Bored piles are usually a kind of non-extruded piles, and some of them are partially extruded piles. The types of bored piles can be divided into: A. According to the size of pile, it can be divided into the following types: small pile; medium pile; large pile; B. According to the piling process, the bored piles can be divided into: dry working method bored piles; mud wall protection method bored piles;
Construction Process of Bored Piles
1.Measuring and Sampling Pile Positioning
2.Shell Burial, Pile Positioning Re-test
3.Drilling Rig Shifting
3.Drilling rig shifting
3.Drilling rig moving
3.Drilling rig moving
3.Drilling rig moving
4. 3、Move the drilling rig
4、Drilling rig start
5、Drilling into the hole
6、Final hole, final hole inspection to detect the depth of the hole
7、Clearing the hole, under the reinforcing cage
8、Second clearing of the hole, testing the specific gravity of the slurry, viscosity, sand content, after the indicators have passed, ready to fill the concrete
9、Excavation and chiseling of the head of the pile
10, pile foundation testing, testing methods include low strain, high strain, ultrasonic testing, core drilling, etc., according to the design requirements
Impact drilled piles construction processImpact drilled piles construction process is:
1, start drilling first in the hole to fill the mud, the relative density of the mud and other indicators according to the soil layer conditions. If there is water in the hole, the clay can be put into the hole directly, and the impact cone can be used to repeatedly impact the slurry with small stroke. General fine-grained soil layer can be used thick slurry, small stroke, high frequency repeated impact smashing, so that the hole wall is solid, not slump and not leakage. To be drilled to a depth of more than the full height of the drill bit plus stroke before the normal impact. In the opening stage 4 ~ 5m, in order to make the drill residue squeezed into the hole wall, reduce the number of times of slagging, normal drilling should be timely slagging, to ensure effective impact on the bottom of the hole.
2, in the process of drilling, should pay attention to stratigraphic changes, for different soil layers, using different drilling speed.
3, the stroke should be based on the soil layer, respectively: generally through the hard dense pebble layer or bedrock drifting stones and other soils in the use of large stroke; through the loose sand, gravel soil or pebbles sandwiched between the soil layer in the use of medium stroke, stroke is too large, the vibration of the bottom of the hole is large, easy to cause slumping; through the high-liquid-limit clay, sandy low-liquid-limit clay, the stroke is used in the middle of the stroke; in the easy to collapse or quicksand section with a small stroke, and should improve the mud, and should be used to ensure effective impact on the hole bottom. Stroke, and should improve the viscosity and relative density of the mud.
4, through the drifting rock or rock layer, such as the surface is not flat, should be put into the clay, small flakes, pebbles, the surface of the pad flat, and then use the drill bit for percussion drilling, to prevent slanting holes, collapsed holes accident; such as the uneven strength of the rock layer, easy to bias holes, can also be used in the above way to backfill the re-drilling; if necessary, put into the cement retaining wall or lengthening of the barrel depth of burial.
5, in the sand and pebble soil and other loose layer drilling, according to 1:1 input clay and small schist (particle size not greater than 375px), with the impact cone with a small stroke repeated impact, so that the mud paste, schist squeezed into the hole wall. If necessary, it must be repeated backfill repeated impact 2 to 3 times. In case of sand flow phenomenon, it is appropriate to increase the proportion of clay to reduce schist, and strive for solid hole wall.
6, when through the sandy low liquid limit clay and other clay soil layer, because the soil layer itself can make slurry, should reduce the input mud consistency, and the use of 0.5m of small stroke, to prevent jamming, buried drilling.
7, pay attention to the length of the wire rope released evenly. Generally in the soft soil layer each time the loose rope 125px ~ 200px, in the dense hard soil layer each time the loose rope 3 ~ 125px, should pay attention to prevent the loose rope is too little, the formation of the "empty hammer", so that the drilling rig, drilling frame and the wire rope by too much accidental load, suffered damage, too much loose rope, will reduce the stroke, reduce the speed of drilling, and seriously make the wire rope entanglement occurred. Seriously make the wire rope entangled in accidents.
What is the construction process for drilled piles?Rig construction
(1) Shroud burial and mud production:
The project adopts steel shrouds matching the diameter of the pile foundation; the shrouds are buried within 4m. The centerline of the buried barrel must coincide with the centerline of the pile, and the plane deviation is allowed to be 50mm, and the inclination of the vertical straight line must be less than 1%. The line with the barrel requires no protrusions in the barrel, tensile strength, pressure, no water leakage.
