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Driving piles with a diesel hammer. Pile diesel hammer

The company "Installation of Piles" offers services for driving reinforced concrete piles with highly productive diesel-type hammers. Our equipment is represented by tubular and rod hammers with a striker weight from 1.5 to 3 tons. These units effectively drive piles into all types of soil common in the central region of Russia.

This page provides information about the technology of driving piles with diesel hammers. We will consider the specification and technical characteristics of this equipment, the types of hammers and their functionality.

Diesel hammers are attachments

Diesel hammers belong to the class of mounted pile driving equipment, which is equipped with a piling rig. The hammer is fixed on the guide nodes of the pile driver's mast by means of a special mounting plate. During operation, it moves in a vertical plane, descending along the mast along with the shaft of the pile being loaded.

The scope of use of diesel hammers is extensive, this technique is used for the following purposes:

  • For driving reinforced concrete piles (square, rectangular, round section, composite structures);
  • For driving metal sheet piles (z-shaped, trough-shaped, flat).

Important: hammers are installed on pile drivers of a wheeled or caterpillar layout. The pile driving mast and diesel hammer have a unified fastening system, which allows the pile driver to be equipped with any model of the unit for impact pile driving.

Rice. 1.1

The cross-section and configuration of piles and sheet piles, with which the diesel hammer can work, depend on the shape of its head - a fastener, through which the hammer is fixed on the shaft of the submerged structure. Each specific section (30 * 30, 40 * 40 cm, etc.) requires the use of an appropriate headband.

In the factory configuration, the diesel hammer has a set of caps for the most common types of piles; if necessary, additional caps are purchased separately.

Types of diesel pile hammers

Diesel hammers are classified into subspecies based on the structural differences of the units. According to the mass parameter of the shock part, the following types of hammers are distinguished:
  • Lightweight - striker weight up to 700 kg;
  • Medium-heavy - up to 2000 kg;
  • Heavy - from 2500 kg.

Important: a division is also made according to the shape of the structure, according to which tubular-type units and rod hammers are classified.

  • Rod hammers
Check out a typical rod hammer layout:


Rice. 1.2: Scheme of a rod hammer

The basic functional units of this equipment include:

  • The piston block fixed on a steel hinged plate;
  • Parallel pipes that act as guide elements of the striker;
  • Diesel fuel injection system into the piston;
  • The cat is a knot that fixes the head of the hammer.


Rice. 1.3

The piston block, which is a cast structure formed in the inner part of the chamber, in turn consists of a piston and compression rings. The fuel injection system is represented by a nozzle connected to the fuel pump through a supply hose.

On the hinged plate fixed over the shank, there are 2 guide frames parallel to each other, connected by a steel bridge on the upper contour. During operation, the striker moves along the frame, in the body of which the fuel detonation chamber is located.

  • Tubular hammers
The layout of tubular units is shown in the following image:


Rice. 1.4

The differences between tubular mechanisms are that the guiding function in this equipment is performed by the body, which is a steel cylindrical pipe. The impact part of the tubular hammer is at the same time its piston, into which the fuel mixture is supplied by the nozzle.



Rice. 1.5


Important: the closed body of tubular hammers makes it possible to implement forced cooling in them, which is absent in rod-type units. Its presence is one of the key advantages of tubular structures over rod hammers - they are subject to long-term operation without interruptions for natural cooling, while when using diesel rod hammers, forced pauses must be maintained in order to prevent overheating of the equipment.

Technical characteristics of diesel hammers

Tubular units are systematically replacing rod-type hammers from use. In addition to the advantage in the form of forced cooling, the reason for this is a significantly increased service life (30-40%) and a better ratio of the weight of the striker to the developed impact power.

The most popular series of diesel hammers in domestic construction are the SP and UR hammers, you can see their technical characteristics in the image below:



Rice. 1.6: Specification of SP series hammers

The weight of the impact part in rod diesel hammers can reach up to 3 tons, while their maximum impact energy does not exceed 42 kJ, the range of the number of pile blows per minute is 45-55 pieces.



Rice. 1.7

Due to the limited power, such structures are used for the installation of reinforced concrete piles and sheet piles in low and medium density soil - tubular hammers are used to implement foundation work in hard soils.

These units can operate in the temperature range from -35 to +40 degrees (in conditions of operation in frost over 20 degrees, the hammer piston assembly must be preheated). For tubular units, the mass of the striker is more variable - its weight can be 5, 3.5, 2.5, 1.8 or 1.25 tons. The range of impact power is from 35 to 170 kJ. The speed of work is up to 45 beats / min.

Pile driving technology with diesel hammers

The principle of operation of tubular and rod-type units is identical. The sequence of operation of the hammers is as follows:
  • Initially, the pile driver is placed at the dive site, then it pulls the pile from the temporary warehouse with winches, the shaft is slinged with cables, the driving position is set and brought under the hammer head;
  • The post is fixed on a pile mast, a hammer is lowered on it and the pile is paired with the head;
  • The impact head of the unit by means of a copra winch rises along the guides to the upper part of the body;
  • After the operator of the pile driver turns on the lever for resetting the striker, it, under the influence of its own weight, falls along the guides to the cap fixed on the head;
  • When the striker falls, the fuel pump is activated and the nozzle supplies diesel fuel to the combustion chamber;
  • Upon contact of the striker and the chabot, the piston hits the cylindrical recesses of the combustion chamber, due to which the mixture in it spontaneously ignites and detonates;
  • Thanks to the energy resulting from the explosion of the fuel, the striker throws up along the guides;
  • When the lifting energy of the striker is balanced by the force of attraction, the striker begins to fall back under its own weight.
As a result Posted: February 11, 2008


[mass of impact part, maximum potential energy, calculated, recommended]

Pile driving with diesel hammers

Diesel hammers differ from steam-air hammers in that the lifting of the shock part is carried out due to the energy of the working stroke of a two-stroke diesel engine. Our industry produces diesel hammers of two types: rod and tubular.

