CN116201118A - Anchor cable dismantling construction method for foundation pit anchor pile - Google Patents

Abstract

The invention provides an anchor cable removal construction method for foundation pit anchor piles. The method includes the steps of locating and numbering the position of the anchor cable, determining the schedule of the stress release degree, determining the rigidity release area of the cross-section of the anchor-stayed pile, cutting and synchronously monitoring and dynamically adjusting the cross-section of the anchor-stay pile. This method can solve the problem of safely and quickly removing the anchor cables of conventional anchor piles under the premise of specific building function requirements, so as to meet the later building function needs. The construction of the present invention is relatively simple, and only needs to determine the rigidity release area of the pile body to cut the anchor pile body to a certain extent, and directly remove the supporting pile and the anchor cable after the stress is released, which has the advantages of simple operation, short construction period and high safety.

Description

A construction method for removing anchor cables for foundation pit anchor piles

technical field

The invention relates to the field of foundation pit engineering, in particular to an anchor cable removal construction method for foundation pit anchor piles.

Background technique

At present, according to the geological conditions, the foundation pit enclosure project can adopt engineering schemes such as soil nailing wall, anchor support, row of piles, anchor piles, and row of piles plus internal support. With the large-scale construction of the city, the surrounding building environment of the foundation pit project is becoming more and more complex, such as power pipe trenches, water supply pipelines, communication pipelines, etc., which put forward higher requirements for the deformation control indicators of the foundation pit enclosure structure.

Anchor-stayed piles, as a structural form with better deformation control, are widely used in foundation pit engineering. During the excavation of the foundation pit, the anchor pile enclosure structure is constructed according to the reverse method. During the backfilling process of the foundation pit, the anchor cable system is directly backfilled between the main structure of the building and the enclosure structure without dismantling.

With the diversification of people's demands on the functions of urban buildings, more changes are taking place in the layout of building functions. Sometimes there are conflicts between the anchor cables and the auxiliary structures of the buildings, and the anchor cables need to be removed before the construction of the auxiliary structures of the buildings. .

The conventional method of demolishing the anchor pile structure in foundation pit support is to first set up the support platform, and then the workers hold the jackhammer to chisel the reinforced concrete structure of the anchor head. After the anchoring structure of the anchor cable on the anchor head fails, the anchor cable The stress is released rapidly, and then the anchor pile structure is demolished. However, the anchor cable is a prestressed structure, which is subjected to a large force and high stress. This traditional demolition method will lead to the sudden release of the high stress of the anchor cable, and the instantaneous rebound of the high stress of the anchor cable will cause injury to the construction workers, and the construction risk is extremely high.

In summary, it is urgent to propose a new universally applicable demolition construction method for the conventional anchor cable system demolition process of anchor-stayed piles.

Contents of the invention

The purpose of the present invention is to provide a kind of anchor cable removal construction method for foundation pit anchor pile, to solve the problems existing in the prior art.

The technical solution adopted to realize the purpose of the present invention is as follows, a construction method for removing anchor cables for foundation pit anchor piles, and the foundation pit enclosure structure adopts a row of piles + anchor cable support system. The lower part of the support pile is embedded in the rock-soil layer. The pile tops of adjacent support piles are provided with connecting beams. The support pile is provided with a plurality of anchor cable holes along the length direction of the pile body. One end of the anchor cable is implanted into the soil around the foundation pit through the anchor cable hole, and the other end is fixed with the support pile through the anchor head. The outbuildings are attached to the side of the main building structure.

The anchor cable removal construction method for foundation pit anchor piles comprises the following steps:

1) Determine the position of the anchor cable that needs to be removed and number it.

2) Preliminary determination of the pile body stress release schedule of the supporting piles. Among them, the pile body stress release schedule is the initially determined anchor cable tension release schedule.

3) According to the initially determined schedule of stress release degree, after each step-by-step cutting depth of the pile body is prepared, the stiffness of the pile body is released step by step, so as to obtain the section stiffness release area of the supporting pile.

4) Install the stress gauge, and cut the section of the support pile body for the first time to the predetermined cutting depth. Wherein, the cutting depth is determined according to the stiffness release area.

5) Wait for the deformation of the support pile. During this process, pile body stress monitoring records are carried out. The stiffness of the supporting pile is slowly released, and the stress of the anchor cable is gradually relaxed.

