Abstract:In order to analyse the mechanical properties of red Pisha-sandstone, the Pisha-sandstones with different particle sizes(<2 mm, 0.50-1.00 mm, 0.25-0.50 mm, and < 0.25 mm)in Jungar Banner, Ordos City, were tested with various dry-wet cycles(1, 3, 5, 7, 9), and the shrinkage deformation and strength characteristics of sandstone were obtained. Results show that the biggest shrinkage is reached after 3 dry-wet cycles for the Pisha-sandstone with < 2 mm particle size(original sandstone), for the sandstone with 0.50-1.00 mm particle size, however, its samples keep a slow contracting deposition. Interestingly, for the sandstone with < 0.25 mm particle size, the soil compactness achieves the maximum value at the 3rd cycle. On this basis, a direct shear device is applied to determine the shear strength of Pisha-sandstones. Under the same vertical load, the shear strength of the stone sample with <2 mm particle size increases with increasing number of cycles, but the maximum increment in the strength is exhibited in 1-3 cycles, and then the strength get large slightly. The shear strength of the sample with 0.50-1.00 mm particle size rises slowly and steadily with increasing number of cycles. The shear strength of the samples 0.25-0.50 mm and <0.25 mm particle sizes decreases a little initially then increases a bit and finally becomes saturated.. For the samples with <2 mm and 0.50-1.00 mm particle sizes, their internal friction angle increases with increasing number of cycles; for the samples with 0.25-0.50 mm and <0.25 mm particle sizes, however, the angle hardly changes with the number. For the samples with <2 mm and 0.50-1.00 mm particle sizes, the cohesion force increases firstly and keep flat basically; the samples with 0.25-~0.50 mm and <0.25 mm particle sizes, the force decreases initially then shows a small increase.
邬尚贇, 李晓丽*, 常平, 李明玉, 陈溯航. 鄂尔多斯红色砒砂岩干湿循环作用下力学性能试验研究[J]. 排灌机械工程学报, 2018, 36(7): 625-631.
WU Shangyun, LI Xiaoli*, CHANG Ping, LI Mingyu,CHEN Suhang. Experimental study on mechanical properties of red Pisha-sandstone under wet-dry cycles in Ordos. Journal of Drainage and Irrigation Machinery Engin, 2018, 36(7): 625-631.
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