Geological and geotechnical investigation on in situ stress regime around the Yangsan Fault Zone in Korea

摘要

For the purpose of designing and analyzing the stability of the B-tunnel, which is a part of the Korea Train Express (KTX) Gyeongbu Line and plans to pass through the existing Gyeongbu Expressway as well as the Yangsan Fault zone, the in situ stress regime on this site has been measured by hydraulic fracturing tests to compare with the geological survey results. The Yangsan Fault is one of the major faults in Korea. Apart from a fold that shows the ductile deformation behavior, a fault shows a characteristic of the brittle deformation behavior and it is very important to perform a drastic survey on the fault to get the information on shape, dimension, mechanical properties, and so forth. Considering the impossibility of any borehole tests in the fault zone, authors used two boreholes, which were excavated in a base rock at both sides of the Yangsan Fault.