阅读说明：本技术 一种用于桩体承载力检测的预制桩帽及施工方法 (Prefabricated pile cap for detecting bearing capacity of pile body and construction method ) 是由 张新 孙福涛 马日克姑 于 2020-04-20 设计创作，主要内容包括：本发明涉及一种用于桩体承载力检测的预制桩帽及施工方法,所述预制桩帽包括：桩帽主体,所述桩帽主体套设于待检测桩体的桩头上,所述桩帽主体包括顶部和侧壁；所述桩帽主体的侧壁上相对于所述桩帽主体的中轴线对称的两侧分别设有吊耳；所述桩帽主体的侧壁上相对于所述桩帽主体的中轴线对称的两侧分别设有用于向所述桩帽主体与所述桩头之间的缝隙内注入灌浆料的注浆接头；所述桩帽主体的顶部设有至少两个排气孔；所述桩帽主体的顶部中心位置处还设有对中观测孔。本发明提供的预制桩帽结构简单,施工方便,节约工期且可重复使用,易于推广,可以极大提高承载力检测的成功率与检测效率。(The invention relates to a prefabricated pile cap for detecting the bearing capacity of a pile body and a construction method, wherein the prefabricated pile cap comprises the following components: the pile cap main body is sleeved on a pile head of a pile body to be detected and comprises a top and a side wall; lifting lugs are respectively arranged on two sides of the side wall of the pile cap main body, which are symmetrical relative to the central axis of the pile cap main body; two sides of the side wall of the pile cap main body, which are symmetrical relative to the central axis of the pile cap main body, are respectively provided with a grouting joint for injecting grouting material into a gap between the pile cap main body and the pile head; the top of the pile cap main body is provided with at least two exhaust holes; and a centering observation hole is also formed in the center of the top of the pile cap main body. The prefabricated pile cap provided by the invention has the advantages of simple structure, convenience in construction, capability of saving the construction period, reusability and easiness in popularization, and can greatly improve the success rate and the detection efficiency of bearing capacity detection.)

1. A precast pile cap for pile body bearing capacity detection, comprising:

the pile cap main body is sleeved on a pile head of a pile body to be detected and comprises a top and a side wall;

lifting lugs are respectively arranged on two sides of the side wall of the pile cap main body, which are symmetrical relative to the central axis of the pile cap main body;

two sides of the side wall of the pile cap main body, which are symmetrical relative to the central axis of the pile cap main body, are respectively provided with a grouting joint for injecting grouting material into a gap between the pile cap main body and the pile head;

the top of the pile cap main body is provided with at least two exhaust holes;

and a centering observation hole is also formed in the center of the top of the pile cap main body.

2. The precast pile cap for pile body bearing capacity detection according to claim 1, wherein each of said grouting joints is provided with a check valve.

3. The precast pile cap for pile body bearing capacity inspection according to claim 1, wherein the slip casting joint is detachably connected to the sidewall of the pile cap body.

4. The preformed pile cap for pile body bearing capacity detection as claimed in claim 1, wherein the inner surface of the pile cap body is coated with a release agent.

5. The precast pile cap for pile body bearing capacity detection of claim 1, wherein the grouting material is CGM grouting material.

6. The precast pile cap for pile body bearing capacity detection of claim 1, wherein the grouting joint is installed at a position near the bottom of the sidewall of the pile cap body.

7. A construction method for detecting the bearing capacity of a pile body is characterized by comprising the following steps:

s1: making a prefabricated pile cap according to any one of claims 1 to 6 according to the size of a pile body to be detected;

s2: cutting the pile after the earthwork is excavated to the designed elevation, and processing the pile head to be smooth;

s3: pouring a concrete cushion layer above the soil body;

s4: after a release agent is coated on the inner surface of the pile cap main body, the prefabricated pile cap is placed on the concrete cushion layer by using the lifting lug;

s5: sealing gaps between the pile cap main body and the concrete cushion layer by adopting foam sealing rubber;

s6: injecting grouting material into a gap between the pile cap main body and the pile head by using the grouting joint;

s7: after grouting is finished, detecting the bearing capacity of the pile body;

s8: and after the detection is finished, recovering the precast pile cap.

8. The construction method according to claim 7, wherein the inner diameter of the precast pile cap is 200mm larger than the outer diameter of the pile body to be detected, and the height of the precast pile cap is 400 mm.