Drilling mud using water and clay preparation, mud relative density 1.2-1.4, if the clay preparation does not reach the required indicators of mud, can be used bentonite or add other new agent method.
(2) Drilling rig in place:
Drilling rig installation must be installed in place in accordance with the piling control points provided by the on-site construction technicians, and the drilling rig installation must be firm and smooth, and the function of each component is flexible and reliable (the site within the scope of piling construction is level, and there is no obstacle in the space of activity). Keep the drilling rig without displacement and sinking during the drilling process.
(3) drilling:
Drilling operations are divided into shifts 24 hours a day continuously, the machinery has a professional staff to look after, and send a person to look after the drilling rig drilling situation and the specific gravity of the mud, and do even if the adjustment, the drilling process to fill out a good drilling construction records. Each shift handover should be handed over to the drilling situation and the next shift should pay attention to.
When the machine is turned on, the drilling is slowed down and accelerated only after all the guiding parts have entered the stratum. In the process of drilling, check the level of the drilling rig and the verticality of the drilling rods at any time to ensure that the verticality of the drilling holes is less than 1%. During the drilling process, pay attention to the geological changes at any time, in case of inconsistency with the geological situation, it should be promptly reported to the technical supervisor and analyze and compare, and if necessary, ask the exploration department and the designers to conduct consultation and analysis, and put forward the concluding comments.
In order to ensure the quality of the project and prevent the hole wall from collapsing, the first in the shroud filled with efficacy qualified Pangrun Clay slurry, the process of hole formation at any time to measure and control the density of the slurry, the specific gravity of the slurry according to the different geological conditions, respectively, to control: viscous soil: 1.02 ~ 1.06; sandy soil: 1.06 ~ 1.10; gravelly soil: 1.10 ~ 1.15.
In the process of drilling, the fall of the The speed of drilling should be uniform, no sudden acceleration, drilling construction work should be done in one go, the pause time should not be too long.
(4) Stop drilling:
In the process of drilling, when the designed pile length is reached, stop drilling in time with the consent of the quality inspector and the supervisory department.
(5) Clearing:
After finalizing the hole, the depth of the hole should be measured and checked by hanging 0.5kg heavy iron weight under the measuring rope, and the hole should be cleared after checking; attention must be paid to maintain the specific gravity of the mud in the hole to prevent the collapse, and deepening of the bottom depth of the hole instead of clearing the hole is not allowed, and the slag in the bottom of the hole should be no more than 5cm, and the overdimension coefficient of the hole should be no more than 1.1 and no less than 1.0, and the perpendicularity of the hole should be less than 1%, and the slag in the bottom of the hole should be less than 1 cm. 1%, hole bottom slag <5cm.
After lowering the pile reinforcement cage and conduit, measure the thickness of slag again, and carry out the second clearing until the slag meets less than 5cm, and the density of slurry is between 1.1-1.2, then the clearing can be stopped. Terminate the clearing hole within 30 minutes must be concrete filling.
(6) Lowering the reinforcing cage
After the first clearing, lowering the reinforcing cage, reinforcing cage placement by the crane mobile installation, lifting using three-point lifting, cage tied pine rods to prevent deformation, to ensure that the cage body is uniformly stressed, not deformed. Installation of the center of the hole slowly into the hole, in order to prevent collision with the hole wall, is strictly prohibited high up and down.
Reinforcing steel cage in place, according to the design requirements of the lower entrance position check, to determine the design position, in time for the fixing of the cage, the use of inserted pipe will be fixed in a solid base position, to ensure that the cage in the process of concrete construction does not displace, do not float, do not sink.
(7) underwater concrete filling:
This project all adopts commercial concrete, pile foundation concrete pouring adopts concrete mixer truck directly into the hole pouring concrete way, commercial concrete to solve the problem of filling pile first plate of concrete large amount. Before pouring, the commercial concrete supply unit must provide the certificate of conformity of commercial concrete, concrete ratio, raw material quality certification file, the site of each can of concrete arranged for a person to do a good job of tower fall test, to maintain the degree of collapse in 180-220mm qualified. Plan to use six commercial concrete truck transportation, to ensure the continuity of pile foundation concrete pouring.
