A kind of stepped cast-in-place pile and construction method thereof

Abstract

The present application relates to the field of foundation construction, and in particular to a stepped cast-in-place pile and a construction method thereof. The stepped pile comprises a stepped hole, a reinforcement frame is placed in the stepped hole, a bottom support rod and a top docking rod are placed at the middle position of the reinforcement frame, the bottom support rod is vertically opposite to the top docking rod, a strain gauge is installed on the bottom support rod, the bottom of the top docking rod is docked with the top of the bottom support rod and then welded and fixed, and a protective cap for shielding the strain gauge is fixed at the bottom position of the top docking rod. During construction, concrete is poured through the pouring main channel, the concrete stays in the maintenance frame and wraps the strain gauge, and then the remaining large amount of concrete is poured into the stepped hole. The stepped pile has the advantages of not damaging the strain gauge during construction and ensuring the use effect of the strain gauge.

Description

Technical Field

[0001] The present application relates to the field of foundation technology, and in particular to a stepped cast-in-place pile and a construction method thereof. Background Art

[0002] Composite foundation refers to an artificial foundation in which part of the soil of a natural foundation is reinforced or replaced during the treatment process, or reinforcement materials are set in the natural foundation. The reinforcement area is composed of a matrix (natural foundation soil or improved natural foundation soil) and a reinforcement. Under the action of load, the matrix and the reinforcement jointly bear the load. According to the load transfer mechanism of the composite foundation, the composite foundation is divided into two categories: vertical reinforcement composite foundation and horizontal reinforcement composite foundation. The vertical reinforcement composite foundation is further divided into three types: bulk material pile composite foundation, flexible pile composite foundation and rigid pile composite foundation.

[0003] In the related art, stepped pile holes are often drilled in the foundation, a reinforcing frame is lowered into the stepped pile holes and concrete is poured to form stepped piles, thereby increasing the foundation reinforcement effect.

[0004] In the above-mentioned cast-in-place step piles, people also need to study the distribution characteristics of the pile axial force and pile side resistance under the upper load. This research process requires the detection of strain gauges built into the step piles. Strain gauges are generally placed inside the reinforcement frame in advance, and then concrete is poured. However, the impact force of pouring concrete can easily damage the strain gauge, resulting in damage to the monitoring function of the strain gauge. Summary of the invention

[0005] In order to avoid damaging the strain gauge during the step pile construction process and ensure the use effect of the strain gauge, the present application provides a stepped cast-in-place pile and a construction method thereof.

[0006] The above technical objectives of this application are achieved through the following technical solutions:

[0007] On the one hand, the present application provides a stepped cast-in-place pile, comprising a stepped hole opened on the ground, a reinforcing frame being placed in the stepped hole, a bottom support rod and a top docking rod being placed at the middle position of the reinforcing frame, the bottom support rod being vertically opposite to the top docking rod, a strain gauge being installed on the bottom support rod, the bottom of the top docking rod being docked with the top of the bottom support rod and then welded and fixed, and a protective cap for shielding the strain gauge is fixedly provided at the bottom position of the top docking rod.

[0008] Optionally, the upper surface of the protective cap is in a convex arc shape.

[0009] Optionally, a maintenance frame is provided at the top of the bottom support rod, the bottom of the maintenance frame is located below the strain gauge, and the strain gauge is covered on all sides of the maintenance frame.

[0010] Optionally, a main perfusion channel is opened in the middle of the top docking rod, two branch channels connected to the main perfusion channel are opened inside the protective cap, and a plurality of perfusion holes connected to the perfusion branch channels are opened at the bottom of the protective cap, and the bottoms of the perfusion holes face the inside of the maintenance frame.

[0011] Optionally, a diverter sleeve is provided at the bottom of the top docking rod, the diverter sleeve is located below the protective cap and fixed to the bottom of the top docking rod, and a surface of the diverter sleeve facing away from the center of the top docking rod is inclined away from the center from top to bottom.

[0012] Optionally, a receiving platform is provided at the bottom center of the reinforcing frame, and a receiving ring sleeve for plugging and cooperating with the bottom of the bottom support rod is provided at the top of the receiving platform.

