CAVITY SURVEY METHOD AND RISK EVALUATION METHOD OF QUAY OR LEVEE

摘要

PROBLEM TO BE SOLVED: To utilize side surface specific part information of a side wall based on a side surface image and estimation data of presence of an underground cavity estimated by an electromagnetic wave radar which is measured from a road, perform specification of an actual cavity existing in an underground of a quay or levee and its risk evaluation, and predict a collapse portion of the cavity for preventing in advance.SOLUTION: An electromagnetic wave radar injecting an electromagnetic wave in a depth direction from an upper part of a quay or levee to an evaluation target area, is scanned, a reflection wave to the injection wave is detected on an upper part, a reflection wave underground cross-section image is created using the reflection wave data, and the underground cavity is surveyed based on the cross-section image, in a cavity survey step of quay or levee. Then, a side surface of the quay or levee is imaged, for acquiring a side surface image, for specifying a specific part of the side surface of the quay or levee in a side surface inspection step for quay or levee. Then, matching of the reflection wave underground cross-section image and side surface image is performed in the scan direction. By matching an estimated cavity and the side surface specific part, the actual cavity is specified, and based on dimension and depth of a top surface of the detected cavity, risk degree is evaluated. Then, based on time-series measurement of these risk factors which are registered, risk degree is evaluated again.