堆石体存在流变,不仅与荷载有关,而且与干湿循环有关。堆石坝的长期变形观测资料也表明,雨季产生的变形常显著高于非雨季。本文通过室内试验模拟日晒雨淋引起的干湿循环作用,研究等围压荷载作用下干湿循环对堆石料长期变形的影响,并依试验所揭示的变形随干湿循环而变化的规律,建立了计算变形的近似公式。结果表明,干湿循环作用引起的堆石变形是不可忽视的,它随循环次数的增加呈非线性发展,并与围压呈正比。在计算堆石料长期变形时,除了考虑荷载作用的流变变形,还需根据年降雨的循环次数计算堆石料长期的变形。
The creep deformation of rockfill is not only dependent on the loading but also the wettingdrying cycle. The long term observation data of rockfill dam also indicate that the deformation in raining season is obviously greater than that in dry season. An experiment in laboratory was carried out to study the influence of wetting-drying cycles on deformation of rockfill under isotropic conmed pressure. The result shows that the creep deformation caused by wetting-drying cycles is not negligible, it increases with the increase of cycle and positively proportional to the refined pressure. A formula for estimating this deformation is proposed based on the experimental data. It is pointed out that the deformation due to raining must be taken into account during calculating the long term deformation ofrockfill dam.