为进一步认识黏土矿物水化膨胀特性,利用新型高温高压泥页岩膨胀仪,通过试验分析了温度、压力及二者共同作用对怀俄明钠基膨润土和钙膨润土水化膨胀性能的影响,并从黏土矿物含水量、颗粒形态、毛管力及颗粒间相互作用等方面进一步分析了黏土矿物水化膨胀过程的微观变化特征。结果表明:温度和压力对黏土矿物水化膨胀性能影响显著,温度越高,黏土矿物水化膨胀量越大,且初始膨胀速率较快;压力对黏土矿物水化膨胀有2方面的作用(促进黏土矿物水化膨胀和抑制其水化膨胀),且与温度密切相关,压力越高初始膨胀速率越小;黏土矿物中含水量、颗粒形态及毛细管力等的变化均影响黏土矿物水化膨胀特性,当黏土矿物中的含水量上升时,黏土颗粒间的粘结力发生较大变化,且颗粒形态产生不均匀变化致使黏土矿物遇水产生不均匀膨胀和强大的膨胀压。
In order to find out the effects of temperature and pressure on the hydration swelling charac- teristics of clay mineral, based on the hydration of Wyoming sodium bentonite and calcium bentonite which is influenced by different temperature and pressure, the lab investigation of the hydration expansion charac- teristics of two clay mineral were carried by new HTP-3A dilatometer,and the microscopic changes in hy- dration expansion was analyzed from water content in clay mineral, particle morphology, capillary force and inter-particle interactions, etc. The results show that, temperature and pressure have an significant effect on hydration expansion characteristics of clay mineral and follow some certain rules. The higher the tempera- ture, the greater the swelling capacity is and the faster the initial expansion rate is. There are two aspects of the role of pressure on the clay mineral hydration expansion closely related with temperature. And higher the pressure, the smaller the initial expansion rate is. Besides, the changes of water content in clay mineral, particle morphology, capillary force and inter-particle interactions are the important factors that the clay mineral has strong water swelling characteristics. The adhesive force between the clay particles changed greatly while the water content in clay mineral increases. The clay mineral has strong uneven water swell- ing characteristic and big swelling pressure which is led by the uneven changes of particle morphology.