Full-rotation steel pipe pile process construction method under low-clearance high-water-level complex geology

Abstract

The invention discloses a full-rotation steel pipe pile technological method under the low-clearance high-water-level complex geology. The construction method comprises the steps that construction preparation is conducted, specifically, according to design requirements, a construction area is determined and arranged, and a site is leveled; a pile foundation is positioned, pile position lofting is conducted, the construction range is determined, and a trepanning gushing prevention device is installed; a drilling machine is in place, drilling construction is conducted, and low-clearance full-rotation steel pipe pile construction is adopted; in the drilling process, the pile-forming steel sleeve is welded in a segmented mode; taking soil by using a grab bucket, digging out the soil body in the steel sleeve by using a low-clearance crawler crane and the grab bucket, meeting the drilling requirement, and checking the final hole elevation until the designed hole bottom elevation is reached. And concrete backfilling is performed in a pile cavity. According to the full-rotation steel pipe pile process construction method under the low-clearance high-water-level complex geology, the construction period is short, the temporary occupied space is small, and the related traffic relief coordination and external communication workload is small; and compared with the conventional underground reinforcement cost, the construction cost is greatly reduced, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field, and more particularly to a full-rotation steel pipe pile process method under complex geological conditions with low headroom and high water levels. Background Art

[0002] With the continuous development of urban construction, construction conditions are increasingly affected and restricted by the surrounding environment. Pile foundation construction in soft soil areas faces more severe challenges. When carrying out reinforcement and other construction around existing buildings, construction work in low-headroom environments is often encountered.

[0003] At this time, it is necessary to comprehensively consider the impact of the construction work space on the equipment, as well as the geological conditions and design requirements, in order to determine the specific process and the selected equipment.

[0004] Therefore, how to provide a full-rotation steel pipe pile process method for low clearance and high water level complex geological conditions with strong adaptability, small construction disturbance, low construction risk and high construction efficiency is a problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0005] In view of this, the present invention provides a full-rotation steel pipe pile process method under complex geological conditions with low clearance and high water level, aiming to solve one of the problems in the above-mentioned background technology, with strong adaptability, small construction disturbance, low construction risk and high construction efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A full-rotation steel pipe pile construction method under low headroom and high water level complex geological conditions, comprising:

[0008] Step 1: Construction preparation: determine the construction area and arrange it according to the design requirements, and level the site;

[0009] Step 2: Position the pile foundation, stake out the pile position, determine the construction scope, and install the hole anti-spout device;

[0010] Step 3: Position the drilling rig and start drilling, using low-headroom, fully-rotating steel pipe piles;

[0011] Step 4: During the drilling process, the pile steel sleeve is welded in sections;

[0012] Step 5: Grab the soil and use a low-headroom crawler crane and grab to remove the soil in the steel sleeve to meet the drilling requirements and check the final hole elevation until the designed hole bottom elevation is reached;

[0013] Step 6: Backfill the cavity inside the pile with concrete.

[0014] Furthermore, in step three of the drilling construction, each section of casing is placed in a pipe clamping device, the pipe clamping hydraulic cylinder is retracted, and the vertical accuracy of the casing is adjusted to the required range using the drilling rig and the guide correction device. After each section of casing is connected and the verticality is checked, the casing is rotated by no less than 360° through the rotating device of the full-rotation drilling rig, and then the blade teeth at the end of the casing are used to cut the soil or obstacles, pressed into the soil, and normal operation begins.

[0015] Furthermore, the steel pipe piles use Φ900mm, 20mm wall thickness steel pipes, 2m per section, and are connected by welded seams. Eight tungsten steel cutter heads are arranged at the bottom of the pipe mouth. The high-strength cutter heads at the pipe mouth cut the soil and reinforced concrete obstacles, and the casing is drilled into the ground. Then, a 50T crawler crane is used with a grab bucket to remove the soil in the pipe until it reaches the designed elevation.

[0016] Furthermore, the backfilling operation is carried out simultaneously with the casing extraction, and the layered backfilling is compacted with a hammer;

[0017] That is, before the casing is officially pulled out, a certain height of clay is first backfilled in the casing, and then backfilled while the casing is pulled out, always keeping the fill surface in the casing higher than a certain height from the bottom of the casing until the last section of the casing is pulled out, and finally backfilled to the ground elevation.

