A hole cleaning device and method for bored cast-in-place piles based on micro-perturbation of hole wall

Abstract

The present invention relates to the technical field of hole cleaning for bored cast-in-place piles, and specifically to a hole cleaning device and method for bored cast-in-place piles based on micro-disturbance of the hole wall, including an air delivery device, a hoisting mechanism, an air-liquid mixer, a sediment stirring device, a slag discharging mechanism, a slurry replenishing mechanism, and a filtering device. One end of the air delivery pipe is connected to an air compressor, and the other end is connected to the air-liquid mixer. The air-liquid mixer is installed on the slag discharging pipe, and the slag discharging pipe is arranged inside the pouring conduit. One end of the slurry replenishing pipe is connected to a grouting machine, and the other end is connected to the sediment stirring device. The sediment stirring device is connected to the hoisting mechanism by a towing rope. During operation, the sediment stirring device is sleeved on the pouring conduit and lowered to the bottom of the pouring conduit, and cooperates with the air delivery device and the slag discharging mechanism to complete the slag cleaning work before pouring concrete for the bored cast-in-place pile. This device is innovated on the basis of the traditional air-lift reverse circulation slag cleaning device, and has the advantages of small air demand, thorough slag cleaning, small disturbance to the hole wall, simple structure, wide application range, etc.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of hole cleaning for bored cast-in-place piles, and particularly relates to a hole cleaning device and method for bored cast-in-place piles based on micro-disturbance of the hole wall. Background Art

[0002] As an important foundation form for improving the bearing capacity of the foundation, bored cast-in-place piles are widely used in infrastructure construction such as housing construction and municipal bridges. The cleaning of sediment after the formation of the bored cast-in-place pile is a key process in pile foundation construction, and the thickness of the sediment directly affects the construction quality of the pile foundation; especially when the underwater cast-in-place pile is in strata such as silty soil, sandy soil, and gravelly soil that are prone to hole collapse, hole cleaning before the pouring of pile body concrete is the key to controlling the thickness of bottom sediment. In engineering, the air-lift reverse circulation slag cleaning method is widely used in the construction of bored cast-in-place piles with large diameters and ultra-deep pile lengths due to its high slag cleaning efficiency and good slag cleaning effect. However, this process also has certain disadvantages. On the one hand, the traditional air-lift reverse circulation slag cleaning process requires large-scale gas transmission and slurry replenishment equipment as well as multiple large slurry ponds, making on-site operation extremely inconvenient. On the other hand, for strata such as silty soil, sandy soil, and gravelly soil that are prone to hole collapse, the hole wall is extremely prone to disturbance during the process of discharging slag and replenishing slurry, and then the phenomenon of hole collapse occurs. For the above reasons, air-lift reverse circulation slag cleaning is rarely used in the construction of small-diameter bored cast-in-place piles in housing construction.

[0003] The "Device and Method for Local Air-Lift Reverse Circulation Bottom Slag Cleaning before Pouring Concrete for Bored Cast-in-Place Piles" disclosed in Chinese Patent CN109853571A sets the slag discharge pipe and slurry replenishment pipe inside the pouring conduit. Using a small-diameter slag discharge pipe for slag discharge solves the use of large-scale equipment, and placing the slurry replenishment pipe inside the pouring conduit avoids disturbing the hole wall. However, this device still has the following disadvantages:

[0004] (1) This device uses an air-slurry mixing three-way pipe to mix compressed gas and slurry. Since the sizes of the bubbles formed by the compressed gas are different, the formed gas-liquid-solid three-phase flow is uneven and has poor stability, directly affecting the slag discharge effect; moreover, this device does not have a check valve at the position of the air-slurry mixing three-way pipe, and after stopping the gas transmission, slurry backflow will occur, blocking the air supply pipe;

[0005] (2) The air supply volume and air pressure of the slag discharge pipe of this device are small, and the self-suction force formed at the bottom slag discharge port is small. Since the bottom sediment is not in a suspended state, finally, the bottom sediment is prone to form a funnel shape, resulting in incomplete slag cleaning. Summary of the Invention

[0006] To solve the deficiencies of the current technology, the present invention combines the existing technology and starts from practical applications to provide a hole cleaning device and method for bored cast-in-place piles based on micro-disturbance of the hole wall, which can effectively solve problems such as uneven mixing of compressed gas with slurry and sediment, and suspension of bottom sediment. Moreover, this device is simple to operate, small and economical, and has a better slag cleaning effect.

