干湿循环下红黏土边坡响应的模型试验

针对降雨/干燥过程中边坡破坏问题,为了解干湿循环过程中红黏土边坡失稳机理以及内部响应过程,以贵州红黏土为研究对象,通过室内堆砌边坡模型,在模型内部不同位置埋设传感器进行了降雨/干燥试验,分析红黏土边坡在干湿循环过程中内部含水率、位移、孔隙水压力变化特征,并观察试验过程中边坡表面破坏发展,探讨红黏土边坡的失稳机理。试验过程中含水率、孔隙水压力皆随着降雨过程而增大,干燥期间逐渐减小,且随着边坡的深度增加,受外界气候变化影响越小,位移在循环过程中逐渐缓慢增加。边坡破坏形式分为降雨过程中面蚀、冲沟,干燥阶段裂缝发育。结果表明:边坡失稳主要是由于整体含水率的增加,导致孔隙水压力上升,土体有效应力下降,横向位移逐渐增加,最终导致滑坡发生,而降雨期边坡表面的破坏以及干燥期裂缝的发育更加剧了这一过程。

Model experiment of response of red clay slope under dry-wet cycle

Aiming at the problem of the slope failure during the rainfall / drying process，a rainfall / drying experiment is carried out through building a slope model in door and embedding sensors inside of various locations of it by taking the red clay in Guizhou Province as the study objective，so as to understand the instability mechanism of the red clay slope and its internal response process，and then the internal water content，displacement and the changing characteristics of pore water pressure of red clay slope during dry-wet cycle are analyzed，while the surface failure development of the slope during the experiment is observed and the instability mechanism of the red clay slope is discussed as well. During the experiment，both the water content and the pore water pressure are to be increased along with the rainfall process and gradually decreased in the drying period，while the impact from the outside climate on them is to be decreased along with the increase of the depth of slope，but the displacement is to be slowly increased in the process of the cycle. The pattern of the slope failure can be divided into surface erosion and gully erosion during rainfall and cracking development during drying. The result shows that the slope instability is mainly caused by the increase of the overall water content，which leads to the rise of pore water pressure，the drop of the effective stress of the soil mass and the gradual increase of the lateral displacement，thus induces a landslide at last; moreover，this process is to be intensified by both the slop surface failure during rainfall and the cracking development during drying.