CN106968252B - Pile pulling recharging method and pile pulling recharging system - Google Patents

Abstract

The invention relates to a method for pulling out piles and refilling and a system for pulling out piles and refilling, belonging to the technical field of pile removal in water conservancy, highway, railway, municipal, bridge and other projects. The method for refilling the extracted piles includes the following steps: 1) exposing the top of the piles to be pulled out after pretreatment; 2) drilling anchor holes and grouting holes for the piles on the top of the piles to be pulled out; 3) placing one end of the anchor cable material Lower it to the bottom of the anchor hole, and its other end exposes the top of the pile to be pulled out; 4) Pour the first slurry into the anchor hole, and fix the anchor cable material in the pile to be pulled out to form an anchor rod; 5) Lift the anchor cable material by lifting equipment. The other end is used to pull up the pile to be pulled. During the process of pulling the pile, the second slurry is refilled through the grouting hole of the pile body, so that the second slurry penetrates into the soil around the pile at the bottom of the pile to be pulled, and the soil body and the to-be-pulled pile are separated. The piles are connected as a whole. The pile-pulling refilling method and the pile-pulling refilling system can quickly and safely pull out the piles, thereby reducing the lifting force, preventing landslides, improving the success rate, and protecting the stability of the underground structures of surrounding buildings.

Description

Pull-out pile re-injection method and pull-out pile re-injection system

technical field

The invention relates to a method for pulling out piles and refilling and a system for pulling out piles and refilling, belonging to the technical field of pile removal in water conservancy, highway, railway, municipal, bridge and other projects.

Background technique

In the shield construction of the existing subway tunnels, it is necessary to raise the whole pile affecting the tunnel construction to a safe height, and the whole pile affecting the tunnel construction is about to be completely or partially pulled out.

However, according to the applicant's knowledge, the existing domestic and foreign pile pulling technology mainly adopts the following methods:

1) Impact crushing method and full casing wear reduction and extraction method; these two pile extraction techniques mainly rely on full casing drilling rigs and large cranes, so they have higher requirements on the construction site, the construction site area is large, and there is no clear height limit on the upper part of the site. However, the actual construction environment is difficult to achieve.

2) The method of full casing static pressure pile pulling, this method uses steel casing and combined with jetting high-pressure water and high-pressure bentonite slurry to remove the surrounding soil of the pile, and then pulls the pile, but the process is more complicated and the actual length is longer. , especially for the extraction of multiple piles that are in close proximity to each other.

3) Directly connect the pile head steel bar in the cast-in-place pile with the pulling pile, and gradually apply force until the pile is pulled out. However, the steel bars in the existing cast-in-place pile have low strength, unreliable welding, and uneven stress, which is easy to pour out the cast-in-place pile. The pile is pulled off, which is not allowed in the construction of pulling piles.

At the same time, according to the applicant's knowledge, during the process of pulling out the pile, a cavity replaced by a water body will be formed at the bottom of the pile, and the loose soil around the cavity is very easy to collapse, destroying the function of the pile and easily adversely affecting the surrounding buildings. The recharge with piles is carried out after the piles are pulled out.

It can be seen that in the existing pile pulling technology, the equipment requirements are high, the land occupation is large, and the risk of using a large crane is high. Fast and safe pile pulling is still a difficult problem, especially for large-diameter piles in a small space. At the same time, the recharge of the existing piles cannot guarantee the function of the original piles, and cannot protect the stability of the underground structure of the surrounding buildings.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to propose a method and a system for pulling out and refilling piles that can quickly and safely pull out piles of different diameters while ensuring the function of the piles.

