Grouting cast-in-place pile construction method for complex geology

Abstract

The invention belongs to the technical field of complex geological construction, and particularly relates to a complex geological grouting cast-in-place pile construction method which comprises the following steps: step 1, tamping the complex geological ground; secondly, the compacted ground is subjected to preliminary drilling, reaming is conducted after drilling is completed, and drilling construction continues after reaming is completed; 3, hole cleaning treatment is carried out; compared with the prior art, by drilling in the soft soil layer and adopting bottom expanding construction at the joint of the hard soil layer and the soft soil layer, the bearing capacity of the pile foundation can be greatly improved under the condition of the same pile length, and the pile length can be reduced, the construction efficiency can be improved and the construction cost can be reduced under the condition of ensuring the same pile foundation bearing capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of complex geological construction, and in particular relates to a grouting pile construction method for complex geological conditions. Background Art

[0002] At present, complex geological conditions are complex and changeable. Common soil types include sand, silt, silty clay, etc., and the thickness and distribution of different soil layers are irregular. With the continuous development and expansion of the city, a large amount of plain fill and miscellaneous fill are used for site leveling and filling projects. The mechanical properties of these soils vary greatly, which brings great challenges to the construction of bored piles. Under complex geological conditions, traditional bored pile construction methods are often difficult to meet the project's requirements for the bearing capacity of pile foundations, and in loose strata such as sand and silt, hole collapse is prone to occur during the drilling process. Summary of the invention

[0003] In view of the above problems, the present invention provides a grouting pile construction method for complex geology.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: a grouting pile construction method for complex geology, comprising the following steps: Step 1: Compact the ground with complex geology; Step 2: Perform preliminary drilling on the compacted ground, expand the hole after drilling, and continue drilling after expanding the hole; Step 3: hole cleaning; Step 4: Grouting pile construction.

[0005] Preferably, step one comprises: using a hydraulic compactor to spot-tamp the ground with complex geology twice, and then adjusting the compaction energy of the hydraulic compactor to low energy to fully compact the ground to be constructed once, and the compaction prints overlap.

[0006] Preferably, the spot tamping adopts a plum blossom or square grid arrangement, and the point tamping point deviation is ±150mm. After the spot tamping is completed, a vibrating roller is used to roll the spot tamped ground for 3-5 times, and then full tamping construction is carried out after the rolling is completed.

[0007] Preferably, step two includes: drilling a hole in the compacted ground using an expanding drill bit through a rotary drilling rig; when the expanding drill bit reaches the expanding position, the deadweight of the rotary drill rod and the pressurized cylinder are used to apply pressure to the bottom of the hole to compact the loose soil at the bottom of the hole; the rotary drill rod is then pressed down to expand the expansion arm of the expanding drill bit outward, driving the rotary drill rod to rotate and cut the hole wall; the rotary drill rod continues to press down to drill the hole, so that the expanding drill bit is in a fully extended state.

[0008] Preferably, after the expansion drill bit completes the construction, the drilling is continued by a positive circulation rotary drilling rig, and the positive circulation rotary drilling rig adopts slow drilling.

[0009] Preferably, the step three comprises: the hole cleaning is performed in two steps, the first hole cleaning is performed by idling the hole cleaning drill bit in the hole for 2-3 times; the second hole cleaning is performed by positive circulation of mud.

[0010] Preferably, the secondary hole cleaning includes: excavating a mud circulation trough, a sedimentation tank and a mud pool on the outside of the hole, so that the mud circulation trough is connected to the hole, the sedimentation tank is connected to the mud pool at the top, the mud circulation trough is connected to the sedimentation tank, and an injection catheter is placed in the hole. The outside of the injection catheter is connected to a hose through a hole cleaning interface. A mud pump is provided on the hose, and the other end of the hose is connected to the mud pool. The mud pump draws mud in the sedimentation tank into the injection catheter, and sends the mud to the bottom of the hole. The mud carries the sediment at the bottom of the hole through the annular space between the injection catheter and the hole wall and returns to the mud rotation trough. The mud carrying the sediment is precipitated in the sedimentation tank and then enters the mud pool.

