CN110872837A - Construction method for transforming empty pile section of rotary excavating cast-in-place pile into dewatering well - Google Patents

Construction method for transforming empty pile section of rotary excavating cast-in-place pile into dewatering well Download PDF

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Publication number
CN110872837A
CN110872837A CN201911206007.8A CN201911206007A CN110872837A CN 110872837 A CN110872837 A CN 110872837A CN 201911206007 A CN201911206007 A CN 201911206007A CN 110872837 A CN110872837 A CN 110872837A
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CN
China
Prior art keywords
pile
dewatering well
hole
water
well
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201911206007.8A
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Chinese (zh)
Inventor
陈枝东
王凤梅
周小吉
张领帅
房江锋
刘迪
刘峻滕
严树
李燕
韩晓峰
张思祺
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Hongye Base Geotechnical Technology Co Ltd
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Shenzhen Hongye Base Geotechnical Technology Co Ltd
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Publication date
Application filed by Shenzhen Hongye Base Geotechnical Technology Co Ltd filed Critical Shenzhen Hongye Base Geotechnical Technology Co Ltd
Priority to CN201911206007.8A priority Critical patent/CN110872837A/en
Publication of CN110872837A publication Critical patent/CN110872837A/en
Pending legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22Piles
    • E02D5/34Concrete or concrete-like piles cast in position ; Apparatus for making same
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/06Restraining of underground water
    • E02D19/10Restraining of underground water by lowering level of ground water

Abstract

The invention relates to the technical field of construction methods, and discloses a construction method for transforming a dewatering well by rotary excavating a cast-in-place pile empty pile section, which comprises a dewatering well part and a water pumping device; the construction method comprises the steps of setting a part, after concrete is poured, of a rotary pile hole as an engineering pile, setting a space above the top of the concrete in the pile hole as an empty pile section, setting the concrete part as the engineering pile, after the concrete is solidified, putting a dewatering well part into the pile hole, enabling underground water above the top of the engineering pile in a foundation pit to penetrate into the dewatering well part, after gravel filling and well washing processes, only pumping out water in the dewatering well part to ensure that construction cannot be hindered due to overhigh underground water level in the foundation pit, utilizing the empty pile section for placing the dewatering well part, combining the process of obtaining the engineering pile by rotary pile hole with the process of placing the dewatering well part, reducing repeated processes, saving a large amount of cost and shortening the construction period of a deep and large foundation pit.

Description

Construction method for transforming empty pile section of rotary excavating cast-in-place pile into dewatering well
Technical Field
The invention relates to the technical field of construction methods, in particular to a construction method for transforming a dewatering well by rotary excavating a cast-in-place pile empty pile section.
Background
In order to provide a good dry construction environment for foundation pit excavation construction and foundation slab structure construction; simultaneously, draining underground water in the foundation pit to ensure that soil layers in the pit are drained and consolidated, and arranging a dewatering well in the excavation process of the foundation pit; and a section of empty pile section is remained after the pile hole is used for manufacturing the engineering pile.
At present, the engineering pile is drilled from the ground until the bottom of a hole, and the engineering pile is poured with concrete only to fill the bottom surface of a foundation pit, namely the part below the designed elevation.
In the prior art, a section of empty pile section is remained after the engineering pile is manufactured in the pile hole, and the empty pile section is unsafe to be remained on the ground and is likely to have a falling accident; the empty pile section occupies the ground, so that the working area during subsequent mechanical and personnel construction is reduced; residual slurry in the empty pile section needs to be extracted by equipment and then is backfilled by using muck, so that the construction cost is high, the treatment is troublesome, and the construction period is long; need set up precipitation well before foundation ditch excavation first layer soil and carry out foundation ditch water level precipitation, it is longer to make the stake hole alone and place the time limit for a project that uses precipitation well spare.
Disclosure of Invention
The invention aims to provide a construction method for transforming an empty pile section of a rotary excavating cast-in-place pile into a dewatering well, and aims to provide a scheme for transforming the empty pile section in a pile hole into the dewatering well.
