In-situ measurement of the strength of deforming subglacial till
In-situ measurement of the strength of deforming subglacial till
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冰下碴变形强度的现场测量
DOI：
10.3189/s0022143000012375
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发表时间：
1994
影响因子：
3.4
通讯作者：
R. Hooke
中科院分区：
文献类型：
--
作者：
N. Iverson;P. Jansson;R. Hooke
本文用一种新的仪器--“阻力计”连续测量了瑞典Storglaciären地下的变形剪切强度。用冰碛物把一个两端为圆锥形的圆柱体弄得粗糙，然后把它拖过冰碛物，记录下圆柱体上的力。与土壤中的圆锥贯入度研究一致，假设冰碛物表现为库仑塑性材料。这允许根据测得的力计算出钱柜的剩余强度。实验室实验结果证实了分析方法的有效性。冰碛物的平均剩余强度为1.55 kPa。误差的一个来源是可能产生的孔隙压力超过液压缸前面，这可能会显着削弱冰碛。计算表明，超孔隙压力并没有在实验过程中发展，但可以在快速滑动的冰川下渗透性较低的基底冰碛层类似的实验中发展。
Abstract The shear strength of deforming till beneath Storglaciären, Sweden, was continuously measured with a new instrument, a “dragometer”. A cylinder with conical ends, roughened with till from the glacier bed, was dragged through the till, and the force on the cylinder was recorded. Consistent with studies of cone penetration in soils, it was assumed that the till behaves as a Coulomb plastic material. This allows the residual strength of the till to be calculated from the measured force. Results from laboratory experiments confirm the validity of the analytical procedure. The average residual strength of the till was ∼55 kPa. A source of error is the potential generation of pore pressure in excess of hydrostatic ahead of the cylinder, which could significantly weaken the till. Calculations indicate that excess pore pressure did not develop during the experiment, but could develop during similar experiments beneath rapidly sliding glaciers with less permeable basal till layers.