CN115748676A

CN115748676A - Punching cast-in-place pile construction method based on sandy gravel geological conditions

Info

Publication number: CN115748676A
Application number: CN202211495579.4A
Authority: CN
Inventors: 李天鹏; 苟智培
Original assignee: China Metallurgical Construction Engineering Group Co Ltd
Current assignee: China Metallurgical Construction Engineering Group Co Ltd
Priority date: 2022-11-27
Filing date: 2022-11-27
Publication date: 2023-03-07

Abstract

The invention discloses a punching cast-in-place pile construction method based on sandy gravel geological conditions, which comprises the following steps: a. embedding a pile casing at a preset position, aligning a pile driver with a pile position, and then installing and fixing the pile driver; b. b, using the pile machine in the step a to carry out impact hole forming operation at a preset position until a pile hole is formed, and carrying out primary hole cleaning on the formed pile hole; c. b, installing a reinforcement cage stopper in the pile hole in the step b, and hoisting the reinforcement cage into the pile hole provided with the reinforcement cage stopper; d. pouring concrete into the pile hole provided with the reinforcement cage in the step c; e. removing the steel reinforcement cage limiting device after the concrete is poured to a preset elevation; by implementing the method, the verticality and the hole wall flatness of the formed hole are effectively controlled, the hole forming quality is improved, the problems of pile foundation protective layer thickness and sediment thickness control and the like are solved, the construction quality is ensured, and the construction efficiency is improved.

Description

Punching cast-in-place pile construction method based on sandy gravel geological conditions

Technical Field

The invention belongs to the technical field of building construction, and relates to a method for constructing a punching cast-in-place pile based on sandy gravel geological conditions.

Background

In recent years, with the continuous development of the building industry, large buildings are continuously updated, the building height is increased, the building volume is increased, the buildings are all grown on the flat ground, the importance of the building foundation is prominent, and various types of pile foundations are the most effective foundation forms to meet the increasing load requirements. The geology of partial areas in China belongs to a landform consisting of a large amount of pebbles with different sizes and formed by washing of an ancient riverbed and other broken stones or fine sands, when underground construction of the landform is carried out, the pebbles have the characteristics of high strength and high wear resistance due to complex geological components, but the whole landform has a smooth surface and extremely low friction, adhesion and strength, so that the geomechanical properties in a construction area are extremely complex, great difficulty is brought to underground engineering operation, unforeseeable and uncontrollable factors appearing in the process of drilling and piling are extremely large, and further serious uncertain influences are generated on the construction period and the quality. When the underground condition is complex, the underground water level is high, the water quantity is large, the water pumping operation cannot be finished, and the soil layer with silty soil and pebble blocks coexists can not be finished, the problems of poor pore-forming quality, including the difficult control of pore-forming verticality and pore wall flatness, the control of pile foundation protective layer thickness and sediment thickness and the like can continuously face in the whole operation process,

in order to solve the above problems, a simple, safe and efficient construction method is needed to ensure the construction quality.

Disclosure of Invention

In view of the above, the invention discloses a method for constructing a punching cast-in-place pile based on sandy gravel geological conditions. By implementing the method, the problems of hole forming verticality and hole wall flatness, pile foundation protective layer thickness and sediment thickness control and the like are effectively controlled, and the construction quality is ensured.

A method for constructing a punching cast-in-place pile based on sandy gravel geological conditions comprises the following steps:

a. embedding a pile casing at a preset position, aligning a pile machine with a pile position, and then installing and fixing the pile machine; the preset position refers to a pile position of a designed cast-in-place pile, the hole forming method is mechanical punching, the pile machine is a punching cast-in-place pile machine and can be a drill rod impact type or a steel wire rope impact type, and the pile machine selection is selected and adjusted according to actual construction conditions, so that the method is a technical method which can be understood by a person skilled in the art and is not described herein again.

b. B, using the pile machine in the step a to carry out impact hole forming operation at a preset position until a pile hole is formed, and carrying out primary hole cleaning on the formed pile hole;

c. b, installing a reinforcement cage stopper in the pile hole in the step b, hoisting the reinforcement cage into the pile hole provided with the reinforcement cage stopper, and performing secondary hole cleaning on the pile hole; through the primary hole cleaning and the secondary hole cleaning, the thickness of the sediments is effectively controlled.

d. Pouring concrete into the pile hole provided with the reinforcement cage in the step c;

e. and (5) removing the steel reinforcement cage limiting stopper after the concrete is poured to the preset elevation.