[0007] The technical solution of the present invention is as follows:

[0008] According to one aspect of the present invention, there is provided a hole cleaning device for bored cast-in-place piles based on micro-disturbance of the hole wall, including an air delivery device, an air-liquid mixer, a slag discharging mechanism and a slurry replenishing mechanism. The air delivery pipe of the air delivery device is connected to the air-liquid mixer, and the air-liquid mixer is installed on the slag discharging pipe of the slag discharging mechanism. The slag discharging pipe passes through the perfusion conduit.

[0009] An equal spiral air outlet pipe communicated with the air delivery pipe is arranged in the mixing cavity of the air-liquid mixer, and air outlet holes with equal radii are uniformly arranged on the side wall of the equal spiral air outlet pipe.

[0010] A sediment stirring device is arranged at the bottom of the borehole. The sediment stirring device is connected to a hoisting mechanism and can make a reciprocating lifting motion along the axis direction of the perfusion conduit under the drive of the hoisting mechanism.

[0011] The slurry replenishing mechanism includes a slurry replenishing pipe, and the slurry replenishing pipe is connected to the sediment stirring device.

[0012] Further, the slag discharging pipe includes an upper slag discharging pipe and a lower slag discharging pipe. The air-liquid mixer includes a first connection port, an air-liquid mixing component and a second connection port. The first connection port and the second connection port are respectively connected to the upper slag discharging pipe and the lower slag discharging pipe.

[0013] The air-liquid mixing component includes the mixing cavity and the equal spiral air outlet pipe. A first slope is arranged at the connection between the mixing cavity and the first connection port, and a second slope is arranged at the connection between the mixing cavity and the second connection port. The first slope and the second slope form a transition at the reduced diameter positions of the mixing cavity and the first connection port and the second connection port.

[0014] Further, the equal spiral air outlet pipe is composed of spiral hollow circles with equal spacing and equal spiral diameter. The air delivery pipe is connected to a first connecting pipe and a second connecting pipe through a tee pipe. The first connecting pipe and the second connecting pipe are respectively communicated with both ends of the equal spiral air outlet pipe through a first air inlet channel and a second air inlet channel, and the cross-sectional areas of the first connecting pipe and the second connecting pipe are both 1 / 2 of the cross-sectional area of the air delivery pipe.

[0015] Further, the spacing between the air outlet holes on the equal spiral air outlet pipe satisfies the following formula:

[0016] ;

[0017] The radius of the air outlet holes satisfies the following formula:

[0018] ;

[0019] Wherein, x is the distance between the air outlet holes, R is the spiral radius of the equal spiral air outlet pipe, N is the number of spiral turns of the equal spiral air outlet pipe, n is the number of air outlet holes, A is the cross-sectional area of the air delivery pipe, and r is the radius of the air outlet hole.

[0020] Furthermore, a first check valve is provided at the connection between the air delivery pipe and the gas-liquid mixer, and a second check valve is provided at the connection between the slurry replenishing pipe and the sediment agitation device;

[0021] The first check valve includes an upper sleeve, a support rod, a spring, a limit ring, a pull ring, a sealing plate, and a lower sleeve;

[0022] The limit ring is fixed at the connection between the upper sleeve and the lower sleeve, and the sealing plate is located inside the lower sleeve and is rotatably connected to the limit ring for closing or opening the limit ring;

[0023] The support rod is fixed in a cross shape on the inner wall of the upper sleeve. One end of the spring is connected to the cross-shaped node of the support rod, and the other end passes through the limit ring and is connected to the pull ring fixed at the center of the sealing plate;

[0024] The structure of the second check valve is the same as that of the first check valve.

[0025] Furthermore, a diagonal support rod is provided on the inner wall of the lower sleeve. The diagonal support rod forms an angle of 45° with the axis direction of the lower sleeve, and the diagonal support rod is used to limit the sealing plate so that the maximum opening angle of the sealing plate is 45°.

[0026] Furthermore, the hoisting mechanism includes a motor and a traction rope. The sediment agitation device is connected to the motor through two calibrated traction ropes;

[0027] The sediment agitation device includes an annular slurry delivery pipe, a sediment agitator, and a counterweight assembly,

[0028] The annular slurry delivery pipe is connected to the traction rope through an earring. The annular slurry delivery pipe can pass through the perfusion catheter from the outside. The slurry replenishing pipe is connected to the annular slurry delivery pipe. A plurality of the sediment agitators are evenly arranged below the annular slurry delivery pipe, and a plurality of the counterweight assemblies are evenly arranged below the annular slurry delivery pipe.

