谈罗夫河上游水土流失治理对策

对罗夫河上游水土流失形成的原因、危害进行了全面详细的分析,提出了切实可行的治理措施和对策,并经实践证明,治理后的区域初步形成了水土保持生态防护体系,控制了水土流失,实现了水土资源的持续利用。     

黄河兰州段泥沙特征对氨氮降解的影响

通过室内模拟试验,研究了不同含沙量、不同粒径的黄河泥沙对水中氨氮降解速率与过程的影响。结果表明：在0～10g／L内,随着泥沙含量的增加,氨氮的降解速率变大;含沙量一定,泥沙粒径越小,氨氮的降解速率越快;相同泥沙含量下,原泥沙对氨氮降解的促进作用要优于清洗后的泥沙。     

黄河三角洲改性含盐水泥土搅拌桩耐久性研究

通过室内试验,研究了黄河三角洲含盐水泥土的劣化规律以及粉煤灰和矿渣微粉对其劣化的抑制效应,并利用X射线衍射（XRD）和扫描电镜（SEM）对劣化机理及外加剂的改性机理进行了分析.结果表明：地下盐水环境对黄河三角洲水泥土有较强的腐蚀作用,其90,180d龄期的抗压强度分别降低了18.5%,21.6%;掺加粉煤灰对黄河三角洲含盐水泥土的早期强度不利,但其后期强度会持续增加;掺加矿渣微粉对黄河三角洲含盐水泥土强度有明显的提升作用,并对其劣化有显著的抑制作用.为防止黄河三角洲含盐水泥土劣化,工程中建议用粉煤灰和矿渣微粉等质量替代60%的水泥,而且矿渣微粉掺量不少于40%.     

黄河口入海泥沙沉积固结过程长期现场观测研究

根据2004年4月至2009年6月在黄河口潮坪进行的长期现场观测试验结果,研究了黄河泥沙沉积后的固结过程。研究发现：入海泥沙沉积后,强度呈线性增长,孔隙水压力消散曲线符合指数模型,5 d内固结基本完成呈现似超固结状态,沿深度方向强度出现分层现象,并逐渐非均匀化。沉积后的泥沙在自重应力和海洋水动力的长期作用下,土体的强度呈现增长-降低-增长的趋势,沿深度非均匀性提高。首次揭示了黄河入海泥沙的快速固结特性及形成的沉积物强度随时间与空间的非均匀性变化规律。     

黄河三角洲地区吹填土地基处理思路初探

为了解决黄河三角洲地区的吹填土地基处理问题,本文以某项工程实例为例,通过分析比较三种常用的施工方法,探讨了适合黄河三角洲地区的吹填土地基处理的最好方法。     

Effect of different land use on soil erosion in the pre-alpine fringe (North-East Italy): Ion budget and sediment yield

Data concerning ion budget from rainfall, runoff and soil loss measurements from two experimental plots located in North-East Italy, under different land cover (beech forest and vineyard, respectively), are reported. The chemical composition of rainfall, soil solution and runoff was determined to study the solute cycle within the soil, and the relationships between water, soil and vegetation. The forest ecosystem is more prone to acidification than the agricultural one; the elemental concentration of runoff water is considerably lower than that of soil solution. Comparing the ion input (rainfall) and output (runoff) at the two sites, it was possible to estimate the ion budget in the two soil-vegetation systems. The runoff amount and the ion balance are related to rainfall volumes and composition; the measured runoff under vineyard is 59% in comparison to the one under beech. The soil loss at the two experimental sites (170 kg/ha and 132 kg/ha, respectively) is quite limited. The measured sediment yield of the two catchments (0.24-0.19 t/ha/year, respectively) is consistent with data reported for native forests of western Europe. Comparing rainfall and soil loss at the two sites proved that maintenance of some form of land cover is advisable if runoff and erosion are to be minimized. In the European context, where the most important consequences of erosion are sedimentation downstream and loss of productivity, this type of data will yield valuable information for the understanding of such processes occurring at catchment scale, and will help policy-makers develop appropriate programs for the territory safeguard.     

