The Consideration about Ground Electric Resistivity at the Longyou Grottoes of China

Abstract

The authors have been applying the Electric Resistivity Method (ERM) to heritage sites since 1995. ERM is one of the non-destructive prospecting techniques which is conveniently employed in the geotechnical field. Information obtained through ERM suggests rock properties, characteristics of discontinuities such as faults, joints and in-bedding materials, water content, and so on. The objective site of this paper is the Longyou Grottoes, situated in the central west of Zhejiang Province, China. 24 large caves, which are presumed to have been constructed around 2300-2400 years ago, were found by chance in 1992, and 5 of them were drained in full scale. The distribution of local lineaments was analyzed in terms of a satellite image, then electric resistivity around the caves, mineral components of the rock formation and cave walls, water qualities of the river, ground surface, and seepage into the caves were investigated. In conclusion, low resistivity zone shows the deterioration of rock formation, and the control of surface water should be materialized as soon as possible.