[0029] Furthermore, the sediment agitator includes a cylinder body communicated with the annular slurry delivery pipe. A conical tip is provided at the bottom of the cylinder body. First slurry outlet holes, second slurry outlet holes, and third slurry outlet holes are provided on the cylinder body. The distance ratios from the first slurry outlet holes, the second slurry outlet holes, and the third slurry outlet holes to the conical tip are 1:3:6;

[0030] The included angle between the first slurry outlet hole and the axis direction of the cylinder body is 45°, the included angles between the second slurry outlet hole and the third slurry outlet hole and the axis of the cylinder body are 60°. The first slurry outlet hole, the second slurry outlet hole and the third slurry outlet hole of the sediment agitator all face the position of the center of the bored pile hole, and slurry outlet hole supports are arranged at the first slurry outlet hole, the second slurry outlet hole and the third slurry outlet hole.

[0031] Furthermore, the length of the counterweight assembly is greater than the length of the sediment agitator, and the counterweight assembly includes a chain and a conical hammer.

[0032] According to another aspect of the present invention, there is provided a hole cleaning method for a hole cleaning device of a bored pile based on micro-disturbance of the hole wall as described above, including the following steps:

[0033] S1. After the bored pile completes the first hole cleaning, lower the steel reinforcement cage and the perfusion catheter, and perform the second hole cleaning before concrete perfusion;

[0034] S2. Set an orifice plate at the drilling hole, place a hoisting mechanism on the orifice plate, the hoisting mechanism is connected to the sediment agitation device through two traction ropes, connect the slurry replenishing pipe to the sediment agitation device through a second check valve, and the sediment agitation device passes through the perfusion catheter and is placed at a position not less than 1 m from the bottom of the catheter;

[0035] S3. Install the gas transmission pipe on the gas-liquid mixer through a first check valve, install the gas-liquid mixer on the slag discharge pipe, and then pass the slag discharge pipe through the perfusion catheter from the inside and place it 20 cm from the bottom of the catheter;

[0036] S4. Start the grouting machine of the slurry replenishing mechanism to replenish slurry into the hole, and at the same time start the motor on the hoisting mechanism to rotate forward and backward, so that the sediment agitation device makes a reciprocating motion along the axis direction of the perfusion catheter at the bottom of the hole;

[0037] S5. Start the air compressor to supply gas to the gas-liquid mixer through the gas transmission pipe, lower the sediment agitation device in time according to the slag discharge condition of the slag discharge pipe, and determine whether the sediment agitation device is lowered to the bottom of the hole according to the scale on the traction rope; the slag discharge pipe discharges the slurry and sediment mixture into the filtering device for sediment and slurry separation until the slurry discharged from the slag discharge pipe does not contain sediment;

[0038] S6. Stop the slurry replenishing of the grouting machine, release the pressure in the slurry replenishing pipe, and then disassemble the slurry replenishing mechanism and the gas transmission device, and the hole cleaning is completed.

[0039] The beneficial effects of the present invention:

[0040] 1. Through the design of a gas-liquid mixer with a unique structure, this device can provide a stable gas-liquid-solid three-phase flow. The compressed gas forms multi-layer equal-velocity bubbles through the spiral gas outlet pipe, etc., enabling the bubbles to be fully mixed with the slurry and sediment, forming a uniform and stable three-phase flow, and producing a better sediment cleaning effect. At the same time, through the sediment agitation device, the sediment at the bottom of the hole can be suspended. Since the slurry replenishment pipe leads to the bottom of the hole and the replenishment slurry flow rate is balanced with the discharge slurry flow rate, the slurry from the upper part of the sediment to the hole opening is basically in a static state, especially providing good protection for the hole walls of easily caving holes such as silt, sand, and gravel soil.

[0041] 2. A unique check valve is designed between the gas delivery pipe and the gas-liquid mixer, and between the slurry replenishment pipe and the sediment agitation device. This can prevent the backflow of mud and sediment from blocking the gas delivery pipe, and also prevent the backflow of the slurry in the slurry replenishment pipe. Moreover, the structural design of the check valve is suitable for stable operation in a complex mud environment.

[0042] 3. The structural design of the sediment agitation device of this device can not only drive the sediment to rise through momentum transfer to form an effective upward flow, but also avoid the impact damage to the hole wall caused by vertical jetting. Through the counterweight assembly, it can not only drive the sediment agitator to sink, but also prevent the sediment agitator from directly inserting into the undisturbed soil at the bottom of the hole and blocking the slurry outlet hole.