[0018] Furthermore, in order to simulate the U-shaped bottom plate opening and groundwater anti-spouting treatment, ground construction t=25mm outer steel casing and cast 0.9m thick reinforced concrete bottom plate at the bottom, and buried above the bottom plate t=20mm inner casing, A blowout prevention device is installed at the mouth of the full-rotation steel casing and the inner casing.

[0019] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method for fully rotating steel pipe piles in complex geological conditions with low headroom and high water levels. This method, combined with the engineering characteristics of limited pile construction space under high-speed railway bridges and construction in a concave U-shaped trough, has a complex engineering environment with low headroom, high water levels, and is located in a water-rich fine sand layer over the entire section. Referring to conventional positive circulation bored piles and taking into account a pile length of 36m, this method effectively solves the construction risks of groundwater upwelling after drilling and collapse of the hole due to inadequate slurry wall protection during drilling, thus ensuring the safety of surrounding sensitive environments such as high-speed railways.

[0020] This construction method has a short construction period, occupies a small temporary site, and involves less traffic coordination and external communication work;

[0021] Moreover, the engineering cost is significantly lower than that of conventional underground reinforcement, thus saving costs;

[0022] This construction method has low construction noise and does not involve the continuous noise generated by the collision of the construction pile frame and the pins during the conventional positive circulation bored pile drilling process. It is more friendly to surrounding residents. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 A construction flow chart of the full-rotation steel pipe pile process method under complex geological conditions with low headroom and high water levels provided by the present invention;

[0025] Figure 2 A schematic diagram of the steel pipe pile drilling process provided by the present invention;

[0026] Figure 3 This is a schematic diagram of the bottom plate opening anti-surge provided by the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] See also Figure 1-3 The embodiment of the present invention discloses a full-rotation steel pipe pile process under complex geological conditions with low headroom and high water level, comprising:

[0029] Step 1: Construction preparation: determine the construction area and arrange it according to the design requirements, and level the site;

[0030] Step 2: Position the pile foundation, stake out the pile position, determine the construction scope, and install the hole anti-spout device;

[0031] Step 3: Position the drilling rig and start drilling, using low-headroom, fully-rotating steel pipe piles;

[0032] Step 4: During the drilling process, the pile steel sleeve is welded in sections;

[0033] Step 5: Grab the soil and use a low-headroom crawler crane and grab to remove the soil in the steel sleeve to meet the drilling requirements and check the final hole elevation until the designed hole bottom elevation is reached;

[0034] Step 6: Backfill the cavity inside the pile with concrete.

[0035] In this embodiment, in step three of the drilling construction, each section of casing is placed in a pipe clamping device, the pipe clamping hydraulic cylinder is retracted, and the vertical accuracy of the casing is adjusted to the required range using the drilling rig and the guide correction device. After each section of casing is connected and the verticality is checked, the casing is rotated by not less than 360° through the rotating device of the full-rotation drilling rig to reduce the frictional resistance between the casing and the soil. The blade teeth at the end of the casing are then used to cut the soil or obstacles, pressed into the soil, and normal operation begins.

[0036] In this embodiment, the steel pipe piles use Φ900mm, 20mm wall thickness steel pipes, 2m per section, and are connected by welded seams. Eight tungsten steel cutter heads are arranged at the bottom of the pipe mouth. The high-strength cutter heads at the pipe mouth cut the soil and reinforced concrete obstacles, and the casing is drilled into the ground. Then, a 50T crawler crane is used with a grab bucket to remove the soil in the pipe to the designed elevation.

[0037] In this embodiment, the backfilling operation is carried out simultaneously with the casing extraction, and the layered backfilling process is compacted with a hammer;

[0038] That is, before the casing is officially pulled out, a certain height of clay is first backfilled in the casing, and then backfilled while the casing is pulled out, always keeping the fill surface in the casing higher than a certain height from the bottom of the casing until the last section of the casing is pulled out, and finally backfilled to the ground elevation.

[0039] In this embodiment, in order to simulate the U-shaped bottom plate opening and groundwater anti-spouting treatment, the ground construction t=25mm outer steel casing and cast 0.9m thick reinforced concrete bottom plate at the bottom, and buried above the bottom plate t=20mm inner casing, A blowout prevention device is set at the mouth of the full-rotation steel casing and the inner casing; the anti-gushing device can refer to the jacking tunnel sealing system, that is, a flange base is set on the top of the Φ1000 steel casing, and bolt holes are set at intervals of 20cm. Each bolt hole is equipped with an M20 high-strength bolt to fix the sliding sealing steel plate. When the U-shaped groove bottom plate is broken to 10cm from the bottom, the Φ900 casing is lowered, and then the sealing steel plate is slid close to the 900 casing and the bolts are tightened. It can be adjusted according to actual conditions during the drilling process; grease is pressed between the inner and outer casings.