The conduit must be sealed to ensure airtight and no leakage. The concrete bucket must be large enough to ensure that the initial concrete filling reaches a buried depth of 1.0m or more.
The bottom of the lowering concrete conduit is 300-500mm from the bottom of the hole, and it should be lowered slowly to prevent collision with the reinforcement cage and affect the position of the copper cage.
In the process of concrete pouring, the rising height of concrete surface should be detected in time, and the catheter should be dismantled at the right time to ensure that the bottom catheter is buried below the concrete surface of not less than 2.0m, and it is strictly prohibited to pull the catheter out of the concrete surface. The amount of concrete overfilled in each pile is controlled to be more than 0.8m.
The concrete filling of each pile must be guaranteed to be completed in one continuous filling, and must not be stopped in the middle.
Do a good job of test block retention, each pile to stay two groups, one group for standard maintenance, a group of the same condition maintenance, in order to test the quality of the pile body.
(8) Pile quality standards:
The depth of the hole must meet the design requirements.
Allowable deviation of hole diameter: -50mm.
Deviation of verticality: less than 1% of pile length.
Pile deviation: 50mm.
Six, steel construction
(1) Basic requirements:
All steel must be raw materials before entering the field of the effectiveness of the test, unqualified products are strictly prohibited from entering the field of use. Check the rebar factory certificate and batch number and whether the incoming material is consistent, check the type of rebar and whether the required is consistent, without the consent of the designers is strictly prohibited to privately carry out the replacement of rebar. Stacked steel must ensure that no pollution, corrosion and ease of construction operations to prevent steel by rain and other erosion affects the effectiveness of steel.
Steel processing site must be flat, clean, to prevent the processing of molding steel deformation and corrosion, pollution. (Site with concrete hardening)
Reinforcing steel construction by experienced professional team construction, construction in strict accordance with the construction procedures and meet the construction specifications and design requirements, all personnel must be licensed.
Reinforcing steel butt welding by experienced professionals, and licensed to work, butt welding must first take a test piece to do butt welding test, in the performance indicators qualified before mass processing, the construction process and then sampling, in order to check the quality of construction.
Steel welding and processing must meet the specification requirements and design requirements, construction shall not damage the steel, affecting the mechanical performance of steel.
(2) piling cage:
Each piling cage adopts a one-time tie molding on the ground, according to the design requirements, the cage in the full length of the main steel bar using flash butt welding welding joints, to achieve the design requirements of the length of the steel bar; the cage outside the helical hoop bar with the main bar using spot welding, the rest of the tie; reinforcing bar with the main bar using the welded form of the wire, the use of welded form of closed circle, closed circle, the form of closed circle. The form of closed circle, closed circle lap weld, weld length double-sided welding 12cm, single-sided welding 24cm, the lap length of the main reinforcement of the pile is 80cm, double-sided weld, weld length of 60cm, to ensure the overall rigidity of the steel cage requirements.
Reinforcing steel butt welding samples for trial testing, must meet the specifications and design requirements.
Processing of molded steel cage must be placed flat to prevent deformation, tied steel cage in the pile filling before the design and supervision and other relevant departments must check and acceptance, fill in the acceptance record. Unqualified products are strictly prohibited to be applied to the project.
The permissible deviation and protective layer thickness of pile reinforcement cage construction must comply with the design requirements and specifications. Reinforcing steel operation in accordance with the operating procedures for construction.
VII, pile construction notes
(1) drilling pile construction sampling, single pile center deviation is not more than 50mm, pile tip slag thickness is not more than 100mm, hole diameter is not less than the design diameter.
(2) After drilling to the design depth, the quality check of hole formation shall be carried out, including: shape of hole wall (hole diameter), hole depth, verticality, and slagging at the bottom of the hole.
(3) If the tested hole diameter, verticality, hole wall stability and back to the silt and other on-site measured indicators do not meet the specifications and design requirements, we should find out the reasons, and take timely remedial measures to facilitate the improvement of the construction process in the future.
(4) Reinforcement cage in the production, installation and transportation process should take measures to prevent unrecoverable deformation. When lifting into the hole, it should not collide with the hole wall, and reliable measures should be taken to fix its vertical position when filling concrete.
(5) Piling quality inspection shall be carried out after piling, and the base pile shall be tested root by root by using unbroken method.
VIII. Inspection after pile forming
(1) Carry out timely inspection after hole formation and pile formation of bored pile construction.
