温度变化对堆石料变形影响的试验研究

Experiments on influence of temperature on deformation of rock fills

高土石坝建设使用的填筑堆石料在外界温度变化时,变形和力学特性会发生改变,可能影响坝体长期变形。首次采用自主研发的大型劣化三轴仪,通过低温、常温、高温及不同温度循环次数下的堆石料流变试验,研究温度对堆石料强度和变形的影响规律。试验发现:堆石料的流变变形受温度影响较大,温度升高,流变量减小,温度降低,流变量增大;经历温度循环次数越多,最终轴向及体积流变量越大。随着流变过程中试样温度的增加,轴向最终流变量呈减小趋势,随着冷却或增热次数增加,轴向和体积变形均呈逐渐减小的趋势。分析认为,温度循环造成堆石料一定程度上的损伤,导致其颗粒强度降低,变形量增大,经历多次温度循环后堆石料内部颗粒的劣化已经完成,变形基本不在明显。

The deformation and mechanical characteristics of rock fills in the construction of high earth-rock dams will be changed along with the temperature, which directly affect the deformation and safety of the dams. Through rheological tests on the rock fills under high, normal or low temperatures and different temperature cycle times by using the large degradation triaxial instrument, the effect of temperature on the strength and deformation of the rock fills is studied. The conclusion is drawn as follows: the deformation of rock fills is influenced by the temperature, the deformation decreases when the temperature increases, and the more the temperature cycle times, the higher the final axial deformation. Along with the increase of the temperature in rheological tests, the final axial deformation decreaseds, with the increase of the number of cooling or heating, and the final axial and volumetric deformations decrease. It is believed that the temperature cycle has a certain degree of damage to the rock fills, resulting in the decrease of the particle strength and the increase of the deformation, and the deformation is not obvious until the degradation of rock fills is completed after many times of the temperature cycle.