黄河三角洲软弱土层中的深基坑支护

黄河三角洲地区土质大部分为粉质粘土，粉土，粉砂，地基土承载力较低，城市地下水位较高。本文以所承建的东胜石油公司综合楼基坑支护方案为例，介绍在黄河三角洲地区，采用钻孔灌注加锚杆加深层搅拌桩止水帷幕进行基坑支护工程的设计施工经验。实践证明，所选定的基坑支护和施工方案是成功的，具有形式简单，受力明确，支护可靠的优点，本工程基坑支护是对黄河三角洲软土条件下深基坑支护形式的一种探索，可供类似工程参考。     

黄河大堤土体三轴抗拉试验研究与应用

土体的抗拉特性与土堤裂缝的产生直接相关,因此,正确认识土的抗拉特性和准确测定抗拉强度指标就显得十分重要。在土体强度特性的研究中,过去多侧重于抗压强度和抗剪强度,对抗拉强度的研究较少。针对黄河大堤典型土质开展了三轴抗拉试验研究,得出了许多有益成果,并就具体应用方法进行了探讨。     

贫困的城市群带如何发展——黄河上游城镇密集区发展透视

黄河上游城市群带是指兰州、西宁两个省会城市及周围的城镇密集区 ,通过分析该城市群带的基本情况和特点 ,对发展中的问题进行透视 ,提出黄河上游城市群带的发展格局 ,探索在国家西部大开发的战略决策指引下 ,城市群带发展的目标、途径和动力机制     

山东黄河冲积区杂填土地基处理实例分析

杂填土的地基处理是目前城市建设中经常面对的问题。山东黄河冲积区杂填土地基具有"浅埋地下水位"和"杂填土下仍分布软弱土层"两个典型特征,这影响着地基处理方法的选取、处理深度的设计、材料和施工机械的选择。根据本区的两个工程实例的勘察资料和建筑物特征,主要分析评价了CFG复合地基、级配砂石换填垫层法和柱锤冲扩桩复合地基3种地基处理方法处理杂填土的适用性。主要从地基处理方法的选用过程、加固机理和计算等方面总结了相关实践经验。     

祁连山黑河上游地区沉积变质型铁矿成矿地质条件分析

文章初步总结了黑河上游地区铁矿分布特征,按其地理分布、成矿时代、含矿建造及成矿地质特征,可划分为走廊南山铁矿带(北带)和托勒山铁矿带(南带)两个成矿带,含矿岩系为泥钙质硅质板岩,层位延伸较稳定,具有一定的层控性,矿石具明显层纹状、条带状构造,其铁矿床成因类型为热水沉积变质型。通过对矿床成因和成矿地质条件分析研究,总结出了该地区成矿找矿模式,提出了进一步的找矿方向。     

植被护坡在路基边坡水土流失治理中的应用

从水土流失的诱发原因和危害入手,分析了在路基工程中植被护坡技术的作用机理、具体特点、实施方法,指出该方法在达到防护要求的同时可兼顾经济、生态环境效益,值得推广。     

The role of geosynthetics in erosion and sediment control: An overview

The use of geosynthetic erosion and sediment materials continues to expand at a rapid pace. From their early beginnings in the late 1950s, geosynthetic materials today are the backbone of the erosion and sediment control industry. Geosynthetic components are an integral part of erosion and sediment materials ranging from temporary products such as hydraulic mulch geofibers, plastic erosion control meshes and nettings, erosion control blankets and silt fences to high performance turf reinforcement mats, geocellular confinement systems, erosion control geotextiles and fabric formed revetments. This paper provides a brief overview of these materials and concepts.     

内蒙古乌尔吉地区水系沉积物工作方法及应用

介绍了内蒙古乌尔吉地区的地质条件,利用水系沉积物,对该地区进行了地球化学勘查,分析了各元素在水系沉积物中的分布特征,结果显示:区内As,Ag,Bi,Zn,Pb,Sb元素相对富集且分布不均匀,有成矿可能;Cu,Au元素虽无明显富集,但有较强的分异性,也有成矿可能;赋矿地质体为晚二叠世林西组、中二叠世哲斯组。     

抽黄灌区泥沙问题的调查与思考

详细介绍了黄河小北干流泥沙淤积的特点及其对东雷抽黄灌区的危害,提出了解决泥沙问题的步骤和措施,论述了在渠首运用先进的自排沙廊道技术解决粗泥沙的重要性、可行性和必要性,以期从源头上解决粗泥沙问题。     