The invention is realized in this way, a construction method for transforming the empty pile section of the rotary digging cast-in-place pile into the dewatering well, which comprises a dewatering well part and a water pumping device for reducing the underground water level of the foundation pit, wherein the construction method comprises the following steps:
1) selecting a proper engineering pile position according to an engineering pile drawing and a precipitation specification, obtaining a pile hole on the engineering pile position through a rotary digging pile process, pouring concrete into the pile hole to obtain a hollow pile section and an engineering pile, standing the concrete of the engineering pile for more than half a month, cleaning the hollow pile section, and waiting for further solidification of the concrete of the engineering pile;
2) after the concrete in the pile hole is solidified, lowering the dewatering well part into the pile hole, and lowering the dewatering well part into the empty pile section;
3) filling gravel materials between the outer wall of the dewatering well element and the hole wall of the hollow pile section until the height of the gravel materials reaches the level of the gravel materials to form a gravel material layer, and filling clay into a space between the upper part of the gravel material layer and the plane where the hole opening of the pile hole is located to stabilize the dewatering well element and the gravel materials;
4) washing the interior of the dewatering well part by using a gas lift reverse circulation method, and removing hole bottom sediments in mud of the dewatering well part;
5) arranging a water pumping device in the pile hole and controlling to start or stop pumping water according to the water level height;
6) and removing the dewatering well member after the foundation pit is excavated.
Further, past in step (1) behind the stake hole cast-in-place concrete, the downthehole mud of stake by the concrete up pushes up, just after the concrete is wandered and is reached the design elevation, do below the design elevation the engineering stake, do not pour into in the stake hole the position of concrete forms empty stake section.
Further, in the step (1), a rotary drilling rig is used for cleaning holes of the hollow pile section, and a sand fishing bucket is used for grabbing sediments in the hollow pile section.
Further, the dewatering well part in the step (2) is lowered by a crane; the dewatering well part comprises a plurality of upper well pipes and a bottom well pipe, a camera is erected at the position of a first upper well pipe of the dewatering well part, and the camera is used for shooting and positioning the position of the dewatering well part.
Further, a viewing device connected with the camera is arranged outside the opening of the pile hole.
Further, the water pumping device in the step (5) comprises a water pumping pump, a liquid level sensor, a control box, a floating rod and an erection rod, wherein the water pumping pump is submerged into the permeation cavity in the dewatering well part, the liquid level sensor is arranged at the upper end of the dewatering well part, and the floating rod is placed in the dewatering well part; the utility model discloses a water pump, including the float, level sensor, water pump, control box, water-level sensor swing joint, the float with level sensor swing joint, level sensor and the water pump respectively with control box electric connection, control box control the water pump begins or stops drawing water.
Further, the suction pump is connected with the suction pipe, the suction pipe is followed precipitation well spare the infiltration chamber extends to precipitation well spare's outside, and is connected to the recovery ditch and discharges in unison.
Further, erect the pole and settle the top of precipitation well spare, and surround arrange around the stake hole, the control box is connected the electric wire that draws water of suction pump passes through erect the pole and toward extend in the precipitation well spare.
Further, erect be provided with on the pole with suction pump swing joint pull the rope, pull the rope with the suction pump is connected, just pull the rope and center on the electric wire that draws water arranges, it is used for pulling to pull the rope the suction pump.
Furthermore, the floating rod is provided with a floater and a vertical rod, the vertical rod is movably connected with the liquid level sensor, a notch is arranged on the vertical rod, a vertically downward liquid level hole is arranged in the liquid level sensor, and the vertical rod penetrates through the liquid level hole and moves up and down in the liquid level hole; the floater is soaked on the liquid level of the water in the permeation cavity, the floater fluctuates up and down along with the height of the liquid level, the floater is fixedly connected with the vertical rod, and the vertical rod is driven to move up and down in the liquid level hole when the floater fluctuates up and down; the liquid level sensor detects the rising or descending amplitude of the vertical rod, transmits a signal to the control box, and the control box controls the water suction pump to start or stop pumping water through the water pumping electric wire.
Compared with the prior art, the construction method for transforming the dewatering well by the rotary excavating bored concrete pile empty pile section provided by the invention has the advantages that the part of the rotary excavating pile hole after concrete is poured is set as the engineering pile, the space above the top of the concrete in the pile hole is set as the empty pile section, the concrete part is the engineering pile, after the concrete is solidified, the dewatering well part is put into the pile hole, the underground water in the foundation pit higher than the top of the engineering pile can permeate into the dewatering well part, after the gravel filling and well washing processes, only water in the dewatering well part needs to be pumped out, the construction cannot be hindered due to overhigh underground water level, the dewatering well part is placed in the empty pile section, the process of obtaining the engineering pile by rotary excavating the pile hole is combined with the process of placing the dewatering well part, repeated processes are reduced, a large amount of cost is saved, and the construction period of the deep foundation pit is shortened.