6) The stress value of the pile to be supported decreases and tends to a stable value. If the actual stress reduction value of the support piles does not match the initial stress release schedule, dynamic adjustments will be made based on the actual monitoring records.

7) Repeat steps 3) to 6) to release the stress of the support pile several times until the stress of the anchor cable is completely relaxed, and then completely remove the anchor cable.

Further, in step 3), the anchor cable tension release schedule is based on a single release of 15% of the anchor cable tension as the standard, and the pile body is cut step by step to reduce the section of the pile body, reduce the stiffness of the pile body, and reduce the progress of the pile body stress surface.

Further, in step 5), the stress change of the support pile is monitored by a stress gauge. The stress gauge is arranged around the anchor head.

Further, displacement monitoring points are set on the bottom of the fertilizer tank of the foundation pit and the ground surface. During the removal of the anchor cable, the displacement monitoring point monitors the relative displacement between the top of the foundation pit and the main structure.

Further, during the removal of the anchor cables, the fertilizer groove of the foundation pit is gradually backfilled.

Further, in step 6), if the measured stress release value is larger, the cutting depth will be reduced in the next pile cutting.

Technical effect of the present invention is beyond doubt:

A. The construction is relatively simple. It is only necessary to determine the stress release schedule of the pile body and the cutting depth of the pile body stiffness release area. After a certain cut is made on the anchor pile body, the anchor cable is removed directly after the pile body stress is completely released. Simple, short construction period, high safety and other advantages;

B. Under the premise of specific architectural functional requirements, the anchor cables of conventional anchor piles can be safely and quickly removed, so as to meet the later architectural functional needs.

Description of drawings

Fig. 1 is the flow chart of construction method;

Figure 2 is a schematic diagram of the plane position of the anchor cable;

Fig. 3 is a schematic diagram of the vertical position of the anchor cable;

Fig. 4 is the schematic diagram of the cutting position of the pile body section of the anchor pile;

Fig. 5 is a schematic diagram of backfilling the foundation pit fertilizer tank;

Figure 6 is a structural diagram of the ancillary buildings built after the anchor cables were removed.

Detailed ways

The present invention will be further described below in conjunction with the examples, but it should not be understood that the scope of the subject of the present invention is limited to the following examples. Without departing from the above-mentioned technical ideas of the present invention, various replacements and changes made according to common technical knowledge and conventional means in this field shall be included in the protection scope of the present invention.

Example 1:

This embodiment provides a construction method for removing anchor cables for anchor piles in foundation pits. The enclosure structure of the foundation pit adopts a pile row + anchor cable support system. The lower part of the support pile 1 is embedded in the rock-soil layer. The pile tops of adjacent support piles 1 are provided with connecting beams. The support pile 1 is provided with a plurality of anchor cable holes along the length direction of the pile body. One end of the anchor cable 2 is implanted into the soil around the foundation pit through the anchor cable hole, and the other end is fixed to the support pile 1 through the anchor head 3 . An outbuilding 9 is attached to the side of the main building structure 8 .

The anchor cable removal construction method for foundation pit anchor piles comprises the following steps:

1) Determine the position of the anchor cable 2 to be removed and number it.

2) Preliminary determination of the pile body stress release schedule of the support pile 1. Among them, the pile body stress release schedule is a schedule for cutting the pile body step by step, reducing the section of the pile body, releasing the stiffness of the pile body, and reducing the stress of the pile body.

3) According to the initially determined stress release schedule, after each step-by-step cutting depth of the pile body is prepared, the stiffness of the pile body is released step by step, so as to obtain the section stiffness release area of the support pile 1. In this embodiment, the stress release schedule of the pile body is the release schedule of the anchor cable tension. According to the single release of 15% of the anchor cable tension as the standard, the pile body is cut step by step to reduce the section of the pile body and reduce the pile body. Stiffness, schedule for reducing pile body stress.

4) Install the stress gauge 5, and cut the pile body section of the support pile 1 for the first time to a predetermined cutting depth. Wherein, the cutting depth is determined according to the stiffness release area. The strain gauge 5 is arranged around the anchor head 3 .

5) Wait for the support pile 1 to be deformed. During this process, the stress variation of the support pile 1 is monitored by the stress gauge 5 . The support pile 1 slowly releases its stiffness, and the stress of the anchor cable 2 gradually relaxes.

