| 王腾飞.不同水化学条件下循环侵水砂岩劣化规律研究[J].地质与勘探,2022,58(6):1281-1290 |
| 不同水化学条件下循环侵水砂岩劣化规律研究 |
| Deterioration Lawof Sandstone with Water Invasion Cycle under Different HydrochemicalConditions |
| 投稿时间：2021-05-26 修订日期：2021-11-12 |
| DOI：10.12134/j.dzykt.2022.06.012 |
| 中文关键词: 循环侵水 酸碱度 孔隙率 峰值强度 劣化系数 |
| 英文关键词: water invasion cycle, pH, porosity, peak strength, deterioration coefficient |
| 基金项目:国家自然科学基金项目（编号：51909149）资助 |
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| 中文摘要: |
| 岩石力学性质的损伤对于工程结构的稳定造成严重影响，尤其是废弃露天矿坑作为尾矿库使用，蓄水与排水导致库岸边坡岩体长期受到复杂水化学环境与循环侵水的耦合作用。为模拟复杂水化学环境与循环侵水的耦合作用对岩石损伤影响，设计了砂岩在酸、中、碱性三种环境下的循环侵水试验，并通过常规三轴压缩试验分析岩石力学参数的弱化规律。研究结果表明：（1）砂岩峰值强度随围压增大呈递增趋势，随循环侵水次数增加呈降低趋势，且峰值强度按pH值排序为7>10>4；（2）砂岩孔隙率随循环次数增加呈增长趋势，其变化率呈降低趋势，且孔隙率按pH值排序为4>10>7，pH=4和pH=10环境中孔隙率明显大于pH=7环境中的孔隙率，表明pH=4和pH=10环境中砂岩同时发生水解反应与化学反应两种劣化，使得孔隙率增大；（3）砂岩粘聚力c和内摩擦角φ呈劣化递增趋势，0次到5次循环阶段，c和φ的劣化程度最大，5次到20次循环阶段，c和φ劣化的趋势逐渐减缓，且c值和φ值按pH排序为7>10>4；（4）对砂岩粘聚力c和内摩擦角φ拟合方程微分后得到微分方程，归一化处理后定义其系数为砂岩劣化系数，得到c和φ的劣化系数按pH排序均为4>10>7，并分别建立c和φ与pH值、循环次数的双变量拟合函数表达式。 |
| 英文摘要: |
| Damage of rock mechanical properties has a serious impact on the stability of engineering structures, especially when abandoned open-pit mines are used as tailings ponds. Water storage and drainage result in the coupling effect of complex hydrochemical environment and cyclic water intrusion on the bank slope of the reservoir for long. In order to simulate the coupling effect of complex hydrochemical environment and cyclic water intrusion on rock damage, this work designed cyclic water intrusion tests of sandstone in acid, medium and alkaline environments, and analyzed the weakening law of rock mechanical parameters by conventional triaxial compression tests. Results show that the peak strength of sandstone increases with the increase of confining pressure, and decreases with the increase of water invasion cycle times, and that the order of peak strength according to pH is 7>10>4. The porosity of sandstone increases with the increase of cycle times, and its change rate decreases. The order of porosity according to pH is 4>10>7, and the porosity in pH=4 and pH=10 environments is significantly higher than that in pH=7. It is indicated that hydrolysis reaction and chemical reaction occur at the same time in pH=4 and pH=10 environment, resulting in increasing porosity. The cohesion c and internal friction angle φ of sandstone show an increasing trend of deterioration. The deterioration degree of c and φ is the largest from 0 to 5 cycles, the deterioration trend of c and φ gradually slows down from 5 to 20 cycles, and the order of c and φ according to pH is 7>10>4. After fitting the differential equation of sandstone c and φ, the differential equation was obtained. After normalization, the coefficient is defined as sandstone deterioration coefficient, and the order of the deterioration coefficient of c and φ according to pH is 7>10>4.The bivariate fitting function expressions of c and φ with pH value and number of cycles were established, respectively. |
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