Abstract Highly mineralized and acid/alkaline groundwater is critical to the short- or long-term stability of fractured rock masses in geological engineering. Understanding the impact of water-rock interactions on mechanical properties of fractured rock masses is important but challenging. This study investigated the physicochemical interactions between chemical solutions and granite fractures which can directly control the mechanical behaviors of fractured rock masses. Direct shear tests were performed on artificial granite fracture samples immersed in chemical solutions with different pHs for 30 and 150 days. The results show that the solution of pH = 2 has the most significant influence on fracture shear properties, followed by the solutions of pH = 12 and pH = 7. The deionized water has the minimal influence on fracture shear properties. The shear properties of fractures immersed in acid and alkaline solutions are sensitive to immersion time, whereas the shear properties of fractures immersed in neutral solutions are not significantly affected by immersion time. The weakening mechanisms of the water-rock chemical interaction are different in different chemical solutions. Dissolution mainly works in acid solutions, whereas the competing minerals dissolution and precipitation/crystallization occur in alkaline solutions. This is why alkaline solutions have less significant influence on fracture shear properties than acid solutions.

中文翻译：

---

浸入化学溶液中的花岗岩裂缝的剪切行为

摘要 高度矿化和酸性/碱性地下水对地质工程中裂隙岩体的短期或长期稳定性至关重要。了解水-岩相互作用对裂隙岩体力学特性的影响很重要，但也具有挑战性。本研究调查了化学溶液与花岗岩裂缝之间的物理化学相互作用，这些相互作用可以直接控制破裂岩体的力学行为。对浸入不同 pH 值的化学溶液中 30 天和 150 天的人造花岗岩断裂样品进行了直剪试验。结果表明，pH=2的溶液对断裂剪切性能的影响最显着，其次是pH=12和pH=7的溶液。去离子水对断裂剪切性能的影响最小。裂缝在酸碱溶液中的剪切特性对浸泡时间很敏感，而在中性溶液中裂缝的剪切特性不受浸泡时间的显着影响。在不同的化学溶液中，水-岩化学相互作用的弱化机制是不同的。溶解主要在酸性溶液中起作用，而竞争性矿物溶解和沉淀/结晶发生在碱性溶液中。这就是为什么碱性溶液对断裂剪切特性的影响不如酸性溶液的原因。在不同的化学溶液中，水-岩化学相互作用的弱化机制是不同的。溶解主要在酸性溶液中起作用，而竞争性矿物溶解和沉淀/结晶发生在碱性溶液中。这就是为什么碱性溶液对断裂剪切特性的影响不如酸性溶液的原因。在不同的化学溶液中，水-岩化学相互作用的弱化机制是不同的。溶解主要在酸性溶液中起作用，而竞争性矿物溶解和沉淀/结晶发生在碱性溶液中。这就是为什么碱性溶液对断裂剪切特性的影响不如酸性溶液的原因。