Diesel hammers are divided into guide rod type and cylinder type according to their structural form. The guide rod type diesel hammer uses the plunger as the hammer seat to press on the pile cap, and the cylinder as the hammer head to rise and fall along two guide rods. When driving piles, first hoist the pile into the gantry of the pile frame, then place the diesel hammer on the top of the pile, lower the hook to lift the cylinder, and then release the hook to let the cylinder fall and insert the plunger to compress the air enclosed in the cylinder. The cylinder continues to fall until the pressure pin outside the cylinder body pushes the rocker of the fuel pump on the hammer seat. The fuel pump sprays oil mist into the cylinder. The oil mist encounters high-temperature gas above the ignition point and immediately explodes. The explosive force impacts downward to make the pile sink, and pushes upward to make the cylinder rise. When the cylinder falls along the guide rod again, the second impact cycle begins again. The barrel-type diesel hammer uses the cylinder as the hammer seat and directly uses the extended inner wall of the cylinder to guide, eliminating two guide rods. The plunger is the hammer head and can move up and down in the cylinder. When driving piles, press the pile cap at the bottom of the hammer seat on the top of the pile, lift the plunger with the hook, and then release the hook to impact downward to compress the air enclosed in the cylinder. And carry out the working process of fuel injection, explosion, impact, ventilation, etc. The diesel hammer works by compressing the diesel to start, so it is necessary to ensure that the closed gas in the cylinder reaches a certain compression ratio. Sometimes when piling on soft soil, it is often unable to ignite and detonate due to the small reaction force and insufficient compression. It is necessary to use a hook to lift the hammer head several times to unhook and impact before it can start. The hammer seat of the diesel hammer is attached with a fuel injection pump, a fuel tank, a cooling water tank and a pile cap. The movable gap between the plunger and the cylinder is sealed with an elastic plunger ring.
A pile driving machine that uses impact force to penetrate the pile into the formation. It consists of a pile hammer, a pile frame and auxiliary equipment. The pile hammer is attached between the two parallel vertical guide rods (commonly known as the gantry) at the front of the pile frame and is lifted by a lifting hook. The pile frame is a steel structure tower with a winch at the rear to lift the pile and the pile hammer. There is a guide frame composed of two guide rods in front of the pile frame to control the direction of piling so that the pile can be accurately penetrated into the stratum according to the designed direction. The tower and the guide frame can be tilted together to drive oblique piles. The guide frame can also be extended downward along the tower to drive underwater piles along the embankment or dock. The pile frame can rotate and move. The basic technical parameters of the pile driver are the weight of the impact part, the impact kinetic energy and the impact frequency. Pile hammers can be divided into drop hammers, steam hammers, diesel hammers, hydraulic hammers, etc. according to the power source of the movement.
Drop hammer pile driver The pile hammer is a steel weight, which is lifted by the winch with a hook and falls freely along the guide frame after being unhooked. The pile hammer of the steam hammer pile driver consists of a hammer head and a hammer seat, powered by steam or compressed air, and there are two types: single-acting steam hammer and double-acting steam hammer. The single-acting steam hammer uses a plunger or cylinder as the hammer head. Steam drives the hammer head to rise, and then it is allowed to fall along the guide rod of the hammer seat to drive the pile. The double-acting steam hammer generally uses a weighted plunger as the hammer head and a cylinder as the hammer seat. The steam drives the hammer head to rise, and then drives the hammer head downward to impact the pile. The up and down reciprocating speed is fast and the frequency is high, which makes the pile vibrate when it penetrates the formation, which can reduce friction resistance and achieve good piling effect. The differential steam hammer with two-way unequal force has a light hammer seat, and the effective impact weight can be relatively increased, and the performance is better. The reversing of the steam inlet and exhaust valve of the steam hammer can be controlled manually or automatically by the flange joystick installed on one side of the hammer head and rising and falling with the hammer head. Both methods can adjust the impact stroke of the steam hammer.
Working conditions
1 If the construction site has a slope, it should meet the requirements of the stability of the pile driver, and the soft site that is not conducive to the operation of the pile driver should be leveled and compacted. When working in the foundation pit and cofferdam, sufficient drainage equipment should be equipped.
2 When the bearing capacity of the work site is less than the allowable ground pressure of the pile driver, a roadbed box or steel plate, sleepers, etc. should be laid.
3 The track laying of the track type pile frame should comply with the relevant provisions of the instruction manual.
4 The safety distance between the overhead transmission line and the pile driver column in the work area should comply with the relevant provisions of GB5144.