小型水电站生命周期碳足迹研究

以某小型水电站为研究对象,采用生命周期碳足迹评价方法,综合选用各类碳足迹计算指标,对其全生命周期碳足迹进行了计算,结果显示其碳足迹总量为18 826.0 t CO_2e,其中建设阶段占84.8%,运行阶段仅占4.7%;报废拆除阶段占10.5%。该电站全生命周期的温室气体排放系数为251.35 g CO_2e/kW·h,虽然比其他大中型水电站要高,但仍远低于燃煤电厂,表明水电工程能起了到有效节能减排的效果。     

护岸工程材料综合能耗和碳排放计算及评价

如何评价护岸工程中材料的能源消耗,是护岸材料环境友好性评价的重点。通过权威部门的数据,结合护岸工程材料的典型加工工序,划分为4个阶段。通过定量计算天然建筑材料加工能耗,以及水泥、钢筋和土工合成材料的能耗,并采用通用的碳排放模式,定量计算和比较了几种典型护岸工程结构型式的碳排放值。研究表明,水下护脚工程中采用预制铰链混凝土的碳排放较大;水上护坡采用混凝土预制块的碳排放为一般干砌块石的近8倍。因此,建议从环保的角度出发,在护岸工程应尽可能减少水泥、钢筋等工业产品的使用。该研究结果为选择合适的环境友好型护岸型式和材料提供了依据。     

我罗斯萨拉托夫水库石笼护岸工程

护岸工程的结构型式多种多样，经过比较，最终选择了在俄罗斯萨拉托夫水库护岸工程中采用石笼结构的护岸型式。石笼结构物具有柔性好、耐腐蚀、抗冲能力强、能适应河床变形、经济等优点．更重要的是，它不会破坏地下水的状况，且有助于草木植物的自然生长，极为适用于护岸工程。介绍了护岸工程实施地段的工程地质构造、自然环境与气候以及工程的实施情况。     

俄罗斯萨拉托夫水库石笼护岸工程

护岸工程的结构型式多种多样,经过比较,最终选择了在俄罗斯萨拉托夫水库护岸工程中采用石笼结构的护岸型式。石笼结构物具有柔性好、耐腐蚀、抗冲能力强、能适应河床变形、经济等优点,更重要的是,它不会破坏地下水的状况,且有助于草木植物的自然生长,极为适用于护岸工程。介绍了护岸工程实施地段的工程地质构造、自然环境与气候以及工程的实施情况。     

浙江省内河航道护岸工程效益简析

内河航道护岸工程是一项具有保护农田、确保航运和行洪畅通,并兼有美化城镇村庄环境等综合效益的专项工程。我省自1982年起在原嘉兴地区试征内河航道护岸费,至1986年决定在全省范围内开征。自1986～1992年间,共征收护岸费6000余万元,新建护岸工程600余 km,采用这种“取之于民,用之于民,专款专用”的办法,促进了航道护岸工程的迅速发展,其社会和经济效益非常显著。     

节能机制下护岸工程软基处理方案评价

以盐河航道整治8标段护岸工程为例,对护岸软土地基处理的能耗构成进行了分析研究,对换填块石、水泥搅拌桩、钢筋混凝土方桩3种软基处理方案的能耗进行了定量计算,得到软基处理能耗与地基处理形式的关系。选取能耗、造价作为定量指标,施工便利性、质量控制作为定性指标,对3种地基处理方案进行综合评价。结果表明,盐河8标段的3种地基处理方案中水泥搅拌桩能耗最低,综合评价最优。论文研究成果可为护岸工程软土地基处理方案的选择提供参考。     

基于生命周期的猴子岩水电站温室气体排放分析

以猴子岩水电站为工程实例,采用生命周期评价方法,分析混凝土面板堆石坝水电枢纽工程在全生命周期内的温室气体排放,并重点考虑建设阶段、运营及维护阶段和拆除阶段。结果表明,猴子岩水电站生命周期温室气体排放系数为10.02 kg CO₂/MW·h,其中建设阶段温室气体排放约占67%,运营及维护阶段及拆除阶段仅约33%。与传统的火力发电相比,猴子岩水电站生命周期温室气体排放表现十分优异,实践证明,大力开发水电能有效的减低温室气体的排放。     

