The technique most commonly used in the Netherlands for inserting and removing steel sheet piles is vibration using a vibratory hammer. When vibrating sheet piling, a sinusoidal, vertical load is applied to the head of the sheet piling by means of a vibrating block. In addition, the mass of the vibrating block also acts as a static load on the sheet piling.
The harmonic load exerted on the sheet piling by the vibrating block creates stress waves in the sheet piling elements. When the sheet piles are driven in, the ground resistance is exceeded by the stress waves. Here, more than in pile driving, the degradation of the soil resistance due to the large number of stress changes is important because the particle velocities in a cross-section of the sheet piling are considerably smaller than in pile driving.
Advantages of vibration are:
Pile driving of sheet piles is no longer very common in the Netherlands. Pile driving involves repeatedly applying a very high, pulse-like load to the head of the sheet piling. This can be done through the free fall of the pile driver, which is driven by steam, diesel oil, or hydraulically.
During pile driving, if a sufficiently high stress wave is applied, the ground resistance along the shaft and at the tip may be temporarily exceeded. The sheet piling will then undergo permanent subsidence. A number of block types are somewhat common in the Netherlands: quick-action hammers, drop blocks, hydraulic blocks and diesel blocks.
The above-mentioned insertion techniques, vibration or pile driving of sheet piles, both cause vibration and noise pollution to the surrounding area. In busy urban environments or in the vicinity of sensitive neighbors, these techniques are therefore often not permitted. One insertion technique that is increasingly used for this reason is the pressing of sheet piles. This involves installing or pulling steel sheet piles by static pressing.
The pressing force that common machines can deliver is generally between 600 and 1500 kN. The pressing force is provided by a hydraulic cylinder. In all systems, single (with Silent Piler system) or quadruple (but not punched) boards are used (for the Quattro Piler system). If insertion is difficult, it can be facilitated by fluidizing (injecting small amounts of water under high pressure). The PZC profile, due to its shape and unique lock form (Ball and Socket), is ideally suited for this method of insertion. No soil enters the lock, which also prevents the accumulation of unwanted materials. ZZ profiles are also excellent for pressurized installation of sheet piles because of their straight shape and precise lock form.