Role of induced electrical polarization to identify soft ground/fractured rock conditions

Jinho Park, Kang Hyun Lee, Hyungjoon Seo, Jinwoo Ryu, In Mo Lee

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

This study attempted to evaluate the role and effectiveness of induced polarization (IP) along with electrical resistivity to identify soft ground/fractured rock. Theoretical studies as well as laboratory-scale experiments were conducted for this purpose. The theoretical study involved deriving the functional relationship between chargeability and influential variables. This was followed by performing a sensitivity analysis using the derived relationship to reveal that the size of narrow pores (r1) exerted the greatest influence on the chargeability followed by the salinity of the pore water (C0). In the laboratory test, a small-scale fractured rock zone was modeled using sandstone as a parent rock. The chargeability and resistivity were measured by changing the size of the joint aperture filled with tap water and/or sea water, the location of the fractured zone, and the thickness of the soil layer in a soil-rock multi-layered ground. The experimental study modeled the jointed zone between competent sandstone layers and indicated that the chargeability was mostly controlled by the size of the narrow pore (r1) of the surface sandstone and not by the porosity of the jointed zone. Hence, it was concluded that the chargeability did not significantly depend on the fractured characteristics of the jointed rock. It could be difficult to clearly distinguish as to whether the low resistivity value is caused by the sea water intrusion or by the increase in porosity of the fractured ground. However, the IP exploration can be effectively utilized to identify sea water intrusion since the chargeability decreased as the salinity of pore water increased. The experimental study on a soil-rock multi-layered ground indicated that the measured chargeability was controlled by the percentage of current flow that passed through the competent rock as well as by the narrow pore size of the rock itself. In conclusion, the ground condition could be easily identified by measuring the IP in conjunction with the electrical resistivity, and this increased the reliability of identifying the existence of sea water, layered ground, and/or the fractured rock.

Original languageEnglish
Pages (from-to)63-72
Number of pages10
JournalJournal of Applied Geophysics
Volume137
DOIs
Publication statusPublished - 2017 Feb 1

Fingerprint

polarization
rocks
sea water
porosity
rock
induced polarization
electrical resistivity
sandstones
seawater
soils
sandstone
salinity
theoretical study
intrusion
porewater
experimental study
water
ground conditions
taps
sensitivity analysis

Keywords

  • Chargeability
  • Electrical resistivity
  • Fractured rock
  • Induced polarization
  • Soft ground

ASJC Scopus subject areas

  • Geophysics

Cite this

Role of induced electrical polarization to identify soft ground/fractured rock conditions. / Park, Jinho; Lee, Kang Hyun; Seo, Hyungjoon; Ryu, Jinwoo; Lee, In Mo.

In: Journal of Applied Geophysics, Vol. 137, 01.02.2017, p. 63-72.

Research output: Contribution to journalArticle

Park, Jinho ; Lee, Kang Hyun ; Seo, Hyungjoon ; Ryu, Jinwoo ; Lee, In Mo. / Role of induced electrical polarization to identify soft ground/fractured rock conditions. In: Journal of Applied Geophysics. 2017 ; Vol. 137. pp. 63-72.
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