Further, in step a, the pile driver is provided with a pile hammer for punching, a vertical tooth nail is arranged on the bottom surface of the pile hammer, and the tooth nail is contacted with the pile hammer before the pile hammer and is inserted into a preset position to prevent the pile hammer from inclining. Meet the region of eccentric atress on the ground of inhomogeneous material, for example there is a big boulder or cobble in one side of predetermineeing the position horizontal direction, will lead to whole pile hammer atress uneven, make the pile hammer form the deflection, and then can produce the power of a horizontal direction, make the pile hammer have lateral shifting's trend, the tooth nail of this moment is inserted ground, the existence of tooth nail, can produce the trend of a reverse effort in order to confront the lateral shifting of pile hammer, it heels to prevent the pile hammer emergence, and then the straightness that hangs down of stake hole and the roughness of pore wall have been guaranteed.

Furthermore, in step c, the steel reinforcement cage stopper includes limiting column, and limiting column's top is provided with the couple, limiting column laminate in the pile wall in stake hole vertical set up in the stake hole, the block of pegging graft of trip in step a protect a top. The conventional steel reinforcement cage limiting device has two types, namely a saddle type limiting device and a wheel type limiting device, and has the advantages of small size, low manufacturing and construction cost, one limiting device is arranged on the steel reinforcement cage in three to four meters, but the defects are obvious, because the limiting device is in point contact with a pile wall, the limiting device is easy to sink into a mud wall in a hole position impacting a hole to cause the steel reinforcement cage to be out of position, under the condition that the hole wall cannot be observed, the number of the limiting devices is increased, the process is complicated, and materials are wasted.

Further, the steel reinforcement cage stopper still includes spacing snap ring, spacing snap ring is installed in the outer fringe at the top of protecting a section of thick bamboo, spacing snap ring and protect and form spacing hole between the section of thick bamboo, the trip inserts spacing hole is spacing by spacing snap ring. The installation of the steel reinforcement cage limiter becomes simple and efficient due to the clamping installation mode.

Further, the steel reinforcement cage stopper is provided with a plurality of, a plurality of steel reinforcement cage stopper is along the circumference equipartition in stake hole. The more the quantity of steel reinforcement cage stopper, the location to the steel reinforcement cage is about accurate reliable, and its quantity can be adjusted according to concrete construction conditions.

Further, the tooth nails are multiple and are arranged along the circumferential direction of the bottom surface of the pile hammer and located at the peripheral position of the bottom surface of the pile hammer. The plurality of pins can provide reverse acting force at the same time, so that the pile hammer is more stable when impacting the preset position.

Furthermore, the tail end of the tooth nail in the vertical direction is a working end, and the working end is in a conical shape with the reduced radial dimension. The design enables the toothed nail to be inserted into the preset position more smoothly.

Further, in the step a, the diameter of the pile casing is 300-400mm larger than the design value of the pile hole.

Further, in the step a, the embedding depth of the pile casing is between 2 and 2.5m, and the axial height of the pile casing is 1.2 to 1.5 times of the embedding depth of the pile casing. The effect of protecting the section of thick bamboo does: controlling the pile position and guiding the drilling tool; protecting the orifice, and isolating the surface water leakage, the orifice and the hole wall soil collapse; maintaining or increasing the head height within the hole increases the hydrostatic pressure against the walls of the hole to prevent collapse of the walls of the hole. If the embedding depth of the casing is too small or the design diameter is too small, the above-described effect cannot be achieved.