(2) When testing the pile foundation, it must be operated by professional personnel and organize the information in time.
(3) After obtaining the test data, organize the technical personnel of the special case department to analyze the data in time, and make corresponding rectification measures in time for the problem piles with reasons, and after the rectification is completed, the next step of construction can be carried out.
What is Drilled Pile Construction Process?Drilled pile construction method
The construction of drilled piles, due to its different selected retaining wall formation, there are two types of mud retaining wall method and full set of pipe construction method.
Mud wall construction method
Impact drilling, punch and grab drilling and rotary drilling can be used to form the mud wall construction method. The process of this construction method is as follows: leveling the site → mud preparation → burying the shield → laying the working platform → installing the drilling rig and positioning → drilling into the hole → clearing the hole and checking the quality of the hole → lowering the reinforcing cage → filling the underwater concrete → pulling out the shield → checking the quality. Construction sequence
(1) Construction preparation
Construction preparation includes: selection of drilling rig, drilling tools, site layout and so on.
The drilling rig is the main device for drilling pile construction, which can be selected according to the geological condition and the application conditions of various drilling rigs.
(2) Installation and positioning of drilling rig
If the foundation for installing the drilling rig is not stable, it is easy to produce bad effects such as tilting of the drilling rig, tilting of the pile and eccentricity of the pile in the construction, so it is required that the installation foundation is stable. For the softer and sloping foundation, bulldozer can be used to bulldoze the foundation and reinforce it with steel plate or sleeper.
In order to prevent the pile position is not allowed, the construction is very important to set the center position and correct installation of the drilling rig, for the drilling rig with a drilling tower, the first use of the power of the drilling rig and the nearby cage with the drilling rod moving roughly positioning, and then jacking up the frame to accurately locate the lifting pulleys, the drilling head or the fixed drilling rod of the card holes with the center of the barrel in a plumb line in order to ensure that the rig's perpendicularity. The deviation of the position of the rig is not more than 2cm.After aligning the piles, use sleepers to pad the beam of the rig, and pull the cable on the top of the tower symmetrically on the axis of the rig.
(3) buried protection tube
The key to the success or failure of drilling is to prevent the collapse of the hole wall. When drilling deeper, in the water table below the hole wall soil under hydrostatic pressure will be collapsed to the hole, and even the phenomenon of sand flow. Borehole if you can keep the wall water table high head, increase the hydrostatic pressure in the hole, can be for the hole wall, to prevent the collapse of the hole. In addition to playing this role, the shield at the same time good isolation of surface water, protection of the ground at the mouth of the hole, fixing the pile hole position and the role of the drill bit guidance, and so on.
The materials used to make the shield are wood, steel and reinforced concrete. Shield requires strong and durable, no water leakage, its inner diameter should be larger than the diameter of the drill hole (rotary drilling about 20cm, submersible drilling, impact or punch grab cone about 40cm), the length of each section is about 2 ~ 3m. generally commonly used steel shields.
(4) mud preparation
Drilling mud consists of water, clay (bentonite) and new additives. It has the effect of floating suspended slag, cooling the drill bit, lubricating the drilling tools, increasing hydrostatic pressure, and forming a mud skin on the hole wall, isolating the seepage inside and outside the hole, and preventing the collapse of the hole. Modulation of the drilling mud and after back to the ring purified mud, should be based on the drilling method and stratigraphy to determine the mud consistency, mud consistency should be depending on the stratigraphic changes or operational requirements of the maneuver to master, mud is too thin, slagging capacity is small, poor wall effect; mud is too thick will weaken the impact function of the drill bit, reducing the speed of drilling.
Drilled piles
(5) Drilling
Drilling is a key process, which must be carried out in strict accordance with the operational requirements to ensure the quality of holes, firstly, attention should be paid to the quality of the opening hole, which must be good for the center line and verticality, and press the good protection cylinder. In the construction, we should pay attention to the new mud and slag pumping (for percussion type), and also check whether there is any skew phenomenon in the hole at any time. When using percussion or punch and grab drilling rig construction, the nearby soil layer is affected by the vibration and the stability of the neighboring holes. Therefore, the drilled hole should be cleared in time to lower the cage and fill the underwater concrete. The order of drilling should also be practical first planning, not only to ensure that the construction of the next pile hole does not affect the last pile hole, but also to make the drilling rigs do not move too far away and interfere with each other.