Drawings
FIG. 1 is a schematic step diagram of a construction method for reconstructing a dewatering well by rotary excavating a cast-in-place pile empty pile section provided by the invention;
FIG. 2 is a schematic front view of an empty pile section and an engineering pile provided by the present invention;
FIG. 3 is a schematic front view of the dewatering well element provided by the present invention;
fig. 4 is a schematic view of the connection between the inner filter layer and the reinforcing steel layer provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The following describes the implementation of the present invention in detail with reference to specific embodiments.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms may be understood by those skilled in the art according to specific circumstances.
Referring to fig. 1-4, preferred embodiments of the present invention are shown.
The construction method for transforming the dewatering well by the rotary excavating cast-in-place pile empty pile section can be used for deep and large foundation pits and can also be used in common foundation pits, and the application range is not limited by the construction method.
A construction method for transforming a dewatering well by rotary excavating a cast-in-place pile empty pile section comprises a dewatering well part 11 and a water pumping device 12, wherein the dewatering well part 11 is used for reducing the underground water level of a foundation pit, and the construction method comprises the following steps:
1) selecting a proper engineering pile 13 pile position according to an engineering pile 13 drawing and precipitation specifications, obtaining a pile hole 14 for pouring concrete on the engineering pile 13 pile position through a rotary digging pile process, pouring concrete into the pile hole 14 to obtain an empty pile section 15 and an engineering pile 13, standing the concrete of the engineering pile 13 for more than half a month, clearing the hole of the empty pile section 15, and waiting for further solidification of the concrete of the engineering pile 13;
2) after concrete in the pile hole 14 is solidified, lowering the dewatering well part 11 into the pile hole 14, and lowering the dewatering well part 11 into the empty pile section 15;
3) filling gravel materials 28 between the outer wall of the dewatering well element 11 and the hole wall of the hollow pile section 15 until the height of the gravel materials 28 reaches the elevation of the gravel materials 28 to form a gravel material 28 layer, and filling clay into a space between the upper part of the gravel material 28 layer and the plane where the hole opening of the pile hole 14 is located to stabilize the dewatering well element 11 and the gravel materials 28;
4) washing the interior of the dewatering well part 11 by using a gas lift reverse circulation method, and removing hole bottom sediments in the slurry of the dewatering well part 11;
5) a water pumping device 12 is arranged in the pile hole 14 and controls to start or stop pumping water according to the water level height;
6) and removing the dewatering well member 11 after the foundation pit is excavated.
The construction method is characterized in that a part of the pile hole 14 which is dug in a rotary mode and is filled with concrete is set as an engineering pile 13, a space above the top of the concrete in the pile hole 14 is set as a hollow pile section 15, the concrete part is the engineering pile 13, after the concrete is solidified, the dewatering well part 11 is placed into the pile hole 14, underground water above the top of the engineering pile 13 in a foundation pit can penetrate into the dewatering well part 11, after gravel materials 28 are filled and a well washing process is carried out, only water in the dewatering well part 11 needs to be pumped out, construction cannot be prevented from being hindered due to overhigh underground water level, the hollow pile section 15 is used for placing the dewatering well part 11, the process of obtaining the engineering pile 13 by rotating the pile hole 14 in a rotary mode and the process of placing the dewatering well part 11 are combined, repeated processes are reduced, a large amount of cost is saved, and the construction period of the deep foundation pit is.
After the concrete is poured into the pile hole 14 in the step (1), slurry in the pile hole 14 is pushed upwards by the concrete, and after the concrete reaches a designed elevation, the engineering pile 13 is arranged below the designed elevation, an empty pile section 15 is formed at a part, which is not poured with the concrete, in the pile hole 14, the engineering pile 13 is obtained firstly, and then the dewatering well element 11 can be placed in the empty pile section 15, so that the engineering steps are proper, and the time is saved.
