Construction method for reinforcing collapsed hole of pile foundation in dry operation

Abstract

The invention relates to a construction method for reinforcing a dry operation pile foundation collapsed hole. Comprising the following steps that S1, a pile hole is drilled, and after the pile hole collapses, the collapsed pile hole is cleaned; s2, a supporting formwork is hoisted into the pile hole, the supporting formwork is provided with a cavity, a filling block is arranged in the cavity of the supporting formwork, then wall protection concrete is poured between the supporting formwork and the hole wall of the pile hole, and the filling block and the supporting formwork are taken out before the wall protection concrete is hardened; and S3, pile foundation construction continues to be completed. After the pile hole collapses, the supporting formwork is arranged in the pile hole to serve as a supporting structure framework, the filling block is arranged in the supporting formwork, and the filling block and the supporting formwork jointly serve as a supporting structure for pile hole retaining wall concrete pouring, so that the strength of the pile hole is enhanced, meanwhile, the concrete recharge amount is reduced, resources are saved, the cost is reduced, and economic benefits are improved; the supporting formwork and the filling blocks in the supporting formwork can be repeatedly used, the using amount of concrete is reduced, and pollution to the environment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation construction, and in particular to a construction method for reinforcing a collapsed hole of a dry pile foundation. Background Art

[0002] Pile foundation collapse refers to the situation in which the soil on the side of the pile hole falls into the hole from the hole wall due to soft soil or uneven force on the pile during pile hole construction, which greatly reduces the foundation bearing capacity of the pile hole. The traditional method to solve this phenomenon is to backfill the hole with concrete, which is to fill the hole with concrete and fix the surrounding soil layers together to increase the stability and bearing capacity of the pile hole. After the concrete is backfilled, drilling is continued to complete the pile foundation construction. Before backfilling the concrete, the soil around the pile hole needs to be cleaned and reinforced.

[0003] The existing pile foundation collapse hole construction has the following problems: 1) After the hole collapses, the entire pile hole is refilled with concrete, which consumes a large amount of concrete and is expensive to handle; 2) After the pile hole is refilled with concrete, a large amount of concrete waste will be generated when drilling again, which not only wastes resources but also causes great environmental pollution; 3) The quality of the reinforcement of the collapsed hole wall is poor. Therefore, a dry operation pile foundation collapse hole reinforcement construction method is urgently needed to solve the above problems. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a construction method for dry operation pile foundation collapse reinforcement, comprising the following steps:

[0005] S1, drilling a pile hole, and after the pile hole collapses, cleaning the collapsed pile hole;

[0006] S2, hoisting a support formwork into the pile hole, the support formwork having a cavity, placing a filling block in the cavity of the support formwork, then pouring retaining wall concrete between the support formwork and the pile hole wall, and taking out the filling block and the support formwork before the retaining wall concrete hardens;

[0007] S3. Continue to complete the pile foundation construction.

[0008] Furthermore, the supporting formwork is a first steel cage, which includes a cage frame and a wire mesh arranged on the cage frame, and the wire mesh is coated on the outside of the cage frame.

[0009] Furthermore, the cage frame includes a vertical frame composed of a plurality of main bars and spiral bars, and the spiral bars are spirally arranged around the vertical frame.

[0010] Furthermore, the distance between the support template and the pile hole wall is not less than 5 cm.

[0011] Furthermore, the wall protection concrete is doped with an early strength agent, and the addition amount of the early strength agent is 2% to 5% of the mass of the concrete.

[0012] Furthermore, the outer wall of the supporting formwork is provided with a plurality of vertical plates, the plate surfaces of the vertical plates are parallel to the vertical direction, and the vertical plates are arranged in sequence and spaced apart along the circumference of the supporting formwork.

[0013] Furthermore, the width of the vertical plate is smaller than the distance between the supporting template and the wall of the pile hole.

[0014] Furthermore, the filling block is a mud block.