倾斜基底护岸结构稳定性分析

结合JTJ300—2000《港口及航道护岸工程设计与施工规范》中推荐的抗滑、抗倾稳定计算方法,考虑倾斜基底对护岸结构稳定性影响以及内河航道船形波等荷载作用效应,对不同倾斜基底护岸进行了受力分析,建立了基于分项系数法的倾斜基底护岸稳定性表达式。算例表明,内倾基底护岸结构有利于提高结构的抗滑稳定性。     

阿什河干流道外香坊段防洪及河道整治工程护岸型式比选

通过对阿什河干流道外香坊段防洪及河道整治工程生态护岸型式比选的简述,阐明了护岸形式比选的基本过程,同时列举了目前应用较为广泛的几种生态护岸型式,并根据其特点进行了对比总结,为相似工程的生态护岸选择提供了参考。     

挡板式护岸的设计与施工

介绍挡板式护岸的设计计算和施工方法，该护岸结构具有技术可靠，经济合理、造型美观，施工简单等特点，在太浦河工程应用获得成功，可满足杭嘉湖地区内河航道护岸要求。     

Modelling the failure modes in geobag revetments

In recent years, sand filled geotextile bags (geobags) have been used as a means of long-term riverbank revetment stabilization. However, despite their deployment in a significant number of locations, the failure modes of such structures are not well understood. Three interactions influence the geobag performance, i.e. geobag-geobag, geobag-water flow and geobag-water flow-river bank. The aim of the research reported here is to develop a detailed understanding of the failure mechanisms in a geobag revetment using a discrete element model (DEM) validated by laboratory data. The laboratory measured velocity data were used for preparing a mapped velocity field for a coupled DEM simulation of geobag revetment failure. The validated DEM model could identify well the critical bag location in varying water depths. Toe scour, one of the major instability factors in revetments, and its influence on the bottom-most layer of the bags were also reasonably represented in this DEM model. It is envisaged that the use of a DEM model will provide more details on geobag revetment performance in riverbanks.     

荆江河段生态护坡结构对近岸水流影响试验研究

为了选择固土能力强、结构稳定、生态影响小的护坡结构,以长江荆江段为例,通过护坡概化模型水槽试验,分析了不同生态护坡结构对近岸水流结构的影响。研究表明:钢丝网石笼和护坡砖本身对近岸水流流速影响较小,对结构下层的土体有较好的守护作用,但在没有辅助措施或植被覆盖的情况下,对表层土体缺乏有效的守护;植被护坡植物能减缓近岸流速、减弱水流对表层土壤的直接冲刷,但守护岸坡稳定性较差,下层土体易被掏刷。将硬质结构护岸与植被护岸相结合,可减弱表层土壤的流失并对岸坡下层土体进行有效守护。将生态型护坡结构运用到长江中游荆江河段航道整治工程中,现场应用效果较好。     

Assessment and prioritization of eco‐revetment projects in urban rivers

Ecological revetment for slope protection in urban rivers requires consideration of economic and ecological aspects and also of social aspects including recreation. Taking the Hunhe River as an example, our study established an evaluation system and a decision‐making method for evaluating and prioritizing the eco‐revetment projects. The Delphi method was used for collecting the opinions of experts, which include the relative importance of the indicators and the relative preference of the alternatives. The former was surveyed by pair comparison and processed applied analytic hierarchy process (AHP). The latter was described via linguistic variables, which need to be changed into the quantitative values for TOPSIS analysis. For that reason, we introduced the fuzzy set theory and established a fuzzy multi‐attribute decision‐making method based on TOPSIS to assess and prioritize the projects. The evaluation system includes economic, social, environment and ecological several aspects totalling eight indicators. The evaluating and prioritizing result of the projects shows that the three‐dimensional vegetation net is the best slope protection measures in the study area. The sensitivity analyses of indicator weights and different calculation methods were performed to demonstrate the reliability of the results. The sensitivity analyses indicate that construction cost and maintenance cost are dominant factors during the alternatives prioritization. The distance calculation method and normalization technique are insensitive to the prioritization results. The methodology proposed by this paper offers an effective and feasible tool for managers to evaluate and choose the optimal engineering measures of riverbank protection. Copyright © 2008 John Wiley & Sons, Ltd.     