Basically, rod-type diesel hammers are produced and used, the impact part of which is a movable cylinder, open from below and moving in guide rods. The high pressure pump, driven by the moving cylinder, delivers fuel to the combustion chamber injector through a tube located in the piston block.

Diesel hammers: a - rod, b - tubular, 1 - axis of the lever for resetting the cylinder; 2 - cat; 3 - cylinder (shock part); 4 - pin (cam); 5 - guide rod, 6 - nozzle, 7 - piston block, 8 - fuel feed lever, 9 - ball joint, 10 - fuel pump, 11 - piston (impact), 12 - cylinder, 13 - purge windows, 14 - heel , 15 - fuel pump, 16 - fuel supply lever, 17 - fuel tank.

In a tubular diesel hammer, a heavy movable piston serves as the shock part, and the cylinder is stationary and acts as a guide structure. The low pressure pump only doses the fuel supply to the combustion chamber; spraying it is achieved by hitting the piston head on the spherical cavity of the cylinder, where fuel comes from the pump.

Rod hammers operate at a lower lift height and a higher compression ratio, which is why their impact energy is 2 to 3 times less than that of the corresponding tubular hammers.

For driving reinforced concrete piles up to 8-10 m long, with a section of 30x30 and 35x35 cm and weighing up to 2-2.5 tons, diesel-rod hammers with a shock weight of 1200-2500 kg are usually used. It is recommended that the ratio of the weight of the impact part of the diesel hammer to the weight of the pile be not less than 1.25. However, for tubular diesel hammers, which have significantly higher impact energy and are more efficient, this ratio can be reduced to 0.7-0.5.

Diesel hammers have their own source of energy, which is especially important when driving short piles, when frequent movements of the piling installation are required. They are applicable to both clay and sandy soils. However, in dense sandy soils, additional washing is recommended.

A serious disadvantage of diesel hammers is their poor startability when immersed in soils with highly compressible layers and in soft pliable soils.

The fact is that the height of the cylinder lift depends on the amount of incoming fuel and the resistance of the soil to the pile sinking. In case of weak soils, the cylinder is thrown up insufficiently, and then, when the shock part falls, the required air compression in the combustion chamber, which is necessary to ignite the fuel mixture, does not occur, and the hammer stops working.

In summer, the startability of rod and tubular diesel hammers ready for operation depends mainly on the amount of pile immersion at one blow (from failure). The startability and stability of the operation of a tubular hammer is ensured with a maximum pile failure of up to 8, and a rod hammer - up to 25-30 cm / blow.

It should be noted that tubular hammers are inferior to rod hammers in terms of starting qualities. When working in cold weather, special fuel additives are used to reliably start a tubular diesel hammer, otherwise, at air temperatures down to -20 ° C, the hammer must be preheated for 20-30 minutes. This, however, is not a big disadvantage and has little effect on performance.

Rod hammers (for example, S-268) work more stably in winter conditions than tubular hammers, and successfully start even at an air temperature of -30 ° C.

In hot, calm weather, the performance of a rod diesel hammer is significantly reduced due to overheating, and after driving every two or three piles, it is necessary to cool the hammer with a raised impact part for 20–30 minutes. To avoid stopping the diesel hammer due to overheating, it is recommended to blow its piston with compressed air. To do this, a small portable compressor, for example, 0-16 (painting), is mounted on the copra frame, and the hose is attached to the boom.

When the soil freezes to 0.5 m, the effective immersion of reinforced concrete piles with a rod diesel hammer can be carried out without the installation of leading wells. When driving into the ground, frozen to a depth of 1.1 m, about 50% of the piles get cracks - in such conditions it is no longer possible to do without leading wells.

It should be noted that diesel hammers cannot work underwater.

The type of hammer is chosen according to the impact energy.


From: milica,  7292 views

1. Product type . An element immersed in the ground with a given bearing capacity. The immersion is carried out by a series of vertical blows on the pile head.

2. The composition of the process. Delivery of piles to the object; installation of piles on the submersible unit; driving piles into the ground until the design "failure".

3. Process entry . The previous work (site) was accepted, test piles were loaded and tested (to determine the actual length of the pile and the time of its immersion).

Tests are carried out on a fully prepared site or at the bottom mark of the project excavation before the start of mass production (or delivery) of piles. During dynamic tests, a pile of design dimensions is immersed by hammer blows to the calculated “failure”. During static testing, the design pile is loaded with a real vertical load (weights). If the test results are positive, an application is given for the manufacture of design piles in a given quantity (per object). If the results are negative, the designers change the length or section of the pile and conduct new tests.

4. materials . Prefabricated reinforced concrete piles. The section of the piles is square, 300x300 mm. Tubular piles with a diameter of 400–800 mm are also used. The length of the piles at the PGS facilities is 5–16 m. At the same time, piles 12–16 m long can be composite of two elements, connected during the immersion process by working joints (Fig. 3.4).

In the construction of bridge supports, tubular shell piles with a diameter of 1200–6000 mm are used. From individual sections 6.0 m long, a pile 20.0–40.0 m long is formed during the immersion process.

Wooden piles can only be used below the groundwater level (wood does not rot in water). Most of the old buildings in St. Petersburg, including cathedrals and palaces, were built on such larch piles. Currently, in the construction of industrial and civil structures (ACS), wooden piles are practically not used.

Steel piles - sheet pile. Steel plates of a special profile, 200–400 mm wide and 6–12 m long. They are used for the installation of retaining walls, fastening the walls of deep pits (p. 31, Fig. 2.4).

4.1. Technique . To immerse piles in the ground, a pile-loading installation (SPU) is used. SPU represents a set of two units - a pile driver and a loader.

Koper includes (Fig. 3.5):

Basic machine (1) - tractor, excavator, car, mobile bridge;
- guide boom - to hold the piles in the desired position; for hanging the submersible mechanism (loader - 3);
- auxiliary equipment - winches for lifting the pile and loader; arrow pointing systems; welded or cast steel caps with a set of shock-absorbing pads (hardwood, reinforced rubber) (Fig. 3.6).

