FULL-SCALE FAILURE TEST ON A STAGE-CONSTRUCTED TEST FILL ON ORGANIC SOIL
FULL-SCALE FAILURE TEST ON A STAGE-CONSTRUCTED TEST FILL ON ORGANIC SOIL
复制标题
有机土壤上阶段建造的测试填土的全面失效测试
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
U. Bergdahl
中科院分区：
文献类型：
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作者：
W. Wolski;Alojzj Szymanski;Z. Lechowicz;R. Larsson;J. Hartlén;U. Bergdahl
在8米厚的非常软的有机和石灰质土壤上建造了一个测试填料。填充物首先分阶段建造，由于不同阶段的固结而增加的剪切强度已成功地用于后续阶段的施工中。在三个初始阶段的变形，孔隙压力和剪切强度的增加进行了仔细监测超过三年半。然后通过连续增加填充物的高度使填充物失效。最终破坏试验在一周内完成，可视为不排水破坏试验。在早期阶段，通过分阶段施工填充物，可以安全地建造两倍于地面原始抗剪强度的填充物。经过另外两年的巩固，甚至这个负载可以加倍到8米厚的填充失败发生之前。破坏沿着非圆形破坏带发生，可明显分为主动剪切区、直接单剪区和被动剪切区。破坏区的形状和位置以及极限荷载取决于可压缩低渗透性土中间软弱层的存在。由于该层固结度有限，其抗剪强度远低于其上、下土层，排水路径较短。如果有更多的时间进行固结，或者通过有效的垂直排水来加快这一过程，最终的填土可能会更高。由于固结的抗剪强度的增加被认为是局限于土壤下面的填充。它是最大的，大约均匀的波峰区域，非常温和地减少到斜坡的中点，然后迅速减少到几乎完全停止在坡脚。这基本上证实了简单模型，即抗剪强度的增加仅限于斜坡中点区域以下的土壤。随着施工的进行，对填土稳定性的评估变得越来越复杂。
A test fill has been built on top of 8 metres of very soft organic and calcareous soils. The fill was first built in stages and the increase in shear strength due to consolidation in the different stages has successfully been utilized in the construction of the subsequent stages. In three initial stages the deformations, the pore pressures and the increases in shear strength were carefully monitored over three and a half years. The fill was then brought to failure by successively increasing the height of the fill. The final failure test was completed in a week and can be considered as an undrained failure test. In the early stages, it was shown that by constructing the fill in stages, it was possible to safely construct a fill twice as thick as the original shear strength in the ground would have permitted. After another two years of consolidation even this load could be doubled to an 8 m thick fill before failure occurred. Failure occurred along a non-circular failure zone which clearly could be divided into zones of active shear, direct simple shear and passive shear. The shape and location of the failure zone and the ultimate load were governed by the existence of a weak layer in the middle of the compressible and low permeable soil. Due to the limited degree of consolidation in this layer, it had a much lower shear strength than the soil above and below with shorter drainage paths. With more time for consolidation or by speeding up the process with effective vertical drains, the final fill could have been made even higher. The increase in shear strength due to consolidation was found to be confined to the soil directly below the fill. It was largest and about uniform under the crest area, decreasing very moderately out to the midpoints of the slopes and then rapidly decreasing to cease almost completely under the toe of the slope. This generally confirmed the simple model that the shear strength increase is confined to the soil below the area within the midpoints of the slopes. Evaluation of the stability of the fill became increasingly complex as the construction progressed.