[0043] 4. This device and method are applicable to the hole cleaning of bored cast-in-place piles formed by various process equipment, and are applicable to the primary hole cleaning and secondary hole cleaning work after hole formation, with strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the hole cleaning device for bored cast-in-place piles based on micro-disturbance of the hole wall provided by the present invention;

[0045] Figure 2 External structure schematic diagram of the gas-liquid mixer of the present invention;

[0046] Figure 3 Internal structure schematic diagram of the gas-liquid mixer of the present invention;

[0047] Figure 4 Schematic diagram of the check valve structure of the present invention;

[0048] Figure 5 Partial component structure schematic diagram of the check valve of the present invention;

[0049] Figure 6 Schematic diagram of the sediment agitation device structure of the present invention;

[0050] Figure 7 Schematic diagram of the sediment agitator structure of the present invention;

[0051] Figure 8 Schematic diagram of the slurry outlet hole structure of the sediment agitator of the present invention;

[0052] Figure 9 This is a schematic structural diagram of the counterweight assembly of the present invention.

[0053] In the figure: 101 - hole wall, 102 - sediment, 103 - grouting conduit, 104 - hole mouth guard plate;

[0054] 210 - air compressor, 220 - air delivery pipe, 230 - first check valve, 231 - upper sleeve, 232 - support rod, 233 - spring, 234 - limit ring, 235 - sealing plate, 236 - diagonal brace, 237 - pull ring, 238 - lower sleeve, 239 - first hinge, 240 - second hinge, 250 - L-shaped joint,

[0055] 3 - gas-liquid mixer, 310 - first connection port, 320 - gas-liquid mixing assembly, 321 - first ramp, 322 - mixing cavity, 323 - second ramp, 330 - second connection port, 340 - tee, 350 - first connecting pipe, 360 - second connecting pipe, 370 - equal spiral gas outlet pipe, 371 - air outlet hole, 372 - first air inlet channel, 373 - second air inlet channel,

[0056] 410 - hoisting mechanism, 420 - towing rope, 430 - motor,

[0057] 5 - sediment agitation device, 510 - annular slurry delivery pipe, 520 - earring, 530 - sediment agitator, 531 - cylinder, 532 - third slurry outlet hole, 533 - second slurry outlet hole, 534 - first slurry outlet hole, 535 - slurry outlet hole support, 536 - conical tip, 540 - counterweight assembly, 541 - chain, 542 - conical hammer,

[0058] 610 - upper slag discharge pipe, 620 - lower slag discharge pipe,

[0059] 710 - grouting machine, 720 - pressure relief valve, 730 - second slurry replenishing pipe, 740 - second check valve, 750 - first slurry replenishing pipe,

[0060] 8 - filtering device, 9 - slurry pit. Detailed implementation manners

[0061] In combination with the accompanying drawings and specific embodiments, the present invention will be further described. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by this application.

[0062] Embodiment 1

[0063] This embodiment provides a hole cleaning device for bored cast-in-place piles based on micro-disturbance of the hole wall. Refer toFigures 1-9 as shown

[0064] The hole cleaning device of this embodiment mainly includes an air delivery device, a hoisting mechanism 410, a gas-liquid mixer 3, a sediment stirring device 5, a slag discharging mechanism, a slurry replenishing mechanism, and a filtering device 8.

[0065] Among them, the air delivery device includes an air compressor 210, an air delivery pipe 220, and a first check valve 230. One end of the air delivery pipe 220 is connected to the air compressor 210, and the other end is connected to the gas-liquid mixer 3. It should be noted that the air compressor 210 required for this device is a small air compressor or a compressed air pump, which is characterized by being light and convenient.

[0066] The hoisting mechanism 410 of this embodiment includes a motor 430 and a towing rope 420. The towing rope 420 has two main functions: one is to connect the motor 430 and the sediment stirring device 5 to drive the sediment stirring device 5 to reciprocate up and down, and the other is that the towing rope 420 is marked with scales to record the depth of the sediment stirring device 5 lowered. It should be noted that there are two motors 430 of the same model, which are controlled by the same switch and can rotate at the same speed.

[0067] As a preferred solution of this embodiment, the slag discharging mechanism includes an upper slag discharging pipe 610 and a lower slag discharging pipe 620. The upper slag discharging pipe 610 and the lower slag discharging pipe 620 are fixedly connected by the gas-liquid mixer 3. A filtering device 8 is provided at the slag discharging outlet of the upper slag discharging pipe 610, and the lower slag discharging pipe 620 can extend into the perfusion catheter 103.

[0068] In this embodiment, a unique structure of the gas-liquid mixer 3 is designed. The gas-liquid mixer 3 mainly includes a first slope 321, a mixing cavity 322, a second slope 323, an equal spiral air outlet pipe 370, a first air inlet channel 372, a first connecting pipe 350, a second air inlet channel 373, a second connecting pipe 360, and a three-way pipe 340. The upper slag discharging pipe 610 is connected to the first connection port 310, and the lower slag discharging pipe 620 is connected to the second connection port 330. It should be noted that the position of the gas-liquid mixer 3 from the bottom of the hole is 1 / 3 of the hole depth (as shown in part A of Figure 1 ). The functions of the first slope 321 and the second slope 323 are to make the mixing cavity 322 and the first connection port 310 and the second connection port 330 form a transition at the variable diameter position. In this embodiment, there is a variable diameter structure between the connection port and the mixing cavity 322, and there is a variable diameter step. Then, the slurry and sediment are likely to accumulate at this place when moving up and down. By setting a slope at the variable diameter position, the variable diameter is smoothly transitioned, so that the sediment does not form an accumulation and block the flow during the upward return process.