Guidance systems provide: placing a pile on a point; vertical alignment; correction of the position of the pile during the immersion process. They provide:

Boom tilt at a certain angle in two planes;
- translational movement of the boom "left-right", "forward-backward".

It should be noted that not all pile drivers have a full set of these movements, most have only boom tilt movements, which complicates guidance and reduces the accuracy of piling.

submersible- a mechanism that, with a force impulse, introduces a pile into the ground (Fig. 3.8, 3.9). It defines the type of technology.

Rational areas of application of various pile drivers:

Tractor installations - driving piles 5–12 m long with a row arrangement of piles (the tractor moves along the row), productivity 20–30 pcs/shift;

Excavator (or on the basis of jib cranes) - immersion of piles 6–16 m long with a cluster arrangement of piles in foundations for columns; from one parking lot, by turning the boom, it immerses all the piles in one bush and goes to another pile cluster. Productivity 15–25 pcs/shift;

Bridge SPU (rail or caterpillar) complete with a hammer - driving piles 5–10 m long with a row arrangement of piles or a field (Fig. 3.7). They have a high productivity of 40–70 piles per shift. For short distances (from house to house) they can move on their own. However, due to high initial costs, such installations are effective only for large volumes of work (more than 1500 piles). Are applied at quarter building of urban microdistricts.

Hammers are used as loaders, which differ in the type of drive: internal combustion hammers (diesel), steam-air and mechanical (suspended). Steam hammers come in single and double action. In single-action hammers, the power of steam or compressed air is used only to lift the impact part, and the working stroke is carried out when it falls onto the pile. Double-acting hammers use the energy of steam or compressed air to increase the impact force. Hammer operation can be manual, semi-automatic and automatic.

The main parameter of the hammer is the mass of the impact part, which, depending on the type of soil, determines the maximum possible length of the pile to be driven.

Diesel Hammer Rod Type(Fig. 3.8, a) includes: a shaft with a piston (2), guide rods (5), a shock part with a cylinder (4) and a piston block, which ends with a hinged support consisting of a spherical heel and a cap. The purpose of the pivot support is to provide a central impact on the pile with a slight misalignment of the hammer and pile. To start the diesel hammer, the impact part with the help of a grapple-cat is lifted by a copra winch to the highest position (Fig. 3.8, a). After that, the grip releases the shock part and, when it falls, compressed air is formed in the cylinder, as a result of which its temperature rises greatly. At this time, a plunger-type pump supplies fuel to the cylinder and the mixture ignites (Fig. 3.8, b). The gases formed during combustion throw the cylinder back to its original position (Fig. 3.8, c), and in the future the hammer works automatically until the fuel supply is cut off. The lifting height of the shock part is regulated by the fuel supply to the cylinder.

For piling, diesel hammers with a mass of the impact part of 600, 1200, 1800 and 2500 kg and a number of blows per minute of 50–100 are used. The lifting height of the impact part of the hammer is 1.0–2.6 m. The advantage of diesel hammers compared to steam-air hammers is that they are more mobile and do not require bulky steam boilers or powerful compressors for their operation. The disadvantage of rod diesel hammers is manifested when driving piles into soft soils, when it is impossible to ensure its automatic operation, since in this case a high degree of air compression is not formed in the combustion chamber, which is necessary to ignite the fuel mixture.

IN tubular diesel hammer(Fig. 3.9) (with a part mass of 1200, 1800 and 2500 kg, respectively), the cylinder (2) is stationary, and the heavy movable piston (4) serves as the shock part. The cylinder at the bottom ends with a fixed chabot, which transmits the blow to the pile through an elastic gasket. The plunger pump delivers fuel to the cylinder. Exhaust gases are released into the atmosphere through a pipe. The principle of operation of a tubular diesel hammer is the same as that of a rod hammer.

Tubular diesel hammers are more reliable in operation and have 1.2–0.5 times greater loading capacity than rod diesel hammers.

The disadvantage of these hammers is that they are difficult to start at low temperatures.

mechanical hammer used for small jobs. It consists of a shock part weighing 1000–3000 kg and a gripping device. After the winch, placed on the pile driver, raises the impact part of the hammer to the required height, the gripping device releases it and, in free fall, the pile is hit. Mechanical hammers are inexpensive, durable and simple in design.

Their disadvantage is that they produce a small number of strokes - 3-4 per minute, with a constant fastening of the rope to the impact part of the hammer, the number of strokes can be increased to 10-12 per minute, but this leads to intensive wear of the winch and copra.

IN double action air-steam hammer the shock part during the working stroke is under the action of gravity and pressure of steam or compressed air. Due to this, the speed of movement of the shock part is much higher and the number of beats per minute has increased to 20.

The advantage of these hammers is their high loading capacity (piles up to 20-25 m long are loaded), and the disadvantage is bulky and heavy steam-powered equipment. At industrial and civil construction sites, double-acting steam-air hammers are practically not used.

The composition of the process:

Breakdown of axes of pile rows;
- Breakdown and fixing of pile points with pins;
- Setting up the unit at a point and setting up piles on it;
- Guidance with the help of the pile assembly to the design point;
- Dive with verticality control and failure measurement;
- When the pile reaches “failure”, the immersion stops regardless of the actual depth of the immersion of the pile.

« Refusal» - the value of the pile immersion from one blow from a series of 10 blows per mm (1.5–4.0 mm), upon reaching which the design bearing capacity of the pile is fully ensured.

The piles delivered from the factory are stored on the edge of the excavation or laid out at the place of immersion (Fig. 3.10).

The fixing of pile points in the amount required “for a shift” is carried out with steel pins with a diameter of 12–16 mm and a length of 300–400 mm. The pile is pulled to the pile driver with a rope through the working block (Fig. 3.11, a) or through the outlet block (Fig. 3.11, b) at distances of more than 15.0 m.

After placing the pile on the SPU, reconciliation in plan and vertically, the hammer is launched. Down to a depth of 1.5–3.0 m, diving is carried out with weak hammer blows when the impact part is dropped from half the height. Then the dive is carried out during normal operation of the hammer. The verticality of the pile is continuously monitored in two directions. When it is visually noticeable that the sinking speed is approaching the calculated "failure", control devices are installed - failure meters, by which the magnitude of the actual pile failure is determined.

