ANISOTROPIC PERMEABILITY AND TORTUOSITY IN DEFORMED WET SEDIMENTS
ANISOTROPIC PERMEABILITY AND TORTUOSITY IN DEFORMED WET SEDIMENTS
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DOI：
10.1029/jb095ib06p09035
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发表时间：
1990-06-10
期刊：
影响因子：
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通讯作者：
MALTMAN, A
中科院分区：
文献类型：
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作者：
ARCH, J;MALTMAN, A
据推测，许多增生棱镜的脱水优先发生在离散构造上。然而，这些构造通常由韧性剪切带中的强烈颗粒重新排列组成，而不是扩张性断裂。这种重新排列促使孔隙率降低，但有自然证据表明，剪切带在某种程度上能够起到脱水通道的作用。试验研究表明，在材料破坏时出现剪切区，此时渗透率在剪切区两侧降低，但平行于剪切区增加近2个数量级。宿主沉积物的主要结构也引起渗透率的各向异性，其数值根据流动方向不同而有数量级的差异。从理论上分析了单轴缩短和单轴剪切不同组合产生的剪切带的流体流道弯曲度。弯曲度的变化既解释了基质材料的渗透率各向异性，也解释了流体沿剪切带流动的难易性，尽管剪切带的孔隙度降低了。
Dewatering in many accretionary prisms is inferred to occur preferentially along discrete tectonic structures. However, these structures commonly consist of intense particle realignment in ductile shear zones rather than dilative fractures. Such realignment prompts a reduction in porosity within the zones, but there is, nevertheless, natural evidence that the shear zones are able somehow to act as dewatering channels. Experimental investigations indicate that shear zones arise at failure of the material, at which point permeability is reduced across the zones but increases by nearly 2 orders of magnitude parallel to them. The primary fabric of the host sediment also induces an anisotropy of permeability, values differ by an order of magnitude according to flow direction. The tortuosity of the fluid flow path is theoretically analyzed for shear zones produced in different combinations of uniaxial shortening and simple shear. Varying tortuosity explains both the permeability anisotropy of the host material and the ease of fluid flow along the shear zones, despite their reduced porosity.