2005 Fiscal Year Final Research Report Summary
Practical Approach of the Underground Space Construction by Explosive Loading in a Borehole
| Project/Area Number |
16360239
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
TATEYAMA Kazuyoshi Ritsumeikan University, College of Science and Engineering, Professor, 理工学部, 教授 (10179731)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Shigeru Kumamoto University, Shock Wave and Condensed Matter Research Center, Professor, 衝撃・極限環境研究センター, 教授・センター長 (80069567)
FUKAGAWA Ryoichi Ritsumeikan University, College of Science and Engineering, Professor, 理工学部, 教授 (20127129)
KIMURA Makoto Kyoto University, Faculty of Engineering, Associate Professor, 工学研究科, 助教授 (30177927)
KISHIDA Kiyoshi Kyoto University, Faculty of Engineering, Associate Professor, 工学研究科, 助教授 (20243066)
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| Project Period (FY) |
2004 – 2005
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| Keywords | shock wave / soil compression / underground space / experiment / numerical simulation / トンネル / 基礎 |
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| Research Abstract |
In the case that an explosive load is subjected in a borehole which has been excavated in the ground, the soil around the borehole wall will be abruptly compressed and then a cavity will be created in the ground, being surrounded by the compressed soil wall. When we apply this idea to the construction of tunnels or foundations, the underground space can be created with the minimum mucking and the reduced lining.
In the first year of the project term, we investigated the characteristics of the wave propagation in the ground due to the blasting. We confirmed that the borehole can effectively be expanded by blasting and then built the code to simulate the phenomena of the impact expansion in the ground. In the second year, the detail characteristics of the wave propagation was discussed in succession by investigating the relationship among the wave propagation and other experimental conditions such as the sort and water content of soil and the initial diameter of borehole, etc. The phenome
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na of the impact soil compression were also observed with a high-speed camera. The following results have been obtained through the research.
1)The attenuation of the wave propagating in the ground is composed with both of the internal attenuation due to the soil compression and the spatial one due to the two-dimensional wave propagation. The internal attenuation is remarkably observed for the compressive soil like clay.
2)Although the diameter of the expanded boreholes was much affected by their initial diameter, the volume of the soil domain compressed by the blasting was not much affected by the initial diameter when the amount of the powder is constant. It means that the diameter of the expanded borehole can be controlled by the initial diameter of the borehole and the amount of the powder.
3)Although the phenomena of the impact compression of the soil by blasting can be monitored with a high-speed camera which can take a photograph every 0.1 ms, the gas inducted during blasting disturbs any clear photograph. Some devices to overcome this problem are expected to be develop.
A technical report was made with the results of the research. Less
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