The design elevation refers to the elevation which is designed and selected at a certain place relative to a certain datum point in the vertical design; the construction of the device is considered comprehensively according to the overall requirements of vertical design, the requirements of traffic, drainage, landscape and other functional aspects and the amount of earth and stone saved.
And (2) cleaning the hollow pile section 15 by using a rotary drilling rig in the step (1), and grabbing the sediment in the hollow pile section 15 by using a sand scooper so as to control the thickness of the sediment at the bottom of the well.
In particular, dewatering well element 11 has an embodiment as shown in fig. 2-3:
the dewatering well element 11 with better filtering effect is placed in the pile hole 14 and comprises a reinforcing steel bar layer 18, an outer filtering layer 19 and an inner filtering layer 20, wherein the outer filtering layer 19 is arranged around the reinforcing steel bar layer 18; the reinforcing steel bar layer 18 is provided with a plurality of reinforcing steel bar gaps from top to bottom, the outer filtering layer 19 covers the reinforcing steel bar gaps, and the reinforcing steel bar layer 18 is enclosed to form a penetration cavity 21; the inner filter layer 20 is arranged at the lower part of the reinforcing steel layer 18, arranged in the permeation cavity 21 and fixedly connected with the reinforcing steel in the reinforcing steel layer 18; the mesh size of the lower part of the outer filtering layer 19 is larger than that of the upper part of the outer filtering layer 19, and the mesh size of the inner filtering layer 20 is the same as that of the upper part of the outer filtering layer 19.
Because of the relation of soil deposition and pressure intensity, more soil is accumulated at the lower part of the dewatering well part 11, the problem of blocking or filtering failure is easy to occur when the outer filtering layer 19 goes down, so that the filtering effect of the dewatering well part 11 is poor, now the inner filtering layer 20 is placed in the permeation cavity 21 formed by enclosing the reinforcing steel layer 18, the outer filtering layer 19 is filtered by one round and then filtered by the inner filtering layer 20 again, so that the filtering effect of the lower part of the dewatering well part 11 is almost consistent with that of the upper part, and a better filtering effect is realized.
The dewatering well element 11 comprises a plurality of sections of upper well pipes 16 and a bottom well pipe 17, wherein the plurality of sections of upper well pipes 16 are formed by a reinforcing steel layer 18, and the bottom well pipe 17 is formed by sequentially enclosing the reinforcing steel layer 18 and an inner filter layer 20; the multi-section upper well pipe 16 and the bottom well pipe 17 form a precipitation well pipe by welding a reinforcing steel bar layer 18 in sequence; the bottom well pipe 17 is located below the precipitation well pipe, which is surrounded by an outer filter layer 19, forming the precipitation well element 11.
Wherein, the outer filtering layer 19 includes a fixing layer and a filtering net layer, the filtering net layer is fixedly connected with the fixing layer and fixed in shape by the fixing layer, the fixing layer is provided with a plurality of penetrating holes for water penetration, the filtering net layer can penetrate water, the fixing layer is used to fix the filtering net layer, when the filtering net layer is a flexible layer, such as a plastic filtering net, the filtering net layer is not deformed due to the pressure of water or the movement of the dewatering well element 11, which results in the deterioration of filtering effect.
And the fixing layer covers the filter screen layer, and when the dewatering well element 11 is placed down to the pile hole 14, the fixing layer protects the filter screen layer from contacting the gravel 28 in the pile hole 14, so that the filter screen layer is prevented from being damaged.
Wherein the anchoring layer comprises a plurality of through-going holes that penetrate onto the filter web layer, the plurality of through-going holes being smaller in size than the smallest particles of the gravel 28, thereby preventing the gravel 28 from touching the filter web layer.
Specifically, the filter screen layer may be made of a plastic filter screen with lower cost, but other flexible filter screens may also be used, which is not limited herein.
Also, the outer filter layer 19 includes two fixing layers, and a filter mesh layer is sandwiched between the two fixing layers, so that the outer filter layer 19 is not easily deformed even under high water pressure, resulting in poor filtering effect; specifically, the fixing layer may be made of iron wire mesh, or may be made of other corrosion-resistant metal mesh, which is not limited herein; and through setting up the fixed layer, the fixed layer also can protect the filter screen, prevents that it from receiving destruction or damage.
And the outer filter layer 19 is arranged around the reinforcing layer 18 so as to enclose the permeate chamber 21.