[0011] Preferably, the step four comprises: separating the grouting conduit from the rubber hose, pouring concrete in the grouting conduit to form the bored pile body, after solidification, lowering the steel cage and the rear grouting conduit into the annular space between the grouting conduit and the hole wall, the rear grouting conduit adopts a high-pressure composite hose, and pouring concrete into the annular space through the high-pressure composite hose, after solidification, burying a seamless steel pipe at a position of 300-500mm on the ground, the seamless steel pipe and the steel cage are fixed by reinforcing ribs, and concrete is poured on the top of the hole through the seamless steel pipe. Preferably, the concrete slurry uses P.042.5 ordinary Portland cement with a water-cement ratio of 0.45-0.6.

[0012] Preferably, the lap width of the tamping prints is greater than or equal to 50 cm.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are: (1) The existing complex geology is divided into a hard soil layer and a soft soil layer from top to bottom. The present invention can greatly improve the bearing capacity of the pile under the same pile length by drilling holes in the soft soil layer and adopting bottom expansion construction at the junction of the hard soil layer and the soft soil layer. It can also reduce the pile length while ensuring the same pile foundation bearing capacity, thereby improving construction efficiency and reducing construction costs; (2) A large amount of existing plain fill and miscellaneous fill are used for site leveling and filling projects. However, the present invention can reduce the initial earthwork excavation work and the difficulty of construction equipment entering and leaving the site after the original plain and miscellaneous fill is treated by hydraulic tamping, which effectively enhances the bearing capacity of the construction area and greatly improves the construction efficiency. (3) The present invention uses a positive circulation rotary drilling rig to drill holes, which can effectively ensure the stability of the hole wall, improve the qualified rate of pile formation, and reduce construction losses; (4) The positive circulation rotary drilling rig equipment used in the present invention has low purchase cost, which can reduce construction cost investment; (5) The present invention adopts secondary hole cleaning, which can reduce the thickness of sediment at the bottom of the hole, improve the bearing capacity of a single pile, and ensure the quality of concrete pouring; (6) The use of post-grouting technology on the side of the bored pile can reduce the settlement and uneven settlement of the bored pile and improve the safety and stability of the building. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following is a brief introduction to the drawings required for describing the embodiment: Figure 1 A flow chart of the grouting pile construction method for complex geology provided in Example 1; Figure 2 The distribution diagram of tamping points in the grouting pile construction method for complex geology; Figure 3 This is the secondary hole cleaning structure diagram for the grouting pile construction method in complex geology.

[0015] Description of reference numerals: 1. Hole cleaning interface; 2. Injection catheter; 3. Annular space; 4. Mud circulation trough; 5. Sedimentation tank; 6. Mud pool. DETAILED DESCRIPTION

[0016] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0017] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0018] Example 1 The following is combined with Figure 1 -Attached Figure 3 The present invention is further described as follows: a grouting pile construction method for complex geology, such as Figure 1 As shown, the following steps are included: Step 1: Compact the ground with complex geology; Step 2: Perform preliminary drilling on the compacted ground, expand the hole after drilling, and continue drilling after expanding the hole; Step 3: hole cleaning; Step 4: Grouting pile construction.

[0019] Step 1 includes: using a hydraulic compactor to compact the ground with complex geology twice, and then adjusting the compaction energy of the hydraulic compactor to low energy to compact the ground to be constructed once, and the compaction prints overlap, such as Figure 2 As shown, the spot tamping adopts a plum blossom or square grid arrangement, and the point tamping point deviation is ±150mm. After the spot tamping is completed, a vibrating roller is used to roll the spot tamped ground 3-5 times, and then full tamping construction is carried out after rolling is completed.

[0020] In the present invention, when the spot tamping is arranged in a square grid, Figure 2 As shown, for example: the first time of tamping requires three rows of tamping, with three tamping marks in one row, and the second time of tamping requires two tamping marks between two rows.

[0021] In the present invention, the compaction points of spot tamping can be arranged according to site conditions.

