钢塔用高强度拉索的组成

本文全面地阐述了钢塔用高强度拉索系统7个部分组成的作用和特点,介绍了国产标准件的性能及其接近国际水平的相配套技术,可供建设、设计和施工部门提高钢塔安全水平作依据。最后,本文推荐用此技术,可推广作跨江大桥的小吊索用。

高碳铬铁渣制备镁橄榄石-尖晶石复相材料的性能研究

以高碳铬铁渣为主要原料制备了镁橄榄石-尖晶石复相材料,研究了热处理温度(1150、1200和1250℃)对复相材料性能的影响。结果表明:高碳铬铁渣中含有发育良好的镁橄榄石及尖晶石,可作为镁橄榄石-尖晶石复相材料的支撑骨架;不同热处理温度会显著影响试样中物相的含量,试样中存在网状结构的尖晶石晶体可提高试样的抗热震性;尖晶石相的存在有利于固溶游离的铬离子,随着热处理温度的升高,铬离子浸出浓度减小;当热处理温度为1200℃时,试样的综合性能最好,常温耐压强度达108.8 MPa,抗热震性达到8次,总铬离子(Cr^(3+)、Cr^(6+))浸出质量浓度为0.14 mg·L^(-1)。

Test of subcritical crack growth and fracture toughness under water-rock interaction in three types of rocks

The subcritical crack growth and fracture toughness in peridotite, lherzolite and amphibolite were investigated with double torsion test. The results show that water-rock interaction has a significant influence on subcritical crack growth. With water-rock interaction, the crack velocity increases, while the stress intensity factor declines, which illustrates that water-rock interaction can decrease the strength of rocks and accelerate the subcritical crack growth. Based on Charlse theory and Hilling & Charlse theory, the test data were analyzed by regression and the correlation coefficients were all higher than 0.7, which shows the correlation is significant. This illustrates that both theories can explain the results of tests very well. Therefore, it is believed that the subcritical crack growth attributes to the breaking of chemical bond, which is caused by the combined effect of the tensile stress and the chemical reaction between the material at crack tip and the corrosive agent. Meanwhile, water-rock interaction has a vital effect on fracture toughness. The fracture toughness of samples under atmospheric environment is higher than that of samples immersed in water. And water-rock interaction has larger influence on fracture toughness in amphibolite than that in peridotite and lherzolite.