Furthermore, the inner filter layer 20 comprises a filter tube 24 and a plurality of fixing blocks 25, wherein the fixing blocks 25 are used for fixing the filter tube 24 on the inner wall of the reinforcing steel layer 18 and are positioned in the permeation cavity 21; the fixing blocks 25 connect the filter pipe 24 with the reinforcing bars, thereby preventing the inner filter 20 from being shaken due to a water pressure problem, thereby causing dust and sand to enter the infiltration chamber 21.
Specifically, the upper end of fixed block 25 is formed with the portion of snatching, snatchs the portion cover and locate on the reinforcing bar, and the lower extreme of fixed block 25 is formed with the clamp and gets the portion of getting, and the pipe wall of filter tube 24 is got to the clamp of getting the portion of getting, realizes fixing the mesh on the reinforcing bar with filter tube 24 through simple structure, and is very convenient.
In addition, the fixing blocks 25 are connected with the same steel bars in pairs in a cross mode, and the lower ends of the fixing blocks 25 in pairs simultaneously clamp the pipe wall of the filter pipe 24, so that a better fixing effect is achieved for the filter pipe 24, and a better filtering effect is achieved.
In addition, the reinforcement layer 18 includes the stirrups 26 and the main reinforcement 27, and a plurality of main reinforcements 27 are erect and are arranged, and a plurality of stirrups 26 are arranged in parallel and around the main reinforcement 27, cramp the main reinforcement 27, form the reinforcing bar clearance between the main reinforcement 27, and engineering stress is stronger.
The main reinforcement 27 is enclosed by the stirrup 26 and then is in a surrounding cage shape, and the main reinforcement 27 and the stirrup 26 enclose a framework forming the cavity wall of the infiltration cavity 21, so that the main reinforcement is more firm.
After the dewatering well element 11 is completely put into the pile hole 14, the groundwater around the empty pile section 15 enters the dewatering well element 11 through the gravel material 28, and the dewatering well element 11 has filtering capability, so the groundwater is filtered into the infiltration chamber 21, and most of silt and the like in the slurry can be filtered, thereby preventing the water pump 29 put in the infiltration chamber 21 from being blocked by the silt, and improving the water pumping stability of the water pump 29.
When the dewatering well element 11 is placed into the empty pile section 15, centralizers need to be arranged at two ends of the dewatering well element 11, the diameters of the centralizers are smaller than the aperture of the empty pile section 15, and the centralizers touch the aperture wall of the empty pile section 15 when the pile section 15 is emptied under the dewatering well element 11, so that the requirement of centralizing the dewatering well element 11 is met.
And (3) the dewatering well part 11 in the step (2) is lowered by a crane, so that the dewatering well part 11 can be stably placed into the hollow pile section 15.
In addition, the process of lowering the dewatering well element 11 must be carried out at one time, so that the dewatering well element 11 can be placed into the empty pile section 15 at one time, and the stable operation of the subsequent construction steps is facilitated.
In addition, in order to ensure that the process of lowering the dewatering well element 11 to empty the pile section 15 can be smoothly progressed, a camera can be erected at the position of the first upper well pipe 16 of the dewatering well element 11 before lowering, and because a person cannot approach the pile hole 14 or should not approach the pile hole 14 when lowering the dewatering well element 11, the camera can be erected at the position of the upper well pipe 16 to shoot and locate the position of the dewatering well element 11 in real time.
And a viewing device connected with a camera can be arranged outside the opening of the pile hole 14, so that a constructor can conveniently provide guidance for placing the dewatering well element 11 for a crane user.
In the step (3), before filling the gravel material 28, the difference between the inside and outside depth values of the dewatering well element 11 cannot be too large, that is, the height of the dewatering well element 11 must be close to the depth of the empty pile section 15, specifically, the difference between the depth of the dewatering well element 11 and the depth of the empty pile section 15 cannot exceed 40 cm.
Also, the gravel material 28 is fed in a sequence of first large particle gravel material 28 and then small particle gravel material 28, specifically wherein the small particle gravel material 28 is sized larger than the filtration pores of the outer filter layer 19 to prevent it from passing directly through the outer filter layer 19 and directly into the infiltration chamber 21.