[0015] Furthermore, continuing the pile foundation construction in step S3 specifically includes:

[0016] S31, secondary hole formation;

[0017] S32, hoisting the second steel cage into the pile hole, and pouring pile foundation concrete into the pile hole to form a pile foundation.

[0018] Furthermore, the drilling of pile holes in step S1 specifically includes:

[0019] S11. Before the pile hole construction, a measurement control network is established on site according to the axis and pile position arrangement, and then the center points of each pile position are measured and placed according to the control network;

[0020] S12, setting a casing on the pile position, wherein the bottom of the casing is buried in the underground clay layer, the top of the casing is higher than the ground, and the surrounding area of ​​the casing is backfilled with clay and compacted in layers;

[0021] S13. After the casing is buried, recalibrate the pile center point to ensure accurate positioning of the pile hole;

[0022] S14. The drilling rig drills holes on the pile position.

[0023] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0024] The invention provides a construction method for reinforcing a collapsed hole of a pile foundation. After the pile hole collapses, a supporting template is arranged in the pile hole as a supporting structure skeleton, and a filling block is arranged in the supporting template. The filling block and the supporting template together serve as a supporting structure for pouring concrete for the pile hole retaining wall. Thus, while reinforcing the strength of the pile hole, the amount of concrete backfilling is saved, resources are saved, costs are reduced, and economic benefits are improved. The supporting template and the filling blocks therein are reusable, which reduces the amount of concrete used and reduces pollution to the environment. The pile hole retaining wall reinforcement effect is good, and there is no need to repeatedly reinforce the hole wall, thereby improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of pile hole reinforcement in the dry operation pile foundation collapsed hole reinforcement construction method provided by the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the drawings, the size and relative size of some parts may be enlarged for clarity.

[0028] In the description of the present invention, unless otherwise clearly stipulated and limited, the terms "connection" and "connected" should be interpreted in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the description of the present invention, terms such as "up", "down", "left", "right", "front", "back", etc., and the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0030] In addition, in the description of the present invention, the terms "first" and "second" are only used to distinguish in the description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0031] The present invention provides a construction method for dry operation pile foundation collapse hole reinforcement, comprising the following steps:

[0032] S1, drilling a pile hole, and after the pile hole collapses, cleaning the collapsed pile hole;

[0033] S2, hoisting the support formwork into the pile hole, the support formwork having a cavity, loading the filling block 2 into the cavity of the support formwork, then pouring the retaining wall concrete 3 between the support formwork and the pile hole wall, and taking out the filling block 2 and the support formwork before the retaining wall concrete hardens;

[0034] S3. Continue to complete the pile foundation construction.

[0035] In actual construction, pile hole collapse includes moderate hole collapse and severe hole collapse, among which, the characteristics of moderate hole collapse are: 1. The hole wall collapses on a large scale, but has not yet caused the entire hole wall to completely lose stability; 2. The hole collapse depth is deep, usually accounting for 10% to 30% of the hole depth. The characteristics of severe hole collapse are: 1. The hole wall completely loses stability and collapses on a large scale; 2. The hole collapse depth is very deep, usually exceeding 30% of the hole depth, and even causes the entire hole wall to collapse. The construction method of pile foundation collapse hole reinforcement described in this application is suitable for dry pile foundation drilling under poor geological conditions, and can solve the problem of moderate hole collapse of pile foundations in soft soil. During the pile foundation construction process, when drilling the pile hole, if the pile hole partially collapses, the pile hole reinforcement is required to allow the pile foundation construction to be completed later. The specific operation is to clean the pile hole after the hole collapse, clean out the mud and rocks that fall into the pile hole, and then hoist the supporting template in the pile hole. The outer diameter of the supporting template is smaller than the diameter of the pile hole. A filling cavity is formed between the supporting template and the wall of the pile hole. The supporting template serves as a supporting structure skeleton. Filling blocks 2 are backfilled in the supporting template. The filling blocks and the supporting template together serve as a supporting structure for pouring pile hole retaining wall concrete. Retaining wall concrete 3 is poured in the filling cavity to form a concrete layer, as shown in the attached manual. Figure 1 As shown, before the concrete hardens, the supporting formwork and the filling block 2 are taken out, and the retaining wall concrete 3 can reinforce the pile hole. The retaining wall reinforcement effect is good, and there is no need to repeatedly reinforce the retaining wall, which improves the construction efficiency. Compared with the traditional method of refilling concrete in the pile hole, the present application only needs to set a layer of concrete on the wall of the pile hole. Firstly, under the premise of ensuring the strength of the wall of the pile hole, the amount of concrete used is greatly reduced, the cost is reduced, and the economic benefit is improved; secondly, the supporting formwork and the filling block 2 filled are reusable, which reduces the amount of concrete used and avoids environmental pollution; thirdly, during the subsequent pile foundation construction, the filling block 2 and the supporting formwork can be taken out. Compared with the traditional method of excavating concrete, the subsequent construction of the present application is more convenient.