6) The stress value of pile 1 to be supported decreases and tends to a stable value. If the actual stress reduction value of support pile 1 does not match the initial stress release schedule, dynamic adjustments shall be made according to the actual monitoring records. If the measured stress release value is larger, the cutting depth will be reduced in the next pile cutting.

7) Repeat steps 3) to 6) to release the stress of the support pile 1 several times until the stress of the anchor cable 2 is completely relaxed, and then the anchor cable 2 is completely removed.

This embodiment can solve the problem of safely and quickly removing the anchor cables of conventional anchor piles under the premise of specific architectural functional requirements, so as to meet the later architectural functional requirements. The construction of this embodiment is relatively simple. It only needs to determine the rigidity release area of the pile body and cut the anchor pile body to a certain extent. After the stress is released, the supporting pile and anchor cable are directly removed. It has the advantages of simple operation, short construction period and high safety. .

Example 2:

Referring to FIGS. 1 to 6 , this embodiment provides a construction method for removing anchor cables for anchor piles in foundation pits. The enclosure structure of the foundation pit adopts a pile row + anchor cable support system. The lower part of the support pile 1 is embedded in the rock-soil layer. The pile tops of adjacent support piles 1 are provided with connecting beams. The support pile 1 is provided with a plurality of anchor cable holes along the length direction of the pile body. One end of the anchor cable 2 is implanted into the rock and soil outside the foundation pit through the anchor cable hole, and the other end is fixed to the support pile 1 through the anchor head 3 . The anchor cable 2 is prestressed through the anchor head 3 and the anchoring force is transmitted to the support pile 1 . The free section of the anchor cable 2 is connected to the anchor head 3 and the anchor section, and the prestress is transmitted to the anchor section by utilizing the elastic deformation characteristic of the free section. The anchoring section finally transfers the earth pressure after the pile row to the soil through the anchor cable 2 through the bonding force between the anchor section and the cemented body, the bearing capacity of the cemented body itself, and the bonding force between the cemented body and the surrounding soil.

An outbuilding 9 is attached to the side of the main building structure 8 . The ancillary building 9 is constructed after the main building structure 8, and the ancillary building 9 overlaps with the pile-anchor support system of the main building structure 8 in space. Therefore, before the construction of the ancillary building 9, it is necessary to support the pile-anchor support system that overlaps with it. The system is partially dismantled.

Referring to Fig. 1, the anchor cable removal construction method for foundation pit anchor pile comprises the following steps:

1) Determine the position of the anchor cable 2 to be removed and number it.

2) Preliminarily determine the schedule of stress release degree of supporting pile 1, the schedule of pile body stress release degree specifically refers to the schedule of cutting the pile body step by step, reducing the section of the pile body, releasing the stiffness of the pile body, and reducing the stress of the pile body. Supporting pile 1 cut pile body depth for the first time and adopts 15cm.

3) The section of the support pile 1 is cut with tools such as pneumatic drills, steel scissors or common hand-push pile cutters, and the cutting depth and progress are carried out step by step according to the above stress release schedule. Before cutting the pile body, it is necessary to install a stress gauge 5 within 50 cm above the cutting line of the pile body, and monitor the stress of the pile body during the process of cutting the pile body.

4) After the first cutting, do a good job of monitoring the pile foundation stress and making monitoring records, and wait for the deformation and stability of the supporting pile 1. During this process, the stiffness of the support pile 1 is slowly released, and the stress of the anchor cable 2 is gradually relaxed.

5) According to the above stress release schedule, use tools such as pneumatic drills, steel scissors or common hand-push pile cutters to cut the pile body step by step, and do a good job of monitoring the stress of the pile body until the stress of the pile body tends to 0 and The monitoring shows that it is in a stable state. The stress release schedule of the support pile 1 should be dynamically corrected in real time based on the measured stress values during the above-mentioned cutting process, and the whole process should be dynamically adjusted to strengthen monitoring. If the actual stress reduction value of the support pile (1) does not match the initially determined stress release schedule, dynamic adjustments will be made according to the actual monitoring records. If the measured stress release value is larger, it will be reduced in the next pile cutting The cutting depth can slowly reduce the stiffness of the pile body to prevent the sudden drop of stress and cause unfavorable working conditions.