Sorption and accumulation of cadmium in the sediment of the Tama River

Cadmium contents in the water and the sediment samples collected from the Tama River and several branches were measured. Cadmium (above 0.005mgl⁻¹) was detected in only four of the water samples, while the sediment samples showed cadmium content of 1.0–9.8 μg g⁻¹ dry sediment. Cadmium concentration in the sediments of the main stream was correlated against ignition loss of the samples and it was found that 1 g of ignition loss (organic matter) corresponded to 35 μg of cadmium.The batch adsorption experiment in the laboratory using an aqueous solution of cadmium for 14 sediment samples with a higher concentration of cadmium indicated that the amount adsorbed by the sediment is highly dependent on the ignition loss. The amount adsorbed on unit mass of ignition loss q_IL could be correlated by a Freundlich-type equilibrium relation as where C is the equilibrium concentration in the aqueous phase ranging between 7 × 10⁻³ and 10 mg l⁻¹, while k_IL and n are equilibrium constants.The adsorption rate measurement showed that the intraparticle diffusion coefficient of cadmium in the sediment was about 1.1 × 10⁻⁶ cm²s⁻¹, which is of a reasonable order of magnitude assuming the pore diffusion mechanism inside the particle.The results suggest that suspended solid particles of high organic content in flowing water contribute significantly to the transport of cadmium along the river.     

Understanding the combined influence of fine sediment and glyphosate herbicide on stream periphyton communities

Pesticides and deposited fine sediment have independently been associated with changes in relative abundance and species richness in aquatic ecosystems, but the interplay between these two stressors in agricultural streams is poorly understood. A 28-day experiment in outdoor stream mesocosms examined the effects of four levels each of fine sediment coverage (0, 25, 75, 100%) and glyphosate-based herbicide concentration (0, 50, 200, 370 μg/L) on periphyton communities (algae and bacteria) in a fully factorial, repeated-measures design. Our aims were to determine whether (i) increased levels of sediment and glyphosate had individual and/or additive effects, (ii) increased sediment reduced the toxicity of glyphosate (antagonistic multiple stressor interaction), or (iii) sediment-adsorbed glyphosate prolonged the effects of exposure (synergistic interaction). We also assigned all algal taxa to three ecological guilds (low-profile, high-profile and motile growth forms) and separately determined their responses to the treatments. As individual stressors, sediment addition affected all algal community-level metrics, whereas glyphosate addition only affected algal community evenness. Bacterial taxon richness was unaffected by either stressor. In combination, however, significant overall sediment by glyphosate interactions were detected, demonstrating synergistic (algal evenness, high-profile and motile guilds) or antagonistic effects (low-profile guild). Our experiment underscores the importance of considering both structural and functional indicators, including algal guild representation, when assessing the mechanisms by which periphyton communities respond to multiple stressors.     

黄河泥砂-粉煤灰蒸压砖的研制

以黄河泥砂、粉煤灰为主要原料,采用化学激发方法生产蒸压砖.通过正交试验,确定了蒸压砖的最佳配比为m(泥砂):m(粉煤灰)=1:2、骨科掺量20%、水固比1:4、困料时间10 h、成型压力16 MPa,其性能达到JC 239--2001<粉煤灰砖>规定的MU20级砌墙砖的要求.     

黄河的治理开发与小浪底工程

据新华社消息,2002年10月16日黄河水 利委员会宣布,黄河首次调水调沙试验获得圆满成功。当年7月4日至15日进行的这次试验,利用小浪底水库人造洪水,以每秒 2600 m~3的大流量,持续放水11天(总用水量 11.5亿 m~3),对黄河下游这段“地上悬河”进行冲刷减淤。在原始河床上,进行如此大规模的调水调沙试验,不仅在世界水利史上是第一次,也是我国黄河治理开发的新的     

喷钢纤维混凝土在引黄工程中的试验与现场应用

本文介绍了山西万家寨引黄工程总干线一、二级泵站C40喷钢纤维混凝土的试验及现场应用的实际情况。通过实际施工应用,概括总结了几点建议和结论。