[0013] On the other hand, the present application also provides a construction method of stepped cast-in-place piles, comprising the following construction steps:

[0014] S1. Dig a stepped hole of the required size on the ground;

[0015] S2. Weld the receiving platform and receiving ring sleeve at the bottom of the reinforcement frame in advance, and put the tied reinforcement frame into the stepped hole;

[0016] S3. Place the bottom support rod into the reinforcement frame and ensure that the bottom support rod is inserted into the receiving ring sleeve. The strain gauge and the maintenance frame surrounding the strain gauge are installed on the top of the bottom support rod in advance.

[0017] S4. Place the top docking rod into the reinforcement frame, dock the top docking rod with the bottom support rod, and weld and fix them at the docking position. A protective cap and a shunt sleeve are welded on the top docking rod in advance. The protective cap is located directly above the strain gauge, the shunt sleeve is located between the protective cap and the strain gauge, and the shunt sleeve is sleeved on the circumference of the top docking rod;

[0018] S5, pouring concrete through the main pouring channel, the concrete flows into the branch pouring channel along the main pouring channel, and finally stays in the maintenance frame and wraps the strain gauge;

[0019] S6. Continue pouring concrete into the stepped holes. The concrete will cover the reinforced frame to form stepped piles.

[0020] Optionally, after the construction of step S5 is completed, the construction can be continued after the concrete in the maintenance frame hardens for 10-30 minutes.

[0021] It can be known from the above technical scheme that before pouring a large amount of concrete into the reinforced skeleton, a small amount of concrete is poured in advance through the main pouring channel, and a small amount of concrete can enter the interior of the maintenance frame and cover the strain gauge, so that the strain gauge can be protected. After the concrete in the maintenance frame hardens, large-scale concrete pouring is carried out on the reinforced skeleton. During the pouring process, on the one hand, the protective cap can block and divert part of the concrete, and on the other hand, the strain gauge has been covered and protected. Therefore, during the entire pouring process, the impact force on the strain gauge is greatly reduced, thereby achieving the goal of not damaging the strain gauge during the step pile construction process and ensuring the use effect of the strain gauge.

[0022] In summary, this application has the following technical effects:

[0023] 1. By setting a protective cap on the top docking rod to shield the falling concrete, the strain gauge can be shielded and protected during the concrete pouring process to prevent the strain gauge from being damaged by the impact force of a large amount of concrete;

[0024] 2. Before pouring a large amount of concrete into the reinforced frame, a small amount of concrete is injected into the maintenance frame through the main pouring channel and the branch pouring channel in advance, so that a small amount of concrete first wraps the strain gauge to form a secondary protection, thereby further reducing the impact damage to the strain gauge during the subsequent pouring of a large amount of concrete;

[0025] 3. By setting the top of the protective cap as a raised arc structure, during the concrete pouring process, the concrete can smoothly fill the entire pouring hole and will not accumulate too much on the top of the protective cap, thereby ensuring the overall quality of the bored pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure after the step pile construction of the present application;

[0027] Figure 2 It is a partial schematic diagram of the docking position of the top docking rod and the bottom support rod in the embodiment of the present application;

[0028] Figure 3 This is a schematic diagram after the reinforcement frame is lowered into the stepped hole;

[0029] Figure 4 This is a schematic diagram after the bottom support rod is installed;

[0030] Figure 5 This is a schematic diagram after the top support rod is installed.

[0031] In the figure, 1. stepped hole; 2. reinforcing frame; 21. receiving platform; 22. receiving ring sleeve; 3. bottom support rod; 31. maintenance frame; 4. top docking rod; 41. protective cap; 411. main perfusion channel; 412. branch perfusion channel; 413. perfusion hole; 42. diversion sleeve; 5. strain gauge. DETAILED DESCRIPTION

[0032] The present application is further described in detail below in conjunction with the accompanying drawings.

[0033] Reference Figure 1 The present application provides a stepped cast-in-place pile, comprising a stepped hole 1 opened at a corresponding position on the ground, wherein the aperture size of the stepped hole 1 decreases from top to bottom like a multi-step pile, and a reinforcing frame 2 is placed in the stepped hole 1. In order to adapt to the shrinking shape of the stepped hole 1, the overall cross-sectional size of the reinforcing frame 2 is also gradually reduced from top to bottom, so as to fill the stepped hole 1 as much as possible and enhance the strength of the concrete after pouring.

