Displacement monitoring provides essential information for safe and rational tunnel excavation.The data obtained allow engineers to analyze and predict tunnel behavior,facilitating the selection of appropriate support...Displacement monitoring provides essential information for safe and rational tunnel excavation.The data obtained allow engineers to analyze and predict tunnel behavior,facilitating the selection of appropriate supports and the evaluation of their effectiveness.In a recent tunnelling project in the Akaishi Mountains of central Japan,displacement monitoring was intensively implemented to ensure the stability of the 4.2-km-long Hirogawara adit,excavated to a maximum depth of 832 m.Analysis revealed a strong correlation between initial and final displacements.However,the tunnel experienced occasional support deformations.To address this,the trend of 3D absolute displacements was analyzed to predict and evaluate asymmetric deformation.The effective use of 1-cycle displacement monitoring proved critical for predicting final displacements and optimizing rock supports,particularly in cases with high overburden and limited geotechnical information.展开更多
The corrosions resulting from defects in painting layers frequently occur in Al alloys, so the application of corrosion preventing systems is also very important. Optimum conditions in terms of electrochemistry in rel...The corrosions resulting from defects in painting layers frequently occur in Al alloys, so the application of corrosion preventing systems is also very important. Optimum conditions in terms of electrochemistry in relation to solution treatment, quenching and artificial aging treatment were established in order to optimize precipitation strengthening conditions intended to enhance the strength of Al alloys. Slow strain rate tests （SSRT） at various applied potentials were conducted in potential range from -1.8 to 0.5 V. The results show that the maximum tensile strengths, elongations and time-to-fracture are shown to be high values. After precipitation strengthening heat treatment, a tendency appear that time-to-fracture increases as elongation increases. In the potential range from -1.3 V to -0.7 V, the specimens show excellent mechanical properties, and thus this range is considered to be a corrosion prevention range.展开更多
Lineaments are often related to faults and lithologic boundaries and in some cases to geomorphic relief. They can be helpfully utilized by investigating active tectonics as preliminary data. In order to assess the dis...Lineaments are often related to faults and lithologic boundaries and in some cases to geomorphic relief. They can be helpfully utilized by investigating active tectonics as preliminary data. In order to assess the distribution and activity of the lineaments around the coastal area of the Korean Peninsula, we have interpreted lineaments using ASTER （Advanced Space borne Thermal Emission and Reflection Radiometer） images. The lineaments range from 2 km to 50 km long and show a dominant NNW-SSE trend. The lineament density along the eastern coast line of the Korean Peninsula is higher than the densities on the southern and western coast lines. The lineament rank is La to Le. However, La and Lb are not in sufficient abundance to have a high possibility to be active. In the Pocheon region, there are Quaternary volcanic activities, and hence there is a possibility of recent crustal movement in this area. We plan to recheck the presence and activity of ASTER lineaments by aerial photographs and field investigations in the future.展开更多
文摘Displacement monitoring provides essential information for safe and rational tunnel excavation.The data obtained allow engineers to analyze and predict tunnel behavior,facilitating the selection of appropriate supports and the evaluation of their effectiveness.In a recent tunnelling project in the Akaishi Mountains of central Japan,displacement monitoring was intensively implemented to ensure the stability of the 4.2-km-long Hirogawara adit,excavated to a maximum depth of 832 m.Analysis revealed a strong correlation between initial and final displacements.However,the tunnel experienced occasional support deformations.To address this,the trend of 3D absolute displacements was analyzed to predict and evaluate asymmetric deformation.The effective use of 1-cycle displacement monitoring proved critical for predicting final displacements and optimizing rock supports,particularly in cases with high overburden and limited geotechnical information.
文摘The corrosions resulting from defects in painting layers frequently occur in Al alloys, so the application of corrosion preventing systems is also very important. Optimum conditions in terms of electrochemistry in relation to solution treatment, quenching and artificial aging treatment were established in order to optimize precipitation strengthening conditions intended to enhance the strength of Al alloys. Slow strain rate tests （SSRT） at various applied potentials were conducted in potential range from -1.8 to 0.5 V. The results show that the maximum tensile strengths, elongations and time-to-fracture are shown to be high values. After precipitation strengthening heat treatment, a tendency appear that time-to-fracture increases as elongation increases. In the potential range from -1.3 V to -0.7 V, the specimens show excellent mechanical properties, and thus this range is considered to be a corrosion prevention range.
文摘Lineaments are often related to faults and lithologic boundaries and in some cases to geomorphic relief. They can be helpfully utilized by investigating active tectonics as preliminary data. In order to assess the distribution and activity of the lineaments around the coastal area of the Korean Peninsula, we have interpreted lineaments using ASTER （Advanced Space borne Thermal Emission and Reflection Radiometer） images. The lineaments range from 2 km to 50 km long and show a dominant NNW-SSE trend. The lineament density along the eastern coast line of the Korean Peninsula is higher than the densities on the southern and western coast lines. The lineament rank is La to Le. However, La and Lb are not in sufficient abundance to have a high possibility to be active. In the Pocheon region, there are Quaternary volcanic activities, and hence there is a possibility of recent crustal movement in this area. We plan to recheck the presence and activity of ASTER lineaments by aerial photographs and field investigations in the future.