[0040] In addition, in this embodiment, during the steel casing drilling construction, since the steel casing is fully rotated and the end cutter head is equipped with a load control device, it can be ensured that the load of the cutter head is within the most appropriate range. The drilling rig can arbitrarily adjust the maximum values of the casing's rotational torque, rotational speed, pressing force and clamping force, and can set the engine to high speed, medium speed and low speed, so efficient construction can be carried out according to the geological and obstacle conditions.

[0041] During drilling, the load on the cutter head and the torque on the casing are determined by the following factors:

[0042] F=Wc+Wd+fR

[0043] F—Load on casing cutter head

[0044] Wc—device weight

[0045] Wd—pressurized cylinder pressure

[0046] R—resistance of casing wall

[0047] Usually, when the casing is rotated and pressed in, the rotation torque is

[0048] T=T1+T2

[0049] T1—Torque T required for the casing to overcome the circumferential resistance

[0050] T2—The rotation torque required when the cutter head cuts the soil

[0051] The torque required for casing drilling = 0.9 * 3.14 * 39.29 * 0.98 = 108 tfm

[0052] The rotary torque of the full-rotation drilling rig is 143tfm>108tfm, which can smoothly press the casing in.

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0054] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A full-rotation steel pipe pile process under low headroom and high water level complex geological conditions, characterized by: The specific steps include: Step 1: Construction preparation: determine the construction area and arrange it according to the design requirements, and level the site; Step 2: Position the pile foundation, stake out the pile position, determine the construction scope, and install the hole anti-spout device; Step 3: Position the drilling rig and start drilling, using low-headroom, fully-rotating steel pipe piles; Step 4: During the drilling process, the pile steel sleeve is welded in sections; Step 5: Grab the soil and use a low-headroom crawler crane and grab to remove the soil in the steel sleeve to meet the drilling requirements and check the final hole elevation until the designed hole bottom elevation is reached; Step 6: Backfill the cavity inside the pile with concrete.

2. The method for fully rotating steel pipe piles in complex geological conditions with low headroom and high water level according to claim 1 is characterized in that: In step three, during drilling construction, each section of casing is placed in a pipe clamping device, the pipe clamping hydraulic cylinder is retracted, and the vertical accuracy of the casing is adjusted to the required range using the drilling rig and the guide correction device. After each section of casing is connected and the verticality is checked, the casing is rotated by no less than 360° through the rotating device of the full-rotation drilling rig, and then the blade teeth at the end of the casing are used to cut the soil or obstacles, pressed into the soil, and normal operation begins.

3. The method for fully rotating steel pipe piles in complex geological conditions with low headroom and high water level according to claim 1 is characterized in that: The steel pipe piles use Φ900mm, 20mm wall thickness steel pipes, 2m per section, and are connected by welded seams. Eight tungsten steel cutter heads are arranged at the bottom of the pipe mouth. The high-strength cutter heads at the pipe mouth use their cutting effect on soil and reinforced concrete obstacles to drill the casing into the ground. Then, a 50T crawler crane is used in conjunction with a grab bucket to remove the soil in the pipe to the designed elevation.

4. The method for fully rotating steel pipe piles in complex geological conditions with low headroom and high water level according to claim 1 is characterized in that: Backfilling is carried out simultaneously with casing extraction, and compaction is carried out with a hammer during the layered backfilling process; That is, before the casing is officially pulled out, a certain height of clay is first backfilled in the casing, and then backfilled while the casing is pulled out, always keeping the fill surface in the casing higher than a certain height from the bottom of the casing until the last section of the casing is pulled out, and finally backfilled to the ground elevation.

5. The method for full-rotation steel pipe pile construction under complex geological conditions with low headroom and high water level according to claim 1 is characterized in that: To simulate the U-shaped bottom plate opening and groundwater anti-spouting treatment, ground construction t=25mm outer steel casing and cast 0.9m thick reinforced concrete bottom plate at the bottom, and buried above the bottom plate t=20mm inner casing, A blowout prevention device is installed at the mouth of the full-rotation steel casing and the inner casing.

Images