复杂地下水环境下石膏质岩的溶蚀特性

石膏质岩具有溶蚀性，在勘察设计阶段应用标准规范对石膏质岩进行围岩分级往往不能满足施工需求.为定量化分析溶蚀对石膏质围岩分级的影响，开展不同循环次数(1、 3、 6、 10次)和不同流速(0、 10、 20 L·h^-1)的干湿循环实验；通过单轴压缩实验，探究石膏质岩在不同流速和干湿循环次数下的力学参数劣化规律.选取BQ值作为围岩分级修正的基础，将单轴抗压强度作为修正指标；建立流速和干湿循环耦合作用下单轴抗压强度折减系数的三维拟合函数，与围岩分级公式相结合，并考虑干湿循环的最大化影响，提出考虑石膏质岩溶蚀性的围岩分级修正方法.结果表明：随着流速和干湿循环次数的增加，单轴抗压强度、单轴抗压强度折减系数持续下降，但下降的比例越来越小；流速和干湿循环次数的耦合作用与单轴抗压强度、单轴抗压强度折减系数均具有良好的相关性，三维拟合函数曲面呈“下凹”状.该研究结果可为考虑石膏质岩溶蚀性的围岩分级提供一种可行的计算方法.

Study on dissolution characteristics and surrounding rock classification of gypsum rock under complex groundwater environment

Gypsum rock is a kind of erosive rock. In the survey and design stage, the application of standards and specifications to the surrounding rock classification of gypsum rock often can not meet the construction needs. In order to quantitatively the influence of dissolution on the classification of gypsum surrounding rock, dry wet cycle experiments with different cycle times (1, 3, 6, 10 times) and different flow rates (0, 10, 20 L / h) are carried out . Through uniaxial compression experiment, the deterioration law of gypsum rock under different flow velocity and dry wet cycle times is explored. The BQ value is used as the basis for the classification correction of surrounding rock, and the uniaxial compressive strength is used as the correction index. The fitting function between the reduction coefficient of uniaxial compressive strength and the coupling of velocity and dry wet cycle is established, which is combined with the classification of surrounding rock. So the correction method of surrounding rock classification considering the solubility of gypsum rock is proposed. The results show that the uniaxial compressive strength and the reduction coefficient of uniaxial compressive strength continue to decrease with the increase of flow rate and the number of dry wet cycles, but the rate of decline is smaller and smaller. The coupling of flow velocity and dry wet cycle times has a very good correlation with uniaxial compressive strength and uniaxial compressive strength reduction coefficient. The results provide a feasible calculation method for surrounding rock classification considering the solubility of gypsum rock.