[0036] Preferably, the cross-section of the support formwork includes but is not limited to circular, square or other shapes. In the present embodiment, the support formwork is a hollow cylinder, which is hoisted in the pile hole and matched with the gap of the pile hole to facilitate pouring of retaining wall concrete between the support formwork and the wall of the pile hole.

[0037] In an optimized implementation mode, the supporting formwork is a first steel cage 1. Of course, the supporting formwork can also be a steel cylinder.

[0038] Specifically, the first steel cage 1 is a cylindrical structure with an opening at the upper end, and the filling block 2 is filled in the cavity of the first steel cage 1. When the first steel cage 1 is taken out, the filling block 2 can be taken out together with the first steel cage 1, and the first steel cage 1 can block the concrete to a certain extent, reducing or avoiding the concrete from entering the first steel cage 1 when pouring the retaining wall concrete. At the same time, it can also prevent the filling block 2 from leaking out of the cage, and the particle size requirements of the filling block 2 are not high, and the filling block 2 has good applicability. A filling block with a large diameter can be set in the first steel cage 1 first, and then a filling block with a small diameter can be set to ensure the strength of the support structure composed of the filling block and the first steel cage 1.

[0039] In the present application, a first steel cage 1 and a filling block 2 are hoisted in the pile hole, and a wall concrete 3 is poured between the first steel cage 1 and the wall of the pile hole, which can be used for reinforcing the pile hole after the hole collapses, and can also be used for protecting the pile hole. During the pile hole construction process, a layer of concrete is set on the wall of the pile hole for reinforcement to avoid the occurrence of hole collapse accidents.

[0040] In an optimized implementation mode, the first steel cage 1 includes a cage frame 11 and a steel mesh 12 arranged on the cage frame 11, and the steel mesh 12 is coated on the outside of the cage frame 11. The height of the first steel cage 1 can be set according to the actual depth of the pile hole drilled, and the first steel cage 1 can be higher than the ground. The cage frame 11 can be manufactured in sections on site. After the cage frame 11 is manufactured, a layer of steel mesh 12 is wrapped on the outside of the cage body. The steel mesh 12 can be fixed on the cage frame 11 by tying wires. The steel mesh 12 can block concrete to a certain extent, and reduce the penetration of concrete into the first steel cage 1 when pouring the wall concrete in the filling cavity.

[0041] In an optimized implementation method, the cage frame 11 includes main bars and spiral bars. A plurality of main bars form a vertical frame. The spiral bars are spirally arranged around the vertical frame. The spiral bars and the main bars are reinforced by spot welding. After the cage frame is assembled, a layer of wire mesh 12 is wrapped around the outside of the cage body.

[0042] Preferably, the cage frame 11 further includes reinforcing ribs, which are connected to main ribs to increase the strength of the cage frame 11, and the main ribs and reinforcing ribs are all welded.

