有机质对草炭土物理力学性质影响的机理分析

草炭土的有机质含量是决定其物理、力学性质的主要因素。通过对草炭土有机质含量和物理力学指标相关特征的研究,对草炭土的压缩、强度特性在不同有机质含量下产生的力学效应机理进行了分析。结果表明：由于有机质疏松的海绵结构及胶结作用在草炭土团聚体中的主导作用,使有机质对草炭土物理力学的相关指标和力学效应均有明显的控制作用。有机质含量的增加使草炭土的压缩性增大,固结系数降低,渗透性下降,对主固结产生很大影响,同时也使有机质中腐殖质的胶结作用相应增强,从而使黏聚力相应增加。上述特性的研究,对于草炭土地区地基处理方案的选择有指导意义,同时为深入研究草炭土的结构特性奠定了基础。     

固定化微生物修复石油污染土壤特性试验

利用梯度稀释法分离筛选原油降解混合菌,采用吸附法将混合菌固定在砾石和草炭土上,探讨固定化混合菌对土壤石油烃的去除效果。结果表明:分离得到的混合菌8-2,菌群结构简单,石油烃降解率可达52.1%。与砾石相比,草炭土所固定的微生物数量和活性较高,可达1.3×108 cfu/g和0.24A487。草炭土固定的混合菌8-2,修复含油量为30g/kg的污染土壤30d后,石油烃降解率达28.4%,高于游离降解菌的24.3%。固定化载体草炭土在修复过程中起到了微生物缓释剂的作用。     

新疆昭苏县草甸土的工程性质试验研究

由于目前对草甸土的工程性质了解甚少,一方面引起了草甸土与草炭土、泥炭等的混淆,另一方面导致了在设计过程中不知如何选择相应的处治措施。鉴于此,以新疆伊犁昭苏县草甸土层为研究对象,参照一般土体的室内土工试验方法,测试了草甸土的比重、重度、烧失量、渗透系数、抗剪强度、无侧限抗压强度等物理力学指标,并将试验结果与国内外草炭土、泥炭、泥炭质土的工程特性进行了对比分析。结果表明:按照有机质含量分类,新疆昭苏县草甸土属于泥炭质土;其含水率处于泥炭质土的低限附近,而重度则高于一般泥炭和泥炭质土的重度,具有较好的渗透性、很高的压缩性;草甸土中的草根可以显著提高土体的黏聚力,但对内摩擦角的影响不明显;无侧限抗压强度试验过程中草甸土未发生类似于一般黏土的剪切破坏,而是产生了很大的压缩变形和鼓胀变形;草甸土在受荷载后主固结沉降完成很快,其主固结系数随着固结压力的增大线性减小;当固结压力超过100 k Pa时,草甸土的主固结比较小,说明此时草甸土的次固结变形量不容忽视,地基沉降计算中应予以考虑。     

石灰改良膨胀土胀缩性质和强度性质的研究

本文根据南宁膨胀土和上思膨胀土掺入石灰的室内试验结果，研究了石灰改良膨胀土胀缩性质、强度性质及其它工程性质，所得出的结果，可为膨胀土地区地基工程和边坡工程参考使用。     

石灰改良膨胀土胀缩性质和强度性质的研究

本文根据南宁膨胀上和上思膨胀土掺入石灰的室内试验结果，研究了石灰改良膨胀土胀缩性质、强度性质及其它工程性质，所得出的结果，可为膨胀土地区地基工程和边坡工程参考使用。     

无公害西红柿栽培管理与病虫害防控要点分析

<正>西红柿别名番茄,味道鲜美,营养价值高,得到了消费者欢迎。随着人们生活水平的提升,对无公害西红柿需求量增加,但种植户因未掌握栽培管理关键点,故而品质低下,产量不高。而本文则对西红柿无公害栽培管理要点进行推广,以供参考。1准备工作1.1营养土配置本着因地制宜原则进行种植要素的配置,如肥料、草炭、田地类型等,且结合设计比例完成营养土制备,促其和后期使用要求相符。1.2播种床     

模型固废三轴固结不排水剪试验及孔压分析

采用草炭、石英砂、高岭土按质量比0.5∶1∶1及1∶1∶1人工配制模型固废。通过应力路径三轴仪,对模型固废开展了固结不排水三轴剪切试验研究,获得其强度特性及孔压变化特性。通过两种不同草炭含量模型固废试验结果对比表明,高草炭含量模型固废在相同应变条件下的剪应力比低草炭含量的大,说明草炭含量增加将使得固废内部颗粒相互作用增强,更有利于其强度发挥。根据不排水剪切过程中孔压的变化特性,获得了草炭含量对孔隙水压力系数的影响规律,得出了固废达到破坏条件时该系数的范围,并与以往真实固废的试验结果进行了对比。     

高桩码头体系被动桩特性分析

针对岸坡变形作用下高桩码头的受力特性,考虑到桩土的共同作用,桩土接触面的非线性行为及地基土弹塑性性质,建立了高桩码头结构体系的有限元模型,并采用弹塑性数值分析方法,研究了码头结构的受力变形规律,得出了一些有参考价值的结论。     