When driving piles, a "Journal of Pile Works" is maintained, in which all piles must be numbered in accordance with the working drawing. For each pile, the following is indicated: the amount of "failure"; dive time; depth of immersion, as well as special circumstances (“rest”, cracks, fracture, backup pile, etc.).

After the “failure” of the pile is reached, the SPU moves to the next pile point. The underloaded part of the pile (“priests”) is subsequently cut off.

In the course of piling, there are often cases when the pile does not reach the calculated “failure” when it is immersed to its full length. In these cases, the following actions are recommended:

One pile did not receive a "refusal", and the following piles give a "refusal". Pile driving is continued, and an alternate pile is driven next to the defective pile;

2-5 piles in a row do not give a "failure". In this case, it is necessary to stop further piling. After the “rest” of the piles (3–7 days), a control finishing is carried out. As a rule, in clayey soils, the phenomenon of "sucking" of the pile is manifested, and usually the control finishing gives values ​​\u200b\u200bthat are less than the calculated "failure";

After the control finishing of a group of piles, no calculated “failure” was received. Piling work is suspended, representatives of the design organization are called in to clarify the dimensions of the piles (usually the length of the pile increases).

Delivery of pile field. Upon delivery, you will be presented with:

Acts for the immersion of backup piles; to replace types of piles;
- act of immersion and testing of test piles;
- executive scheme of loaded piles;
- passports for piles;
- acts on the arrangement of joints (with composite piles);
- pile log (indicating the failure of each pile).

Cutting pile heads. For the installation of a grillage, it is necessary to provide a design mark for the top of the piles. This is ensured by cutting the pile heads to the required size. The cutting process is quite laborious. The difficulty lies in the fact that it is necessary to cut two different materials: stone (concrete) and steel (rebar), which require different technologies and cutting tools.

At present, cutting pile heads is carried out mainly by hand, using pneumatic and electric hammers. To reduce the volume of concrete chipping (Fig. 3.13), a steel crimp frame is used. Reinforcing bars are cut by fire or cutting machines.

Limited use of mechanical methods of cutting pile heads:

- force shearing with hydraulic jacks (Fig. 3.14, a, b);
- cutting with a circular saw;
- fracture of the pile head with special equipment based on a tractor (Fig. 3.14, c).

Currently, thermal, explosive, cryogenic technologies for cutting pile heads are also being developed.

Advantages of impact pile driving technology:

High performance;
- immersion of piles in almost any type of soil;
- a significant increase in the bearing capacity of the pile (by 15–30%) due to soil compaction under the tip.

Flaws:

Dynamic impact on the pile (there must be a margin of safety);
- large dynamic impacts on buildings and structures located nearby.

If there are dilapidated or emergency buildings near the construction site, this technology is unacceptable.

Source: Technology of building processes. Snarsky V.I.

From the enterprises of the construction industry, piles are delivered ready for immersion in the ground. Depending on the characteristics of the soil, there are a number of methods for piling, including impact, vibration, indentation, screwing, using undercutting and electroosmosis, as well as various combinations of these methods.

The impact method is based on the use of impact energy (impact impact), under the influence of which the pile with its lower pointed part is introduced into the ground. As it sinks, it shifts soil particles to the sides, partially down or up. As a result of immersion, the pile displaces a volume of soil that is almost equal to the volume of its immersed part. A smaller part of this soil is on the day surface, a large part is mixed with the surrounding soil and significantly compacts the soil base. The zone of noticeable soil compaction around the pile is 2...3 pile diameters.

The impact load on the pile head is created by special mechanisms:

  • steam-air hammers, which are driven by the force of compressed air or steam directly acting on the impact part of the hammer;
  • diesel hammers, the operation of which is based on the transfer of energy from the combustion gases of the impact part of the hammer;
  • vibratory hammers - transmission of oscillatory movements of the working body to the pile (use of vibration);
  • vibrohammers - a combination of vibration and impact on the pile.

Vibratory pile drivers and vibratory hammers are more commonly used for driving large-diameter tubular shell piles, driving into the ground, and extracting sheet piles.

The working cycle of hammers of all types consists of two cycles: an idle stroke, during which the impact part rises to a certain height, and a working stroke, during which the impact part moves down at high speed until it hits the pile. In a number of pile hammers, the working stroke occurs only under the action of the mass of the shock part; such hammers are called single-action hammers.

In double-acting hammers, at the point of maximum lift, the impact part receives additional energy, this energy and the mass of the impact part of the hammer act on the pile. During the operation of the hammer, its body remains motionless on the head of the pile being driven, the impact part of the hammer moves inside the body. The energy of combustion not only raises the impact part of the hammer to its maximum height, but also acts on it with a blow when it falls down under the action of gravity. The supply of fuel and its ignition, depending on the position of the shock part, are performed automatically.

Diesel hammers, in comparison with steam-air hammers, are characterized by higher productivity, ease of operation, autonomy of action and lower cost. Autonomy is ensured by lifting due to the power stroke of a two-stroke diesel engine.

At construction sites, rod and tubular diesel hammers are used (Fig. 6.5). The shock part of the rod diesel hammers is a movable cylinder, open from below and moving in the guide rods. When the cylinder falls on a stationary piston, a mixture of air and fuel ignites in the combustion chamber. The gases formed as a result of the combustion of the mixture throw the cylinder up, after which a new blow occurs and the cycle repeats.

In tubular diesel hammers, a fixed cylinder with a heel is the guide of the entire structure. The shock part is a movable piston with a head. The ignition of the mixture occurs when the piston head strikes the surface of the spherical cavity of the cylinder.