In addition, the gravel material 28 is filled to the height calculated by the engineering in the step (3), and the filling is stopped; and clay sealing is needed at the position of 2-4m from the gravel material 28 to the opening position of the pile hole 14, namely, the space between the upper part of the gravel material 28 layer and the plane where the opening of the pile hole 14 is positioned is filled with clay, so that the aim of completely fixing the dewatering well element 11 and the gravel material 28 can be fulfilled.
In the step (4), the well washing time is determined according to the thickness of the sediment at the bottom of the hole of the hollow pile section 15, specifically, the thickness of the sediment at the bottom of the hole is measured by a flat hammer and sharp hammer comparison method, and the sediment at the bottom of the hole is ensured to be less than or equal to 100 mm; before the interior of the dewatering well element 11 is washed, the descending depth of the washing guide pipe is preferably 300-400 mm from the sediment surface, and the descending depth of the washing air pipe is determined by 0.55-0.65 of the ratio of the distance from the air-slurry mixer to the slurry surface to the depth of the empty pile section 15.
When air is blown into the dewatering well part 11, slurry is firstly blown into the dewatering well part 11, namely slurry is supplemented, when the well washing of the dewatering well part 11 is stopped, the well washing air pipe is firstly closed, then the slurry conveying of the well washing guide pipe is stopped, and in the process of well washing of the dewatering well part 11, the slurry supplementing amount is particularly required to be paid attention, so that hole collapse caused by insufficient slurry supplementing is strictly prevented; in the actual operation process, the air supply quantity is from small to large, the air pressure output by the well washing air pipe is slightly larger than the water head pressure brought to the bottom of the dewatering well element 11 by the well washing guide pipe, when the sediment at the bottom of the hole is thick, the block size is large or the sediment is hardened, the air supply quantity of the well washing air pipe can be properly increased, and the well washing guide pipe is shaken to facilitate slag discharge; along with the discharge of sediment, the sediment thickness of the hollow pile section 15 and the hole bottom of the dewatering well part 11 is smaller, and the well washing guide pipes are matched at the same time to keep the distance between the pipe bottom opening of the well washing guide pipe and the sediment surface; after the dewatering well element 11 is washed, the specific gravity, viscosity and sediment thickness of slurry in the hollow pile section 15 and even the hole of the dewatering well element 11 need to meet the design requirements.
The air quantity of an air compressor used for supplying air to a well washing air pipe is 6-9 m 3/min, the diameter of a water outlet pipe of a well washing guide pipe is larger than 200mm, the diameter of an air supply pipe of the well washing air pipe is 25mm, a slurry gas mixer connected with the well washing air pipe and the well washing guide pipe is made of water pipes with the diameter of 25mm, and 6 rows of holes are drilled in the length range of about 1m, wherein 4 holes with the diameter of 8mm are drilled in each row.
And after the interior of the dewatering well part 11 is cleaned, the proportion of the hollow pile section 15, namely the mud in the hole in the dewatering well part 11, is less than 1.20, the viscosity is 18-20 s, and the thickness of sediment at the bottom of the hole is less than 5 cm.
The water pumping device 12 in the step (5) comprises a water pumping pump 29, a liquid level sensor 30, a control box 31, a floating rod 32 and a erection rod 33, wherein the water pumping pump 29 is submerged into the permeation cavity 21 in the dewatering well part 11, the liquid level sensor 30 is arranged at the upper end of the dewatering well part 11, and the floating rod 32 is placed in the dewatering well part 11; the float rod 32 is movably connected with the liquid level sensor 30, the liquid level sensor 30 and the water pump 29 are respectively and electrically connected with the control box 31, and the control box 31 controls the water pump 29 to start or stop pumping water.
The water pump 29 is connected with a water pumping pipe, which extends from the infiltration cavity 21 of the precipitation well part 11 to the outside of the precipitation well part 11 and is connected to the recovery ditch for uniform discharge.
The erection rod 33 is arranged above the dewatering well element 11 and around the pile hole 14, and the pumping electric wire of the control box 31 connected with the pumping pump 29 extends into the dewatering well element 11 through the erection rod 33.
Because the suction pump 29 is influenced by gravity, the electric wire that draws water is erect pole 33 and is straightened through suction pump 29, and erect pole 33 and have the lift piece, place the electric wire that draws water through erectting pole 33, utilize the lift piece, can place the electric wire that draws water and can will draw water the electric wire mistake and inhale when the suction pump 29 is drawing water, stopped the potential safety hazard.