[0069] In this embodiment, the equal-helix gas outlet pipe 370 is composed of spiral hollow rings with equal spacing and equal helix diameter. Both ends of the equal-helix gas outlet pipe 370 are air inlets, which are respectively connected to the first air inlet channel 372 and the second air inlet channel 373. As shown in the figure, the gas transmission pipe 220 is located outside the mixing cavity 322. It is connected to an L-shaped joint 250 through a first check valve 230. The outlet of the L-shaped joint 250 is connected to a tee pipe 340. The two outlets of the tee pipe 340 are respectively connected to a first connecting pipe 350 and a second connecting pipe 360. The first connecting pipe 350 is connected to the first air inlet channel 372, and the first air inlet channel 372 is connected to the air inlet at the head end of the equal-helix gas outlet pipe 370. The second connecting pipe 360 is connected to the second air inlet channel 373, and the second air inlet channel 373 is connected to the air inlet at the end of the equal-helix gas outlet pipe 370. It should be noted that the first air inlet channel 372 and the second air inlet channel 373 are of equal-diameter structure, and the cross-sectional area is 1 / 2 of the cross-section A of the gas transmission pipe 220 to ensure the uniformity of air intake.

[0070] In this embodiment, the helix diameter 2R of the equal-helix gas outlet pipe 370 is slightly smaller than the inner diameter of the mixing cavity 322. The number of helix rings is N. The air outlet holes 371 with equal radius r are evenly arranged on the side wall of the equal-helix gas outlet pipe 370. Let the number of air outlet holes 371 be n, and the spacing between the air outlet holes 371 be x. Then, the design of the spacing between the air outlet holes 371 and the radius of the air outlet holes 371 needs to satisfy the formula:

[0071] ,

[0072] ;

[0073] The purpose of the above design is to ensure that the gas is fully diffused in the mixing cavity 322, avoid the formation of flow blind areas due to too large a spacing between adjacent holes, and prevent the large air outlet volume near the air inlet end and uneven exhaust caused by too large a hole diameter, and the low exhaust efficiency caused by too small a hole diameter.

[0074] As a preferred solution of this embodiment, the gas-liquid mixer 3 and the gas transmission pipe 220 are connected together through the first check valve 230. Referring to the figure shown, the first check valve 230 includes an upper sleeve 231, a support rod 232, a spring 233, a limit ring 234, a pull ring 237, a sealing plate 235, an inclined support rod 236, and a lower sleeve 238. The limit ring 234 is fixed at the connection of the upper sleeve 231 and the lower sleeve 238. The opening and closing of the hole in the middle of the limit ring 234 controls the communication between the upper sleeve 231 and the lower sleeve 238. The sealing plate 235 is located in the lower sleeve 238 and is rotatably connected to the limit ring 234 by a first hinge 239 and a second hinge 240. Obviously, the inner diameter of the limit ring 234 is smaller than the diameter of the sealing plate 235.

[0075] The support rod 232 is fixed to the inner wall of the upper sleeve 231 in a cross shape. The pull ring 237 is fixed at the center of the sealing plate 235. One end of the spring 233 is connected to the cross-shaped node of the support rod 232, and the other end is connected to the pull ring 237. It should be noted that when the first check valve 230 is not working, the sealing plate 235 closely adheres to the limit ring 234 under the action of the spring 233, closing the limit ring 234, and an isolation space is formed between the upper sleeve 231 and the lower sleeve 238.

[0076] As the main key point in the design of the first check valve 230, the maximum opening angle of the sealing plate 235 is 45°. The included angle between the inclined support rod 236 and the axis direction of the lower sleeve 238 is 45°. One end is fixed to the inner wall of the lower sleeve 238. When the sealing plate 235 opens at 45°, it just contacts the other end of the inclined support rod 236. After the first check valve 230 stops working, the sealing plate 235 quickly fits with the limit ring 234 under the dual action of the spring 233 and the slurry, completing the reverse flow prevention work of the slurry.

[0077] It should be noted that the first check valve 230 and the second check valve 740 mentioned in the present invention have the same structure. The second check valve 740 is arranged between the second slurry replenishing pipe 730 and the annular slurry conveying pipe 510.

