PHC tubular pile 2, so that the sludge 4 in the range is changed into slurry through high-pressure rotary spraying and stirring.

3. Then spraying high-pressure compressed air into the inner cavity of the PHC tubular pile 2 through an air compressor 6 configured by a high-pressure rotary spraying drilling machine 5, carrying out rotary spraying and stirring to obtain sludge 4 of slurry, extruding the inner cavity of the PHC tubular pile 2, measuring the depth of the sludge 4 in the PHC tubular pile 2 through a measuring rope 11, and repeatedly using the stirring and extruding method until the depth of the sludge 4 in the inner cavity of the PHC tubular pile 2 is reduced to a depth of 7m below the crack position of a joint welding seam 3 of the PHC tubular pile 2; the depth dimensions of 7m here are respectively: the depth of 3m is the pile core reinforcement size required by 3m above and below the crack position of the joint weld 3 of the PHC tubular pile 2 needing pile core reinforcement, and the depth of 4m is the buffer depth size of mud sedimentation from the time of cleaning sludge 4 gradually completed in the inner cavity of the PHC tubular pile 2 to the time of pouring pile core reinforcement concrete.

Step three: pile core reinforcement at the defect part of the PHC pipe pile needing pile core reinforcement;

1. according to the specification of each PHC tubular pile 2 to be reinforced by a pile core, a circular tray 7 with the diameter being 10mm smaller than the diameter of the inner cavity of the PHC tubular pile 2 to be reinforced by the pile core is respectively made of a steel plate with the thickness of 3mm, a circumferential line is drawn on the upper surface of the circular tray 7 by taking the center of the circle of the circular tray 7 as the center of the circle, the radius of the circumferential line is close to half of the radius of the circular tray 7, then a plurality of phi 14-phi 20 thread reinforcing steel bars 8 for reinforcing the pile core of the PHC tubular pile 2 are vertically welded on the upper surface of the circular tray 7 along the circumferential line at equal intervals, the length of the thread reinforcing steel bar 8 for reinforcing the pile core is 6m, then two points on the outer side of the circumferential line of the circular tray 7 are separated by 180 degrees, each round steel bar with the diameter of phi 6mm is vertically welded, the other end of the round steel bar is made into a hanging ring shape, the length is the size from the, form a screw thread reinforcing steel bar 8 and a suspender 9 hung in the inner cavity of the PHC tubular pile 2.

2. The round tray 7 is placed downwards, the round tray 7, the thread reinforcing steel bars 8 and the hanging rods 9 are vertically placed into an inner cavity of the PHC tubular pile 2 together, the thread reinforcing steel bars 8 are controlled to be 3m in size up and down by taking the split position of the joint welding seam 3 of the PHC tubular pile 2 as a central line, after the thread reinforcing steel bars 8 with the length of 6m are controlled to be 3m in size, the cross arm 10 made of short steel bars transversely penetrates through the hanging rings of the two hanging rods 9, the cross arm 10 is placed at the pile top of the PHC tubular pile 2, and the arrangement of the thread reinforcing steel bars 8 at the split position of the joint welding seam 3 of the PHC tubular.

3. The method comprises the steps of putting a well submersible pump into an inner cavity of a PHC tubular pile 2, jacking the PHC tubular pile 2 to a depth range of 7m below a crack position of a joint welding line 3 of the PHC tubular pile 2, pumping out turbid water containing a little slurry, then injecting C40 or concrete with a higher strength grade into the inner cavity of the PHC tubular pile 2 by using a concrete pump truck, enabling the pouring height to be 6m upwards from the position where a circular tray 7 is arranged, simultaneously keeping a poured concrete test block, carrying out low-strain detection on pile body quality of the PHC tubular pile 2 reinforced by a pile core after the concrete strength meets the design strength requirement, and carrying out subsequent process construction after the low-strain detection of the quality of the PHC tubular pile 2 is qualified.

Claims

1. A construction method for reinforcing a PHC tubular pile core in a mucky soil layer area is characterized by comprising the following steps:

step one, determining a PHC tubular pile (2) needing pile core reinforcement;

step two, cleaning sludge (4) in the inner cavity of the PHC tubular pile (2) needing pile core reinforcement;

and step three, pile core reinforcement at the defect part of the PHC pipe pile (2) needing pile core reinforcement.

2. The construction method for reinforcing the pile core of the PHC tubular pile in the mucky soil layer area, which is disclosed by the claim 1, is characterized in that the first step is as follows:

1.1, performing pile forming quality detection on PHC tubular piles (2) in an excavated foundation area of a soil body (1) one by adopting a low-strain detection method;

1.2, respectively marking the PHC tubular piles (2) with the quality grades of II, III and IV according to the low-strain detection report result, carrying out reinforcement treatment on the quality defects of the PHC tubular piles (2) by adopting a pile core reinforcement mode for the PHC tubular piles (2) of II and III, and directly judging the PHC tubular piles (2) of IV as waste piles and directly carrying out pile repair.

