Changes in permeability caused by dynamic stresses in fractured sandstone
Changes in permeability caused by dynamic stresses in fractured sandstone
复制标题
裂隙砂岩动应力引起的渗透率变化
DOI：
10.1029/2009gl039852
复制
发表时间：
2009-10-21
影响因子：
5.2
通讯作者：
Manga, Michael
中科院分区：
文献类型：
--
作者：
Liu, Weiqun;Manga, Michael
振动引起的渗透性变化被用来解释地震引起的各种水文响应。在不排水条件下，我们测量了裂隙砂岩在反复震动下渗透率的变化。所施加的震动的频率和振幅与距离破裂断层的断层长度相似的地震的频率和振幅相似。为了评估移动的颗粒的作用，我们还向裂缝中加入了粉砂大小的颗粒。我们发现，在一般情况下，渗透率下降后，震动。添加颗粒的样品显示出更大的渗透率变化。振动引起的颗粒运输阻塞狭窄的裂缝孔径可以解释一些观察结果。我们还发现，渗透率的降低往往伴随着样品的收缩，表明裂缝孔径有时会减少，大概是通过动员颗粒和去除保持裂缝打开的凹凸不平。引文：Liu，W.，和M. Manga（2009），裂缝砂岩中动态应力引起的渗透率变化，Geophys。保留信函：36，L20307，doi：10.1029/2009GL039852。
Shaking-induced changes in permeability have been invoked to explain a wide range of hydrologic responses to earthquakes. We measure the evolution of permeability in fractured sandstone in response to repeated shaking under undrained conditions. The frequency and amplitude of the imposed shaking are similar to those from earthquakes at distances of similar to a fault length from the ruptured fault. To assess the role of mobile particles, we also add silt-sized particles to the fractures. We find that, in general, permeability decreases after shaking. The samples with added particles show larger changes in permeability. Shaking-induced transport of particles to block narrow fracture apertures can explain some of the observations. We also find that decreases in permeability are often accompanied by a contraction of sample indicating that fracture apertures sometimes decrease, presumably by mobilizing particles and removing asperities that hold fractures open. Citation: Liu, W., and M. Manga (2009), Changes in permeability caused by dynamic stresses in fractured sandstone, Geophys. Res. Lett., 36, L20307, doi: 10.1029/2009GL039852.