One of the technical solutions proposed by the present invention to solve the above-mentioned technical problems is: a method for pulling out piles and refilling, comprising the following steps:

1) Expose the top of the pile to be pulled out after pretreatment, and equip multiple high-strength anchor cable materials and lifting equipment at the same time;

2) An anchor hole extending toward the bottom of the pile to be pulled is drilled at the top of the pile to be pulled, and a pile grouting hole penetrating the top and bottom surfaces of the pile to be pulled is drilled;

3) Lower one end of the anchor cable material to the bottom of the anchor hole, and the other end of the anchor material exposes the top of the pile to be pulled;

4) pouring the first slurry into the anchor hole, and after the first slurry is solidified and reaches the set strength, the anchor cable material is fixed in the to-be-pulled pile to form an anchor rod;

5) Lift the other end of the anchor cable material by lifting equipment to pull up the pile to be pulled out. During the process of pulling up the pile to be pulled out, refill the second slurry through the grouting hole of the pile body, so that the second slurry penetrates into the to-be-pulled pile. Pull out the soil around the pile at the bottom of the pile, and connect the soil with the pile to be pulled out as a whole.

The second technical solution proposed by the present invention to solve the above-mentioned technical problems is: a pile-pulling refilling system, which is used in the above-mentioned pulling-pile refilling method, and the pile-pulling refilling system is arranged in the soil body and is fixed in the soil body and the top is exposed. The vicinity of the to-be-pulled pile, including a plurality of high-strength anchor cable materials and lifting equipment, is characterized in that: the top of the to-be-pulled pile is provided with anchor holes extending toward the bottom of the to-be-pulled pile, and the to-be-pulled pile is made on the top. There are pile grouting holes penetrating the top surface and bottom surface of the pile body, one end of the anchor cable material is set at the bottom of the anchor hole, and the other end of the anchor cable material is exposed at the top of the pile to be pulled out; the anchor hole is filled with solidified After that, it is used to fix the anchor cable material in the pile to be pulled out to form the first slurry of the anchor rod. The lifting device is used to lift the other end of the anchor cable material to pull up the pile to be pulled out. The pile body is grouted. The holes are used to refill the second grout during pile extraction.

The invention directly drills an anchor hole extending to the bottom of the pile to be pulled at the top of the pile to be pulled, drills a pile grouting hole through the top surface and the bottom surface of the pile to be pulled, and then drills one end of the anchor cable material. It is lowered to the bottom of the anchor hole, the other end of which is exposed to the top of the pile to be pulled out, the first slurry is poured into the anchor hole, the anchor cable material is fixed in the pile to be pulled out to form an anchor rod, and finally the anchor cable is lifted by lifting equipment The other end of the material is used to pull up the pile to be pulled out. During the process of pulling up the pile to be pulled out, the second slurry is refilled through the grouting hole of the pile body, which has the following effects:

1) The anchor rod in the existing geotechnical anchoring technology is skillfully transferred to the pulling pile. Compared with the traditional thinking of pulling the pile, the surface of the pile is fixed and lifting and pulling. The present invention breaks through this. The mindset is that when the piles are pulled out, they are first drilled for anchoring and then pulled out, which is very unexpected.

The invention can not only carry out anchoring and lifting for different diameters (large, medium and small) piles to be pulled out, but also reinforce the pulled piles, which can effectively prevent the broken piles in the pulled piles and quickly and safely pull out the large-diameter piles, especially It is very suitable for the removal of multiple piles that are close to each other in a small space. The whole is very reliable and stable, the safety is greatly improved, and a lot of cost is saved, and the efficiency is improved.

2) By drilling the pile grouting holes through the top and bottom surfaces of the pile to be pulled out, in the process of pulling up the pile to be pulled, the second slurry is refilled through the grouting hole of the pile to ensure the structural safety of the pile. , to protect the stability of the underground structure of surrounding buildings and prevent landslides. At the same time, it can balance the internal and external atmospheric pressure, reduce the lifting force and improve the success rate. It is particularly important that when only the construction requirements of pulling out the pile are required, in the process of pulling the pile, the second slurry is refilled through the grouting hole of the pile body, so that the second slurry can penetrate into the surrounding soil of the pile at the bottom of the pile to be pulled out. The soil body is connected with the pile to be pulled out as a whole, so that the remaining piles that are not completely pulled out can still be used.