9. The construction method according to claim 7, wherein in step S2, the pile head is 300mm to 350mm higher than the designed earth elevation.

10. The construction method according to claim 7, wherein the thickness of the concrete pad is 100mm, and the edge of the concrete pad exceeds the edge of the precast pile cap by at least 100 mm.

Technical Field

The invention relates to the field of pile foundation building construction, in particular to a prefabricated pile cap for detecting the bearing capacity of a pile body and a construction method.

Background

At present, the application of composite foundation treatment technology in the foundation treatment of road bridges and house buildings is more and more extensive, wherein according to the requirements of composite foundation technical specifications: after the strength of the pile body meets the loading requirement, and a single-pile vertical compression load test (static load test) needs to be carried out 28 days after construction is finished, so as to detect the bearing capacity of the pile body, however, because the pile body of the rigid pile composite foundation is usually a plain concrete pile, a cement fly ash gravel pile and the like, the pile body is not provided with reinforcing bars, and is easy to break in the test process, and the test data is influenced. According to the traditional method for manufacturing the cast-in-place concrete pile cap, although the problem of pile body breakage can be solved, the construction is complex, the bearing capacity detection can be carried out only after the pile cap is maintained to the designed strength, and the detection method is time-consuming and labor-consuming.

Disclosure of Invention

The invention provides a prefabricated pile cap for detecting the bearing capacity of a pile body and a construction method, which aim to solve the technical problem.

In order to solve the above technical problem, the present invention provides a prefabricated pile cap for detecting bearing capacity of a pile body, comprising: the pile cap main body is sleeved on a pile head of a pile body to be detected and comprises a top and a side wall; lifting lugs are respectively arranged on two sides of the side wall of the pile cap main body, which are symmetrical relative to the central axis of the pile cap main body; two sides of the side wall of the pile cap main body, which are symmetrical relative to the central axis of the pile cap main body, are respectively provided with a grouting joint for injecting grouting material into a gap between the pile cap main body and the pile head; the top of the pile cap main body is provided with at least two exhaust holes; and a centering observation hole is also formed in the center of the top of the pile cap main body.

Preferably, each grouting joint is provided with a check valve.

Preferably, the grouting joint is detachably connected with the side wall of the pile cap main body.

Preferably, the inner surface of the pile cap body is coated with a release agent.

Preferably, the grouting material is CGM grouting material.

Preferably, the grouting joint is installed on the side wall of the pile cap main body at a position close to the bottom.

The invention also provides a construction method for detecting the bearing capacity of the pile body, which comprises the following steps:

s1: manufacturing the prefabricated pile cap according to the size of the pile body to be detected;

s2: cutting the pile after the earthwork is excavated to the designed elevation, and processing the pile head to be smooth;

s3: pouring a concrete cushion layer above the soil body;

s4: after a release agent is coated on the inner surface of the pile cap main body, the prefabricated pile cap is placed on the concrete cushion layer by using the lifting lug;

s5: sealing gaps between the pile cap main body and the concrete cushion layer by adopting foam sealing rubber;

s6: injecting grouting material into a gap between the pile cap main body and the pile head by using the grouting joint;

s7: after grouting is finished, detecting the bearing capacity of the pile body;

s8: and after the detection is finished, recovering the precast pile cap.

Preferably, the inner diameter of the prefabricated pile cap is 200mm larger than the outer diameter of the pile body to be detected, and the height of the prefabricated pile cap is 400 mm.

Preferably, in step S2, the pile head is 300mm to 350mm higher than the designed elevation of the earthwork.

Preferably, the thickness of the concrete cushion layer is 100mm, and the edge of the concrete cushion layer exceeds the edge of the precast pile cap by at least 100 mm.

Compared with the prior art, the prefabricated pile cap for detecting the bearing capacity of the pile body and the construction method have the following advantages:

1. the prefabricated pile cap structure is adopted, the requirements on site construction conditions are low, only the site is required to be smooth and the hoisting requirements are met, and the requirements on seasons, weather, machinery and workers are low;

2. the construction process is simple, complicated procedures such as pile cap earthwork excavation, reinforcement binding, template erecting, concrete pouring, maintenance and the like are required in the traditional method, only the pile cap is hoisted and grouted, and the operation is simple;

3. the pile head protection effect of the invention is superior to that of the traditional concrete pile cap, and the test load can be uniformly transmitted to the pile body to be detected, so that the pile head is uniformly stressed, and the test data is more accurate;

4. the prefabricated pile cap is adopted, the integrity is good, the prefabricated pile cap is not easy to damage in a static load test, the next group of static load test can be carried out after recovery and maintenance, and when the prefabricated pile cap is used, a single prefabricated pile cap can be reused for 5-10 times, so that the use cost is lower;

5. the invention can save a large amount of construction period, the traditional pile cap needs to wait for the concrete curing of the pile cap for more than 28 days, and the static load test can be carried out only when the strength is reached, the invention can reach the test strength only by curing for 4 days, thereby improving the working efficiency and shortening the static load test period.