冻融对河道淤泥气泡混合土性质影响试验研究

为了研究冻融作用对具有高含水特征河道淤泥气泡混合土(FMLSS)性质的影响,利用室内试验对河道淤泥气泡混合土在冻融条件下的物理力学性质进行了试验研究。试验结果表明,冻融作用对FMLSS的体积、密度和强度等物理力学性质影响比较明显,且受影响程度与冻融循环次数、气泡掺入比、水泥掺入比、含水量及表面暴露条件等因素密切相关。     

陈垃圾土的压缩性试验研究

首先介绍了重庆市主城区填埋场的现状，论述了深入研究陈垃圾土压缩特性的重要性。作者在简要总结了采样场内陈垃圾土的基本物理性质后。通过室内侧限压缩试验(亦称固结试验)，得出了描述陈垃圾土压缩性质的基本参数，如αv、Es、mv和Cc等，试验表明陈垃圾土是一种不同于常见土类的高压缩性欠固结土，试验结果可为填埋场再利用和已封闭填埋场的沉降计算提供依据。     

Link between DOC in near surface peat and stream water in an upland catchment

Hydrologic transport of dissolved organic carbon (DOC) from peat soils may differ to organo-mineral soils in how they responded to changes in flow, because of differences in soil profile and hydrology. In well-drained organo-mineral soils, low flow is through the lower mineral layer where DOC is absorbed and high flow is through the upper organic layer where DOC is produced. DOC concentrations in streams draining organo-mineral soils typically increase with flow. In saturated peat soils, both high and low flows are through an organic layer where DOC is produced. Therefore, DOC in stream water draining peat may not increase in response to changes in flow as there is no switch in flow path between a mineral and organic layer. To verify this, we conducted a high-resolution monitoring study of soil and stream water at an upland peat catchment in northern England. Our data showed a strong positive correlation between DOC concentrations at -1 and -5 cm depth and stream water, and weaker correlations between concentrations at -20 to -50 cm depth and stream water. Although near surface organic material appears to be the key source of stream water DOC in both peat and organo-mineral soils, we observed a negative correlation between stream flow and DOC concentrations instead of a positive correlation as DOC released from organic layers during low and high flow was diluted by rainfall. The differences in DOC transport processes between peat and organo-mineral soils have different implications for our understanding of long-term changes in DOC exports. While increased rainfall may cause an increase in DOC flux from peat due to an increase in water volume, it may cause a decrease in concentrations. This response is contrary to expected changes in DOC exports from organo-mineral soils, where increase rainfall is likely to result in an increase in flux and concentration.     

软土地基工程勘察技术要点及问题分析

软土指天然孔隙比大于或等于1.0且天然含水量大于液限的细粒土,包括淤泥、淤泥质土、泥炭、泥炭质土等,软土往往给工程建设造成了不利影响。本文对软土地基的危害进行了分析,对软土地基工程的勘察和地基处理进行了探讨。     

吉林省CNG汽车加气站的发展趋势

介绍了吉林省CNG汽车加气站的发展现状,指出吉林省CNG汽车加气站供气不足、天然气汽车市场存在空白等问题。从建设模式、储气量和经济性方面对L—CNG汽车加气站与CNG汽车加气站进行比较,认为L—CNG汽车加气站在经济性和安全供气等方面具备优势。分析了L—CNG汽车加气站的市场前景,认为L—CNG汽车加气站是吉林省汽车加气站的发展趋势,建议若条件允许,优先建设L—CNG汽车加气站。     

Influence of zeolite on the availability of radiocaesium in soil to plants.

Plant availability of radiocaesium is usually high immediately after incorporation in a soil. However, for some Swedish soils, e.g, peat soils, a high radiocaesium uptake in plants has also been observed during a second growth period after contamination. For these soils the reduction in the plant availability of the nuclide seems to be a slow process. In the last two years the mineral zeolite has become of interest and has been tested as a caesium binding agent in both animal and in soil-plant systems. The aim of this study was to evaluate the time dependency and the effect of zeolite on the plant availability of radiocaesium in a peat soil-plant system. The pot experiments designed for this purpose were carried out in a climate chamber, using winter wheat as the test crop. A significant reduction of the uptake of 134Cs was obtained in wheat when increasing amounts of zeolite were added. This reduction in plant uptake, up to a factor of 8, might depend on two factors. One is that zeolite has reduced the activity concentration of radiocaesium in the soil solution available to the plant roots. The other is that the potassium added with the natural zeolite increased the degree of dilution of caesium in the soil solution. Also, increasing equilibration time for caesium in soil before sowing brought about an effective reduction in the caesium uptake.     