The improvement of one of the above technical solutions is: in the step 2), a static blasting hole extending toward the bottom of the pile to be pulled is drilled at the top; in the step 5), the After pulling up the pile at the other end of the anchor cable material, first pour the crushing agent into the static blasting hole and block the orifice of the static blasting hole with fast-hardening cement for 12-18 hours, and then use the crushing equipment to break the pile body.

The effect of adopting the above technical scheme in the present invention is: by drilling a static blasting hole extending to the bottom of the pile to be pulled out, after the other end of the anchor cable material is lifted by the lifting device to pull up the pile, the static blasting hole is first Pour the crushing agent into the hole and block the orifice of the static blasting hole with fast-hardening cement for 12-18 hours, and then use the crushing equipment to break the pile body. Combined with concrete cutting and gas cutting steel bars, the concrete can be quickly decomposed and the pile is broken. The upper part is removed, and the pile pulling project is smoothly transferred to the next process and the next pile.

One of the improvement of one of the above-mentioned technical solutions is: in the step 1), a working platform is provided on other piles near the pile to be pulled or the soil around the pile to be pulled; in the step 5) Among them, the lifting equipment is a center-through jack, a hoist or a hoist set on the working platform, and the through-core jack, crane or winch continuously stretches the other end of the anchor cable material to continuously pull up the pile to be pulled out .

The effect of adopting the above technical scheme in the present invention is: the present invention provides a working platform on other piles near the pile to be pulled or on the soil body around the pile to be pulled, and the lifting equipment adopts the through-core jack, hoisting jack, etc. In this way, the other end of the anchor cable material can be continuously tensioned by the through-core jack, crane or hoist, and the pile can be pulled up continuously, and the overall structure is simple and reliable.

One of the improvements of one of the above-mentioned technical solutions is: the working platform is a reinforced concrete platform, a steel structure frame platform or a composite structure platform; on a platform or a combined structure platform; the crane or hoist is arranged on a reinforced concrete platform, a steel structure frame platform or a combined structure platform.

The effect of adopting the above technical solutions in the present invention is: the present invention can continuously pull up the piles whose heads are located above the ground or below the ground as a whole by setting up a reinforced concrete platform, a steel structure frame platform or a composite structure platform, and the overall structure is simple. reliable.

One of the improvements of one of the above technical solutions is that: the working platform is a caisson platform, and the through-core jack is fixed on the caisson platform.

The effect of adopting the above technical solutions in the present invention is that the present invention is particularly suitable for the piles located below the surface of the earth to be continuously pulled up by setting the caisson platform, and the overall structure is simple and reliable.

The second improvement of one of the above technical solutions is: the depth of the anchor hole and the length of the anchor rod are less than the length of the pile to be pulled out and greater than the minimum anchoring length of the anchor rod, and the minimum anchoring length L of the anchor rod. Calculate as follows:

In the formula, a is the safety factor; σ is the strength of the anchor cable material; A is the cross-sectional area of the anchor cable material; d is the diameter of the anchor hole; τ is the shear strength of the anchor rod and the hole wall.

The third improvement of one of the above technical solutions is: the anchor cable material is provided with three grouting pipes whose outlets are located at the bottom, middle and upper parts of the anchor hole; pressure grouting is used to pour the first slurry into the anchor hole, and the The first slurry is a slurry formed by mixing PO52.5 cement, cement slurry pore grouting agent and water, and the water-to-binder ratio of the first slurry is 0.35 to 0.45; a mortar mixer and a grouting pump are used to carry out pressure grout.

The second improvement of the above technical solution is: the top of the pile to be pulled is provided with a static blasting hole extending toward the bottom of the pile to be pulled; the static blasting hole is filled with a crushing agent and blocked with fast-hardening cement blocks. .

The improvement of the second technical solution above is that a working platform is provided on other piles near the piles to be pulled out or on the soil around the piles to be pulled out.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings:

FIG. 1 is a schematic diagram of the pile pulling device adopted in the method for pulling out the pile and refilling the refilling system according to the first embodiment of the present invention.

FIG. 2 is a left side view of FIG. 1 .

