Allelopathic effects of giant foxtail on germination and radicle elongation of loblolly pine seed

Water extracts of giant foxtail grass inhibited germination and radicle elongation of loblolly pine seed in a laboratory test. Most of the toxic effects came from extracts of dried foxtail tops, with lesser amounts from fresh tops and roots. Soil texture affected the phytotoxicity of the extracts. Eight chemical compounds known to be phytotoxins inSetaria were identified in extracts of foxtail leaves but could not be found in soil samples under the leaves.     

软土中的基坑支护工程实例分析

武汉某地下车库基坑处于深厚淤泥中 ,采用排桩 +土层锚杆支护与放坡 +网喷分段支护方式 ,本文根据现场地质、地形条件 ,对本工程支护过程中支护桩与土体变形作了具体分析。     

高架桥中异形板裂缝的分析与加固

从分析某高架桥中异形板板底裂缝的特点及成因着手 ,对设计与施工工艺诸方面提出防止裂缝的对策和对裂缝进行加固的全过程。     

黑土土壤质量演变初探I：不同开垦年限黑土主要质量指标演变规律

根据土壤质量的定义和研究方法 ,对黑土的主要质量指标演变规律进行初步研究。结果表明 :黑土的颗粒组成受开垦历史影响的程度较小 ,其质地没有发生显著变化 ;黑土的有机质、全氮、全硫和全磷随着黑土开垦时间的增加而不断降低 ;速效磷随黑土开垦时间的增加有增高的趋势。经过统计分析 ,黑土中粉砂(0.05～0.002mm)含量与细砂(0.25～0.05mm)和粘粒(<0.002mm)含量具有相关性,黑土有机质含量与全氮、全硫、全磷和速效钾具有明显的正相关。因此 ,初步认为黑土中粉粒和有机质含量可以作为土壤物理和养分方面的质量指标     

Predicting plant yields using soil testing for phosphorus: Effects of error in the estimation of the maximum yield on interseasonal comparisons of yield prediction

Results from long-term field experiments in south-western Australia are presented in the form of relationships between yield, expressed as a percentage of the maximum yield, and soil test for phosphorus (P) values. Maximum yields were not always indicated by well defined yield plateaux. Different methods have been used to estimate the maximum yield value which is used to calculate yield as a percentage of the maximum yield so as to remove interseasonal variation. For all of these methods and for the same site, the same P fertilizer (superphosphate), and the same plant species, the relationship between yield and soil test P differed for different years. Consequently fertilizer recommendations based on the assumption that this relationship is constant are likely to be incorrect. We therefore question the validity of the common practice in soil testing programmes of using percentage yield values to remove interseasonal variation.     

水电站施工期水土流失预测

水电站建设的水土流失问题主要体现在施工期和运行期，并以施工期的影响较为突出．如不采取必要的减免措施，将会对周围生态环境造成无法挽回的损失。本文阐述了水电站建设水土流失的几种常用的预测方法，对水土流失量进行预测，并结合具体工程实例对水电站建设过程中新增水土流失量进行了预测。     

PTC预应力管桩在软土地基处理中的施工工艺

结合PTC预应力管桩在沪宁高速公路扩建工程中的应用，从路基底板的施工、PTC预应力管桩的施工方面对其施工工艺进行了介绍，总结了PTC预应力管桩在软土地基处理中的应用优点。     

软土地基水泥搅拌桩室内配合比试验分析

对广州南沙某工程软土地基搅拌桩室内不同配比的水泥土标准试件进行对比试验,研究软土地基搅拌桩施工中水泥、石膏等添加剂的最佳配比方案,对指导搅拌桩的现场施工有着重要的意义。     

土钉支护在深基坑开挖中的应用

深圳某银行办公楼的深基坑支护采用了土钉支护，不但保证了施工质量，而且缩短了工期，减少了投资，以此工程为例介绍了土钉支护的土力学参数计算、结构设计、施工方案、技术措施和取得的显著效果。     

Geotechnical properties of the soft soil in Guangzhou College City

The paper describes some geotechnical properties of the soft soils in Guangzhou College City, China, which are difficult to both sample and test. Laboratory and in situ tests were carried out to assess the physical and mechanical indices of the soils. The data were statistically analyzed and linear regression undertaken such that equations could be developed by which the geotechnical properties of the soft soils can be predicted. The statistical validity of the degree of correlation confirmed that using these equations, the mechanical indices can be estimated from physical indices determined by routine testing.