[0022] Step two includes: using an expanding drill bit to drill a hole in the compacted ground through a rotary drilling rig; when the expanding drill bit reaches the expanding position, i.e., the junction of the hard soil layer and the soft soil layer in complex geology, the deadweight of the rotary drilling rod and the pressurized cylinder are used to apply pressure to the bottom of the hole to compact the loose soil at the bottom of the hole; the expanding arm of the expanding drill bit is then expanded outward by pressing down the rotary drilling rod, driving the rotary drilling rod to rotate and cut the hole wall; the rotary drill rod continues to press down the hole for 10 cm to put the expanding drill bit in a fully extended state.

[0023] In the present invention, accurate measurement is required after the bottom expansion is completed, by indirectly measuring the displacement of the drill rod.

[0024] In the present invention, after the expansion drill bit completes the construction, the positive circulation rotary drilling rig is used to continue drilling. The positive circulation rotary drilling rig adopts slow drilling. During the drilling process of the positive circulation rotary drilling rig, the mud can carry the drilled soil chips out of the hole in time.

[0025] In the present invention, the mud used by the positive circulation rotary drilling rig is bentonite slurry. During the drilling process, the operator needs to observe whether the drill rod is vertical at any time and strictly control the drilling speed to ensure the stability of the hole wall.

[0026] Step three includes: hole cleaning is carried out in two times, the first hole cleaning is to run the hole cleaning drill bit idly in the hole for 2-3 times; the second hole cleaning is to use mud positive circulation hole cleaning.

[0027] like Figure 3As shown, the secondary hole cleaning includes: excavating a mud circulation groove 4, a sedimentation tank 5 and a mud pool 6 on the outside of the hole, so that the mud circulation groove 4 is connected to the hole, the sedimentation tank 5 is connected to the mud pool 6 at the top, the mud circulation groove 4 is connected to the sedimentation tank 5, and then a perfusion catheter 2 is placed in the hole. The outside of the perfusion catheter 2 is connected with a hose through a hole cleaning interface 1. A mud pump is arranged on the hose. The other end of the hose is connected with the mud pool 6. The mud pump draws the mud in the sedimentation tank 5 into the perfusion catheter 2 and sends the mud to the bottom of the hole. The mud carries the sediment at the bottom of the hole through the annular space 3 between the perfusion catheter 2 and the hole wall and returns to the mud rotation groove 4. The mud carrying the sediment is precipitated in the sedimentation tank 5 and then enters the mud pool 6.

[0028] In the present invention, a baffle is provided between the sedimentation tank 5 and the mud tank 6 .

[0029] In the present invention, after the secondary hole cleaning is completed, the mud in the sedimentation tank 5 can be separated and processed by mud processing equipment to filter and remove the sediment.

[0030] Step four includes: separating the grouting conduit 2 from the hose, pouring concrete in the grouting conduit 2 to form the bored pile body, and after solidification, lowering the steel cage and the post-grouting conduit into the annular space 3 between the grouting conduit 2 and the hole wall. The post-grouting conduit adopts a high-pressure composite hose, and concrete is poured into the annular space 3 through the high-pressure composite hose. After solidification, a seamless steel pipe is buried at a position of 300-500mm on the ground. The seamless steel pipe and the steel cage are fixed by reinforcing ribs, and concrete is poured on the top of the hole through the seamless steel pipe. In the present invention, the concrete slurry adopts P.042.5 ordinary Portland cement with a water-cement ratio of 0.45-0.6.

[0031] In the present invention, the lap width of the tamping prints is greater than or equal to 50 cm.

[0032] In the present invention, the seamless steel pipes are distributed in a circle on the outer circumference of the steel cage, and a plurality of seamless steel pipes are provided, and equal amounts of grouting are adopted for the plurality of seamless steel pipes.