[0078] As a preferred solution of this embodiment, the sediment agitation device 5 is arranged at the bottom of the hole (as shown in part B in Figure 1 ), and is connected to the motor 430 by a towing rope 420. As shown in the reference drawings, the sediment agitation device 5 includes an earring 520, an annular slurry conveying pipe 510, a sediment agitator 530, and a counterweight assembly 540. The earrings 520 are symmetrically arranged on the annular slurry conveying pipe 510, and the sediment agitators 530 are evenly arranged on the annular slurry conveying pipe 510.

[0079] Furthermore, the sediment agitator 530 is composed of a cylinder body 531, a conical tip 536, a first slurry outlet hole 534, a second slurry outlet hole 533, a third slurry outlet hole 532, and a slurry outlet hole support 535.

[0080] It should be noted that the distance ratios from the first slurry outlet hole 534, the second slurry outlet hole 533, and the third slurry outlet hole 532 to the conical tip 536 are 1:3:6. The included angle between the first slurry outlet hole 534 and the axis direction of the cylinder body 531 is 45°. The included angles between the second slurry outlet hole 533 and the third slurry outlet hole 532 and the axis of the cylinder body 531 are 60°. The purpose of this angle design is that it can drive the sediment 102 to rise through momentum transfer to form an effective upward flow, and can also avoid the impact damage to the hole wall caused by vertical jetting. The function of the first slurry outlet hole 534 is to disturb the sediment 102, and the functions of the second slurry outlet hole 533 and the third slurry outlet hole 532 are to keep the sediment 102 in a suspended state.

[0081] As a preferred solution of this embodiment, the slurry outlet support 535 is sleeved on the exposed ends of the first slurry outlet 534, the second slurry outlet 533, and the third slurry outlet 532, and is fixed on the side wall of the cylinder 531. Obviously, the function of the slurry outlet support 535 is to reinforce the slurry outlet.

[0082] Furthermore, the distribution spacing of the sediment agitators 530 is controlled between 10 - 15 cm. One side of the slurry outlet of each sediment agitator 530 faces the center of the bored pile hole. The purpose is to avoid the spraying coverage blind area and reduce the risk of scouring the hole wall at the same time.

[0083] As a preferred solution of this embodiment, the counterweight assembly 540 includes a chain 541 and a conical hammer 542. The counterweight assemblies 540 are evenly distributed on the annular slurry delivery pipe 510, and the distribution spacing is controlled between 20 - 30 cm. It should be noted that the length of the counterweight assembly 540 is greater than the length of the sediment agitator 530. The purpose is that the counterweight assembly 540 can not only drive the sediment agitator 530 to sink, but also prevent the sediment agitator 530 from directly inserting into the undisturbed soil at the bottom of the hole and blocking the slurry outlet.

[0084] Embodiment 2

[0085] In Embodiment 1, a hole cleaning device for bored cast-in-place piles based on micro-disturbance of the hole wall of the present application is described in detail. This embodiment provides an implementation method of the above device, which specifically includes the following steps:

[0086] S1. After the first hole cleaning of the bored cast-in-place pile is completed, the steel reinforcement cage and the perfusion conduit 103 are lowered. Before the concrete is poured, a second hole cleaning is required.

[0087] S2. Place the hoisting mechanism 410 on the hole mouth guard plate 104. One end of two traction ropes 420 is connected to the earring 520 on the sediment agitation device 5. Connect the second slurry supply pipe 730 to the sediment agitation device 5 through the second check valve 740. The sediment agitation device 5 passes through the perfusion conduit 103 and is placed at a position not less than 1 m from the bottom of the conduit.

[0088] S3. The gas delivery pipe 220 is installed on the gas-liquid mixer 3 through the first check valve 230. The upper slag discharge pipe 610 and the lower slag discharge pipe 620 are connected by the gas-liquid mixer 3, and then they pass through the perfusion conduit 103 and are placed 20 cm from the bottom of the conduit.

[0089] S4. Start the grouting machine 710 to supply slurry to the hole. At the same time, start the motor 430 on the hoisting mechanism 410 to rotate forward and backward, so that the sediment agitation device 5 makes a reciprocating motion along the axis direction of the perfusion conduit 103 at the bottom of the hole.

[0090] S5. Start the air compressor 210 to supply air to the gas-liquid mixer 3 through the air delivery pipe 220. Lower the sediment agitation device 5 in a timely manner according to the slag discharge condition of the upper slag discharge pipe 610, and determine whether the sediment agitation device 5 has been lowered to the bottom of the hole according to the scale on the orifice traction rope 420. The upper slag discharge pipe 610 discharges the slurry and sediment mixture into the filtering device 8 for sediment and slurry separation. The separated slurry is discharged into the slurry pit 9 through the first slurry replenishment pipe 750 for recycling until the slurry discharged from the upper slag discharge pipe 610 does not contain sediment 102.

