在高放废物处置库的运营过程中, 核废料的衰变热和混凝土老化产生的碱性孔隙水均会对缓冲回填材料的工作性能产生影响. 为了研究碱热耦合对缓冲回填材料膨胀特性的影响, 采用高庙子 (Gaomiaozi, GMZ) 膨润土和花岗岩岩屑混合材料, 选用 NaOH 溶液模拟碱性孔隙水, 利用水浴锅提供恒温溶液, 并将溶液在自主研制的耐腐蚀固结仪中不断循环, 分别开展 25 和 50 ${^\circ}$C 两种温度以及 0.1、0.5 和 1.0 mol/L 3 种碱性溶液浓度下的膨胀力试验, 获得了各试样的膨胀力时程曲线. 试验结果表明: 当温度相同时, 试样的最大膨胀力和稳定膨胀力均随碱性溶液浓度的增加而降低; 当同一浓度碱性溶液入渗时, 试样的最大膨胀力和稳定膨胀力均随掺岩率的增大而降低; 相同掺岩率及入渗碱性溶液浓度的试样的最大膨胀力和稳定膨胀力均随温度的升高而降低. 碱性溶液对膨胀力的衰减程度随溶液浓度的增加而增大, 随温度的升高而增大. 对于膨润土-花岗岩岩屑混合物, 在相同入渗溶液浓度和相同反应温度下, 膨胀力衰减率随掺岩率的增大而降低.

During the life of a high-level radioactive waste repository, the decay heat of nuclear waste and alkaline pore water produced by the aging of concrete affect the working performance of the buffer material. To study the effects of alkali-thermo coupling on the swelling characteristics of buffer materials, NaOH solution is used in this study to simulate alkaline pore water, and a water bath pot is used to provide a constant temperature solution, where the solution is continuously circulated in a self-developed corrosion-resistant consolidator. The evolution curves of the swelling force are obtained through swelling force experiments under concentrations of 0.1, 0.5, and 1.0 mol/L and temperatures of 25 $^\circ$C and 50 $^\circ$C. Results showed that at the same temperature, the maximum and final swelling force of the sample decreased with an increase in the solution concentration. In addition, at the same concentration of alkaline solution infiltration, the maximum and final swelling force of the sample decreased with an increase in the granite mixing rate. Under the same granite mixing rate and same infiltration solution, the maximum and final swelling force of the sample decreased with an increase in temperature. The attenuation degree of swelling force increased with increases in solution concentration and temperature. For the mixture of crushed granite and bentonite, under the same temperature and same infiltration solution, the attenuation degree of swelling force decreased with an increase in the granite mixing rate.