Further, the angle of the cone angle of the working end is between 45 ° and 60 °, and the vertical length of the working end is between 1/3 and 3/4 of the vertical length of the tooth pin. The small angle of the cone angle can cause the radial size of the tail end of the tooth nail to be small and the tooth nail is easy to break; the taper angle is too large to be easily inserted into the bottom surface of the predetermined position. In the practical application process, because the diameter of the tooth nail is determined, when the angle of the taper angle of the working end is determined, the vertical length of the working end is determined, in the process of punching operation, the working end can be abraded to a certain extent, the length proportion of the working end can be used as a judgment index for evaluating the abrasion degree of the tooth nail, the working end needs to be ground again after being abraded, the length proportion can be correspondingly changed, when the length proportion of the working end is too large, the tooth nail is seriously abraded, the work of the pile hammer can be influenced, and at the moment, the tooth nail needs to be replaced; when the occupation ratio of the tooth nail is too small, the diameter selection of the tooth nail or the angle selection of the cone angle of the working end is improper, and the tooth nail needs to be reselected.

The invention has the beneficial effects that:

the invention discloses a punching cast-in-place pile construction method based on sandy gravel geological conditions. The bottom surface of the pile hammer is provided with the tooth nail of the pile hammer, so that the tooth nail is contacted with the pile hammer before the pile hammer is inserted into a preset position during punching, a supporting force is provided for the pile hammer, the phenomenon that the pile hammer inclines is effectively avoided due to the fact that the pile hammer is deflected or turned over when falling to the ground due to uneven stress, the trend of the lateral movement of the pile hammer is resisted, the flatness of the wall of the pile hole is improved, the verticality of the pile hole is also improved, and the hole forming quality is improved; the limiting upright posts are used for replacing the traditional saddle type and wheel type limiters, and point support is replaced by a line support mode, so that the dislocation of the reinforcement cage can be effectively avoided, the reinforcement cage can be always kept at the central position, and the consistency of the thickness of a protective layer is ensured; the installation of the steel reinforcement cage limiter is simple and efficient due to the clamping installation mode; the thickness of the sediment is effectively controlled. By implementing the method, the hole forming verticality and hole wall flatness are effectively controlled, the problems of pile foundation protective layer thickness and sediment thickness control and the like are solved, the construction quality is ensured, and the construction efficiency is improved.

Drawings

FIG. 1 is a flow chart of the construction of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a pile hammer according to an embodiment of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a schematic view of the location distribution of the spikes according to an embodiment of the present invention;

FIG. 5 is a schematic structural view of a tooth pin according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of the operation of the pile hammer of the present invention;

FIG. 7 is a schematic view of the working principle of the steel reinforcement cage stopper according to the embodiment of the present invention;

FIG. 8 is an enlarged view of a portion of FIG. 7 at B;

fig. 9 is a schematic diagram illustrating the position distribution of the reinforcement cage stopper according to the embodiment of the present invention.

Detailed Description

FIG. 1 is a flow chart of the construction of an embodiment of the present invention; FIG. 2 is a schematic structural diagram of a pile hammer according to an embodiment of the present invention; FIG. 3 is an enlarged view of a portion of FIG. 2 at A; FIG. 4 is a schematic view of the location distribution of the spikes according to an embodiment of the present invention; FIG. 5 is a schematic structural view of a tooth pin according to an embodiment of the present invention; FIG. 6 is a schematic diagram of the operation of the hammer of the present invention; FIG. 7 is a schematic view of an embodiment of the present invention showing the operation of a cage stop; FIG. 8 is an enlarged view of a portion of FIG. 7 at B; fig. 9 is a schematic diagram illustrating the position distribution of the reinforcement cage stopper according to the embodiment of the present invention. It should be noted that in the description of the present specification, the terms "upper", "lower", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be configured in a specific orientation, and operate, and thus, should not be construed as limiting the present invention.