FIG. 3 is a schematic diagram of the anchor hole, the pile grouting hole and the static blasting hole drilled on the pile to be pulled in FIG. 1 .

Detailed ways

Example 1

As shown in Figure 1, Figure 2 and Figure 3, the method for pulling out piles and refilling in this embodiment includes the following steps:

1) After pretreatment, the top of the pile 1 to be pulled out is exposed, and at the same time, multiple high-strength anchor cable materials 2 and lifting equipment are installed.

The pile 1 to be pulled out in this embodiment is a friction pile buried in the soil, a partial rock-socketed end bearing pile, or an occlusal pile, a cap pile and a driven pile buried at a certain depth below the surface, a friction pile or an end bearing pile The head of the pile is exposed to the surface.

The anchor cable material 2 in this embodiment can be made of metal hard or soft material. Made of hard metal, such as: bonded strands, prestressed strands, prestressed strands, high-strength steel wires, high-strength steel wire ropes or high-strength steel bars, etc.; also can be made of non-metallic hard or soft materials , for example: fiber, plastic or nylon, etc.

2) An anchor hole 1-1 extending toward the bottom of the pile to be pulled is drilled at the top of the pile 1 to be pulled, and a pile grouting hole 1-2 is drilled on the pile 1 to be pulled through its top and bottom surfaces. The anchor hole 1-1 in this embodiment is one anchor hole located at the center of the cross section of the pile 1 to be pulled or at least two anchor holes evenly distributed along the center circumference of the cross section of the pile 1 to be pulled.

The anchor hole 1-1 in this embodiment is drilled by a crawler drilling rig D150, with a single power of 75kW; and a 15m3, 1.3MPa air compressor with a power of 135kW. The working efficiency is 60m/8hr. After drilling the hole, use clean water to clean the dry slurry and drain the free water. Before lowering the anchor cable material 2, use a plug to block the hole to prevent foreign matter from entering the hole. If the pile to be pulled is still used as an engineering pile, in order to avoid damage to the pile by the crawler drilling rig, a geological drilling rig can be used to drill. If the top surface of the pile 1 to be pulled is below the ground surface, the center and diameter of the pile can be determined through investigation, and the anchor hole 1-1 and the grouting hole 1-2 of the pile body can be drilled by the casing method.

3) Lower one end of the anchor cable material 2 to the bottom of the anchor hole 1-1, and the other end exposes the top of the pile 1 to be pulled out, or lower it to the anchor of the anchor hole in the occlusal pile, the cap pile or the driven pile, etc. The other end of the cable material 2 is exposed to the ground.

4) Pour the first slurry into the anchor hole 1-1, and after the first slurry is solidified and reaches the set strength, the anchor cable material 2 is fixed in the pile to be pulled 1 to form an anchor rod;

The depth of the anchor hole 1-1 and the length of the anchor rod in this embodiment are less than the length of the pile to be pulled 1 and greater than the minimum anchoring length of the anchor rod. The minimum anchoring length L of the anchor rod is calculated as follows:

In the formula, a is the safety factor; σ is the strength of the anchor cable material; A is the cross-sectional area of the anchor cable material; d is the diameter of the anchor hole; τ is the shear strength of the anchor rod and the hole wall.

5) Before pulling up, a large amount of water can be poured to soften the pile bottom of the pulling pile 1, balance the internal and external atmospheric pressure, etc., and then lift the other end of the anchor cable material 2 through the lifting equipment to pull up the pile 1 to be pulled out. In the process of lifting the pile 1 to be pulled out (in this embodiment, after the obvious vertical displacement is generated from pulling up, it can be set to 10 cm, of course, it can also be set to other sizes), refill the second slurry through the grouting holes 1-2 of the pile body , so that the second slurry penetrates into the soil around the pile at the bottom of the pile 1 to be pulled, and connects the soil body with the pile 1 to be pulled as a whole.

The curtain grouting method can be applied to the recharge of the pile to improve the quality of the recharge; for the situation where the soil around the pile to be pulled 1 has poor stability and is close to the surrounding buildings, it can be used while pulling while grouting, or even double-slurry liquid-solid. Knot grouting.

