| Many geological accidents under construction have recently occurred on civil engineering projects in Japan. One of the most epoch making accidents was the giant sinkhole accident in Fukuoka city in 2016, induced by the collapse of a tunnel under construction. The tunnel has been excavated just several meters under the surface of unconformity between Paleogene sedimentary rocks and Quaternary deposits. Misunderstanding of geo-risk induced the accident; causative geological factors are the irregularity of the unconformity surface and the inhomogeneity of the weathered and jointed rock mass. After that, Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the Public Works Research Institute (PWRI) have started to make new guidelines for geo-risk management on civil engineering works. We are now analyzing present geo-risk management systems of MLIT etc., and discussing improvement point of geo-risk management by the analysis of trouble cases. Important key words in geo-risk management, we temporarily consider, are geological uncertainty, likelihood of geo-risk, public geologist and geo-risk manager. Most important point is to develop the skill of engineering geologists for risk finding, risk assessment and risk communication. Especially, we need to develop new technique for the evaluation, expression and communication of the likelihood of geo-risk and geological uncertainty included in geological investigation results such as engineering geological maps, profiles. Next important point is the participation of engineering geologists through the project as a member of public engineers and/or public geologists. Third point is the assignment of geo-risk manager in the project who controls geo-risk management procedure. |