And erect and be provided with on the pole 33 and pull the rope with suction pump 29 swing joint, pull the rope and be connected with suction pump 29, and pull the rope and arrange around the electric wire that draws water, pull the rope and be used for pulling suction pump 29, when needs pull out suction pump 29 from precipitation well spare 11, only need pull the rope can.
Also, an air bag 34 is provided on the suction pump 29, and the air bag 34 is disposed at the upper end of the suction pump 29, away from the suction port of the suction pump 29.
The floating rod 32 is provided with a floater and a vertical rod, the vertical rod is movably connected with the liquid level sensor 30, a notch is arranged on the vertical rod, a vertically downward liquid level hole is arranged in the liquid level sensor 30, and the vertical rod penetrates through the liquid level hole and moves up and down in the liquid level hole; the float is soaked on the liquid level of the water in the permeation cavity 21, can fluctuate along with the height of the liquid level, is fixedly connected with the vertical rod, and can drive the vertical rod to move up and down in the liquid level hole when fluctuating.
And the liquid level sensor 30 detects the rising or falling amplitude of the vertical rod and transmits a signal to the control box 31, and the control box 31 controls the water suction pump 29 to start or stop water suction through the water suction wire.
Also, when the water pump 29 is controlled to pump water, the water pump 29 cannot pump water for a long time.
In the step (6), when the dewatering well element 11 is dismantled, the gravel materials 28 are firstly removed, and then the dewatering well element 11 is hoisted out by a crane.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A construction method for transforming a dewatering well by rotary excavating a cast-in-place pile empty pile section is characterized by comprising a dewatering well member and a water pumping device, wherein the dewatering well member is used for reducing the underground water level of a foundation pit, and the construction method comprises the following steps:
1) selecting a proper engineering pile position according to an engineering pile drawing and a precipitation specification, obtaining a pile hole on the engineering pile position through a rotary digging pile process, pouring concrete into the pile hole to obtain a hollow pile section and an engineering pile, standing the concrete of the engineering pile for more than half a month, cleaning the hollow pile section, and waiting for further solidification of the concrete of the engineering pile;
2) after the concrete in the pile hole is solidified, lowering the dewatering well part into the pile hole, and lowering the dewatering well part into the empty pile section;
3) filling gravel materials between the outer wall of the dewatering well element and the hole wall of the hollow pile section until the height of the gravel materials reaches the level of the gravel materials to form a gravel material layer, and filling clay into a space between the upper part of the gravel material layer and the plane where the hole opening of the pile hole is located to stabilize the dewatering well element and the gravel materials;
4) washing the interior of the dewatering well part by using a gas lift reverse circulation method, and removing hole bottom sediments in mud of the dewatering well part;
5) arranging a water pumping device in the pile hole and controlling to start or stop pumping water according to the water level height;
6) and removing the dewatering well member after the foundation pit is excavated.
2. The construction method for transforming the dewatering well into the empty pile section of the rotary excavating cast-in-place pile according to claim 1, characterized in that after concrete is poured into the pile hole in the step (1), slurry in the pile hole is pushed upwards by the concrete, and after the concrete spreads to reach a designed elevation, the engineering pile is arranged below the designed elevation, and the empty pile section is formed at a part of the pile hole which is not poured with the concrete.
3. The construction method for transforming the dewatering well into the empty pile section of the rotary excavating cast-in-place pile according to claim 2, characterized in that in the step (1), the rotary excavating drilling machine is used for cleaning the hole of the empty pile section, and a sand scooper is used for grabbing the sediment in the empty pile section.
4. The construction method for transforming the dewatering well by the rotary excavating bored concrete pile empty pile section according to claim 3, wherein the dewatering well member in the step (2) is lowered by a crane; the dewatering well part comprises a plurality of upper well pipes and a bottom well pipe, a camera is erected at the position of a first upper well pipe of the dewatering well part, and the camera is used for shooting and positioning the position of the dewatering well part.
5. The construction method for transforming the dewatering well into the empty pile section of the rotary excavating cast-in-place pile according to claim 4, wherein a viewing device connected with the camera is arranged outside an orifice of the pile hole.