Fig.6.5. Diagrams of diesel hammers:

a - rod; b - tubular; / - movable cylinder; 2 - guide rods; 3 - piston; 4 - movable piston; 5 - head; 6 - fixed cylinder; 7 - support part

The main advantage of a tubular-type diesel hammer over a rod-type hammer is that, with the same mass of the impact part, they have a significantly greater (2 ... 3 times) impact energy. The following ratio of the mass of the impact part of the hammer to the mass of the pile is recommended: for rod hammers 1.25; for tubular - 0.5 ... 0.7. For single-action hammers, the number of strokes per 1 minute is 45 ... 100, the mass of the shock part is up to 2500 kg. Similarly, for double-acting hammers, the number of strokes per minute is up to 300, the mass of the impact part is up to 1200 kg.

The hammer kit includes a cap that is necessary for fixing the pile in the guides of the pile driving installation, protecting the pile head from destruction by hammer blows and evenly distributing the blow over the pile area. In this regard, the internal cavity of the cap should correspond to the shape and dimensions of the pile head and be rigidly fixed on it.

To lift and install the pile in a predetermined position and to drive the piles with the transfer of force from the pile hammer in a strictly vertical position, special devices are used - copra (Fig. 6.6). The main working part of the copra is its boom, along which a hammer is installed before diving, lowered and raised as the pile is driven. Inclined piles are driven into the ground by pile drivers with an inclined boom. Headframes are rail-mounted (universal metal tower-type headframes) and self-propelled - based on cranes, tractors, excavators and vehicles with an arrow 9 ... 18 m long.

Universal pile drivers have a significant deadweight of up to 20 tons. The installation and dismantling of such pile drivers, the installation of crane tracks for them are quite labor-intensive processes, therefore universal pile drivers are used for driving piles more than 12 m long with a large amount of pile work at the facility.

Rice. 6.6. Piling pile drivers:

6 - pavement; b - rail universal; c - based on an excavator; Mr. Tractor; d - by car; / - cabin, 2 - pile mast; 3 - bridge; 4 - rail track; 5 - pile; b - head with blocks; 7 - undercarriage; 8 - turntable; 9 - hammer; 10 - base machine; II-arrow; 12 - spacer; 13 - hydraulic cylinder; 14 - retractable mechanism; 15 - hydraulic cylinder for lifting and tilting the boom; 16 - pile lifting mechanism; 17 - movable frame

The most common in industrial and civil construction are piles 6 ... 10 m long, which are driven using self-propelled pile drivers. Such installations are maneuverable and have mechanical devices for pulling and lifting to the required height of the pile, fixing the pile head in the cap, in the vertical alignment of the boom with the pile before driving.

Pile driving consists of three main repetitive operations:

■ moving and installing a pile driver at the place of pile driving;

■ lifting and placing the pile in position for driving;

■ pile driving.

The center of gravity of the pile hammer must coincide with the direction of pile driving. The pile hammer is lifted to a height sufficient to install the pile, with some margin for the hammer stroke, and fixed in this position. When driving steel and reinforced concrete piles with single-action hammers, it is necessary to use caps to soften the impact and protect the pile head from destruction.

The pile driving process includes placing the pile in the design position, putting on the cap, lowering the hammer and the first blows on the pile from a height of 0.2 ... From each impact, the pile sinks to a certain depth, which decreases as the pile deepens. In the future, there comes a moment when the depth of pile driving is almost imperceptible. In practice, the pile sinks into the ground by the same small amount, called failure.

Failure - the depth of immersion of a pile for a certain number of blows, usually a single-action hammer, or per unit of time for double-action hammers. The failure rate is the average of 10 or a series of strikes per unit time.

Pledge - a series of blows performed to measure the average failure value: for steam-air hammers in a pledge 20 ... 30 blows; for diesel hammers of single action in the pledge of 10 blows; for double-acting diesel hammers, failure is determined in 1 min. blockages.

Measurements are carried out with an accuracy of 1 mm, driving is stopped upon receipt of the failure specified for the project (calculated). If the average failure in three successive pledges does not exceed the calculated one, then the pile driving process is considered completed.

If, when driving, the pile did not reach the design mark, but the specified failure has already been received, then this failure may turn out to be false, due to a possible overstress in the soil from driving previous piles. After 3...4 days, the pile can be loaded to the design mark.

Vibrating pile driving carried out using vibration mechanisms that exert dynamic effects on the pile, which make it possible to overcome the frictional resistance on the side surfaces of the pile, the frontal resistance of the soil that occurs under the tip of the pile, and immerse the pile to the design depth (Fig. 6.7). The immersion speed and vibration amplitude are affected by the mass of the vibrating parts of the pile and the vibrator, its eccentricity, the density of the soil involved in the vibrations, and the vibration frequency of the vibrator. Due to vibration, driving piles into the ground requires efforts sometimes ten times less than when driving. In this case, a partial vibrational compaction of the soil occurs, including under the pile head. The compaction zone for different soils is 1.5...3 pile diameters.

Rice. 6.7. Vibrodriving piles:

a - pile submersible installation; b - vibrator with sprung surcharge; in - vibrohammer; I - vibratory hammer, 2 - excavator; 3 - pile; 4 - electric motor, 5 - loading plates; 6 - vibrator; 7 - unbalances; 8 - headpiece; 9 - springs; 10 - shock part with an electric motor; 11 - striker; 12 - anvil

To immerse piles in the ground by vibrating, vibratory pile drivers are used, which are suspended from the mast of the pile driving installation and rigidly connected to the pile head. The operation of the vibrator is based on the principle that the horizontal centrifugal forces caused by the imbalances of the vibrator cancel each other out, while the vertical forces are summed up. The amplitude of vibrations and the mass of the vibration system, which includes a pile, caps and a vibratory driver, must provide vibration to the adjacent soil layers, their inclusion in this system, as a result, the soil grains move apart under the contour of the immersed part of the pile.

The method is most suitable in sandy soils, water-saturated fine and dusty soils, where the sinking speed can reach 3.5...7 m/min. This method is used to drive solid and hollow reinforced concrete piles, shell piles, and metal sheet piles.

In clayey and heavy loamy soils, a clay pad may appear under the tip of the pile, which reduces the bearing capacity of the pile by up to 40%. Therefore, at the final stage of immersion, for the last 15 ... 30 cm, the pile is immersed in the ground by impact.