[0043] In an optimized implementation mode, the upper end of the first steel cage is a tapered portion, the diameter of which gradually decreases from top to bottom, and the upper end of the retaining wall concrete is tapered after pouring. After the pile hole is constructed in the later stage, concrete is poured in the pile hole to form a pile foundation, and the tapered upper part of the retaining wall concrete can transfer the load to the stratum around the pile hole, thereby strengthening the supporting strength of the pile foundation.

[0044] In an optimized implementation method, the spacing between the first steel cage 1 and the pile hole wall is not less than 5 cm, concrete is poured between the first steel cage 1 and the pile hole wall to form wall concrete, and for the collapsed hole section, the entire collapsed hole space needs to be filled densely with concrete.

[0045] The optimized implementation method is to extend the conduit between the first steel cage 1 and the wall of the pile hole, then pour the wall concrete, observe the degree of coagulation and hardening of the concrete, take out the first steel cage 1 and the filling block 2 before the concrete coagulates and hardens, and continue to complete the pile foundation construction after the wall concrete hardens. In order to improve the early strength of concrete, the concrete is doped with an early strength agent, and the addition amount of the early strength agent is 2% to 5% of the mass of the concrete.

[0046] Specifically, if the hole collapse is serious, C20 grade concrete doped with early strength agent can be used to cast the pile hole wall concrete, and the first steel cage and filling blocks should be removed within 1 hour; under normal circumstances, C15 concrete is used for hole wall casting, and the first steel cage and filling blocks should be removed before the wall concrete solidifies and hardens, and the concrete hardening time should not exceed 6 hours.

[0047] In an optimized implementation method, the outer wall of the support formwork is provided with a plurality of vertical plates, the plate surface of the vertical plates is parallel to the vertical direction, and the vertical plates are arranged in sequence along the circumference of the support formwork. Specifically, the outer wall of the first steel cage 1 is provided with a plurality of vertical plates extending into the retaining wall concrete. After the first steel cage 1 is taken out, a plurality of vertical receiving grooves are formed on the retaining wall concrete. When the pile foundation concrete is poured later, the pile foundation concrete will be filled into the receiving grooves of the retaining wall concrete, which can improve the connection reliability between the new and old concretes.

[0048] In an optimized implementation manner, the width of the vertical plate is smaller than the distance between the first reinforcement cage 1 and the wall of the pile hole.

[0049] In an optimized implementation mode, the filling block 2 is a mud block, which can be a mud block dug out when the pile hole is drilled, and is convenient to obtain. Of course, the filling block 2 can also be a stone.

[0050] In an optimized implementation mode, the pile hole drilling in step S1 specifically includes:

[0051] S11. Before the pile hole construction, a measurement control network is established on site according to the axis and pile position arrangement, and then the center points of each pile position are measured and placed according to the control network;

[0052] S12. A casing is installed on the pile position. The diameter of the casing is 200 to 1000 mm larger than the diameter of the pile hole. The axis of the casing coincides with the axis of the pile hole. The casing and the pile hole are coaxially arranged. The lower part of the casing is inserted into the ground, and the bottom of the casing is buried in the clay layer for at least 0.5 m. The top of the casing is not less than 0.3 m above the ground. The surroundings of the casing are backfilled with clay and compacted in layers. The inclination of the casing is not more than 1%, and the deviation between the axis of the casing and the center line of the pile hole does not exceed 30 mm.

[0053] S13. After the casing is buried, recalibrate the pile center point to ensure accurate positioning of the pile hole;

[0054] S14. When drilling on the pile position, the drilling rig should be regularly measured and positioned to ensure the pile hole size and verticality and other parameters. If the pile hole collapses, emergency measures should be taken to clean the pile hole.

[0055] After cleaning the pile hole, hoist the first steel cage 1 and the filling block 2 in the pile hole, and then pour the retaining wall concrete 3 between the first steel cage 1 and the pile hole wall. Before the retaining wall concrete 3 solidifies and hardens, take out the first steel cage and continue to complete the pile foundation construction.