[0034] A receiving platform 21 is provided at the bottom center of the reinforcement frame 2. Specifically, the receiving platform 21 is formed by welding a steel plate or a steel bar directly to the reinforcement frame 2. The upper surface of the receiving platform 21 is horizontal. A receiving ring sleeve 22 is welded at the edge of the upper surface of the receiving platform 21. The cross-sectional shape of the receiving ring sleeve 22 is an inverted triangle. The purpose of the inverted triangle is that after concrete is poured into the stepped hole 1, the receiving platform 21 can have a larger contact area with the concrete, and the side surface can be more strongly extruded and coated, thereby improving stability.

[0035] A bottom support rod 3 and a top docking rod 4 are provided inside the reinforcing frame 2. Specifically, the bottom end of the bottom support rod 3 is inserted into the receiving ring sleeve 22 and forms an interference fit with the receiving ring sleeve 22, thereby ensuring the stable vertical state of the bottom support rod 3. A strain gauge 5 is fixedly provided at a position close to the top of the bottom support rod 3. The connection method between the strain gauge 5 and the bottom support rod 3 can be determined according to actual conditions, such as welding the bottom support rod 3 to the frame of the strain gauge 5, or directly tying the strain gauge 5 to the surface of the support rod, or opening a transverse hole on the bottom support rod 3 and directly inserting the strain gauge 5 into the transverse hole.

[0036] A maintenance frame 31 is provided near the top of the bottom support rod 3. The bottom support rod 3 vertically passes through the maintenance frame 31 and is welded and fixed to the maintenance frame 31. The strain gauge 5 is located inside the space surrounded by the maintenance frame 31, and the top of the maintenance frame 31 is not lower than the upper surface of the strain gauge 5. In this embodiment, the top of the maintenance frame 31 is set higher than the upper surface of the strain gauge 5. The inner side surface of the maintenance frame 31 is an inclined slope, and its inclination direction is from top to bottom toward the center of the bottom of the maintenance frame 31.

[0037] The top docking rod 4 is located directly above the top support rod, and the two are welded and fixed at the docking point. The welding method adopts multi-point welding, which is easy to operate and firmly welded. The top docking rod 4 is welded and fixed with a protective cap 41 at a position close to its bottom. The top surface of the protective cap 41 is a raised arc shape and the bottom surface is a flat structure. The protective cap 41 faces the maintenance frame 31. In the process of pouring concrete into the stepped hole 1, the protective cap 41 plays a role of shielding and guiding diversion, so that the strain gauge 5 will not be subjected to the high-intensity impact of the concrete, thereby improving the protection of the strain gauge 5.

[0038] Recombination Figure 2 It can be seen that a vertical main perfusion channel 411 is opened inside the top docking rod 4, and the main perfusion channel 411 extends all the way to the inside of the protective cap 41. Two perfusion branch channels 412 separated from each other at the bottom are opened inside the protective cap 41. The perfusion branch channels 412 are connected to the main perfusion channel 411, and a plurality of connected perfusion holes 413 are provided at the bottom of the perfusion branch channels 412. The perfusion holes 413 are directly opposite to the inside of the maintenance frame 31.

[0039] A diverter sleeve 42 is provided below the protective cap 41 , and the diverter sleeve 42 is sleeved around the top docking rod 4 and fixed by welding. The side of the diverter sleeve 42 is inclined, and the inclination direction is gradually away from the central axis of the top docking rod 4 from top to bottom.

[0040] Before pouring concrete over a large area of ​​the stepped hole 1, a proper amount of concrete is first poured into the main pouring channel 411. The poured concrete passes through the main pouring channel 411, the branch pouring channel 412 and the pouring hole 413 and enters the interior of the maintenance frame 31, and finally covers the strain gauge 5. During the pouring process, the impact force on the strain gauge 5 is small due to the small amount of concrete poured. At the same time, the diversion sleeve 42 can divert the poured concrete to both sides, further protecting the strain gauge 5. After the concrete in the maintenance frame 31 is hardened, the remaining concrete is continued to be poured into the reinforcement frame 2, which can not only protect the strain gauge 5, but also ensure the overall molding quality of the cast-in-place pile.

