Chen Lei, Jia Baoxin, Zhang Shuguang
Civil Engineering Institute, Liaoning Technical University, Fuxin 123000, China.
Guangxi Key Laboratory of Geotechnical Mechanics and Engineering, Guilin University of Technology, Guilin 541004, China.
Materials (Basel). 2022 Feb 21;15(4):1613. doi: 10.3390/ma15041613.
Chemical corrosion has a significant impact on the properties of rock materials. To study the mechanical behavior and energy mechanism of rock under chemical corrosion, this paper took the sandstone of Haitangshan tunnel in Fuxin as the research object, used a NaSO solution to simulate different chemical environments, carried out a triaxial loading test on sandstone through the MTS815.02 test system, and analyzed the mechanical parameters and energy damage evolution law of sandstone under different chemical environments. The test results showed that the basic mechanical parameters (peak strength , peak strain , elastic modulus , cohesion , and internal friction angle ) and characteristic stress parameters (closure stress , initiation stress , and dilatancy stress ) of sandstone first increased and then decreased with the increase of pH in the NaSO solution, Poisson's ratio showed the opposite trend, and the extreme values of all parameters were taken when pH = 7. The influence degree of different pHs on the mechanical parameters of sandstone were as follows: strong acid environment (pH ≤ 4) > strong alkali environment (pH ≥ 10) > weak acid environment (4 ≤ pH < 6) > weak alkali environment (8 ≤ pH < 10) > neutral environment (6 < pH< 8). The total energy and elastic strain energy increased first and then decreased, and the dissipated energy was the opposite. The damage variable decreased first and then increased. With the increasing concentration of the NaSO solution, all the above parameters changed monotonically. Based on the energy theory, the damage evolution equation considering the effect of the NaSO concentration was established. Combined with the test data, the model was verified and the result was good. Under the action of NaSO corrosion, Ca in calcite and Fe in hematite were dissolved and precipitated. With the gradual increase of Ca and Fe concentration, the damage variable increased gradually. The relationship between the two ion concentrations and the damage variable approximately satisfied a linear function.
化学腐蚀对岩石材料的性能有显著影响。为研究化学腐蚀作用下岩石的力学行为及能量机制，本文以阜新海棠山隧道砂岩为研究对象，采用NaSO溶液模拟不同化学环境，通过MTS815.02试验系统对砂岩进行三轴加载试验，分析不同化学环境下砂岩的力学参数及能量损伤演化规律。试验结果表明，砂岩的基本力学参数（峰值强度、峰值应变、弹性模量、内聚力和内摩擦角）和特征应力参数（闭合应力、起裂应力和扩容应力）随NaSO溶液pH值的增大先增大后减小，泊松比呈相反趋势，且所有参数在pH = 7时取极值。不同pH值对砂岩力学参数的影响程度为：强酸环境（pH≤4）＞强碱环境（pH≥10）＞弱酸环境（4≤pH＜6）＞弱碱环境（8≤pH＜10）＞中性环境（6＜pH＜8）。总能量和弹性应变能先增大后减小，耗散能则相反。损伤变量先减小后增大。随着NaSO溶液浓度的增加，上述所有参数均单调变化。基于能量理论，建立了考虑NaSO浓度影响的损伤演化方程。结合试验数据对模型进行验证，结果良好。在NaSO腐蚀作用下，方解石中的Ca和赤铁矿中的Fe发生溶解和沉淀。随着Ca和Fe浓度的逐渐增加，损伤变量逐渐增大。两种离子浓度与损伤变量之间的关系近似满足线性函数。