[0056] A secondary hole is formed in the pile hole where the retaining wall concrete has been poured. The filling block is dug out with a rotary drilling rig, and the pile hole is cleaned again to complete the formation of the pile hole. A second steel cage is made and hoisted into the pile hole as the skeleton of the pile foundation. The pile hole is cleaned again, a concrete conduit is placed under the pile hole, and concrete is poured to form the pile foundation. The conduit and casing are removed, and the pile foundation construction is completed after the concrete solidifies and hardens.

[0057] Of course, the filling blocks in the pile hole can be taken out together with the first steel cage, without the need for a rotary drilling machine. The second steel cage can use the first steel cage, which can save construction costs. After the first steel cage is pulled out and cleaned, it can be used as the second steel cage and used permanently as an engineering component.

[0058] In the present application, a first steel cage and a filling block are placed in the collapsed pile hole as a supporting structure so that wall concrete can be poured between the first steel cage and the pile hole wall. The wall reinforcement effect is good, and there is no need to repeatedly reinforce the hole wall, which improves construction efficiency, reduces the amount of concrete backfilling, reduces costs, and avoids causing environmental pollution.

[0059] Those skilled in the art will appreciate that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the present invention. Although embodiments of the present invention have been described, it should be understood that the present invention should not be limited to this embodiment, and those skilled in the art can make changes and modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A construction method for dry pile foundation collapse reinforcement, characterized in that: The following steps are involved: S1, drilling a pile hole, and after the pile hole collapses, cleaning the collapsed pile hole; S2, hoisting a support formwork into the pile hole, the support formwork having a cavity, placing a filling block in the cavity of the support formwork, then pouring retaining wall concrete between the support formwork and the pile hole wall, and taking out the filling block and the support formwork before the retaining wall concrete hardens; S3. Continue to complete the pile foundation construction.

2. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: The supporting formwork is a first steel cage, which includes a cage frame and a steel wire mesh arranged on the cage frame, and the steel wire mesh is covered on the outer side of the cage frame.

3. The construction method for dry pile foundation collapse reinforcement according to claim 2, characterized in that: The cage frame comprises a vertical frame composed of a plurality of main bars and spiral bars, and the spiral bars are spirally arranged around the vertical frame.

4. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: The distance between the support template and the pile hole wall is not less than 5cm.

5. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: The wall protection concrete is mixed with an early strength agent, and the addition amount of the early strength agent is 2% to 5% of the mass of the concrete.

6. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: The outer wall of the supporting formwork is provided with a plurality of vertical plates, the plate surfaces of the vertical plates are parallel to the vertical direction, and the vertical plates are arranged in sequence and at intervals along the circumference of the supporting formwork.

7. The construction method for dry pile foundation collapse reinforcement according to claim 6, characterized in that: The width of the vertical plate is smaller than the distance between the supporting template and the wall of the pile hole.

8. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: The filling block is a mud block.

9. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: Continuing the pile foundation construction in step S3 specifically includes: S31, secondary hole formation; S32, hoisting the second steel cage into the pile hole, and pouring pile foundation concrete into the pile hole to form a pile foundation.

10. The construction method for dry pile foundation collapse reinforcement according to claim 1, characterized in that: The pile hole drilling in step S1 specifically includes: S11. Before the pile hole construction, a measurement control network is established on site according to the axis and pile position arrangement, and then the center points of each pile position are measured and placed according to the control network; S12, setting a casing on the pile position, wherein the bottom of the casing is buried in the underground clay layer, the top of the casing is higher than the ground, and the surrounding area of ​​the casing is backfilled with clay and compacted in layers; S13. After the casing is buried, recalibrate the pile center point to ensure accurate positioning of the pile hole; S14. The drilling rig drills holes on the pile position.

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