[0041] The present application also discloses a construction method of a stepped cast-in-place pile, Figures 2 to 5 , including the following steps:

[0042] S1, dig a stepped hole 1 of the required size on the ground;

[0043] S2, welding the receiving platform 21 and the receiving ring 22 at the bottom of the reinforcing frame 2 in advance, and placing the tied reinforcing frame 2 into the stepped hole 1;

[0044] S3, install the strain gauge 5 and the maintenance frame 31 on the bottom support rod 3 in advance, and install the protective cap 41 and the diversion sleeve 42 on the top docking rod 4 in advance;

[0045] S4, placing the bottom support rod 3 into the reinforcement frame 2, and ensuring that the bottom support rod 3 is inserted into the receiving ring sleeve 22;

[0046] S5, placing the top docking rod 4 into the reinforcement frame 2, docking the top docking rod 4 with the bottom support rod 3, and welding and fixing them at the docking position;

[0047] S6, pouring concrete through the main pouring channel 411, the concrete flows along the main pouring channel 411 into the branch pouring channel 412, and finally stays in the maintenance frame 31 and wraps the strain gauge 5;

[0048] S7, let it stand for 10-30 minutes until the concrete in the maintenance frame 31 hardens;

[0049] S8. Continue pouring concrete into the stepped hole 1, and the concrete covers the reinforced skeleton 2 to form a stepped pile.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A stepped cast-in-place pile, comprising a stepped hole (1) opened on the ground, characterized in that: A reinforcing frame (2) is placed in the stepped hole (1), a bottom support rod (3) and a top docking rod (4) are placed at the middle position of the reinforcing frame (2), the bottom support rod (3) and the top docking rod (4) are vertically opposite to each other, a strain gauge (5) is installed on the bottom support rod (3), the bottom of the top docking rod (4) is docked with the top of the bottom support rod (3) and then welded and fixed, and a protective cap (41) for shielding the strain gauge (5) is fixedly arranged at the bottom position of the top docking rod (4); the top of the bottom support rod (3) is A maintenance frame (31) is provided at the top position, the bottom of the maintenance frame (31) is located below the strain gauge (5), and the maintenance frame (31) surrounds the strain gauge (5); a main perfusion channel (411) is provided in the middle of the top docking rod (4), two branch channels connected to the main perfusion channel (411) are provided inside the protective cap (41), a plurality of perfusion holes (413) connected to the perfusion branch channels (412) are provided at the bottom of the protective cap (41), and the bottoms of the perfusion holes (413) face the inside of the maintenance frame (31).

2. A stepped cast-in-place pile according to claim 1, characterized in that: The upper surface of the protective cap (41) is in a convex arc shape.

3. A stepped cast-in-place pile according to claim 2, characterized in that: A flow distribution sleeve (42) is arranged at the bottom of the top docking rod (4), the flow distribution sleeve (42) is located below the protective cap (41) and is fixed to the bottom of the top docking rod (4), and a side surface of the flow distribution sleeve (42) away from the center of the top docking rod (4) is arranged to be inclined away from the center from top to bottom.

4. The stepped cast-in-place pile according to claim 1, characterized in that: A receiving platform (21) is arranged at the center of the bottom of the reinforcing frame (2), and a receiving ring sleeve (22) for plugging and matching with the bottom of the bottom support rod (3) is arranged at the top of the receiving platform (21).

5. A construction method for stepped cast-in-place piles, characterized in that: The construction steps include: S1, digging a stepped hole (1) of a required size on the ground; S2, welding a receiving platform (21) and a receiving ring (22) at the bottom of the reinforcing frame (2) in advance, and placing the tied reinforcing frame (2) into the stepped hole (1); S3, placing the bottom support rod (3) into the reinforcement frame (2), and ensuring that the bottom support rod (3) is inserted into the receiving ring sleeve (22), and the strain gauge (5) and the maintenance frame (31) surrounding the strain gauge (5) are installed in advance on the top of the bottom support rod (3); S4, placing the top docking rod (4) into the reinforcement frame (2), docking the top docking rod (4) with the bottom support rod (3), and welding and fixing them at the docking position, a protective cap (41) and a flow diversion sleeve (42) are welded in advance on the top docking rod (4), the protective cap (41) is located directly above the strain gauge (5), the flow diversion sleeve (42) is located between the protective cap (41) and the strain gauge (5), and the flow diversion sleeve (42) is sleeved on the circumference of the top docking rod (4); S5, pouring concrete through the main pouring channel (411), the concrete flows along the main pouring channel (411) into the branch pouring channel (412), and finally stays in the maintenance frame (31) and wraps the strain gauge (5); S6. Continue pouring concrete into the stepped hole (1), so that the concrete covers the reinforcement frame (2) to form a stepped pile.

6. A step-type cast-in-place pile construction method according to claim 5, characterized in that: After the construction in step S5 is completed, the construction is continued after the concrete in the maintenance frame (31) hardens for 10-30 minutes.

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