[0091] S6. Stop the slurry replenishment of the grouting machine 710, open the pressure relief valve 720 to release the pressure in the second slurry replenishment pipe 730, and drive the sealing plate 235 to reset under the action of the spring 233 in the sediment agitation device 5 and the second check valve 740. Then disassemble the slurry replenishment mechanism and the air delivery device, and the hole cleaning is completed.

[0092] As can be seen from the above embodiments, the present device can provide a stable gas-liquid-solid three-phase flow. The compressed gas forms multi-layer equal-velocity bubbles through the spiral air delivery device, etc., so that the bubbles are fully mixed with the slurry and sediment, forming a uniform and stable three-phase flow, and producing a better slag cleaning effect. A check valve is designed between the air delivery pipe and the gas-liquid mixer to prevent the reverse flow of slurry and sediment from blocking the air delivery pipe. The sediment agitation device can keep the sediment at the bottom of the hole in a suspended state. Since the slurry replenishment pipe leads to the bottom of the hole and the slurry replenishment flow rate is balanced with the slurry discharge flow rate, the slurry from the upper part of the sediment to the orifice section is basically in a static state, especially providing good protection for the hole walls of easily caving holes such as silt, sand, and gravel soil. Moreover, the present device and method are applicable to the hole cleaning of bored cast-in-place piles formed by various process equipment, and are applicable to the first and second hole cleanings after hole formation.

Claims

1. A hole cleaning device for bored cast-in-place piles based on micro-perturbation of the hole wall, comprising an air delivery device, an air-liquid mixer, a slag discharging mechanism and a slurry replenishing mechanism. The air delivery pipe of the air delivery device is connected to the air-liquid mixer, and the air-liquid mixer is installed on the slag discharging pipe of the slag discharging mechanism. The slag discharging pipe passes through the casting conduit. It is characterized in that an equal-spiral air outlet pipe communicating with the air delivery pipe is arranged in the mixing cavity of the air-liquid mixer, and air outlet holes with equal radii are uniformly arranged on the side wall of the equal-spiral air outlet pipe; a sediment stirring device is arranged at the bottom of the drill hole. The sediment stirring device is connected to a hoisting mechanism and can make reciprocating lifting motions along the axis direction of the casting conduit under the drive of the hoisting mechanism; the slurry replenishing mechanism includes a slurry replenishing pipe, and the slurry replenishing pipe is connected to the sediment stirring device; the hoisting mechanism includes a motor and a traction rope, and the sediment stirring device is connected to the motor through two calibrated traction ropes; the sediment stirring device includes an annular slurry delivery pipe, a sediment stirrer and a weight assembly; the annular slurry delivery pipe is connected to the traction rope through an earring. The annular slurry delivery pipe can pass through the casting conduit from the outside. The slurry replenishing pipe is connected to the annular slurry delivery pipe. A plurality of the sediment stirrers are uniformly arranged below the annular slurry delivery pipe, and a plurality of the weight assemblies are uniformly arranged below the annular slurry delivery pipe; the sediment stirrer includes a cylinder body communicating with the annular slurry delivery pipe. A conical tip is arranged at the bottom of the cylinder body. First slurry outlet holes, second slurry outlet holes and third slurry outlet holes are arranged on the cylinder body. The distance ratios from the first slurry outlet holes, the second slurry outlet holes and the third slurry outlet holes to the conical tip are 1:3:6; the angle between the first slurry outlet hole and the axis direction of the cylinder body is 45°. The angles between the second slurry outlet holes and the third slurry outlet holes and the axis of the cylinder body are 60°. The first slurry outlet holes, the second slurry outlet holes and the third slurry outlet holes of the sediment stirrer all face the position of the pile hole center of the cast-in-place pile. Slurry outlet hole supports are arranged at the first slurry outlet holes, the second slurry outlet holes and the third slurry outlet holes.

2. The hole cleaning device for bored cast-in-place piles based on micro-perturbation of the hole wall according to claim 1, characterized in that, the slag discharging pipe includes an upper slag discharging pipe and a lower slag discharging pipe. The air-liquid mixer includes a first connection port, an air-liquid mixing component and a second connection port. The first connection port and the second connection port are respectively connected to the upper slag discharging pipe and the lower slag discharging pipe. the air-liquid mixing component includes the mixing cavity and the equal-spiral air outlet pipe. A first slope is arranged at the connection between the mixing cavity and the first connection port, and a second slope is arranged at the connection between the mixing cavity and the second connection port. The first slope and the second slope form a transition at the reduced-diameter positions of the mixing cavity and the first connection port and the second connection port.

