Test study of high liquid limit clay modified by quick lime used as sub-grade material

Through laboratory test, the relationships among change of compactibility, liquid/plastic limit, free swell, swell ratio without load, california bearing ratio (CBR) and soakage (after being soaked in water), and mix-ratio of quick lime and time were studied. The results show that optimum water content, plastic limit and CBR of high liquid limit clay improved by quick lime increase with the increase of mix-ratio of quick lime, while the maximum dry density, liquid limit, plasticity index, soakage (after being immersed in water), free swell, and swell ratio without load decrease with the increase of mix-ratio of quick lime. Plastic limit of high liquid clay improved by quick lime gradually increases with time, while the liquid limit, plasticity index, free swell and swell ratio without load gradually decrease with time. When the mix-ratio of quick lime exceeds 2%, after 14 d, swell ratio without load of the improved clay is zero, its free swell is about 30% of that of untreated soil, and its plasticity index is less than 26 for sub-grade material, satisfying the requirement by 'Specifications for Design of Highway Subgrade'.

5种废电池浸泡液对日本三角涡虫生存与摄食的影响

背景与目的:涡虫对水质变化敏感,通过观察废电池浸泡液对日本三角涡虫(Dugesia japonica)生存与摄食的影响探讨涡虫作为指示动物检测废电池污染的可行性。材料与方法:制备白象牌普通型电池(BX1)、白象牌低汞型电池(BX2)、南孚牌无汞碱性电池(NF)、金强牌无汞电池(JQ)和松下牌无汞电池(SX)废电池浸泡液,每种浸泡液设未稀释组、稀释10倍组、稀释50倍组、稀释100倍组和稀释500倍组,另设矿泉水为对照。将日本三角涡虫分别放入其中饲养,观察废电池浸泡液对他们生存与摄食的影响。结果:5种废电池浸泡液均对涡虫产生不同程度的致死和抑制摄食作用。与对照组比较,在稀释50倍浸泡液中饲养96h,SX无显著致死毒性(P>0.05);NF、BX1、BX2和JQ致死毒性十分显著(P<0.01),致死毒性大小依次为:NF>BX1>BX2≈JQ>SX。同种电池浸泡液浓度越大,对涡虫生存的影响越大。涡虫在稀释50倍浸泡液中饲养50min,其5种废电池浸泡液均明显抑制摄食(P<0.01),其抑制摄食的强度依次为:NF>JQ>BX2≈BX1>SX。结论:用涡虫监测废电池对水质的污染具有一定的应用价值。

红钢HPB235铸坯表面夹渣原因分析

2008年9月，昆钢红钢HPB235钢坯出现严重的表面夹渣，经过工艺研究和统计分析，找到了出现问题的主要原因是钢水【Mn】／【Si】低，钢水流动性差，生成了大量的高熔点氧化物浮渣，未能及时捞净，在结晶器弯月面处冷凝成团而形成。红钢据此采取相应的措施，铸坯质量明显改善。