When choosing low-frequency pilers (up to 420 rpm) used when driving heavy reinforced concrete piles and tubular piles with a diameter of 1000 mm or more, it is necessary that the moment of the eccentrics exceed the mass of the vibration system by at least 7 times for light soils and 11 times for medium soils. and heavy soils.

To immerse light piles weighing up to 3 tons and a metal sheet pile into soils that do not show great frontal resistance under the tip of the pile, high-frequency (from 1500 counts / min) vibratory hammers with sprung surcharge are used, consisting of the vibrator itself and an additional prigruz with the electric motor located on it.

The vibration method is most effective for non-cohesive water-saturated soils. The application of the method for driving piles into low-moisture dense soils is possible only with the construction of leading wells, i.e., with preliminary drilling of wells.

More versatile is vibroimpact method driving piles with vibratory hammers. During the operation of the vibratory hammer, along with the vibrational effect on the pile, the striker is periodically lowered, exerting a dynamic effect on the pile head.

Spring vibratory hammers are the most common. In them, when shafts with unbalances rotate in opposite directions, constant vibrations are created. When the gap between the striker and the anvil of the pile is less than the oscillation amplitude, the striker periodically strikes the pile through the anvil. Vibratory hammers can self-adjust, i.e., increase the impact energy with increasing soil resistance to pile sinking. The mass of the impact part of the vibrohammer in relation to the immersion of reinforced concrete piles must be at least 50% of the mass of the pile and be 650 ... 1350 kg.

The vibro-impact method is applicable in cohesive dense soils, and allows 3-8 times faster, at the same power as the vibration method, to drive piles into the soil due to simultaneous vibration and driving. In this case, a rigid connection of the vibratory driver with the pile must be ensured.

Vibration pressing method is based on a combination of vibration or vibro-impact impact on the pile and static weight. The vibropressure unit consists of two frames. On the rear frame there is an electric generator powered by a tractor engine and a double-drum winch, on the front frame there is a guide boom with a vibratory driver and blocks through which the pressing rope from the winch passes to the vibrator. In the working position, the vibratory driver, located above the place of immersion of the pile, lifts the pile and sets it together with the fixed head at the place of its driving. When the vibrator and winch are turned on, the pile is loaded due to its own weight, the mass of the vibratory driver and part of the tractor mass, transferred by the pressing rope through the vibrator to the pile. At the same time, the pile is subjected to vibration created by a low-frequency loader with a sprung plate.

The vibropressure method does not require the arrangement of tracks for moving the working unit, it excludes damage and destruction of piles. Especially effective when driving piles up to 6 m long.

pile driving indentation used for short piles of solid and tubular section (3 ... 5 m). Static indentation is carried out in the following sequence: the pile is installed in a vertical position in the guide boom of the unit. Next, the head of the pile is lowered and the head is fixed, which transfers pressure from the base machine (tractor, excavator) through the system of blocks and tackles directly to the pile, which, thanks to this pressure, gradually sinks into the ground. After the pile reaches the design mark, the dive is stopped, the cap is removed, the unit moves to a new position. Static indentation is applicable using two mechanisms simultaneously involved (Fig. 6.8).

Driving piles by screwing is based on the screwing of steel and reinforced concrete piles with a steel tip using mobile units mounted on the basis of cars or other self-propelled vehicles. The method is most often used in the construction of foundations for masts of power lines, radio communications and other structures, where the bearing capacity of screw piles and their pull-out resistance can be used to a sufficient extent (Fig. 6.9).


Rice. 6 8 Scheme of pile driving by static indentation

1 - winch and traction rope for lowering the base plate and lifting the head, 2 - stretching boom; 3 - blocks; 4 - boom frame, 5 - cap with blocks, b - pressing rope, 7 - pressing winch, 8 - base plate, 9 - pull-off block of pressing rope, 10 - pile; II - frame, 12 - tractor

Rice. 6.9. Scheme of the process of screwing piles;

a) the design of the tip prn immersion in soft soils; b) the same, in dense soils, in the Svan immersion scheme; 1 working body tilt reducer, 2 - working body (capstan), 3 - pile; 4 - pile tip; 5 - outriggers

The screwing unit consists of a working body, drives for rotation and tilt of the working body, a hydraulic system, a control panel, four hydraulic outriggers and auxiliary equipment. The working body of the capstan is a mechanism consisting of two pairs of grippers and an electric motor. The grippers compress the pile and transmit rotation from the electric motor to it. Depending on the purpose (transfer of load over a large area or penetration into dense soils), the helical blades of the tips can have a diameter of up to 3 m, the minimum diameter of the blades is 30 cm; the length of the piles can exceed 20 m.

The design of the working body allows you to perform the following operations: pull the screw pile into the pipe of the working body (preliminary, an inventory metal shell is put on the pile), provide a given pile immersion angle within 0 ... 450 from the vertical, immerse the pile into the ground by rotation with simultaneous use of efforts. This force, if necessary, can be used when turning the pile out of the ground. The rotation of the working body is carried out from the power take-off through the appropriate gearboxes.

The work steps for driving piles using the screw driving method are similar to the operations performed when driving piles using driving or vibration driving methods. Only instead of installing and removing the headgear with this method, they put on and remove the metal sheath.

After screwing the screw pile (pipe diameter reaches 1 m), its internal cavity is filled with concrete. The speed of immersion of screw piles depends on the diameter of the blade and the characteristics of the soil and is in the range of 0.2 ... 0.6 m / min.

The advantages of screw piles are in their high bearing capacity, the possibility of smoothly sinking into the ground, and the perception of negative forces.

Pile driving by washing the soil is used in non-cohesive and slightly cohesive soils - sandy and sandy loam. It is advisable to use flushing for piles of large cross-section and great length, but it is unacceptable for hanging piles. The method consists in loosening the soil under the action of water flowing under pressure at the tip of the pile from one or more pipes fixed on the pile! and partially washed out (Fig. 6.10). At the same time, soil resistance at the pile tip decreases, and water rising along the pile erodes the adjacent soil, thereby reducing friction on the side surfaces of the pile. As a result, the pile sinks into the ground under the action of its own weight and the weight of the hammer installed on it.