吉林省天然气产业发展形势

分析了吉林省天然气产业发展现状,总结了存在的问题,提出了有序发展天然气产业的建议,展望了全省天然气发展形势。     

Geo-engineering properties and settlement of peaty soils at an industrial site (Turkey)

Peats consist of the partly decomposed remains of vegetation, which have accumulated in waterlogged areas. They are often unsuitable for supporting structures of any kind due to their high water content, high compressibility, low shear strength and high degree of spatial variability. The paper reports a preliminary study on peats from industrial sites in the city of Kayseri, Turkey. The soils in the study area are classified as peat to muck. The peats are fibrous at shallow depth and become amorphous as they extend to some 8 m depth. The ranges of geo-engineering properties are generally consistent with those reported in the literature, with some variation due to their higher mineral soil contents. The behavior of the peats is essentially frictional, with high friction and relatively small cohesion. The direct shear tests yielded higher shear strengths than those from the triaxial tests, due to the fact that the peat specimens used in the direct shear tests were rich in fibers and mineral soils. Back analysis of the settlement of heavy rolls of metal wires laid on the peat generally confirmed the consolidation properties of the soil determined in laboratory.     

Fractionation of total water soluble aluminium in extracts from peat and sand soil samples by ion‐exchange method followed by GF AAS

This study attempted the use ion‐exchange resins in order to fractionate total water soluble aluminium in extracts collected over acidic peat and alkaline sand soils. Extraction was performed in neutral and acidic conditions in order to imitate the behaviour of natural or acid rains. The total aluminium content in soil extracts and fractions was determined by graphite furnace atomic absorption spectrometry (GF AAS). In order to retain aqua Al³⁺ and hydroxycomplexes of aluminium Chelex 100 was used. It was found that fractionation of the aluminium in extracts depends strictly on the type of soil. When neutral spring water was used for the extraction the content of water soluble aluminium was found to be over two times higher in case of peat soil when compared with sand soil extract. Acidification of water by addition of HNO₃ and H₂SO₄ (2:1) pronounced in much extend the extraction efficiency of aluminium only form sand soils (over 10 times) but did not change proportion in fractionation of the particular aluminium species. Admittedly in the case of peat soils no significant increase in total aluminium content was observed but the concentration of cationic forms in acidic extract increased twofold when compared with the neutral extract.     

Effect of clay content and wetting-and-drying on radiocaesium behaviour in a peat and a peaty podzol

The interaction of radiocaesium with peat under two moisture regimes was studied in laboratory experiments and by growing ryegrass in pot experiments to simulate changing field moisture conditions. A peat untreated and treated with 5% by weight of clay containing 46% illitic minerals, and a peaty podzol naturally containing 4.5% mineral matter on a dry weight basis were contaminated with (134)Cs and incubated. The soils were exposed to 8 wetting-and-drying cycles or kept constantly wet during 40 days. Extraction of the peat with 1 M CH(3)COONH(4) (pH 7) repeated after each wetting-and-drying cycle indicated increasing (134)Cs fixation with time of incubation. The peat treated with clay showed a much higher (134)Cs fixation than that without clay. The pot experiment with the incubated soils showed a (134)Cs transfer to ryegrass of the same order for the peaty podzol as for the peat treated with clay. For the peat untreated with clay the (134)Cs transfer to ryegrass was much greater. Wetting-and-drying the peat, with or without clay, increased the overall yield of grass and the concentration and uptake of (134)Cs over 5 consecutive harvests. K-fertilisation increased the yield of plant material (except for the peat with added clay), decreased the concentration of (134)Cs, but had no significant effect (p=0.05) on the resultant uptake of (134)Cs. Mixing clay with the surface layer of organic soils appears to be an effective means of decreasing radiocaesium transfer to field crops in fallout situations.     

昆明某泥炭质土深大基坑支护设计与施工技术

结合工程案例,总结了昆明泥炭质土地质条件下深大基坑的支护设计和施工的特点及难点。通过监测数据的验证,说明了环形内支撑支护体系在深厚泥炭质土地层深基坑工程中的优势。     

Land management as a factor controlling dissolved organic carbon release from upland peat soils 1: Spatial variation in DOC productivity

The importance of soil storage in global carbon cycling is well recognised and factors leading to increased losses from this pool may act as a positive feedback mechanism in global warming. Upland peat soils are usually assumed to serve as carbon sinks, there is however increasing evidence of carbon loss from upland peat soils, and DOC concentrations in UK rivers have increased markedly over the past three decades. A number of drivers for increasing DOC release from peat soils have been proposed although many of these would not explain fine-scale variations in DOC release observed in many catchments.We examined the effect of land use and management on DOC production in upland peat catchments at two spatial scales within the UK. DOC concentration was measured in streams draining 50 small-scale catchments (< 3 km²) in three discrete regions of the south Pennines and one area in the North Yorkshire Moors. Annual mean DOC concentration was also derived from water colour data recorded at water treatment works for seven larger scale catchments (1.5-20 km²) in the south Pennines. Soil type and land use/management in all catchments were characterised from NSRI digital soil data and ortho-corrected colour aerial imagery.Of the factors assessed, representing all combinations of soil type and land use together with catchment slope and area, the proportion of exposed peat surface resulting from new heather burning was consistently identified as the most significant predictor of variation in DOC concentration. This relationship held across all blanket peat catchments and scales.We propose that management activities are driving changes in edaphic conditions in upland peat to those more favourable for aerobic microbial activity and thus enhance peat decomposition leading to increased losses of carbon from these environments.