As shown in the figure, the method for constructing the punched cast-in-place pile based on the sandy gravel geological condition specifically comprises the following steps:

a. embedding a pile casing 7 at a preset position, aligning a pile driver with a pile position, and then installing and fixing the pile driver; the preset position refers to a designed pile position of a cast-in-place pile, and comprises the ground and an underground space where the pile position of the cast-in-place pile is located, the hole forming method is mechanical punching, the pile machine is a punching cast-in-place pile machine and adopts a steel wire rope impact type, the pile casing 7 of the embodiment is processed and manufactured by a steel plate with the thickness of 10mm, the height is 3m, the inner diameter is 400mm larger than the pile diameter, and the upper part of the pile casing 7 is provided with 1-2 grout overflow holes; the protective cylinder 7 is embedded by adopting a press-in method, and the top surface of the protective cylinder 7 is higher than the ground water level by 2m and is higher than the ground by 0.5m; when the pile casing 7 is buried in sandy soil and other soft ground layers, loose soft soil below the pile casing 7 is dug out by at least 0.5m, and clay is filled and tamped layer by layer. When the soil is changed and the requirement cannot be met, the pile casing 7 must be lengthened, so that the casing feet fall on the hard soil layer. In the process of burying the pile casing 7, the deviation between the center of the pile casing 7 and the center of a pile position is required to be not more than 50mm, the vertical inclination of the pile casing 7 is not more than 1%, and the burying depth of the pile casing 7 is 2.5m. In general, the embedding depth is not less than 1.0-1.5 m in the cohesive soil layer, and not less than 2m in the sandy soil. And after the pile casing 7 is buried, measuring and recording the top elevation of the pile casing 7 so as to measure the hole depth. The pile driver is moved to the pile position needing punching by a crane, the pile driver is aligned with the pile position, the front edge of a crown block of the pile driver and the center of the pile position are on the same plumb line, after the pile driver is arranged in place, a pile driver operator cooperates with a measurer to center, place and level the drilling machine, the drilling machine is ensured to be horizontal and tamped, and the center deviation is controlled within +20 mm.

b. B, using the pile machine in the step a to carry out impact hole forming operation at a preset position until the pile hole 11 is formed, and carrying out primary hole cleaning on the formed pile hole 11;

in the embodiment, before the punching operation is carried out, the slurry is prepared by mixing the clay or bentonite with plasticity index IP larger than 10 with water, and if necessary, a certain proportion of cement is added to ensure that the prepared slurry meets related performance and technical indexes, and the specific gravity of the slurry is controlled to be 1.1-1.15 g/cm ³ The sand content of the newly prepared mud is not more than 4%, the colloid content is not less than 90%, and the consistency is not less than 14S; meanwhile, in the drilling process, a slurry consistency instrument is adopted to check the slurry consistency at any time, and if the slurry consistency is not met, the adjustment is carried out in time. In the embodiment, a mud pool with the size of 6 x 3 x 2.5m is dug near each pile position, and the mud pool is only used for circulating mud in the hole during punchingThe device is used circularly, and a safety enclosure is required to be manufactured around the mud pit.