Drawings

Fig. 1 is a schematic structural diagram of a prefabricated pile cap for detecting bearing capacity of a pile body according to an embodiment of the present invention;

fig. 2 is a top view of a prefabricated pile cap for pile bearing capacity detection according to an embodiment of the present invention.

In the figure: 10-pile cap main body, 11-top, 12-side wall, 13-lifting lug, 14-grouting joint, 15-check valve, 16-grouting material, 17-exhaust hole, 18-centering observation hole, 20-pile head, 21-soil body, 22-concrete cushion layer and 23-foam sealing glue.

Detailed Description

In order to more thoroughly express the technical scheme of the invention, the following specific examples are listed to demonstrate the technical effect; it is emphasized that these examples are intended to illustrate the invention and are not to be construed as limiting the scope of the invention.

The invention provides a prefabricated pile cap for detecting bearing capacity of a pile body, which is shown in figures 1 and 2 and comprises: the pile cap comprises a pile cap main body 10, wherein the pile cap main body 10 is sleeved on a pile head 20 of a pile body to be detected, the pile cap main body 10 comprises a top part 11 and a side wall 12, and in the embodiment, the pile cap main body 10 can be formed by welding steel plates with the thickness of more than 5 mm; the two symmetrical sides of the side wall 12 of the pile cap main body 10 relative to the central axis of the pile cap main body 10 are respectively provided with a lifting lug 13, in the embodiment, the lifting lugs 13 are positioned at the left side and the right side of the pile cap main body 10 and are welded and fixed by adopting the same steel plate and used for hoisting and recycling the prefabricated pile cap, in the test process, the lifting lugs 13 do not influence the test operation, and the hoisting machinery can be utilized to hoist the prefabricated pile cap for recycling after the test is finished; the two sides of the sidewall 12 of the pile cap main body 10, which are symmetrical with respect to the central axis of the pile cap main body 10, are respectively provided with grouting joints 14 for injecting grouting material 16 into a gap between the pile cap main body 10 and the pile head 20, in this embodiment, the front and rear sides of the pile cap main body 10 are respectively provided with grouting joints 14 to prevent blockage during grouting, and it should be noted that the lifting lug 13 and the grouting joint 14 may be respectively located on two mutually perpendicular diameters on the same horizontal plane or different horizontal planes of the pile cap main body 10, or may be located on two parallel diameters on different heights of the pile cap main body 10; the top 11 of the pile cap main body 10 is provided with at least two vent holes 17, in this embodiment, the number of the vent holes 17 is 4, and the 4 vent holes 17 are uniformly distributed on the top 11 and used for discharging bubbles in grouting material 16 during grouting; the center of the top 11 of the pile cap main body 10 is also provided with a centering observation hole 18, a mark can be made in the center of the pile head 20 before hoisting, and the centering observation hole 18 is used for observation during hoisting, so that the axis of the prefabricated pile cap 10 is ensured to be opposite to the axis of the pile head 20, and the axis of a tested pile is ensured to be pressed in the test process.

Preferably, with continued reference to fig. 1 and 2, each grouting joint 14 is provided with a check valve 15 to prevent backflow of grouting material 16; preferably, the grouting connector 14 is detachably connected to the sidewall 12 of the pile cap body 10, for example, screwed, so that it can be replaced in time if a blockage occurs during grouting.

Preferably, the inner surface of the helmet body 10 is coated with a release agent (not shown) to facilitate the separation of the helmet from the grout 146 for recycling after the inspection.

Preferably, the grouting material 16 is CGM grouting material, which has the characteristics of good self-fluidity, quick hardening, early strength, no shrinkage, slight expansion and the like, and can reach the strength above C40 after being poured for 3 days to reach the test standard, thereby improving the working efficiency and shortening the static load test period.

