Brazilian disc tests were undertaken on a number of red sandstone samples with different water absorption ratios.The tensile strength of the red sandstone decreases as the water absorption ratio increases.The fracture...Brazilian disc tests were undertaken on a number of red sandstone samples with different water absorption ratios.The tensile strength of the red sandstone decreases as the water absorption ratio increases.The fracture surfaces of failed red sandstone discs were scanned by Talysurf CLI 2000.With the aid of Talymap Gold software,based on ISO25178,a set of statistical parameters was obtained for the fracture surfaces.The maximum peak height(S_p),maximum pit height(S_v) and maximum height(S_z) of the fracture surfaces exhibited the same decreasing trend with increasing water absorption.Sa and Sku values for the fracture surfaces showed a downward trend as the water absorption ratio increased.The fractal dimensions of fracture surfaces were calculated and found to decrease as the water absorption ratio increased.Through analysis of PSD curves,the smallest dominant wavelength was observed to reflect the roughness of the fracture surfaces.Additionally,the results suggest that the roughness of fracture surfaces becomes small as the water absorption ratio increases.展开更多
作为一种土壤改良材料,保水剂能够有效提高土壤的保水能力,改善干旱和恶劣环境下的植物生长环境,已广泛应用于农业和生态恢复领域。该研究聚焦于不同温度和冷冻条件下保水剂的吸持水性能变化,探究不同温度、冷冻方法、成分、粒径对保水...作为一种土壤改良材料,保水剂能够有效提高土壤的保水能力,改善干旱和恶劣环境下的植物生长环境,已广泛应用于农业和生态恢复领域。该研究聚焦于不同温度和冷冻条件下保水剂的吸持水性能变化,探究不同温度、冷冻方法、成分、粒径对保水剂吸持水性能的影响,通过单因素、多因素方差分析和熵权逼近理想点排序法(technique for order preference by similarity to ideal solution, TOPSIS)法,对10种保水剂的吸持水性能进行分析和研究。结果表明:1)这10种保水剂在吸水倍率方面呈现出极大的差异,为167.99~527.5 g/g,这与保水剂的主要成分密切相关,主要成分为高分子聚合物的保水剂吸水倍率较高,保水剂的主要成分对其保水性能也有显著的影响,多数复合型的保水剂在保水性能上较优;2)保水剂的吸水速率受粒径的影响较大,呈现出随粒径的增大而下降的趋势,低温会限制保水剂的吸水速率,同时,显著影响保水剂的保水性能,保水率随环境温度的上升,呈现增加趋势;3)多因素方差分析表明,保水剂的粒径对反复吸水倍率的衰减率和冷冻/冻融后的吸水倍率具有极显著影响(P <0.001),而冷冻/冻融过程同样会显著影响保水剂的吸水倍率和保水率(P <0.001)。4)通过熵权TOPSIS法分析可知,不同保水剂,在吸水、保水和耐寒性能上表现不一,以聚丙烯酸钾为主要成分的保水剂,其综合性能排序相对靠前。研究可为保水剂的应用和新型保水剂的开发提供理论依据和参考。展开更多
基金Project(E21527)supported by Open Research Fund Program of Hunan Provincial Key Laboratory of Shale Gas Resource Utilization,Hunan University of Science and Technology,ChinaProjects(51174088,51174228)supported by the National Natural Science Foundation of China+1 种基金Project(2013CB035401)supported by the National Basic Research Program of ChinaProject(2015zzts077)supported by the Fundamental Research Funds for the Central Universities,China
文摘Brazilian disc tests were undertaken on a number of red sandstone samples with different water absorption ratios.The tensile strength of the red sandstone decreases as the water absorption ratio increases.The fracture surfaces of failed red sandstone discs were scanned by Talysurf CLI 2000.With the aid of Talymap Gold software,based on ISO25178,a set of statistical parameters was obtained for the fracture surfaces.The maximum peak height(S_p),maximum pit height(S_v) and maximum height(S_z) of the fracture surfaces exhibited the same decreasing trend with increasing water absorption.Sa and Sku values for the fracture surfaces showed a downward trend as the water absorption ratio increased.The fractal dimensions of fracture surfaces were calculated and found to decrease as the water absorption ratio increased.Through analysis of PSD curves,the smallest dominant wavelength was observed to reflect the roughness of the fracture surfaces.Additionally,the results suggest that the roughness of fracture surfaces becomes small as the water absorption ratio increases.
文摘作为一种土壤改良材料,保水剂能够有效提高土壤的保水能力,改善干旱和恶劣环境下的植物生长环境,已广泛应用于农业和生态恢复领域。该研究聚焦于不同温度和冷冻条件下保水剂的吸持水性能变化,探究不同温度、冷冻方法、成分、粒径对保水剂吸持水性能的影响,通过单因素、多因素方差分析和熵权逼近理想点排序法(technique for order preference by similarity to ideal solution, TOPSIS)法,对10种保水剂的吸持水性能进行分析和研究。结果表明:1)这10种保水剂在吸水倍率方面呈现出极大的差异,为167.99~527.5 g/g,这与保水剂的主要成分密切相关,主要成分为高分子聚合物的保水剂吸水倍率较高,保水剂的主要成分对其保水性能也有显著的影响,多数复合型的保水剂在保水性能上较优;2)保水剂的吸水速率受粒径的影响较大,呈现出随粒径的增大而下降的趋势,低温会限制保水剂的吸水速率,同时,显著影响保水剂的保水性能,保水率随环境温度的上升,呈现增加趋势;3)多因素方差分析表明,保水剂的粒径对反复吸水倍率的衰减率和冷冻/冻融后的吸水倍率具有极显著影响(P <0.001),而冷冻/冻融过程同样会显著影响保水剂的吸水倍率和保水率(P <0.001)。4)通过熵权TOPSIS法分析可知,不同保水剂,在吸水、保水和耐寒性能上表现不一,以聚丙烯酸钾为主要成分的保水剂,其综合性能排序相对靠前。研究可为保水剂的应用和新型保水剂的开发提供理论依据和参考。
