Experimental constraints on dynamic fragmentation as a dissipative process during seismic slip
Experimental constraints on dynamic fragmentation as a dissipative process during seismic slip
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DOI：
10.1098/rsta.2016.0002
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发表时间：
2017-09
期刊：
影响因子：
--
通讯作者：
T. Barber;W. Ashley Griffith
中科院分区：
文献类型：
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作者：
T. Barber;W. Ashley Griffith
各种断层损伤组构，从主滑移带的断层泥到断层损伤带的碎屑和粉碎岩，都被归因于地震破裂过程中高应变率的脆性变形。过去的实验工作表明，在应力-应变速率空间中存在一个临界阈值，通过该阈值，岩石破坏将从沿几个离散的裂隙面的破坏过渡到强烈的碎裂。我们在Arkansas Novaculite(AN)和Westly Granite(WG)上给出了新的实验结果，其中我们量化了单轴压缩载荷下动态破碎产生的断裂表面积，并在微观上考察了原有矿物各向异性对耗散过程的控制。对产生的新断口面积显著增加的测试(约6.0m2 g−1)，高于WG(0.07m2 g−1)。对消耗到脆性断裂中的能量部分的估计对工作组来说意义重大(约。5%)，但在AN中似乎很大(10%到40%)。这些结果对地震期间预计的极端载荷条件下的耗散能量的分配以及将高速实验室岩石力学实验扩展到天然断裂带具有重要的意义。这篇文章是《断层、摩擦和削弱：从慢速运动到快速运动》主题的一部分。
Various fault damage fabrics, from gouge in the principal slip zone to fragmented and pulverized rocks in the fault damage zone, have been attributed to brittle deformation at high strain rates during earthquake rupture. Past experimental work has shown that there exists a critical threshold in stress–strain rate space through which rock failure transitions from failure along a few discrete fracture planes to intense fragmentation. We present new experimental results on Arkansas Novaculite (AN) and Westerly Granite (WG) in which we quantify fracture surface area produced by dynamic fragmentation under uniaxial compressive loading and examine the controls of pre-existing mineral anisotropy on dissipative processes at the microscale. Tests on AN produced substantially greater new fracture surface area (approx. 6.0 m2 g−1) than those on WG (0.07 m2 g−1). Estimates of the portion of energy dissipated into brittle fracture were significant for WG (approx. 5%), but appeared substantial in AN (10% to as much as 40%). The results have important implications for the partitioning of dissipated energy under extreme loading conditions expected during earthquakes and the scaling of high-speed laboratory rock mechanics experiments to natural fault zones. This article is part of the themed issue ‘Faulting, friction and weakening: from slow to fast motion’.