珊瑚岛礁护岸对礁坪上极端波浪传播特性的影响

极端波浪要素是珊瑚岛礁护岸工程设计的重要参数。利用大比尺波浪水槽,采用1: 15的模型比尺开展试验,从波浪形态、增水、波速、波谱等方面研究了珊瑚岛礁护岸对礁坪上极端波浪传播特性的影响规律。护岸工程产生了明显的阻水效应:对于波浪形态,反射波的影响使得波浪在礁缘破碎更为剧烈; 显著增加了礁坪增水,最大增水值是自然地形下的4倍,影响在波周期较短时更为显著; 减小了波速约20%~35%,其影响随波周期的减小而增强; 对于波谱,护岸的存在使得波浪的非线性相互作用更加复杂,降低了波浪在礁缘处的主频能量,但同时增大了礁坪上的主频及高频能量; 护岸距礁缘距离对堤前水位具有重要影响,随该距离的增加,堤前时均水位先增加后降低。     

河流水冰沙耦合模型研究Ⅱ：验证与应用

北方河流冬季河冰运动会带来凌汛灾害威胁,研究流凌运动对水流、泥沙和河道的影响具有重要工程意义。本文在平面二维河冰动力学模型基础上,建立二维水冰沙耦合数值模型。基于三角形的非结构网格,采用具有迎风特性的Petrov-Galerkin型有限元法计算非恒定水流过程、非恒定非均匀沙输运和河床冲淤变化,利用无网格的SPH法计算河冰运动,基于河冰对岸滩的刮擦切应力计算岸坡侵蚀,再利用双泥沙休止角法分析不同含水层岸坡的稳定坡面。该模型创新性地耦合水沙理论和河冰理论,能模拟北方河流全季节及河冰全过程的水位流量波动、河冰运动、泥沙输移、河床冲淤及岸滩崩塌过程。通过实验条件下溃坝引起的岸坡崩塌侵蚀验证了模型的准确性和可靠性,研究结果显示该模型能再现水流、河冰、泥沙、河床及河岸间的复杂耦合作用,揭示河冰刮擦对岸滩侵蚀破坏的促进机理,可进一步支撑冬季河道防凌减灾和岸滩水土保持研究。     

Investigating effect of water level variation and surface tension crack on riverbank stability

During high flow season, the rise and fall of river water level could induce riverbank instability and threaten structural safety of flood-protection facilities on floodplains. Through a flume experiment, this paper investigates the influences of three factors (namely, drawdown rate of river stage, initial water elevation, and riverbank slope angle) on riverbank stability due to the fall of river water level. From the laboratory experiments it was observed that tension crack appeared in all riverbank failure cases and all failure patterns were of planar type. Moreover, this paper presents a riverbank stability analysis model that explicitly incorporates the integral effect of all forces acting upon the failure plane and tension crack. The prediction accuracy of the proposed model is examined by using experimental data obtained in this study and field data of the Hotophia Creek in the USA and the Sieve River in Italy. A comparison of model simulation results with and without considering tension crack clearly indicates the importance and necessity of including tension crack for achieving good accuracy in riverbank stability simulations. For practical application of the improved riverbank stability model, two empirical formulas for estimating tension crack location and failure plane angle were examined and modified to enhance their appropriateness in riverbank stability simulation. Finally, the improved model with the modified empirical formulas was verified to show its good prediction in riverbank stability analysis.     

堤坝护面开孔砌块抗浪稳定性试验研究

护面砌块作为堤坝结构的组成部分,其抗浪能力对堤坝的整体稳定起着重要作用。通过较大比尺物理模型,针对我国堤坝设计的具体情况,对一种新型开孔勾连块体的抗浪稳定性进行试验研究,分析砌块厚度、戗台、波浪周期等因素的影响,得到砌块抗风浪稳定厚度计算式。建议护岸设计中应采用均衡设计的理念,综合考虑波浪荷载,将其平衡分配给护面、垫层和基土,对海岸、河流、大型湖泊和水库等水利工程的护岸和堤坝抗浪稳定设计具有指导意义。     

加筋生态护坡技术的应用与发展

在越来越注重工程生态性的今天,生态护坡在道路、堤防、城市水利等方面得到了广泛应用。然而很多情况下,生态护坡在强度上无法满足工程设计的要求。加筋生态护坡是土工织物与植草相结合形成的一种护坡形式,在保证工程生态性的同时大大提高了生态护坡的强度,近年来逐渐得到重视与应用。综合介绍了加筋生态护坡的发展历程,将其概括为传统生态护坡、普通加筋生态护坡和高性能加筋生态护坡3个阶段,在此基础上对加筋生态护坡使用的不同结构型式和材质的土工合成材料进行了分类总结,针对国内外加筋生态护坡技术的研究现状和主要结论,结合实例分析了加筋生态护坡的工程应用,指出在保护边坡、减少水土流失及改善生态环境方面的作用。最后,展望了未来需要研究的方向。