(6) Clearing
The depth, diameter, position and shape of the drilling hole are directly related to the quality of the pile and the curvature of the pile body. For this reason, in addition to close observation and supervision in the drilling process, after the drilling reaches the depth required by the design, the depth of the hole, hole position, hole shape, hole diameter and so on should be checked. When the final hole check fully meets the design requirements, the bottom of the hole should be cleaned up immediately to avoid too long an interval so that the mud settles and causes the hole to collapse. For friction pile when the hole wall is easy to collapse, the slag thickness is required to be no more than 30cm before filling underwater concrete; when the hole wall is not easy to collapse, no more than 20cm.For column pile, the slag thickness is required to be no more than 5cm before shooting water or wind.The method of clearing the holes is applied flexibly by using different drilling rigs. Usually can be used positive loop rotary drilling rig, reverse loop rotary machine vacuum mud suction machine and slag pumping cylinder and other clearing holes. One of the suction mud machine to clear the hole, the required device is not much, easy to operate, clear the hole is also more thorough, but in the unstable soil layer should be used with caution. The principle is to use the compressor to produce high-pressure air blown into the suction mud machine pipeline will be blown out of the mud.
(7) Filling of underwater concrete
After clearing the hole, the prefabricated steel cage can be lifted vertically into the hole, which should be fixed after positioning, and then the concrete will be filled with conduit, which should not be interrupted when filling, or else it will be easy to break the pile.
Full set of pipe construction method
Construction sequence of full set of pipe construction method. The general construction process is: leveling the site, laying the working platform, installing the drilling rig, pressing the casing, drilling the hole, placing the reinforcement cage, preventing the conduit, pouring the concrete, pulling the casing, and checking the quality of the pile.
The main construction steps of the full set of casing construction method are similar to the mud wall protection method except that mud and hole cleaning are not required. The verticality of the pressed-in casing depends on the verticality at the beginning of excavation at a depth of 5-6m. Therefore, the verticality should be checked with the use of level and plumb.
Screw drilling post-compaction grouting construction process
Post-compaction grouting construction process
4.2 Post-compaction grouting construction technical requirements
4.2.1 Post-compaction grouting construction control quotes
(1) Post-compaction grouting can be carried out after 2 days of piling, and the specific time can be adjusted depending on the construction situation of the base pile. The specific time can be adjusted according to the situation of foundation pile construction, but generally should not exceed 30 days after the pile is formed (in case of special circumstances, early grouting is allowed);'
(2) The quality control of post grouting adopts the method of double-control of grouting volume and grouting pressure, with the control of the cement injection volume as the main control, and the control of the termination pressure of the pumping as the supplementary control;'
(3) P.O 32.5 cement is used as the cement, and the water/cement ratio of the grout is 0.60~0.5~1.0%. The water-cement ratio is 0.60~0.75;
(4) The amount of cement pressed in and the pumping termination pressure are according to the following table:
Pile type Pile diameter/effective pile length Grouting at each pile end Grouting at each pile side
Cement pressed in and pumping pressure Cement pressed in and pumping pressure
Grouting pile 1000mm/36.50m&38.00m 1600~1800kg ≮2.0MPa 600~800 kg ≮1.5MPa
Specific construction control standards:
a. Cement compaction reaches 70% of the design value in the table, and the pumping pressure is more than 6.0MPa can stop the grout;
b. Cement compaction reaches 70% of the design value in the table, and the pumping pressure is less than 70% of the predetermined pressure in the table. When the pumping pressure is less than 70% of the predetermined pressure in the table
, the water-cement ratio should be adjusted downward and the grouting should be continued to meet the predetermined pressure;
c. If the cement grout is overflowing from the side of the pile, the water-cement ratio should be adjusted downward, and the grouting should be performed intermittently until the quantity of cement grouted meets the requirements in the above table.
4.2.2 Setting of post-pressure slurry pipeline
(1) Pile end and pile side pressure slurry valves are made according to the patented products of Groundwork Research Institute of China Academy of Building Research. The pile end is set with two pressure slurry pipelines, and the pile side is set with one pressure slurry pipeline (see the diagram of pressure slurry device for details).