3. The hole cleaning device for drilled cast-in-place piles based on micro-perturbation of the hole wall according to claim 1, characterized in that the equal-spiral air outlet pipe is composed of spiral hollow circles with equal spacing and equal spiral diameters. The air delivery pipe is connected to a first connecting pipe and a second connecting pipe through a tee pipe. The first connecting pipe and the second connecting pipe are respectively communicated with the two ends of the equal-spiral air outlet pipe through a first air inlet channel and a second air inlet channel, and the cross-sectional areas of the first connecting pipe and the second connecting pipe are both 1 / 2 of the cross-sectional area of the air delivery pipe.

4. The hole cleaning device for bored cast-in-place piles based on micro-perturbation of the hole wall according to claim 3, wherein, The spacing between the air outlet holes on the equal-spiral air outlet pipe satisfies the following formula: ； The radius of the air outlet hole satisfies the following formula: ； where x is the spacing between the air outlet holes, R is the spiral radius of the equal-spiral air outlet pipe, N is the number of spiral circles of the equal-spiral air outlet pipe, n is the number of air outlet holes, A is the cross-sectional area of the air delivery pipe, and r is the radius of the air outlet hole.

5. The hole cleaning device for bored cast-in-place piles based on micro-disturbance of hole wall according to claim 1, wherein, A first check valve is provided at the connection between the gas transmission pipe and the gas-liquid mixer, and a second check valve is provided at the connection between the grout replenishing pipe and the sediment agitation device; The first check valve includes an upper sleeve, a support rod, a spring, a limit ring, a pull ring, a sealing plate, and a lower sleeve; The limit ring is fixed at the connection between the upper sleeve and the lower sleeve. The sealing plate is located inside the lower sleeve and is rotatably connected to the limit ring to close or open the limit ring; The support rod is fixed to the inner wall of the upper sleeve in a cross shape. One end of the spring is connected to the cross-shaped node of the support rod, and the other end passes through the limit ring and is connected to the pull ring fixed at the center of the sealing plate; The structure of the second check valve is the same as that of the first check valve.

6. The hole cleaning device for bored cast-in-place piles based on micro-perturbation of hole wall according to claim 5, wherein, Diagonal braces are provided on the inner wall of the lower sleeve. The diagonal braces form an angle of 45° with the axial direction of the lower sleeve. The diagonal braces are used to limit the sealing plate so that the maximum opening angle of the sealing plate is 45°.

7. The hole cleaning device for bored cast-in-place piles based on micro-disturbance of hole wall according to claim 1, wherein, The length of the counterweight assembly is greater than the length of the sediment agitator. The counterweight assembly includes a chain and a conical hammer.

8. The hole cleaning method of the hole cleaning device for bored cast-in-place piles based on micro-perturbation of hole wall according to any one of claims 1-7, characterized in that, It includes the following steps: S1. After the first hole cleaning of the bored pile is completed, lower the steel reinforcement cage and the perfusion conduit, and perform the second hole cleaning before the concrete perfusion; S2. Set an orifice plate at the drilling hole, place a hoisting mechanism on the orifice plate. The hoisting mechanism is connected to the sediment agitation device through two traction ropes. Connect the grout replenishing pipe to the sediment agitation device through the second check valve, and lower the sediment agitation device through the perfusion conduit to a position not less than 1 m from the bottom of the conduit; S3. Install the gas transmission pipe on the gas-liquid mixer through the first check valve, install the gas-liquid mixer on the slag discharge pipe, and then pass the slag discharge pipe through the perfusion conduit from the inside to a position 20 cm from the bottom of the conduit; S4. Start the grouting machine of the grout replenishing mechanism to replenish grout into the hole. At the same time, start the motor on the hoisting mechanism to rotate forward and backward, so that the sediment agitation device makes a reciprocating motion along the axial direction of the perfusion conduit at the bottom of the hole; S5. Start the air compressor to supply gas to the gas-liquid mixer through the gas transmission pipe. Lower the sediment agitation device in a timely manner according to the slag discharge condition of the slag discharge pipe, and determine whether the sediment agitation device is lowered to the bottom of the hole according to the scale on the traction rope; The slag discharge pipe discharges the slurry and sediment mixture into the filtering device for sediment and slurry separation until the slurry discharged from the slag discharge pipe does not contain sediment; S6. Stop the grouting machine from replenishing grout, release the pressure in the grout replenishing pipe, and then disassemble the grout replenishing mechanism and the gas supply device, and the hole cleaning is completed.

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