Subcritical crack propagation in stressed carbonate rocks in a chemically reactive environment is a fundamental mechanism underlying many geomechanical processes frequently encountered in the engineering of geo-energy, including unconventional shale gas, geothermal energy, carbon sequestration and utilization. How a macroscopic Mode I crack propagates driven by a reactive fluid pressurizing on the crack surfaces with acidic agents diffusing into the rock matrix remains an open question. Here, the carbonate rock is modeled as an elasto-viscoplastic material with the mineral mass removal process affecting the rock properties in both elastic and plastic domains. A blunt-tip crack is considered to avoid any geometrically induced singularity problem and to allow a numerical analysis on the evolution of the chemical field being linked to the micro-cracking activities in front of the crack tip, affecting the delivery of acid. The model is capable of reproducing an archetypal three-region behavior of subcritical crack growth in a reactive environment. The crack propagation exhibits a prominent acceleration in Region III due to a two-way mutually enhancing feedback between mineral dissolution and the degradation process, which is most pronounced in front of the crack tip. With the consideration of initial imperfections in the rock, the macroscopic crack propagation is further accelerated with a secondary acceleration arising due to self-organization of micro-bands inside the chemically enabled plasticity zone.

化学反应环境中受应力碳酸盐岩的亚临界裂纹扩展是地能工程中经常遇到的许多地质力学过程的基本机制，包括非常规页岩气、地热能、碳封存和利用。宏观 I 型裂纹如何由反应流体在裂纹表面加压以及扩散到岩石基质中的酸性剂驱动而扩展仍然是一个悬而未决的问题。在这里，碳酸盐岩石被建模为弹粘塑性材料，矿物质量去除过程会影响弹性和塑性域中的岩石特性。钝端裂纹被认为可以避免任何几何引起的奇点问题，并允许对与裂纹尖端前面的微裂纹活动相关的化学场的演变进行数值分析，从而影响酸的输送。该模型能够重现反应环境中亚临界裂纹扩展的典型三区域行为。由于矿物溶解和降解过程之间的双向互增强反馈，裂纹扩展在区域 III 中表现出显着的加速，这在裂纹尖端前面最为明显。考虑到岩石中的初始缺陷，由于化学塑性区内微带的自组织而产生二次加速，宏观裂纹扩展进一步加速。