For multiple piles adjacent to the pile to be pulled 1, in order to avoid connecting the adjacent piles during the grouting process, which affects the pulling-up of the next pile, it is necessary to cast the same pile with the same pile.

In order to avoid the pulling up of the surrounding piles by the refilling, the cementitious material with extremely low tensile and shear strength can be refilled, which only plays the role of filling.

Commercial mortar is used for refilling with a pump truck. For the grouting hole, an air outlet and water outlet pipe can be placed to the bottom of the pile, and the top of the pile can be quickly grouted through a funnel. Realize fast and reliable grouting of the pile bottom.

In step 1) of this embodiment, a working platform 3 is provided on other piles near the pile 1 to be pulled or the soil around the pile to be pulled; the working platform 3 can be a reinforced concrete platform, a steel structure frame platform or a combination of Structural platform, can also be a caisson platform, and so on.

In order to quickly decompose the concrete and realize the removal of the upper pile body of the pile to be pulled 1, the pile pulling project will be smoothly transferred to the next process and the next pile:

In this embodiment, in step 2), static blasting holes 1-3 extending toward the bottom of the pile 1 to be pulled are drilled at the top.

In this embodiment, in step 5), after the other end of the anchor cable material 2 is lifted by the hoisting equipment to pull up the pile, the crushing agent is poured into the static blasting holes 1-3 and the static blasting hole 1 is blocked with fast-hardening cement -3 orifice for 12-18 hours, and then the pile body is crushed by crushing equipment.

The static blasting holes 1-3 are drilled in advance at the parts to be blasted, and are distributed in a "cross" shape. The crushing agent adopts SCA-2 type (silent crushing agent), which is suitable for the environment of 10-25 °C. It is prepared according to 5 kg of crushing agent per bag and 1.5 liters of water. After stirring, it is ensured that the crushing agent is completely dissolved in the water to form a slurry. The slurry must be poured into the static blasting hole 1-3 within 10-15 minutes after stirring, and filled to 15mm away from the orifice, pour the slurry into the hole and stir in the hole to ensure that there is no air hole in the drilled hole; After filling, plug the orifice with fast-hardening cement; the effect can be achieved after 12-18 hours.

In order to simply and reliably pull up the pile 1 continuously, in step 5) in this embodiment, the lifting device is the through-center jack 5 arranged on the working platform 3, and the through-center jack 5 is installed and fixed on the reinforced concrete through the reaction force frame 4 On the platform, steel structure frame platform or composite structure platform; when it is necessary to pull out the piles located below the surface as a whole, the through-core jack 5 is fixed on the caisson platform, and so on. The piercing jack 5 continuously tensions the other end of the anchor cable material 2 to continuously pull up the pile 1 to be pulled out.

In order to ensure the grouting is dense, the anchor cable material 2 in this embodiment is provided with three grouting pipes whose outlets are located at the bottom, middle and top of the anchor hole 1-1 respectively; pressure grouting is used to pour the first grout into the anchor hole 1-1 , the first slurry is a slurry composed of PO52.5 cement, cement slurry grouting agent and water, and the water-to-binder ratio of the first slurry is 0.35 to 0.45; a mortar mixer and a grouting pump are used for pressure grouting . Before grouting, the mortar block production test can be carried out to ensure that the 3d strength of the test block reaches 25MPa, and the 10d strength reaches 30MPa. Of course, a normal grouting pipe can also be used, and the first slurry can also be mortar or sand, and so on.

Pressure grouting (priming the first grout) is carried out using a mortar mixer and a grouting pump. The first grout is grouted from the bottom upwards. When grouting to the last grouting pipe, open the last grouting pipe until it reaches the design position. Three groups of cement slurry test blocks were made for each grouting, and mortar blocks were used. After 3d and 7d, the test blocks were pressed, and they could be upgraded after the strength was reached.

