Study on large direct shear test of coal gangue soil-rock mixture under wetting-drying cycles
LIU Hongwei1，2，3，YOU Shiqi1，JIAN Wenbin1，2，3，HUANG Yun1，FENG Song4，DENG Tao4
(1. Zijin School of Geology and Mining，Fuzhou University，Fuzhou，Fujian 350108，China；2. Fujian Key Laboratory of Geohazard Prevention，Geological Engineering Survey in Fujian Province，Fuzhou，Fujian 350002，China；3. Key Laboratory of Geohazard Prevention of Hilly Mountains，Ministry of Natural Resources，Geological Engineering Survey in Fujian Province，Fuzhou，Fujian 350002，China；4. College of Civil Engineering，Fuzhou University，Fuzhou，Fujian 350108，China)
A large amount of coal gangue is generated during coal excavation and preparation. The coal gangue accumulates on the ground surface and is easily affected by environment and causes disasters. The mechanism of the effects of drying-wetting cycles and stone content on the strength characteristics of coal gangue is investigated through large-scale direct shear tests. The influence of proportion of rock( ) and the number of drying and wetting on the volume and relative breakage rate( ) of soil-rock mixture was revealed. The equation of shear strength degradation of soil-rock mixture under drying-wetting cycles was established. The test results showed that as the rock content increases，the internal friction angle of the coal gangue soil-rock mixture increased linearly，while the cohesion exhibited a downward trend. The gangue soil-rock mixture exhibited obvious shear shrinkage during the shear process. The shear strength and maximum normal strain of the mixture increased with an increase in rock content but decrease with the number of drying-wetting cycles. The shear strength of the soil-rock mixture significantly deteriorated during the first drying-wetting cycle，and it did not change significantly after three drying-wetting cycles. The drying-wetting cycle enhanced the fragmentation tendency of rock in the soil-rock mixture，raised the of the rock，and increased the content of soil particles(particle size＜5 mm). The increased with the number of drying-wetting cycles，while under low normal stress( = 200 kPa)，the drying-wetting cycles had a limited impact on rock fragmentation.
刘红位1，2，3，游诗琪1，简文彬1，2，3，黄 云1，冯 嵩4，邓 涛4. 干湿循环下煤矸石土石混合体大型直剪试验研究[J]. 岩石力学与工程学报, 2025, 44(2): 331-341.
LIU Hongwei1，2，3，YOU Shiqi1，JIAN Wenbin1，2，3，HUANG Yun1，FENG Song4，DENG Tao4. Study on large direct shear test of coal gangue soil-rock mixture under wetting-drying cycles. , 2025, 44(2): 331-341.
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2025, Vol. 44 