In the embodiment, a punched geological profile is drawn before punching, and proper impact grabbing and punching speeds and mud with different indexes are selected according to different soil layers. The punching operation is continuously carried out without interruption, the drill is driven at a low speed after the slurry is manufactured, and the drill is converted into the normal speed for drilling after the whole drill enters a soil layer. The hammer is started to be impacted densely with a low hammer height of 0.4-0.6 m, and the wall is protected by adding the slate, gravel (or stone) and clay slurry in time to extrude and compact the hole wall 4 until the hole depth reaches 3-4 m below the bottom of the protection cylinder 7, the speed can be accelerated, the hammer is increased to more than 1-2.0 m, the normal impact is carried out, and the specific gravity of the slurry is measured and controlled at any time. In the process of flushing, the consistency of the slurry in the hole is often detected, and when the consistency is not required, the consistency is immediately adjusted. After drilling to a designed height, checking the aperture, the hole depth, the hole position and the verticality to confirm that the drilled hole is qualified, immediately cleaning the hole once, wherein the hole cleaning method adopts a slurry changing method. The thickness of the sediment before the underwater concrete is poured can meet the design requirement. When cleaning the hole, the mud pump is started to remove stone slag and large-particle slag in the hole by using mud circulation, clear water is timely added in the mud circulation process to reduce the mud proportion in the hole, and the stone slag is left in the sediment tank through three-stage sedimentation of the mud tank, so that the performance indexes such as the mud proportion, the sand content, the viscosity and the like in the hole are ensured.

c. B, installing a reinforcement cage stopper in the pile hole 11 in the step b, hoisting the reinforcement cage 8 into the pile hole 11 provided with the reinforcement cage stopper, and performing secondary hole cleaning on the pile hole 11; the thickness of the sediment is effectively controlled through primary hole cleaning and secondary hole cleaning.

In this embodiment, the sounding pipe has still been arranged on 8 inboard circumferencial directions of steel reinforcement cage, connects and consolidates the welding fastness with the ferrule after the pipeline mantle fiber, and the top is lengthened to ground parallel and level. The allowable deviation of the installation verticality of the sound measuring tube is not more than 50 per thousand, and the hole wall 4 at the joint is smooth and smooth in transition. The bottom hole of the sounding pipe can be wound and sealed by plastic adhesive tapes from two layers to three layers, and the sounding pipe can be used as a grouting treatment hole if the bottom of the pile is in a problem. Collision of the hole wall 4 should be prevented in the installation process of the steel reinforcement cage 8, and when the steel reinforcement cage is difficult to place, the reason should be found out, and the steel reinforcement cage cannot be forcibly placed. After the reinforcement cage 8 is installed in place, appropriate measures should be taken to fix the reinforcement cage 8, and the reinforcement cage 8 is prevented from floating upwards in the concrete pouring process. In order to prevent the cage body from deforming, reinforcing steel bars are arranged in the cage every 2m, and triangular ribs are additionally welded at proper positions of the top of the cage. This embodiment is in pile hole 11 well position for further guaranteeing that steel reinforcement cage 8 has evenly arranged a plurality of saddle steel reinforcement cage 8 protective layer limiters in the circumference at the bottom of steel reinforcement cage 8, middle part and top. After the steel reinforcement cage 8 is hoisted, a guide pipe is required to be arranged in the pile hole 11, the guide pipe is made of a seamless steel pipe with the wall thickness of 5mm, the diameter phi is 250, the distance between the guide pipe and the steel reinforcement is kept to be 100mm, before the guide pipe is used, whether the guide pipe leaks air, leaks water and deforms or not is checked, whether the joint connection is firm and reliable or not is checked, a water tightness test is carried out by periodically lengthening, and the pressure during the water pressure test is not less than 1.5 times of the maximum pressure born by the guide pipe during concrete pouring. And opening and secondary hole cleaning after the guide pipe is installed. The primary hole cleaning adopts a rubber pipe to go deep into the bottom of the hole and then is performed with slurry circulation by a slurry pump, the primary hole cleaning reduces the slurry concentration, the secondary hole cleaning is prevented from being difficult to clean due to excessive silt, and the smooth descending of the reinforcement cage 8 is ensured; and after the secondary hole cleaning is carried out after the guide pipe is placed down, the guide pipe is used for penetrating into the bottom of the hole, a slurry pump is connected to the top of the guide pipe, and then the slurry pump is started for secondary slurry circulation. The pressure of a slurry pump is utilized to suspend the sediment at the bottom of the hole under the impact action of the ejected gas, meanwhile, slurry is injected by a slurry pump through a guide pipe, the kinetic energy of the flowing slurry impacts the sediment at the bottom of the pile hole 11, rock grains, sand grains and the like in the sediment are in a suspended state, the suspended sediment is brought out of the pile hole 11 along with the circulating flow of the slurry by utilizing the adhesive force of slurry colloid, the suspended sediment flows to a slurry tank through a slurry ditch, the filtered slurry enters the hole again after the sediment in the slurry is filtered, and the process is repeatedly circulated until the thickness of the sediment at the bottom of the hole meets the standard requirement. The specific gravity of the secondary hole cleaning slurry is controlled to be 1.05-1.1, the viscosity is less than or equal to 20s, the sand content is less than or equal to 2%, and the thickness of the sediment at the bottom of the hole is less than or equal to 50mm.