As shown in Fig. 1, Fig. 2 and Fig. 3, the pile-pulling refilling system of the present embodiment is used in the above-mentioned pulling-pile refilling method. The vicinity of the pile 1 to be pulled out includes a plurality of high-strength anchor cable materials 2 and lifting equipment.

The to-be-pulled pile 1 of the pulling-pile-refilling system of the present embodiment is also a friction pile buried in the soil, a partially rock-socketed end bearing pile, or an occlusal pile, a cap pile and a driven pile buried at a certain depth below the surface. , the head of the friction pile or end bearing pile is exposed to the surface.

The anchor cable material 2 of the pile-pulling and refilling system in this embodiment can also be made of metal hard or soft materials, such as: bonded steel strands, prestressed steel strands, prestressed steel strands, high-strength steel wires, High-strength steel wire rope or high-strength steel bar, etc.; it can also be made of non-metallic hard or soft materials, such as fiber, plastic or nylon, etc.

The top of the pile to be pulled 1 is formed with an anchor hole 1-1 extending toward the bottom of the pile to be pulled, the pile 1 to be pulled is formed with a pile grouting hole 1-2 penetrating its top surface and bottom surface, and the anchor cable material 2 One end is set at the bottom of the anchor hole 1-1, and the other end of the anchor cable material 2 is exposed at the top of the pile 1 to be pulled out; the anchor hole 1-1 in this embodiment is an anchor hole located in the center of the cross section of the pile 1 to be pulled out or along the At least two anchor holes are evenly distributed around the center of the cross section of the pulling pile 1 .

The anchor hole 1-1 is filled with the first slurry that is used to fix the anchor cable material 2 in the pile 1 to be pulled to form the anchor rod after curing, and the lifting device is used to lift the other end of the anchor cable material 2 to pull up the to-be-pulled pile. Pulling the pile 1, the grouting hole 1-2 of the pile body is used to refill the second slurry during the pulling of the pile.

The depth of the anchor hole 1-1 and the length of the anchor rod of the pull-out pile reinjection system of the present embodiment are also smaller than the length of the pile to be pulled 1 and greater than the minimum anchoring length of the anchor rod. The minimum anchoring length L of the anchor rod is calculated by the following formula :

In the formula, a is the safety factor; σ is the strength of the anchor cable material; A is the cross-sectional area of the anchor cable material; d is the diameter of the anchor hole; τ is the shear strength of the anchor rod and the hole wall.

The top of the pile 1 to be pulled in this embodiment is provided with static blasting holes 1-3 extending toward the bottom of the pile to be pulled; the static blasting holes 1-3 are filled with a crushing agent and blocked with fast-hardening cement blocks.

In this embodiment, a working platform 3 is provided on other piles near the pile 1 to be pulled out or on the soil body around the pile 1 to be pulled out. The hoisting equipment is a piercing jack 5 provided on the working platform 3, and the working platform 3 is a reinforced concrete platform, a steel structure frame platform, a composite structure platform or a caisson platform, and so on.

The through-core jack 5 is installed and fixed on the reinforced concrete platform, the steel structure frame platform or the combined structure platform through the reaction force frame 4 . When it is necessary to pull out the pile which is entirely below the surface, the through-core jack 5 is fixed on the caisson platform, and so on. The through-core jack 5 is used to continuously tension the other end of the anchor cable material 2 to continuously pull up the pile 1 to be pulled out.

The anchor cable material 2 of the pile pulling and refilling system in this embodiment is also provided with three grouting pipes whose outlets are located at the bottom, the middle and the upper part of the anchor hole 1-1 respectively.

Embodiment 2

The method for pulling out piles and refilling in the present embodiment is an improvement on the basis of Embodiment 1, and the difference from Embodiment 1 is:

The total length of the pile to be pulled 1 to be lifted in this embodiment is 24m, the diameter of the pile is 1500mm, and the height of the pile to be lifted is 7-8m, accounting for 30% of the total length of the pile to be pulled 1 24m. After calculation, the design load of pile pulling force is 8000kN, and the check load is 10000kN.