The arrangement of tubes for washing soil with a diameter of 38 ... 62 mm can be lateral, when two or four tubes with tips are located on the sides of the pile, and central, when a single or multi-jet tip is placed in the center of a hollow driven pile. With lateral flushing, in comparison with the central flushing, more favorable conditions are created to reduce the friction forces along the side surface of the piles. With a lateral arrangement, the jet pipes are fixed in such a way that the tips are at the piles 30 ... 40 cm above the tip.

To wash the soil, water is supplied to the pipes under a pressure of at least 0.5 MPa. When washing away, the adhesion between the soil particles under the sole and partially along the side surface of the piles is broken, which can subsequently lead to a decrease in the bearing capacity of the pile. Considering that the pile will have to take the load in the future, immersion with washing is carried out only to a predetermined level, and then it is driven to the design depth (by 0.5 ... 2.0 m) using a pile driving rig. With this method of immersion, productivity increases by 30 ... 40% compared to pure driving, fuel is saved. After stopping the water supply and stabilizing the groundwater level, the soil is compacted and tightly compresses the pile.

Rice. 6.10. Undermining the soil for piling:

a) - immersion of square piles with soil washing: / - hammer; 2 ~ rope supporting jet pipes; 3 - pressure hose; 4 - jet pipes; 5 - pile; b - the location of the jet pipes; in - the tip of the jet pipe

The use of the washing method is not allowed if there is a threat of subsidence of nearby structures, as well as in general on subsiding soils.

Pile driving using electroosmosis is used in water-saturated dense clay soils, in moraine loams and clays. For the practical implementation of the method, the pile already immersed in the ground is connected to the positive pole (anode) of the DC electrical network, and the adjacent pile prepared for immersion in the ground is connected to the negative pole (cathode). When the current is turned on around the pile with a positive pole, the soil moisture decreases sharply, while in the neighboring pile with a negative pole, on the contrary, it sharply increases. In a more humid environment, the pile sinks into the ground faster, which allows the use of lower power pile driving equipment.

After the driving is completed and the piles are disconnected from the power source in the soil, the former stabilization of the soil and its moisture state is quickly restored. Thanks to this, only by reducing the humidity around the driven pile, its bearing capacity increases significantly.

If reinforced concrete piles are additionally equipped with metal strips during the osmosis method, which will occupy 20 ... .30% reduction in labor and dive time compared to pure electroosmosis. Compared to pile driving, the use of additional features of electroosmosis allows you to speed up the process of piling into the ground by 25-40%.

Pile driving sequence. The procedure for driving piles depends on their location in the pile field and the parameters of the pile driving equipment. The sequence of pile driving is determined by the technical map or the project for the production of works, it depends on the size of the pile field and soil properties. Three schemes are applicable - ordinary, when all piles are sequentially driven in one row; spiral, when driving piles from the center to the piles of the outer rows and sectional, when the entire field is divided into separate sections along the width of the building, in which driving is carried out according to the row pattern (Fig. 6.11).

Rice. 6.11. Scheme of an ordinary pile driving system:

a - with a rectilinear arrangement of piles in separate rows; 6 - when piles are arranged in bushes; /... IS - pile driving sequence

The spiral scheme provides for driving piles in concentric circles from the center to the edges of the pile field, which makes it possible to obtain the minimum length of the path of the pile driving installation.

In addition, when piles are immersed around it, the soil is additionally compacted. With a spiral scheme, newly driven piles are always located along the outer contour of the pile field, so the intensity of an already driven field has a minimal effect.

With large distances between individual piles, the driving sequence can be determined mainly by technological considerations, primarily by the equipment used. For some tower-type pile drivers, the masts are supported by retractable frames that are displaced by about 1 m. With such pile piles, two rows of piles can be driven from one parking lot at once, which significantly reduces [the path of the pile driver and the time for its movement. During the construction of the underground part of residential buildings, cranes equipped with hinged pile driver equipment were used, moving along the rail track along the edge of the building excavation.

When constructing pile foundations for buildings of great length, it is rational to use a bridge pile driver (Fig. 6.12), which is a mobile bridge along which a trolley with a pile driver moves. Piles 8 ... 12 m long are hammered with a diesel hammer. The advantage of the bridge piling installation is the ability to accurately install piles at the place of driving, the preliminary laying of piles in the work area significantly reduces the operations of pulling and fixing the pile on the pile driver, which significantly increases productivity and quality of work.

When driving piles, the main factors determining the choice of method and pile driving equipment are the physical and mechanical properties of the soil, the amount of pile work, the type of piles, the depth of their immersion, the performance of the used pile driving installations and pile loaders.

The scope of the upcoming work is measured by the number of piles that need to be driven, or the total length of the part of the piles immersed in the ground.

P and c. 6.12. Scheme of piling with a bridge piling installation:

1 - head with blocks; 2 - diesel hammer; 3 - pile; 4 - pile driver; 5 - rails; 6 - mobile bridge, 7 - pile feeding crane

The choice of equipment for piling and the number of piling installations depend on these volumes, the specifics of the soil conditions and the specified work time.

Our company carries out work on driving and driving piles in small and medium volumes on high-speed equipment. You can find out more about when piling machines are justified. Call us and we will help you with piling. And now we will talk about diesel hammers, which are used on pile-driving equipment, including our pile-driving equipment.

Types of diesel pile hammers

The classification of impact equipment used in pile work is carried out on the basis of its design features, according to which diesel hammers of tubular and rod type are distinguished.

As a guide element of the impact part of the hammer, in rod-type structures, two vertical rods are used, while in tubular units, a fixed pipe is used.

Also, pile drivers are divided into groups based on the mass of the shock part. Allocate hammers with a striker weight:

  • up to 0.6 tons - light;
  • up to 1.8 tone - medium;
  • over 2.5 tons - heavy.

Consider each type of diesel hammers in more detail.