[0033] As the technical solution of the present invention, the hardware setting provided is only for the convenience of realizing specific braking control based on the hardware facilities. How to realize braking control and braking control method specifically are not the technical problems to be solved and the objects to be protected by the present invention. At the same time, the communication methods between the devices all adopt the existing communication methods, which are not the invention points of the present application.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A grouting pile construction method for complex geology, characterized in that: The following steps are involved: Step 1: Compact the ground with complex geology; Step 2: Perform preliminary drilling on the compacted ground, expand the hole after drilling, and continue drilling after expanding the hole; Step 3: hole cleaning; Step 4: Grouting pile construction.

2. The grouting pile construction method for complex geology according to claim 1 is characterized in that: The step one comprises: using a hydraulic compactor to spot compact the ground with complex geology twice, and then adjusting the compaction energy of the hydraulic compactor to low energy to compact the ground to be constructed once, and the compaction marks are overlapped.

3. The grouting pile construction method for complex geology according to claim 2 is characterized in that: The spot tamping adopts a plum blossom or square grid arrangement, and the spot tamping point deviation is ±150mm. After the spot tamping is completed, a vibrating roller is used to roll the spot tamped ground for 3-5 times, and full tamping construction is carried out after the rolling is completed.

4. The grouting pile construction method for complex geology according to claim 1 is characterized in that: The second step comprises: drilling a hole in the compacted ground using an expanding drill bit through a rotary drilling rig; when the expanding drill bit reaches the expanding position, the deadweight of the rotary drilling rod and the pressurized oil cylinder are used to apply pressure to the bottom of the hole to compact the loose soil at the bottom of the hole; the rotary drilling rod is then pressed down to expand the expansion arm of the expanding drill bit outward, driving the rotary drilling rod to rotate and cut the hole wall; the rotary drill rod continues to press down to drill the hole, so that the expanding drill bit is in a fully expanded state.

5. The grouting pile construction method for complex geology according to claim 4 is characterized in that: After the expansion drill bit completes the construction, drilling is continued through the positive circulation rotary drilling rig, which uses slow drilling.

6. The grouting pile construction method for complex geology according to claim 5 is characterized in that: The step three comprises: the hole cleaning is performed in two times, the first hole cleaning is to run the hole cleaning drill bit idly in the hole for 2-3 times; the second hole cleaning is to use mud positive circulation hole cleaning.

7. The grouting pile construction method for complex geology according to claim 6 is characterized in that: The secondary hole cleaning comprises: excavating a mud circulation trough (4), a sedimentation tank (5) and a mud pool (6) outside the hole, so that the mud circulation trough (4) is connected to the hole, the sedimentation tank (5) is connected to the mud pool (6) at the top, the mud circulation trough (4) is connected to the sedimentation tank (5), and then placing an injection conduit (2) in the hole. The outer side of the injection conduit (2) is connected to a hose through a hole cleaning interface (1). A mud pump is arranged on the hose. The other end of the hose is connected to the mud pool (6). The mud pump draws mud from the sedimentation tank (5) into the injection conduit (2) and sends the mud to the bottom of the hole. The mud carries the sediment at the bottom of the hole through the annular space (3) between the injection conduit (2) and the hole wall and returns to the mud rotating trough (4). The mud carrying the sediment is precipitated in the sedimentation tank (5) and then enters the mud pool (6).

8. The grouting pile construction method for complex geology according to claim 7, characterized in that: The step 4 comprises: separating the grouting conduit (2) from the rubber hose, pouring concrete in the grouting conduit (2) to form a cast-in-place pile body, and after solidification, lowering a steel cage and a post-grouting conduit into the annular space (3) between the grouting conduit (2) and the hole wall, the post-grouting conduit using a high-pressure composite hose, pouring concrete into the annular space (3) through the high-pressure composite hose, and after solidification, burying a seamless steel pipe at a position of 300-500 mm above the ground, the seamless steel pipe and the steel cage are tied and fixed by reinforcing bars, and concrete is poured on the top of the hole through the seamless steel pipe.

9. The grouting pile construction method for complex geology according to claim 8, characterized in that: The concrete slurry uses P.042.5 ordinary Portland cement with a water-cement ratio of 0.45-0.

6.

10. The grouting pile construction method for complex geology according to claim 3, characterized in that: The overlap width of the compacted prints is greater than or equal to 50cm.

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