In this way, the anchor cable material 2 adopts 4 bundles of CPS15A-12 shear force dispersion anchor cables. Each bundle of CPS15A-14 shear-distributed anchor cables adopts 14-φ15.24 high-strength, low-relaxation steel strands with a tensile strength of 1860MPa.

The hoisting equipment in this embodiment still adopts the through-center jacks 5, and four sets of 4000kN through-center jacks 5 are selected as the lifting power equipment. Considering the efficiency of 0.8, the total lifting capacity reaches 12800kN.

Before setting out the line, firstly prepare the position of the reaction force frame 4 on the floor, and then determine the position of the anchor hole 1-1 according to the position of the reaction force frame 4 that can be laid out. The anchor holes 1-1 in this embodiment are four anchor holes whose centers are distributed at the four corners of a square with a side length of 60cm. The hole diameter of the anchor holes 1-1 is 150mm. The side lengths of the square are parallel and perpendicular to the reaction frame beam respectively. .

Since the pile circumference is affected by the connection of the retaining wall and the canal wall, the crawler drilling rig D150 can be used to eliminate the connection through drilling. When the connection is eliminated, the drilling range should be appropriately enlarged and deepened to prevent large reaming and collapsing in the range below the strong connection. The strong connection elimination selection is performed at the same time as the anchor hole 1-1.

The friction between the pile circumference and the soil layer is partially eliminated by drilling a certain number of holes around the pile and properly flushing the pile to eliminate the friction around the pile. The bottom diameter of the hole is 50 PVC flower tube, on the one hand to prevent the hole from collapsing, on the other hand, when the second slurry is refilled through the pile grouting hole 1-2, the water body at the bottom of the pile grouting hole passes from the pile to the bottom of the pile grouting hole. The top hole overflows; the second slurry penetrates into the soil around the pile at the bottom of the pile 1 to be pulled, connects the soil body with the pile 1 to be pulled as a whole, strengthens the soil around the pile, and restores the function of the pile 1 to be pulled.

The timing and pressure of recharge can be determined based on the observation of building settlement. For the safety of the building, the refilling should be done sooner rather than later, and the adjacent piles have a compacting effect, so it should be sooner rather than later. If the recharge pressure is too large, it is easy to cause the surrounding buildings to rise. This time the resistance range is relatively small, and the low pressure recharge not exceeding 1MPa is used.

The pile pulling is divided into the following stages. The estimated lifting force is divided into 10 levels, each level is observed for 10 minutes, and the data is measured every minute, and the relationship between the displacement of the pile top with time and the change with the load is analyzed. Simultaneously monitor surface settlement displacement, structural stress and deformation. The estimated lifting force is 8000kN, and the specific load classification is 800kN, 1600kN, 2400kN, until the starting load. Embodiment 3

The method for pulling out piles and refilling in this embodiment is an improvement on the basis of Embodiments 1 and 2. The difference from the above-mentioned embodiment is that in this embodiment, in step 5), the hoisting equipment adopts a working The crane or hoist on the platform 3 continuously stretches the other end of the anchor cable material 2 to continuously pull up the pile 1 to be pulled. The crane or hoist is installed on the reinforced concrete platform, the steel structure frame platform or the combined structure platform.

The present invention is not limited to the above-described embodiments. All technical solutions formed by equivalent replacements fall within the protection scope of the present invention.

Claims (10)

1. A pile pulling and recharging method is characterized by comprising the following steps:

1) exposing the top of the pile to be pulled out through pretreatment, and simultaneously preparing a plurality of high-strength anchor cable materials and hoisting equipment;

2) drilling an anchor hole extending to the bottom in the pile to be pulled at the top of the pile to be pulled, and drilling a pile body grouting hole penetrating through the top surface and the bottom surface of the pile to be pulled;

3) one end of the anchor cable material is lowered to the bottom of the anchor hole, and the other end of the anchor cable material is exposed out of the top of the pile to be pulled;

4) pouring first slurry into the anchor hole, and fixing the anchor cable material into the pile to be pulled to form an anchor rod after the first slurry is solidified and reaches a set strength;

5) and lifting the other end of the anchor cable material by using lifting equipment to pull up the pile to be pulled, and recharging the second slurry through the pile body grouting hole in the process of pulling up the pile to be pulled so that the second slurry permeates into the soil body around the pile at the bottom of the pile to be pulled and connects the soil body and the pile to be pulled into a whole.

