The geological processes, including earthquake, engineering excavation, weathering, erosion and transport caused a large number of loose accumulation bodies. The stone content in these loose accumulation bodies were different, and the instability induced by rainfall leaded to geological disasters including landslides and debris flows, which seriously threaten the production and living of local residents and the operation of large projects. It is thus crucial to conduct the model tests of different stone content and rainfall intensity using the large scale model platform, and to analyze the influence of stone content and rainfall intensity on the deformation and instability of loose accumulation. The results showed that the evolution of volume water content could be divided into four stages during the rainfall process of loose accumulation. The moisture content almost remained unchanged in stageⅠ, and then increased rapidly in stageⅡ. In stage Ⅲ, the moisture content reached its peak value, and then lightly decreased; after this, the moisture content increase slowly in stage Ⅳ. The larger the rock content, the smaller the volume moisture content of the same rainfall intensity and time, and the earlier the tensile failure occurs at the back edge. The smaller width of the corresponding tensile failure, the shorter duration of the slope failure continues. When the rainfall duration was same, the greater the rainfall intensity, the greater the volume moisture content is. The higher the rainfall intensity, the higher the volume moisture content of the loose accumulation body. Under different rainfall intensities, the volume moisture content of loose accumulation body varies with each other. The stability influence of rainfall intensity on loose accumulation body was more obvious. The greater intensity of rainfall, the main tensile cracks of loose deposits were smaller, and the main tensile cracks time, the maximum crack width, and the instability of the maximum displacement cumulative rainfall duration decreased more significantly. The results would provide references for predicting the instability and calamity in loose accumulations during disaster area.