1. Rod.

You can see rod-type devices in image 1.1:

Rice. 1.1

The design of a rod diesel hammer consists of the following main elements:

  • Piston block mounted on a pivot support;
  • Two vertical guide rods;
  • Fuel mixture supply system;
  • The device for fixing the pile column - "cat".

The piston block is a monolithic structure cast inside the hammer body. It includes the piston itself and compression rings, a fuel supply hose, a nozzle for spraying the fuel mixture and a pump that drives it.

The piston block is motionlessly fixed on a hinged support, from the bottom wall of which two guide rods emerge.

Rice. 1.2

The bars, for a more rigid fixation, are connected by a traverse in the upper part. During operation, the impact part of the hammer moves along the guide rods, on the lower wall of the body of which there is a chamber for combustion of the fuel mixture.

2. Tubular.

Tubular type structures are shown in image 1.3.


Rice. 1.3

The structure of all tubular hammers is completely unified, they are designed according to established standards and have identical design features.

The tubular diesel hammer consists of the following parts:

  • "Cats" - for capturing and fastening a pile column, the cat has an automatic locking and dropping mechanism;
  • Impact striker - it is represented by a piston equipped with compression rings;
  • Chabot - the impact surface with which the striker comes into contact during the operation of the hammer;
  • The working cylinder, inside which the detonation of fuel;
  • Lubrication and cooling systems;
  • Guide tube made of high strength steel.

Rice. 1.4

Unlike rod-type hammers, tubular structures have a forced water cooling system, which makes it possible to continuously operate these devices, while rod hammers must have regular breaks after each hour of pile driving, necessary for natural cooling of structural elements.

You can choose the one you want piling installation in the section of our equipment.

Technical characteristics of diesel hammers

Tubular diesel hammers are considered to be the most advanced and efficient designs. With the same weight of the striker, they are able to drive heavier piles (two to three times the difference in the weight of the pile column).

The hammer consists of the following parts:

  • cylinder (or rods)
  • woman (shock part, striker) moving inside the cylinder
  • shabot (the lower part of the hammer, to which the headpiece is attached)

Spherical recesses on the woman and the chabot, when in contact, form a combustion chamber. Diesel fuel is injected into it by injection, which, when the woman hits the shaft, under the high pressure created in the combustion chamber, spontaneously ignites and throws the woman to the top point. After that, the fall of the woman resumes.

Thus, the hammer produces a series of blows on the pile, plunging it into the ground, the process can be clearly seen on video:

The disadvantages of rod structures also include low durability (operational life, on average, is almost two times less than the service life of tubular hammers).

Rod diesel hammers, due to the limited impact energy, which is 27-30% of the potential energy that the impact hammer can develop, are used exclusively for plunging pile pillars into weak, low-density soil.

The most common rod diesel hammers with a mass of impact striker of 2500 and 3000 kilograms, such designs are capable of delivering impact energy up to 43 kJ, while the number of blows per minute is limited to 50-55. We have this technique.: Piling technique .


Rice. 1.5

Diesel hammers of tubular type are used for immersion of reinforced concrete driven piles in any kind of soil. If it is necessary to work in permafrost soil conditions, pre-drilled leader wells are used for driving piles.

Operating temperature range tubular pile driving hammers varies from -45 to +45 degrees. If pile work is performed at temperatures below 25 degrees, additional heating of the piston block is required before starting the hammer.

Impact weight in tubular diesel hammers it can be 1.25, 1.8, 2.5, 3.5 and 5 tons. The striker, depending on the weight, can develop an impact force of 40 to 165 kJ. The maximum number of hammer blows in one minute of work is 42.

Pile driving technology with a diesel hammer

Diesel hammer - specific pile driving equipment that is hung on the mast of a pile driving machine, that is, it is a hinged pile driving mechanism. The principle of operation of the pile hammer is to strike the pile with the force of its own weight.

Features of pile driving technology will vary depending on the type of equipment used.

Consider the main stages of driving piles with a diesel rod hammer:

  • Upon completion of the slinging and fixing of the pile, the "cat", fixed on the pile driver winch, goes down and engages with the impact part of the hammer;
  • The cat and the striker are lifted with the help of a winch along the guides to the maximum upper position;
  • The operator activates the reset lever and the shock part, under its own weight, falls down to the hinged head fixed on the pile column;
  • In the process of lowering the striker, the air inside the cylinder is compressed and increases its temperature (up to 650 degrees);
  • When the impact head is in contact with the hinged head of the pile, fuel is injected into the cylinder by a nozzle, which is mixed with compressed air;
  • Upon impact, self-ignition of the fuel mixture occurs, the gas released as a result of detonation repels the impact striker to the upper initial position;
  • In the process of lifting, the speed of movement under the weight of the striker decreases, and the shock part falls back to the hinged head fixed on the pile column. The process is repeated anew until the operator of the pile driver turns off the fuel pump.

Rice. 1.6

The sequence of operation of the tubular hammer when driving piles is as follows:

  • The piston part docks with the cat and rises to the upper position with the help of a copra winch;
  • The automatic undocking of the piston and the cat is performed and the impact part is lowered along the guide tube;
  • In the process of the piston falling, the pump is activated, which pumps fuel into a special recess located on the upper wall of the chabot body;
  • With further lowering of the piston, air is compressed inside the hammer tube;
  • When the piston hits the chabot, the fuel mixture detonates, while half of the energy is used to immerse the pile column, another part is used to throw the piston to its original position.

Rice. 1.7

The pile column is immersed as a result of the impact of two types of energy - shock (coming from the mass of the striker) and gas-dynamic, which is released at the moment of detonation of the fuel mixture.

Our company will deliver the equipment to the facility

The company "Bogatyr" performs pile work in strict accordance with the requirements of SNiP and other regulatory documents.

The pile driving technology is fully signed in the documents specially developed for the time of pile work: PPR (project for the production of works), technological map, etc., in the course of work, a summary sheet of pile driving is maintained. Thus, the process is in the full sense of production and its strict execution, especially during pile driving, is monitored by the person responsible for the pile work.