2. The pile pulling and recharging method of claim 1, wherein: in the step 2), drilling a static blast hole extending to the bottom of the pile to be pulled at the top of the pile to be pulled; in the step 5), after the other end of the anchor cable material is lifted by a lifting device to pull up the pile, firstly, a crushing agent is poured into the static blast hole and the orifice of the static blast hole is blocked by quick-hardening cement for 12-18 hours, and then, the pile body is crushed by a crushing device.

3. A pile pulling and recharging method as defined in claim 1 or 2, wherein: in the step 1), a working platform is arranged on other piles near the pile to be pulled or on soil around the pile to be pulled; in the step 5), the hoisting equipment is a penetrating jack, a crane or a winch which is arranged on the working platform, and the penetrating jack, the crane or the winch continuously stretches the other end of the anchor cable material to continuously pull up the pile to be pulled.

4. The pile pulling and recharging method of claim 3, wherein: the working platform is a reinforced concrete platform, a steel structure frame platform or a combined structure platform; the center-penetrating jack is fixedly arranged on the reinforced concrete platform, the steel structure frame platform or the combined structure platform through a reaction frame; the crane or the winch is arranged on the reinforced concrete platform, the steel structure frame platform or the combined structure platform.

5. The pile pulling and recharging method of claim 3, wherein: the working platform is a sunk well platform, and the center penetrating jack is fixed on the sunk well platform.

6. A pile pulling and recharging method as defined in claim 1 or 2, wherein: the depth of the anchor hole and the length of the anchor rod are smaller than the length of the pile to be pulled and larger than the minimum anchoring length of the anchor rod, and the minimum anchoring length L of the anchor rod is calculated according to the following formula:

in the formula, a is a safety factor; sigma is the strength of the anchor cable material; a is the cross-sectional area of the anchor cable material; d is the anchor eye diameter; tau is the shear strength of the anchor rod and the hole wall.

7. A pile pulling and recharging method as defined in claim 1 or 2, wherein: the anchor cable material is provided with three grouting pipes with outlets respectively positioned at the bottom, the middle part and the upper part of the anchor hole; pouring first slurry into the anchor hole by adopting pressure grouting, wherein the first slurry is slurry formed by mixing PO52.5 cement, a cement slurry pore canal grouting agent and water, and the water-cement ratio of the first slurry is 0.35-0.45; and (5) performing pressure grouting by adopting a mortar stirrer and a grouting pump.

8. A pile pulling and recharging system is used in the pile pulling and recharging method of claim 1, and is arranged near a pile to be pulled which is fixed in a soil body and exposed at the top, and comprises a plurality of high-strength anchor cable materials and hoisting equipment, and is characterized in that an anchor hole extending towards the bottom in the pile to be pulled is formed at the top of the pile to be pulled, a pile body grouting hole penetrating through the top surface and the bottom surface of the pile to be pulled is formed in the pile to be pulled, one end of each anchor cable material is arranged at the bottom of the anchor hole, and the other end of each anchor cable material is exposed out of the top of the pile to be pulled; the anchor hole is filled with first slurry which is used for fixing the anchor cable material in the pile to be pulled out after solidification so as to form an anchor rod, the hoisting equipment is used for lifting the other end of the anchor cable material so as to pull up the pile to be pulled out, and the pile body grouting hole is used for recharging second slurry in the pile pulling process.

9. The pile pulling and recharging system of claim 8, wherein: a static blasting hole extending towards the bottom in the pile to be pulled is formed in the top of the pile to be pulled; and a breaking agent is poured into the static blasting hole and a rapid hardening cement block is blocked.

10. The pile pulling and recharging system of claim 8, wherein: and working platforms are arranged on other piles near the pile to be pulled or soil around the pile to be pulled.

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