d. Pouring concrete into the pile hole 11 provided with the reinforcement cage 8 in the step c; the concrete is poured by adopting pouring equipment for continuous one-time pouring.

e. And (5) removing the steel reinforcement cage limiting stopper after the concrete is poured to the preset elevation. When the concrete is poured to the controlled elevation, the plurality of limiting upright columns 6 are respectively lifted out by using a crane before the concrete is solidified.

In the embodiment, before the step a, relevant construction preparation work is carried out, site leveling is carried out before construction, if soft and weak positions are met, replacement filling with a certain depth is adopted, so that the strength of the construction site is ensured, the bottom surface of the arrangement position of the pile machine is leveled and tamped after the site is leveled, and meanwhile construction water, the position of a mud pit and a construction access way are uniformly arranged. The field needs to be hardened, so that the equipment is convenient to walk, the route is reasonable, and the strength is ensured not to sink. And according to the control points provided by the design, a GPS field arrangement control network is adopted for rechecking. According to the coordinate value of the central axis of the pile foundation, the central line of the pile foundation, the central point of the pile foundation and the like are lofted by a coordinate method or a polar coordinate method, the standard pile is driven, the lofting error of the central line is controlled within the range of 1cm, a cross control pile is arranged in a safe area about 3m away from the center of the pile, the cross protection pile is fixed by mortar, the checking is convenient, and the pile number is marked on the pile. During construction, the pile guard needs to be properly taken care of and cannot be displaced or lost. And the subsequent construction process can be carried out after the pile position measurement is checked and rechecked to be qualified.

In this example, 50m per perfusion ³ The concrete must have 1 group of test blocks, for the concrete less than 50m ³ At least 1 test block group. After the concrete is solidified, the sound measurement and bearing capacity test are carried out on the concrete cast-in-place pile according to the design and standard requirements, and the subsequent construction such as pile head breaking and bearing platform breaking can be carried out after the concrete is qualified.

In this embodiment, the steel reinforcement cage stopper in step c includes limiting column 6, and the top of limiting column 6 is provided with the couple, limiting column 6 laminate in the pile wall of stake hole 11 vertical set up in

stake hole

11, 10 peg graft block in step a the top of protecting a section of thick bamboo 7. The conventional steel reinforcement cage limiting device is a saddle type limiting device or a wheel type limiting device, the two limiting devices have the advantages of being small in size and low in manufacturing and construction cost, one limiting device is arranged on the steel reinforcement cage 8 in a position of three to four meters, the defects are obvious, the limiting device is in point contact with a pile wall, the limiting device is easily sunk into a mud wall in a hole position impacting a hole, the steel reinforcement cage 8 is out of position, the number of the limiting devices is increased under the condition that the hole wall 4 cannot be observed, the process is tedious, materials are wasted, in the technical scheme of the invention, the limiting upright post 6 is selected to limit the steel reinforcement cage 8, the point support is replaced by a line support, the steel reinforcement cage 8 can be effectively prevented from being out of position, the steel reinforcement cage 8 can be guaranteed to be always kept in the central position, and the consistency of the thickness of a protective layer is guaranteed.

