Effect of pore fluid pressure on the frictional strength of antigorite serpentinite
Effect of pore fluid pressure on the frictional strength of antigorite serpentinite
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孔隙流体压力对蛇纹石摩擦强度的影响
DOI：
10.1016/j.tecto.2012.10.017
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Takahashi,
中科院分区：
文献类型：
--
作者：
Okazaki;K.;I.;Katayama;M.;Takahashi,
叶蛇纹石蛇纹岩的三轴变形实验表明，在较宽的孔隙压力范围内（50<Pp<143 MPa），剪应力与有效正应力之间存在系统的相关性。在干燥条件下，使用Ar气体作为孔隙流体，稳态摩擦系数（μ）估计为0.66±0.01。相比之下，在使用蒸馏水作为孔隙流体的湿条件下，μ=0.51±0.01（即，低于干燥条件下）。这种μ的差异可能是由蛇形表面上的带电水引起的，这降低了潮湿环境中滑动表面的摩擦阻力。剪应力和有效正应力之间的线性关系表明，库仑定律适用于滑动面在注入和喷出的孔隙流体。由于孔隙流体压力升高，这导致了显著的机械弱化;因此，板块边界上的凹凸体的位置可能受俯冲板块界面上流体的非均匀分布控制。
Triaxial deformation experiments on antigorite serpentinite show a systematic correlation between shear stress and effective normal stress over a wide range of pore pressures (50<Pp<143MPa). Under dry conditions using Ar gas as the pore fluid, the steady-state friction coefficient (μ) is estimated to be 0.66±0.01. In contrast, under wet conditions using distilled water as the pore fluid, μ=0.51±0.01 (i.e., less than under dry conditions). This difference in μ may be caused by charged water on the serpentine surface, which reduces the frictional resistance of the sliding surface in wet environments. The linear correlation between shear stress and effective normal stress suggests that Coulomb's law applies to sliding surfaces during the injection and ejection of pore fluids. This results in a significant mechanical weakening due to elevated pore fluid pressures; consequently, the locations of asperities on plate boundaries may be controlled by the heterogeneous distribution of fluids on the subducting plate interface.