不同加载速率和地基处理方式下软土地基稳定性的研究

考虑到公路工程建设过程中软地基的稳定性直接影响公路工程的安全性,提出了基于不同加载速率和地基处理方式下软土地基的稳定性研究方法。结合土体弹塑性模型,利用三维有限元数值分析方法对不同工况下软土地基的结构稳定性进行仿真计算。算例结果表明,软土地基的形变速率大小同地基所处的状态稳定等级并无紧密联系,需考虑多种因素后综合决定。而加载速率对软土地基的变形速率影响明显,在实际工程应用中,软土地基的不同处理方式将对其稳定性有重要影响,地基排水性好,将大幅提升软土地基的稳定性,且其稳定性不宜采用单一的变形速率指标来界定。研究可为软土地基下的工程监测提供参考。     

道路软基处理水泥土室内配比试验研究

通过室内配比试验了解掺灰量,龄期和土质对水泥土抗压强度的影响,为软基处理水泥土的设计和施工提供科学依据。     

九里山煤矿区土壤重金属污染状况研究

为了研究煤矿的长期开采活动对矿区土壤重金属污染的影响,以河南省煤炭基地九里山矿区为试验区,科学系统地进行土壤采样,对矿区土壤中的重金属元素As,Cr,Cd,Ph,Hg进行分析。结果表明：矿区土壤重金属综合污染程度达到了Ⅲ级轻度污染。     

丛枝菌根真菌在有机污染物污染土壤植物修复中的应用

综述了丛枝菌根真菌-植物体系在有机物污染土壤修复中的效果;分析了丛枝菌根真菌促进植物修复的机理;并探讨了影响丛枝菌根真菌在有机物污染土壤植物修复作用的因素。文章最后总结了目前这一技术存在的问题,并提出了相关建议。     

西山天然草地土壤——菊科植物系统铅铬分布特征

通过对昆明西山菊科植物和天然草地土壤中铅、铬含量的测定,再经统计学分析,结果表明昆明西山受试植物对铅富集能力比对铬强,其中有5种植物对铅的相对吸收系数Ar〉1表现对Pb的富集,余下9种则表现对Pb的稀释。受试菊科植物中除了风毛菊外,对铬的相对吸收系数均小于1,呈现出铬在土壤配分关系中的稀释作用。     

水性聚氨酯聚丙烯酸酯细乳液的制备及在调湿涂料中的应用

首先以聚氧化丙烯二醇(PPG)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)为主要单体,甲基丙烯酸羟乙酯(HEMA)为接枝试剂,合成了接枝聚氨酯预聚体(PU-HEMA),进一步与丙烯酸酯进行共聚反应,制备了水性聚氨酯/聚丙烯酸酯(PU-PA)细乳液。考察了单体用量及PA/PU质量比对乳液性能的影响,发现DMPA、HEMA最佳用量分别为3%和6%。采用FTIR、TG、SEM对PU-PA进行了表征。然后以PU-PA为成膜物,硅藻土、膨润土等为颜填料,所制备的PU-PA调湿涂料(PU-PA-C)性能达到国家内墙涂料和建筑涂料标准,其耐洗刷性大于900次,最大吸水率达到206%。该涂料吸/放湿(水)性能强,可用于室内调湿涂料的涂刷。     

Accurate Determination of Moisture Content of Organic Soils Using the Oven Drying Method

Abstract

The accuracy of moisture content values determined for organic soil using the oven drying method is dependent on the oven drying temperature. Some charring of the organic fraction occurs at the standard oven drying temperature of 110 ± 5°C; pore water remains in the soil when temperatures below 100°C are used. A new technique to determine the specific oven drying temperature that yields the correct value of the moisture content for organic soils is presented. Routine moisture content tests should be conducted at the standard oven drying temperature; moisture content values determined on the basis of the recommended oven drying temperature of 60°C include a larger error. A moisture content parameter is introduced to facilitate direct comparison of moisture content values calculated on the basis of different oven drying temperatures.     

Phosphorus content in soil, uptake by plants and balance in three European long-term field experiments

The fate of phosphorus (P) derived from mineral fertilisers and organic manures, and the effective P balance, have been assessed in three long-term field experiments at Rothamsted (UK), Bad Lauchstaedt (Germany) and Skierniewice (Poland). This paper discusses the plant availability, uptake and overall utilisation of P over the last 30 years, based on soil test P availability indices and crop analyses determined by the standard methods used in each of the three countries. The data suggest that differences in soil type significantly influence the dynamics of P at the three locations, but most significantly between a loess Chernozem at Bad Lauchstaedt with a high organic matter content and the soils at the other two locations which have a low organic matter content. The application of P either as inorganic fertiliser or organic manure had a considerable influence on the availablity, uptake, leaching or fixing of P, but the crop recovery rate of P from mineral fertiliser did not exceed 35% with the smallest recovery (average 18%) occurring in the soil with the highest clay content at Rothamsted. At Bad Lauchstaedt and Rothamsted the most efficient utilisation of P (averages of 47% and 37%, respectively) was from soils treated with farmyard manure (FYM), with the greater quantity of P either leached or fixed (8 and 25 kg ha^-1 y^-1, respectively) occurring in soils treated with superphosphate. At Skierniewice, however, the reverse was true. Overall, the most efficient crop utilisation from mineral P (30% average) was from the loamy sand at Skierniewice. P balances for the three locations show that quantitatively, for the same P input, the amount of P either leached from or fixed in the plough layer of Broadbalk field, Rothamsted, was 2–3 times greater than at Skierniewice and 3–6 times greater than at Bad Lauchstaedt. The results suggest that differences in the soil physico-chemical properties, climate, the availability of other major nutrients, and the form in which P is applied, all influence the effectiveness of P fertilisation and P balance. The investigation highlights the importance of maintaining long-term field experiments and archived soil and crop samples on a world-wide basis for understanding nutrient cycling and fertility dynamics.     

二灰改良土在高速铁路路基中的应用研究

基于高速铁路路基对填料的严格要求 ,改良土成为高速铁路不可回避的问题。结合秦沈快速铁路工程实际 ,进行了石灰粉煤灰改良土的物理力学特性试验。试验表明 ,二灰改良土用作高速铁路路基基床底层材料是可行的     

锌肥有效施用的土壤条件研究

通过田间试验、相关分析研究了松嫩平原黑土和黑钙土的锌肥有效施用条件。结果表明 :当土壤 p H>7.2、石灰含量 >3.9%、砂粒含量 >40 %、代换量 <15 cm ol/ kg、有机质含量 <2 %、土壤有效锌含量低于缺锌临界值0 .8m g/ kg时 ,施用锌肥具有明显的增产效果。而在高磷情况下会降低土壤锌有效性 ,易引起玉米缺锌加重。吉单10 1和四单 8两个玉米品种对锌缺乏最为敏感。