Quick clay—A case study of chemical perspective in Southwest Sweden
Quick clay—A case study of chemical perspective in Southwest Sweden
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DOI：
10.1016/j.enggeo.2005.09.014
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发表时间：
2005-12
影响因子：
7.4
通讯作者：
Y. Andersson-Sköld;J. Torrance;B. Lind;K. Odén;R. Stevens;K. Rankka
中科院分区：
文献类型：
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作者：
Y. Andersson-Sköld;J. Torrance;B. Lind;K. Odén;R. Stevens;K. Rankka
在瑞典、挪威和加拿大，大多数大型和严重的粘土滑坡都涉及到快速粘土，这种土壤在受到扰动时会从正常的坚实地面变成液态物质。粘土滑坡的位置、发生时间和规模很难预测，大型滑坡可能造成巨大的破坏。在20世纪60年代和70年代初，对瑞典的快速粘土进行了一些地球化学研究，但没有对瑞典快速粘土的孔隙水化学、矿物学、岩土性质和其他参数之间的相互关系进行系统研究。这些研究是国家和普遍的利益，因为许多组合的岩石粉源区和沉积条件发生在瑞典中部和波罗的海地区在冰川消退。在这项研究中，岩土工程性质有关的现场化学在一个快速粘土网站进行了广泛的研究，并在瑞典西南部的其他两个地点进行现场取样。本区粘土矿物主要为非膨胀性层状硅酸盐矿物（伊利石）和原生矿物（石英、长石），这与前人的粘土矿物学研究结果相一致。在所有三个地点都发生了大量的沥滤。在广泛研究的地点苏尔特，在最深处发现盐度最低，推断淡水的沥滤是通过水从下面的基岩向上和横向穿过沉积物的运动完成的。这与当地的环境一致，基岩山急剧上升到海洋沉积物表面以上100米。在这个位置也可以预计到自流压力。敏感性与盐度之间存在相关性（负相关），但有迹象表明，与速粘土行为一致的最大盐度或电导率高于其他地方的报告。然而，对于高灵敏度，盐度与其他地方报道的大致相同。在钻孔最深处，孔隙水中Fe、Al含量较高，呈还原状态。需要进一步开展工作，以确认盐度的差异，并调查盐度和潜在的分散剂之间可能的相互作用，如缺氧条件在该地区的作用。特别需要在低盐度条件下沉积物积累的地点开展进一步工作。在所有三个位置，高重塑剪切强度和低敏感性已被视为表面附近的孔隙水阳离子浓度下降。
Quick clay, a soil that changes from normal firm ground to a liquid mass when it is disturbed, has been involved in most of the large and serious clay slides in Sweden, Norway and Canada. The location, time of occurrence and size of quick clay slides are difficult to predict and large slides may cause great devastation. Some geochemical studies of Swedish quick clay were done in the 1960s and early 1970s, but no systematic studies of the interrelationships of pore water chemistry, mineralogy, geotechnical properties and other parameters on quick clays in Sweden have been published. Such studies are of national and general interest because of the many combinations of rock flour source areas and sedimentation conditions that occurred across central Sweden and into the Baltic Sea area during deglaciation. In this study, geotechnical properties related to the in situ chemistry at one quick clay site were extensively studied, and spot sampling was conducted at two other locations in Southwest Sweden. In this area the clay minerals mainly are non-expanding phyllosilicate minerals (illite) and primary minerals (quartz, feldspar), which is consistent with previous studies of quick clay mineralogy. Extensive leaching has occurred at all three locations. At the extensively studied site, Surte, the lowest salinity was found at the greatest depth, inferring that the leaching by fresh water was accomplished by water movement upward and laterally through the sediment from the underlying bedrock. This is consistent with the local setting where bedrock hills rise sharply to over 100 m above the marine sediment surface. An artesian pressure would also be anticipated at this location. There is a correlation (negative) between sensitivity and salinity but there is an indication that the maximum salinity or electrical conductivity consistent with the quick clay behaviour is higher than reported elsewhere. However, for high sensitivities the salinity is about the same as reported elsewhere. In the deepest part of the borehole, there is a higher content of Fe and Al in the pore water, indicating reduced state. Further work is needed to confirm the difference in salinity and to investigate the possible interplay of salinity and potential dispersing agents such as the role of anoxic conditions, in this region. Further work is especially needed in the locations where the sediment accumulation occurred under lower salinity conditions. At all three locations, high remoulded shear strength and low sensitivity have been seen near the surface together with a decrease in pore water cation concentrations.