Preferably, referring to fig. 1, the grouting joint 14 is installed on the sidewall 12 of the pile cap body 10 near the bottom, and fills the gap between the prefabricated pile cap and the pile head 20 from bottom to top, so as to avoid the generation of bubbles and interlayer.

The invention further provides a construction method for detecting the bearing capacity of the pile body, please refer to fig. 1 and fig. 2, which includes the following steps:

s1: according to the size of a pile body to be detected, manufacturing the prefabricated pile cap, wherein specifically, the inner diameter of the prefabricated pile cap is 200mm larger than the outer diameter of the pile body to be detected, and the height of the prefabricated pile cap is 400 mm;

s2: cutting the pile after the earthwork is excavated to the designed elevation, chiseling redundant pile head concrete to ensure that the pile head 20 is 300-350 mm higher than the designed elevation of the earthwork, and processing the pile head to be smooth;

s3: removing impurities around the pile head 20, pouring a concrete cushion layer 22, such as a C15 concrete cushion layer, above the soil body 21, wherein the thickness of the concrete cushion layer 22 is 100mm, the edge of the concrete cushion layer 22 exceeds the edge of the prefabricated pile cap by at least 100mm, controlling the surface flatness of the concrete cushion layer 22, and ensuring that the prefabricated pile cap can be horizontally placed;

s4: after a release agent is coated on the inner surface of the pile cap main body 10, the prefabricated pile cap is placed on the concrete cushion layer 22 by using the lifting lug 13 through a tower crane or other hoisting equipment, the relative position of the prefabricated pile cap and the pile head 20 is adjusted, for example, a mark is made in the center of the pile head 20 before hoisting, and the axis of the prefabricated pile cap 10 is ensured to be opposite to the axis of the pile head 20 by observing through the centering observation hole 18 during hoisting, so that the axis of the test pile is ensured to be pressed in the test process;

s5: sealing gaps between the pile cap main body 10 and the concrete cushion layer 22 by using foam sealing rubber 23;

s6: grouting material 16, such as CGM grouting material, is injected into the gap between the pile cap main body 10 and the pile head 20 by using the grouting joint 14, the side wall 12 of the pile cap main body 10 can be slightly knocked and vibrated during grouting, so that grouting compactness and no air bubbles are ensured, the grouting progress can be observed through the exhaust hole 17 and/or the centering observation hole 18, and grouting can be stopped when the grouting material 16 overflows from the exhaust hole 17 and the centering observation hole 18;

s7: after grouting is finished and the design strength is reached, detecting the bearing capacity of the pile body;

s8: after the detection is finished, the prefabricated pile cap is recovered, the next bearing capacity detection test can be carried out, and when the prefabricated pile cap is used, a single prefabricated pile cap can be reused for 5-10 times, so that the use cost is reduced.

The invention is suitable for pile bodies which have lower compressive property and are easy to damage, such as plain concrete piles, cement fly ash gravel piles (CFG piles), secondary-ash concrete piles and the like, and the prefabricated pile caps and the pile heads 20 are integrated after grouting so as to improve the compressive property of the pile heads and ensure that the pile heads 20 are not damaged in the test process. Of course, the invention is also applicable to other rigid pile bodies, such as reinforced concrete piles, prestressed pipe piles, large-diameter thin-wall tubular piles, steel pipe piles and the like.

In summary, the prefabricated pile cap for detecting the bearing capacity of the pile body and the construction method thereof provided by the invention comprise a pile cap main body 10, wherein the pile cap main body 10 is sleeved on a pile head 20 of the pile body to be detected, and the pile cap main body 10 comprises a top 11 and a side wall 12; lifting lugs 13 are respectively arranged on two sides of the side wall 12 of the pile cap main body 10, which are symmetrical relative to the central axis of the pile cap main body 10; two sides of the sidewall 12 of the pile cap body 10, which are symmetrical relative to the central axis of the pile cap body 10, are respectively provided with a grouting joint 14 for injecting grouting material 16 into a gap between the pile cap body 10 and the pile head 20; the top 11 of the pile cap main body 10 is provided with at least two exhaust holes 17; the top 11 of the pile cap main body 10 is also provided with a centering observation hole 18 at the center. The prefabricated pile cap provided by the invention has the advantages of simple structure, convenience in construction, capability of saving the construction period, reusability and easiness in popularization, and can greatly improve the success rate and the detection efficiency of bearing capacity detection.

It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.