(2) The slurry conduit adopts the national standard welded pipe for low-pressure fluid transportation. Nominal caliber of pile end slurry conduit φ25 (1′), wall thickness of 3.25mm (Note: the actual wall thickness of steel pipe shall not be less than 3.25mm); pile side slurry conduit. Pipe nominal caliber φ20 (3/4′), wall thickness 2.75mm; pile end pressure slurry conduit welded casing nominal caliber φ32, wall thickness 3.25mm.
(3) Pressure slurry conduit setting according to the detailed drawings shown in the set points are as follows (see attached drawings):
a. Pressure slurry conduit are set up at the upper end of the pipe threads, pipe hoops and plugs; pile end pressure slurry conduit is equipped with a lower end of the G1′ thread and the G1′ threads. The lower end of the pile end slurry conduit is provided with G1′ threads and a pipe hoop for screwing the pile end slurry valve; the lower end of the pile side slurry conduit is provided with G3/4′ threads and a tee for plugging the pile side slurry valve.
b. The connecting lines of the slurry conduit are casing welded, and the welding must be continuous and closed, and the weld is full and even, with no holes or trachoma (each weld joint should be knocked off the slag to check the quality of the welding, and meet the requirements before proceeding to the next process).
c. Pressure slurry conduit and reinforcing cage fixed with 12 lead wire cross-tie fixing method, tie should be firm, tie points should be uniform. The pile end slurry conduit is tied on the inner side of the reinforcing hoop, and the tying point is at each reinforcing hoop; the pile side slurry conduit is tied on the outer side of the spiral hoop, and the tying point spacing is 1.5m.
d. The upper end of the slurry conduit should not be lower than 200mm below the ground level of the pile construction work (it can be adjusted slightly depending on the specific situation); the lower end of the pile end slurry conduit is 400mm away from the bottom of the longitudinal cage of the reinforcement cage (Note: the bottom of the cage has a reinforcing hoop and the bottom of the cage is also tied to the bottom of the reinforcement hoop, and the tie point should be even). (Note: the lowest reinforcing hoop should also be adjusted to the place; pile side pressure slurry conduit lower set elevation of about -34.30m, 10m from the bottom of the cage.)
e. Reinforcing steel cage lifting into the hole in the process of inserting the pile side pressure slurry valve, reinforcing steel cage before the final position of the welded pile empty section of the pressure slurry conduit;
f. Reinforcing steel cage into the hole in the process of lifting and placing should not be twisted repeatedly and downward collision; the reinforcing steel cage must be be sunk to the bottom, not suspended!
g. Pile concrete filling is completed, vertical hole backfill, should be inserted with obvious signs, prohibited vehicles crushing.
4.2.3 Post-pressure grouting mechanical device
(1) The grouting pump adopts 3SNS-type high-pressure grouting pump, with rated pressure of not less than 8MPa, rated flow rate of 76L/min, and power of 18kW.
(2) The grouting pump control and monitoring pressure gauge is a 2.5-level 16MPa anti-seismic pressure gauge.
(3) Liquid slurry mixer is YJ-340 type liquid slurry mixer matched with grouting pump, with volume of 0.34m3 and power of 4kW.
(4) Cement slurry pipeline should be used as high-pressure fluid pumping hose, with rated pressure of not less than 8MPa.
4.2.4 Post-pressure grouting construction materials
Cement used in pressure grouting has a mark of P.O 32.5, cement grade of 16MPa. P.O 32.5, the cement should meet the requirements of relevant technical specifications.
What is the difference between drilled piles, immersed tube piles, mixing piles and exploding piles?
Hello! In terms of piling process, drilled pile is formed by drilling machine, then filling concrete inside; immersed pipe filling pile is driven into the soil, then filling concrete while pulling out the steel pipe; exploding and expanding piles, also called tamping and expanding piles (exploding and expanding inside the rock), is to drive the piles to the specified depth, filling hard concrete, using tampers to tamp (or expanding the head of the pile with an explosion), forming an enlarged head, and then filling the upper part of the concrete. These three kinds of piles are all reinforced concrete piles, the difference is that the bored pile is to clear out the soil inside the pile, and the immersed pipe pile is to squeeze the soil inside the pile to the periphery of the pile, and the exploding pile can be formed by both methods, just expanding the head of the pile to improve the bearing capacity of the pile. Mixed pile is generally used to strengthen the foundation soil, is the use of pressurized method of cement slurry pressed into the soil, the side of the side with special mechanical mixing of soil and mud, the formation of "mud and water" piles, in order to improve the bearing capacity of the foundation.