受酸腐蚀花岗岩反复加卸载后力学性能研究

Study on Mechanical Properties of Acid Corroded Granite after Repeated Loading and Unloading

【目的】地下工程在施工时常面临着反复加卸载和酸腐蚀的双重影响,导致岩石的物理力学性质发生劣化,对工程造成不良影响,有必要开展相关研究。【方法】为了探究水化学环境下岩石反复加卸载力学性能劣化机理,选取在不同水化学溶液浸泡后的花岗岩进行反复加卸载试验,分析破坏形式并研究pH值和腐蚀时间以及加载次数对应力、应变影响的规律。【结果】结果表明:在水化学溶液腐蚀和反复加卸载双重耦合作用下,随着腐蚀作用加强,破坏形态由剪切破坏向劈裂破坏转变,由脆性向塑性转化比较明显;轴向应变和轴向应力随加载次数的增加逐渐增大,随着水溶液pH值的减小其峰值强度没有减小,反而有小幅上升。【结论】在水化学溶液腐蚀和反复加卸载耦合的作用下,花岗岩力学性能劣化明显。研究结果可为岩体工程在酸腐蚀和循环加卸载耦合作用下的长期稳定性的评价提供试验参考和依据。

[Purposes]The construction of underground engineering often faces the dual effects of repeated loading and unloading and acid corrosion,resulting in the deterioration of the physical and mechanical properties of rocks,which has a negative impact on the project,it is necessary to carry out relevant research.[Methods]In order to explore the degradation mechanism of rock mechanical properties under repeated loading and unloading in a hydrochemical environment,granite samples soaked in different hydrochemical solutions were selected for repeated loading and unloading tests.The failure forms were analyzed and the effects of pH value,corrosion time,and loading times on stress and strain were studied.[Findings]The results show that under the dual coupling effect of water chemical solution corrosion and repeated loading and unloading,as the corrosion effect intensifies,the fracture morphology changes from shear failure to splitting failure,and the transition from brittleness to plasticity is more obvious;The axial strain and axial stress gradually increase with the increase of loading times,and the peak strength does not decrease with the decrease of pH value of the aqueous solution,but slightly increases.[Conclusions]Under the coupling effect of water chemical solution corrosion and repeated loading and unloading,the mechanical properties of granite deteriorate significantly.The research results provide experimental reference and basis for the evaluation of long-term stability under the coupling effects of acid corrosion and cyclic loading and unloading in rock engineering.