6. The construction method for reconstructing the dewatering well by the rotary excavating bored concrete pile empty pile section according to any one of claims 1 to 5, wherein the pumping device in the step (5) comprises a pumping pump, a liquid level sensor, a control box, a floating rod and an erection rod, the pumping pump is submerged into the infiltration cavity in the dewatering well member, the liquid level sensor is arranged at the upper end of the dewatering well member, and the floating rod is placed in the dewatering well member; the utility model discloses a water pump, including the float, level sensor, water pump, control box, water-level sensor swing joint, the float with level sensor swing joint, level sensor and the water pump respectively with control box electric connection, control box control the water pump begins or stops drawing water.
7. The construction method for transforming the dewatering well through the rotary excavating cast-in-place pile empty pile section according to claim 6, wherein a water pumping pipe is connected to the water pumping pump, extends from the permeation cavity of the dewatering well part to the outside of the dewatering well part, and is connected to a recovery ditch to be uniformly discharged.
8. The construction method of the dewatering well for transforming the empty pile section of the rotary excavating cast-in-place pile as claimed in claim 7, wherein the erection rod is arranged above the dewatering well member and around the periphery of the pile hole, and the control box is connected with a pumping wire of the pumping pump and extends into the dewatering well member through the erection rod.
9. The construction method for transforming the dewatering well through the empty pile section of the rotary excavating cast-in-place pile as claimed in claim 8, wherein a pulling rope movably connected with the water pump is arranged on the erection rod, the pulling rope is connected with the water pump and arranged around the water pumping electric wire, and the pulling rope is used for pulling the water pump.
10. The construction method for transforming the dewatering well into the empty pile section of the rotary excavating cast-in-place pile as claimed in claim 6, wherein the floating rod is provided with a floater and a vertical rod, the vertical rod is movably connected with the liquid level sensor, the vertical rod is provided with a notch, a vertically downward liquid level hole is arranged in the liquid level sensor, and the vertical rod penetrates through the liquid level hole and moves up and down in the liquid level hole; the floater is soaked on the liquid level of the water in the permeation cavity, the floater fluctuates up and down along with the height of the liquid level, the floater is fixedly connected with the vertical rod, and the vertical rod is driven to move up and down in the liquid level hole when the floater fluctuates up and down; the liquid level sensor detects the rising or descending amplitude of the vertical rod, transmits a signal to the control box, and the control box controls the water suction pump to start or stop pumping water through the water pumping electric wire.
CN201911206007.8A 2019-11-29 2019-11-29 Construction method for transforming empty pile section of rotary excavating cast-in-place pile into dewatering well Pending CN110872837A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104032760A (en) * 2013-03-05 2014-09-10 李孝虎 Foundation pit construction tube well dewatering method
CN104060621A (en) * 2013-09-03 2014-09-24 中国建筑第四工程局有限公司 Construction method for super vacuum dewatering well and well tube structure used in construction method
CN104878771A (en) * 2015-06-05 2015-09-02 北京地矿工程建设有限责任公司 Construction method for vacuum tube well dewatering system
CN105133581A (en) * 2015-09-10 2015-12-09 深圳市市政工程总公司 Three-in-one construction method for uplift pile, lattice column and precipitation well in supporting structure
CN105201000A (en) * 2015-09-28 2015-12-30 中国十七冶集团有限公司 Wide foundation pit precipitation method capable of remotely monitoring
CN107869146A (en) * 2017-11-23 2018-04-03 北京地矿工程建设有限责任公司 A kind of method with clean-out machine Dewatering well

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104032760A (en) * 2013-03-05 2014-09-10 李孝虎 Foundation pit construction tube well dewatering method
CN104060621A (en) * 2013-09-03 2014-09-24 中国建筑第四工程局有限公司 Construction method for super vacuum dewatering well and well tube structure used in construction method
CN104878771A (en) * 2015-06-05 2015-09-02 北京地矿工程建设有限责任公司 Construction method for vacuum tube well dewatering system
CN105133581A (en) * 2015-09-10 2015-12-09 深圳市市政工程总公司 Three-in-one construction method for uplift pile, lattice column and precipitation well in supporting structure
CN105201000A (en) * 2015-09-28 2015-12-30 中国十七冶集团有限公司 Wide foundation pit precipitation method capable of remotely monitoring
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