| 講演要旨(和文) | | 地山の評価手法としての物理探査は，規模が大きくなりがちで工費の負担も大きくなりやすい．今回，トンネル内部から上部地盤に対して宇宙線ミュー粒子探査を実施し，地山の状態を調べた．ミュー粒子探査により得られた相対密度分布は，観測地点付近が周囲に比べて低密度であるという結果となった．これを地山等級や地山強度比と比較したところ，地山等級の低いところと低密度領域，地山強度比の低いところと低密度領域が対応していた．これは，地山の劣化が進行し，地山の状態を表す指標が低いところほど低密度領域となっている可能性があると考えた．ミュー粒子探査による相対密度分布と地山の状態が関連しているかについては，他の場所でもミュー粒子探査を行い，地山の状態を表す指標と比較して確認する必要がある． |
|
|
| | 講演要旨(英文) | | Conventional geophysical exploration methods as an evaluation of natural ground tend to be large in spatial scale and costs. In this study, we attempted to investigate the upper ground from inside a tunnel by cosmic-ray muon. The relative density distribution by cosmic-ray muon investigation showed the lower density near the observation site than the surrounding area. We compared the relative density distribution with the natural ground classification and the natural ground strength. It resulted in that the lower density corresponded to the lower ground classification and the lower ground strength. This might be because the degradation of the natural ground resulted in deterioration of the natural ground parameters, and therefore these areas might have lower density. To confirm the relation between the cosmic-ray muon investigation results and the condition of the natural ground, we need more samples of muon investigations of the natural grounds and to compare them with the indices of the condition of the natural ground. |
|
|
|
| |
|