The steel reinforcement cage stopper further comprises a limiting clamping ring 9, wherein the limiting clamping ring 9 is installed at the outer edge of the top of the pile casing 7, a limiting hole is formed between the limiting clamping ring 9 and the pile casing 7, and the limiting hole is inserted into the limiting hole and limited by the limiting clamping ring 9. The installation of steel reinforcement cage stopper becomes simple high-efficient for the mounting of joint.

In this embodiment, the steel reinforcement cage limiters are three and are uniformly distributed along the circumferential direction of the pile hole 11. The more the quantity of steel reinforcement cage stopper, the location to steel reinforcement cage 8 is about accurate reliable, and its quantity can be adjusted according to concrete construction conditions.

In this embodiment, the pile driver in step a is provided with a pile hammer 1 for punching, and the tooth nail 2 is vertically arranged on the bottom surface of the pile hammer 1; during punching, the tooth nail 2 is contacted with the pile hammer 1 before and is inserted into a preset position to prevent the pile hammer 1 from inclining; in the area of eccentric stress on the ground made of uneven materials, as shown in fig. 6, a pebble 5 is arranged on the left side of the horizontal direction of the bottom surface of a pile hole 11, the stress of the whole pile hammer 1 is uneven after the pile hammer 1 falls down, so that the pile hammer 1 generates a horizontal rightward force, the pile hammer 1 has a transverse moving trend, the tooth nail 2 is inserted into the bottom surface 3 of the pile hole 11 at the moment, and the existence of the tooth nail 2 can generate a horizontal leftward acting force to resist the transverse moving trend of the pile hammer 1, so that the pile hammer 1 is prevented from tilting, and the perpendicularity of the pile hole 11 and the flatness of the hole wall 4 of the pile hole 11 are ensured.

In the embodiment, eight pins 2 are arranged, the pins 2 are arranged along the circumferential direction of the bottom surface of the pile hammer 1, and the eight pins 2 are all arranged at the peripheral position of the bottom surface of the pile hammer 1; as shown in fig. 3, the pile hammer 1 of the present embodiment has a four-wing structure, and each wing of the pile hammer 1 is provided with two pins 2. The support effect of hammer 1 is optimized by arranging it at the periphery of the bottom surface. The plurality of pins 2 can provide a reverse acting force at the same time, so that the pile hammer 1 is more stable when impacting the preset position.

In this embodiment, the end of the tooth nail 2 in the vertical direction is a working end 201, and the working end 201 is a taper with a reduced radial dimension. The working end 201 in this embodiment is a pyramid, and the working end 201 is subjected to quench hardening treatment, and the pyramid is selected because the pyramid is better processed, and certainly, a conical structure may be selected so that the smooth insertion of the stud 2 into the preset position is preferable, which is not described herein again.

In this embodiment, the length of the tooth nail 2 is 300mm, the vertical length of the working end 201 is 100mm, and the angle of the taper angle of the working end 201 is 53 °. The small angle of the cone angle can lead to the small radial size of the tail end of the tooth nail 2, and the tooth nail is easy to break; the taper angle is too large to be easily inserted into the bottom surface of the predetermined position. In the practical application process, because the diameter of the tooth nail 2 is determined, when the angle of the taper angle of the working end 201 is determined, the vertical length of the working end 201 is determined, and in the process of punching operation, the working end 201 is worn to a certain extent, the length proportion of the working end 201 can be used as an evaluation index for evaluating the wear degree of the tooth nail 2, the working end 201 needs to be ground again after being worn, the length proportion can be correspondingly changed, when the length proportion of the working end 201 is too large, the tooth nail 2 is seriously worn, the work of the pile hammer 1 can be influenced, and at this time, the tooth nail 2 needs to be replaced; if the proportion of the pin 2 is too small, it means that the diameter of the pin 2 is not selected properly or the angle of the taper angle of the working end 201 is selected properly and needs to be selected again.