6) Repeat steps 3) to 5) to release the stress of the support pile 1 several times until the stress of the anchor cable 2 is completely relaxed, and then the anchor cable 2 is completely removed.

Example 3:

The main steps of this embodiment are the same as those of Embodiment 1, wherein, in step 4), the stress change of the support pile 1 is monitored by the stress gauge 5 . The strain gauge 5 is arranged around the anchor head 3 .

Example 4:

The main steps of this embodiment are the same as those of Embodiment 1, wherein displacement monitoring points 4 are set on the bottom of the fertilizer tank of the foundation pit and the ground surface. During the removal of the anchor cable, the displacement monitoring point 4 monitors the relative displacement between the top of the foundation pit and the main structure.

Example 5:

The main steps of this embodiment are the same as those of Embodiment 1, wherein, during the removal of the anchor cables, the fertilizer groove of the foundation pit is gradually backfilled.

Claims (6)

1. The anchor cable dismantling construction method for the foundation pit anchor pile is characterized by comprising the following steps of: the foundation pit support structure adopts a pile row and anchor cable supporting system; the lower part of the support pile (1) is embedded into a rock soil layer; the pile tops of the adjacent supporting piles (1) are provided with connecting beams; the support pile (1) is provided with a plurality of anchor rope holes along the length direction of the pile body; one end of the anchor cable (2) penetrates through the anchor cable hole to be implanted into the soil body at the periphery of the foundation pit, and the other end of the anchor cable is fixed with the supporting pile (1) through the anchor head (3); the auxiliary building (9) is attached to the side of the main building structure (8);

the anchor cable dismantling construction method for the foundation pit anchor pile comprises the following steps:

1) Determining the position of an anchor cable (2) to be dismantled, and numbering;

2) Preliminarily determining a pile body stress release degree schedule of the support pile (1); the pile body stress release schedule is a schedule for sequentially cutting the pile body step by step, reducing the section of the pile body, releasing the rigidity of the pile body and reducing the stress of the pile body;

3) After the cutting depth of each step pile body is planned according to the preliminarily determined stress release degree schedule, the rigidity of the pile body is gradually and orderly released, and therefore a section rigidity release area of the support pile (1) is obtained;

4) Installing a stress measuring meter (5), and cutting the section of the pile body of the support pile (1) for the first time to reach a preset cutting depth; wherein the depth of cut is determined by the stiffness release zone;

5) Waiting for the deformation of the support pile (1); in the process, pile body stress monitoring and recording are carried out; the supporting piles (1) slowly release rigidity, and the stress of the anchor cables (2) is gradually relaxed;

6) The stress value of the pile (1) to be supported is reduced and tends to be stable; if the stress reduction value of the actual support pile (1) is not matched with the preset stress release schedule, carrying out dynamic adjustment according to the actual monitoring record;

7) Repeating the steps 3) to 6), releasing the stress of the support pile (1) for a plurality of times until the stress of the anchor cable (2) is completely relaxed, and then completely dismantling the anchor cable (2).

2. The anchor line demolishing construction method for foundation pit anchor piles according to claim 1, wherein: in the step 3), the pile body stress release degree schedule is an anchor cable tension release schedule, the pile body is cut step by step according to the anchor cable tension released by 15% in a single time as a standard, the pile body section is reduced, the pile body rigidity is reduced, and the pile body stress is reduced.

3. The anchor line demolishing construction method for foundation pit anchor piles according to claim 1, wherein: in the step 5), monitoring the stress change condition of the support pile (1) through a stress measuring meter (5); the stress measuring meter (5) is arranged at the periphery of the anchor head (3).

4. The anchor line demolishing construction method for foundation pit anchor piles according to claim 1, wherein: displacement monitoring points (4) are arranged at the bottom of the foundation pit fertilizer tank and on the ground surface; in the anchor cable dismantling process, the displacement monitoring point (4) monitors the relative displacement between the foundation pit top and the main body structure.

5. The anchor line demolishing construction method for foundation pit anchor piles according to claim 1, wherein: and in the anchor cable dismantling process, the foundation pit fertilizer groove is gradually backfilled.

6. The anchor line demolishing construction method for foundation pit anchor piles according to claim 1, wherein: in step 6), if the measured stress release value is larger, the cutting depth is reduced in the next pile body cutting.

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