3. The construction method for reinforcing the pile core of the PHC tubular pile in the mucky soil layer area, which is disclosed by the claim 1, is characterized in that the second step is as follows:

2.1, measuring the filling depth of the sludge (4) in the inner cavity of each PHC tubular pile (2) needing pile core reinforcement by using a measuring rope (11) according to the cracking position depth of the joint welding seam (3) of each PHC tubular pile (2) with the class II and class III quality grades in a low-strain detection report at the defect position of each PHC tubular pile (2) with the class II and class III quality grades, usually at the position of the joint welding seam (3) of the uppermost PHC tubular pile (2), and generally at the depth of about 10-15 m;

2.2, using a high-pressure rotary spraying drilling machine (5) to sequentially stir the sludge (4) in each cavity from the PHC tubular pile (2) needing pile core reinforcement to the depth of 7m below the crack position of the joint welding seam (3) of the PHC tubular pile (2) from the pile top while carrying out rotary spraying through high-pressure water, so that the sludge (4) in the range is converted into slurry through high-pressure rotary spraying and stirring;

and 2.3, spraying high-pressure compressed air into the inner cavity of each PHC tubular pile (2) needing pile core reinforcement through an air compressor (6) configured by a high-pressure rotary spraying drilling machine (5), rotatably spraying and stirring the sludge (4) into slurry, extruding the inner cavity of each PHC tubular pile (2), measuring the depth of the sludge (4) in the PHC tubular pile (2) through a measuring rope (11), and repeatedly using the stirring and extruding method until the depth of the sludge (4) in the inner cavity of each PHC tubular pile (2) needing pile core reinforcement is reduced to the depth of 7m below the cracking position of the joint welding seam (3) of the PHC tubular pile (2).

4. The construction method for reinforcing the pile core of the PHC tubular pile in the mucky soil layer area, which is disclosed by the claim 1, is characterized in that the third step is as follows:

3.1, according to the specification of each PHC tubular pile (2) needing pile core reinforcement, respectively manufacturing a circular tray (7) with the diameter smaller than that of the inner cavity of the PHC tubular pile (2) needing pile core reinforcement by using a steel plate, drawing a circumferential line on the upper surface of the circular tray (7) by taking the circle center of the circular tray (7) as the circle center, vertically welding a plurality of thread reinforcing steel bars (8) needing pile core reinforcement along the circumferential line at equal intervals, then vertically welding two round steel bars (12) at two points outside the circumferential line of the circular tray (7) at intervals of 180 degrees, manufacturing the other end of each round steel bar into a hanging ring shape, and forming a hanging rod (9) with the length exceeding the pile top of the PHC tubular pile (2) needing pile core reinforcement to the crack position of the joint welding line (3) of the PHC tubular pile (2) needing pile core reinforcement for hanging the thread reinforcing steel bars (8) in the inner cavity of the PHC tubular pile (2) needing pile core reinforcement;

3.2, the circular tray (7) is placed downwards, the circular tray (7), the thread reinforcing steel bars (8) and the hanging rods (9) are vertically placed into an inner cavity of the PHC tubular pile (2) needing pile core reinforcement together, the split position of the joint welding seam (3) of the PHC tubular pile (2) is taken as a central line, after the thread reinforcing steel bars (8) are arranged on and under the inner cavity by half of the length of each thread reinforcing steel bar (8), a cross arm (10) made of short steel bars transversely penetrates through the hanging rings of the two hanging rods (9), the cross arm (10) is placed at the pile top of the PHC tubular pile (2), and the arrangement of the thread reinforcing steel bars (8) at the split position of the joint welding seam (3) of the PHC tubular pile (2) is completed;

3.3, putting the PHC tubular pile (2) to be reinforced by the pile core into an inner cavity of the PHC tubular pile (2) by using a well submersible pump, jacking the PHC tubular pile (2) to a depth range of 7m below a joint welding seam (3) of the PHC tubular pile (2), pumping out turbid water slightly containing mud, then injecting C40 or concrete with higher strength grade into the inner cavity of the PHC tubular pile (2) by using a concrete pump truck, wherein the pouring height is 6m upwards from the set position height of the circular tray (7), and simultaneously reserving a poured concrete test block, after the concrete strength reaches the design strength requirement, performing low-strain detection on the pile body quality of the PHC tubular pile (2) reinforced by the pile core, and performing subsequent process construction after the low-strain detection on the quality of the PHC tubular pile (2) is qualified.

5. The construction method for reinforcing the pile core of the PHC tubular pile in the mucky soil area is characterized in that the circular tray (7) is made of a steel plate with the thickness of 3mm, and the diameter of the circular tray is 10mm smaller than that of the PHC tubular pile (2); the diameter of the thread reinforcing steel bar (8) is 14-20mm, and the length is 6 m; the diameter of round steel bar (12) is 6mm, and length is for being used for this PHC tubular pile (2) pile bolck that need the stake core reinforcement to this PHC tubular pile (2) joint welding seam (3) 3m size under 3m size again of splitting apart the position.