In this embodiment, the top of the stud 2 is horizontally provided with a mounting plate 202, and the stud 2 is mounted on the bottom surface of the pile hammer 1 through the mounting plate 202. The mounting plate 202 is arranged to increase the contact area between the stud 2 and the pile hammer 1, so that the connection between the stud 2 and the pile hammer 1 is firmer, and the connection between the pile hammer 1 and the stud 2 is prevented from loosening or falling off in the punching process. Hammer 1 in this embodiment is cast iron material, its hardness is big, more be favorable to punching a hole, and the selection of tooth nail 2 is manganese-containing high carbon tool steel, its toughness is good, the cost is cheap easily obtained, be favorable to antagonizing the trend of hammer 1's lateral shifting promptly, but the cost can be controlled again, but its welding performance is not good, in addition the diameter of tooth nail 2 itself is compared in hammer 1 littleer, if direct welding then easily leads to the welding insecure, consequently be provided with mounting panel 202 in this embodiment, and set up the round hole on mounting panel 202, the round hole is inserted at the top of tooth nail 2, it makes tooth nail 2 and mounting panel 202 form wholly to carry out plug welding from top to bottom, then weld steel sheet and hammer 1, increase impact strength that can show like this, reduce the risk that the fragility drops. This is a technical means that can be understood by those skilled in the art, and is not described herein in detail.

Finally, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for constructing a punching cast-in-place pile based on sandy gravel geological conditions is characterized by comprising the following steps of: the method comprises the following steps:

a. embedding a pile casing at a preset position, aligning a pile driver with a pile position, and then installing and fixing the pile driver;

c. b, installing a reinforcement cage stopper in the pile hole in the step b, hoisting the reinforcement cage into the pile hole provided with the reinforcement cage stopper, and performing secondary hole cleaning on the pile hole;

2. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as recited in claim 1, wherein: in the step a, the pile driver is provided with a pile hammer for punching, the bottom surface of the pile hammer is provided with a vertical tooth nail, and during punching, the tooth nail is contacted with the pile hammer before the pile hammer and is inserted into a preset position to prevent the pile hammer from inclining.

3. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as claimed in claim 1, wherein: in the step c, the steel reinforcement cage stopper comprises a limiting upright post, a hook is arranged at the top of the limiting upright post, the limiting upright post is attached to the pile wall of the pile hole and is vertically arranged in the pile hole, and the hook is inserted and clamped at the top of the pile casing in the step a.

4. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as recited in claim 3, wherein: the steel reinforcement cage stopper further comprises a limiting snap ring, the limiting snap ring is installed at the outer edge of the top of the protective cylinder, a limiting hole is formed between the limiting snap ring and the protective cylinder, and the snap ring is inserted into the limiting hole and limited by the limiting snap ring.

5. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as claimed in claim 1, wherein: the steel reinforcement cage stopper is provided with a plurality of, a plurality of the steel reinforcement cage stopper is along the circumference equipartition in stake hole.

6. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as recited in claim 1, wherein: the tooth nails are arranged along the circumferential direction of the bottom surface of the pile hammer and are located at the peripheral positions of the bottom surface of the pile hammer.

7. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as recited in claim 2, wherein: the tail end of the tooth nail in the vertical direction is a working end, and the working end is in a conical shape with the radial size reduced.

8. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as claimed in claim 1, wherein: in the step a, the diameter of the pile casing is 300-400mm larger than the design value of a pile hole.

9. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as recited in claim 1, wherein: in the step a, the embedding depth of the pile casing is 2-2.5m, and the axial height of the pile casing is 1.2-1.5 times of the embedding depth of the pile casing.

10. The method for constructing a punched cast-in-place pile based on sandy gravel geological conditions as recited in claim 7, wherein: the angle of the taper angle of the working end is between 45 DEG and 60 DEG, and the vertical length of the working end is between 1/3 and 3/4 of the vertical length of the tooth nail.