Behavior of a Pile Expanded by Electrical Shock Wave

Abstract

This paper introduces the Pulse Discharge Technology (PDT) piling method. The PDT piling method installs in-situ piles using electrical pulse power. The pulse power is a physical value that indicates the energy change per unit time. The power depends on how fast the energy is released. If a unit of energy is discharged in 1 sec, a watt of power will be generated. If the energy is discharged in 1 µs (10⁻⁶ sec), the power will be 1MW. Since the pulse power pushes the ground, using the pulse power enables the hole to be expanded and the ground to be improved by compaction. Therefore, the pile installed by PDT appears to be able to efficiently develop shaft and end-bearing capacity. A series of experiments and load tests were conducted in order to investigate the characteristics of expansion and bearing capacity. It was found that the coefficient of expansion increases with an increase of the number of pulse discharges and has an inverse proportion to the standard penetration test value, N. It was also examined that the piling technique using pulse power can be expected to not only increase end-bearing capacity, but also shaft resistance.

Keywords:

• bored pile
• coefficient of expansion
• end-bearing capacity
• pulse discharge technology
• pulse power
• shaft resistance

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Erratum

Notes

Note: USCS: Unified Soil Classification System; SPT: Standard Penetration Test; SM: Silty Sand; GP: Poorly graded Gravel; CL: Clay.

Note: *Safety Factor = 2.5. PDT, SIP, PHC pile methods are all bored pile method. D: Dynamic load tests. PDT: Pulse Discharge Technology. PDTD: the Dynamic load test of the installed piles using PDT pile method. SIP: Soil cement Injected Precast pile. SIPD: the Dynamic load test of the installed piles using SIP method. PHC: Pre-tensioned spun High strength Concrete. KN: Kilo Newton.

Note: PDTS: Static load test of the installed piles using PDT pile method. SIPS: Static load test of the installed piles using SIP method. KN: Kilo Newton