Generally I'd walk away and let ignorance be it's own punishment, but since it's a moderator I'll oblige them.
But next time please consider asking for more information, before dismissing.
"...
Cutting Charges
Cutting charges include linear-shaped charges, which have been available for several years, and the more recently introduced cutting tape.
Linear-Shaped Charges. These charges use high-velocity explosive energy to accelerate a v-shaped liner material (usually copper) into a high-velocity jet (Welch, 1995) that can penetrate and cut the steel. A linear-shaped charge can be housed in a specially manufactured ring-shaped container made to fit around the outside of a pile, or it can be used with a running tool and an articulated device for making an inside cut. When accurately positioned to a precisely calculated stand-off distance between the charge and the target, smooth cuts can be obtained. The stand-off distance is a function of the thickness of the steel.
There are several limitations to using linear-shaped charges:
*
If an external charge is used to cut a pile, there is no attenuation of the explosive energy afforded by the soil.
*
To pass by stabbing guides in the pile, an internal-shaped charge must be the articulated type.
*
If the thickness of the pile section is unknown (possible in older structures), if the pile is out of round, if the charge is not placed directly against the target, or if a stabbing guide is at the proposed cut elevation, a successful cut may not be obtained.
*
Shaped charges require long lead times (several weeks) to fabricate the containers and articulated devices and cost about four or five times more than bulk charges.
*
Divers can place the shaped charges, but safety and cost considerations must be taken in consideration.
*
Performance of a shaped charge depends on the presence of an air gap between the liner of the charge and the target (pile or caisson). Water infiltration between the charge and the pile greatly diminishes performance (Welch, 1995).
Future Explosive Cutting Techniques
Cutting Charges
A refinement of rigid, linear-shaped charges that may be useful in the future is explosive cutting tape. Explosive cutting tape is a flexible version of a linear-shaped charge. The explosive and the liner are extruded into a shaped charge housed in a flexible jacket that allows the tape to contact the pile and maintain a proper stand-off distance. Although the new type charge is flexible, variations in the shape and dimensions of the liner may cause problems, and the jacket may compress in the high ambient pressures of deeper water (more than 300 feet). Divers would be required to place the charges. According to the manufacturer, who prepared a committee presentation, explosive tape is not as efficient as linear-shaped charges and may not perform well in deep water."
http://www.nap.edu/books/NI000141/html/17.html