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Tsuji, Masakuni*; Kobayashi, Shinji*; Mikake, Shinichiro; Sato, Toshinori; Matsui, Hiroya
Procedia Engineering, 191, p.543 - 550, 2017/00
Times Cited Count：11 Percentile：92.43(Mining & Mineral Processing)This paper shows the application of two post-grouting works to a gallery at 500 m depth of Mizunami Underground Research Laboratory in Japan. Three new grouting concepts were applied to the post-grouting works; a new grout material, a new injection system, and a new post-grouting zone. As for a grout material, "durable liquid-type colloidal silica grout (CSG)" was applied to seal the narrow fractures. As for an injection system, "complex dynamic grouting method" was applied to improve the penetrability of the grout material. The grouting works were successful in reducing the abundant water inflow from the rock mass with many fractures.
Xiong, Z.; Naoe, Takashi; Wan, T.; Futakawa, Masatoshi; Maekawa, Katsuhiro*
Procedia Engineering, 101, p.552 - 560, 2015/03
Times Cited Count：1 Percentile：62.19(Engineering, Multidisciplinary)Very high-cycle fatigue behaviour of SUS316L, which is used as the structural material of the spallation neutron sources, was investigated through the ultrasonic fatigue test with the strain rate of 10
s
. Cross-sectional hardness distributions of the fatigue-failed specimens for solution annealed (SA) and cold worked (CW) 316L were measured to understand the cyclic hardening or softening. In addition, the tensile tests of the fatigue-failed specimens were performed at room temperature. Furthermore, the nonlinear ultrasonic system was used for evaluating the dislocation density variation. The results showed the cyclic hardening in the region of very high-cycle fatigue in the case of SA. In contrast, in the case of 10%CW, cyclic softening occurred when the number of cycles below 10
and followed by cyclic hardening. In the case of 20%CW, cyclic softening was observed when the number of cycles below 10
, while cyclic hardening occurred subsequently.
Zhou, Z.; Kuwamura, Hitoshi*; Nishida, Akemi
Procedia Engineering, 10, p.1433 - 1439, 2011/00
Times Cited Count：2 Percentile：72.87(Engineering, Multidisciplinary)Brittle fracture of structural steel for building use, in general, is triggered by a ductile crack initiated at notched surface after undergoing a noticeable amount of plastic strain. The initiation of the ductile crack correlates to the stress triaxiality-plastic strain states in the notched section. As stress triaxiality and plastic strain are usually derived from finite element analysis, two material models with voids (Gurson-Tvergaard-Needleman model) and without voids (Mises model) are used to do the analyses to study the stress triaxiality-plastic strain states in notched steels. The results show that the effect of micro voids on stress triaxiality-plastic strain states of notched steels is small until stability limit and become significant gradually after stability limit.
