Dissolution and oxidation of mudstone under stress
Dissolution and oxidation of mudstone under stress
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应力作用下泥岩的溶解与氧化
DOI：
10.1139/t93-006
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
M. Chigira
中科院分区：
文献类型：
--
作者：
M. Chigira
在实验室中，在15°C、pH值为3 - 7、溶解氧含量为4 - 16mg/L的水中，在高达0.49MPa的应力下，模拟了自然界中软泥岩长达70天的风化过程，其特征是存在一个氧化带和一个下方的溶解带。当水呈酸性时，氢离子从岩石 - 水界面通过岩石扩散，并在一个明确的溶解前沿优先且容易地侵蚀泥岩中对酸不稳定的方解石，在前沿后方留下一个溶解带。在溶解带中，密度降低，孔隙度增加，超声纵波速度降低，抗剪强度降低。溶解前沿向未反应的岩石迁移，迁移速率由已反应的溶解带中氢离子的扩散控制，因此该速率受施加在岩石上的应力影响；当岩石受到应力时，有效扩散率变小。氧气也通过岩石扩散到一个明确的氧化前沿并且……
Weathering of soft mudstone in nature, characterized by the presence of an oxidized zone and an underlying dissolved zone, was simulated in the laboratory in 15 °C water with a pH of 3–7 and dissolved oxygen contents of 4–16 mg/L under stresses up to 0.49 MPa for as long as 70 days. When the water is acid, hydrogen ions diffuse from the rock–water interface through the rock and attack acid-labile calcite in mudstone preferentially and easily at a well-defined dissolution front, leaving a dissolved zone behind the front. Density decreases, porosity increases, ultrasonic P-wave velocity decreases, and shear strength decreases in the dissolved zone. The dissolution front migrates toward unreacted rock, and the migration rate is controlled by the diffusion of hydrogen ions in the reacted dissolved zone, so the rate is influenced by the stress exerted on the rocks; the effective diffusivity becomes smaller when the rock is stressed. Oxygen also diffuses through the rock to a well-defined oxidation front and ch...