| DOI: | 10.2172/1234608
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| 报告号: | LLNL--TR-676586
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| 报告题名: | Wall-Friction Support of Vertical Loads in Submerged Sand and Gravel Columns |
| 作者: | Walton, O. R.; Vollmer, H. J.; Hepa, V. S.
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| 出版年: | 2015
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| 发表日期: | 2015-08-25
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| 总页数: | 18
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| 国家: | 美国
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| 语种: | 英语
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| 英文摘要: | Laboratory studies of the âfloor-loadsâ under submerged vertical columns of sand and/or gravel indicate that such loads can be approximated by a buoyancy-corrected Janssen-silo-theory-like relationship. Similar to conditions in storage silos filled with dry granular solids, most of the weight of the sand or gravel is supported by wall friction forces. Laboratory measurements of the loads on the floor at the base of the water-filled columns (up to 25-diameters tall) indicate that the extra floor-load from the addition of the granular solid never exceeded the load that would exist under an unsupported (wide) bed of submerged sand or gravel that has a total depth corresponding to only two column-diameters. The measured floorloads reached an asymptotic maximum value when the depth of granular material in the columns was only three or four pipe-diameters, and never increased further as the columns were filled to the top (e.g. up to heights of 10 to 25 diameters). The floor-loads were stable and remained the same for days after filling. Aggressive tapping (e.g. hitting the containing pipe on the outside, manually with a wrench up and down the height and around the circumference) could increase (and occasionally decrease) the floor load substantially, but there was no sudden collapse or slumping to a state without significant wall friction effects. Considerable effort was required, repeatedly tapping over almost the entire column wall periphery, in order to produce floor-loads that corresponded to the total buoyancy-corrected weight of granular material added to the columns. Projecting the observed laboratory behavior to field conditions would imply that a stable floor-load condition, with only a slightly higher total floor pressure than the preexisting hydrostatic-head, would exist after a water-filled bore-hole is filled with sand or gravel. Significant seismic vibration (either a large nearby event or many micro-seismic events over an extended period) would likely be necessary before the full (buoyancy-corrected) weight of the sand and/or gravel would be âdeliveredâ to the bottom of the submerged column. |
| URL: | http://www.osti.gov/scitech/servlets/purl/1234608
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| Citation statistics: |
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| 资源类型: | 研究报告
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/41790
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| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
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| 1234608.pdf（929KB） | 研究报告 | -- | 开放获取 | | View
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| Recommended Citation: | |
Walton, O. R.,Vollmer, H. J.,Hepa, V. S.. Wall-Friction Support of Vertical Loads in Submerged Sand and Gravel Columns. 2015-01-01.
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