梅州水库输水隧洞防渗加固工程及其新材料应用

利用实测资料,分析广州市梅州水库输水隧洞渗水的原因及其防渗加固工程,介绍了防渗加固工程时采用ICG包钢型无机灌浆料对原隧洞衬砌混凝土与钢管之间缝隙进行灌浆处理的新材料应用。防渗加固工程完工蓄水后,经过汛期的蓄洪考验,水库输水隧洞出口原渗水处没有出现渗水,加固效果良好。     

浅谈双膜盲沟网在盘道岭隧洞洞身排水上的应用

盘道岭隧洞作为引大入秦工程的"咽喉",其安全运行直接影响到引大入秦工程的供水保证率。目前洞内仍存在隧洞裂缝和洞身渗水等安全隐患,为解决以上问题,在盘道岭隧洞加固改造中,将双膜盲沟网沿隧洞洞身裂缝安装,利用渗水层和排水体将隧洞地下渗水导出衬砌混凝土以外,降低渗水压力,排除渗水对新浇筑混凝土的渗透破坏,保证隧洞衬砌混凝土施工的质量,实施效果良好。     

跋山水库放水洞除险加固工程方案分析

通过收集跋山水库放水洞现状,对其工程现状安全进行复核,复核结果表明:跋山水库放水洞满足设计最大泄量要求;在正常运行工况下,隧洞结构满足要求,但在高水位工况下,衬砌混凝土易产生环向受拉坡坏。为了改善隧洞受力情况,采用帷幕灌浆加固围岩裂隙;通过方案比选,采用喷锚原混凝土层对隧洞进行加固的方案可满足过水需求,同时方案投资较低。可为类似工程除险加固复核及处理提供参考。     

引大入秦工程盘道岭隧洞病害分析及加固方案

盘道岭隧洞地层岩性复杂,地质条件恶劣,通水运行至今,几经大的加固处理,目前洞内仍多处存在安全隐患,如多处侧墙和拱顶有新裂缝出现,原裂缝有发展变化趋势,隧洞洞壁大量渗水,侧墙纵缝有析出物。本次加固采用现浇钢筋混凝土衬砌,设置排水管导引至隧洞底部,安全隐患的洞段得到加固,裂缝和渗水得到有效处理,且糙率降低,过水能力满足过流能力,存在的问题都基本得到了解决。     

水工地下隧洞衬砌混凝土渗水裂缝处理

水工地下隧洞衬砌混凝土为满足抗冲耐磨要求,一般混凝土设计标号高、水泥用量大,加上基岩硬度大,弹模高等原因,即使采用低温混凝土浇筑,最高温度也超过了允许标准。在隧洞衬砌混凝土浇筑形成后,结构混凝土由于受到内外温差所引起的温度应力影响,产生不均匀收缩而出现裂缝,特别是在地下水位较高的隧洞会出现以垂直于水流方向的环向有一定水压渗水裂缝。在处理这类渗水裂缝的过程中采用了高渗透改性环氧浆材,灌浆施工工艺采用打斜孔埋管和无损贴嘴灌浆的方法,裂缝处理的效果满足设计的质量要求。     

水工地下隧洞衬砌混凝土渗水裂缝处理

水工地下隧洞衬砌混凝土为满足抗冲耐磨要求,一般混凝土设计标号高、水泥用量大,加上基岩硬度大,弹模高等原因,即使采用低温混凝土浇筑,最高温度也超过了允许标准.在隧洞衬砌混凝土浇筑形成后,结构混凝土由于受到内外温差所引起的温度应力的影响,产生不均匀收缩而出现裂缝,特别是在地下水位较高的隧洞会出现以垂直于水流方向的环向有一定水压渗水裂缝.在处理这类渗水裂缝的过程中采用了高渗透改性环氧浆材,灌浆施工工艺采用打斜孔埋管和无损贴嘴灌浆的方法,裂缝处理的效果满足设计的质量要求.     

跋山水库放水洞钢筋混凝土衬管裂缝化学灌浆处理

跋山水库位于山东省沂水县境内沂河干流中上游，是一座具有防洪、灌溉、发电、养殖等综合效益的大型水利枢纽工程。该枢纽工程放水洞位于大坝东侧山体内，为人工开凿的水工隧洞，洞身为钢筋混凝土衬管，直径为3．5m，全长300m，隧洞洞身围岩节理裂隙发育，局部较破碎。由于当时施工时未较好的设置伸缩缝，在围岩压力及温度应力作用下，洞身衬管产生裂缝。隧洞衬砌后由于衬管与围岩之间充填灌浆不实，接触间隙较大，因此当库水位稍高时，渗水沿围岩裂隙、混凝土衬管裂缝及衬管与围岩之间的间隙由下游渗出，当放水洞空洞时，渗水又通过裂缝及混凝土的薄弱部位渗漏进洞内，造成空洞时大量漏水。     

某工程导流洞出口塌方影响段的加固处理

某工程受降雨等因素影响，导流洞出口发生塌方。为了施工安全，为了防止洞内塌方进一步内移和出口边坡发生二次塌方，对塌方影响段隧洞采取了加固处理：在隧洞腰部有鼓包变形的钢支撑上布置横向钢支撑，临时加固隧洞，确保了前期施工安全；对D0＋525．00～D0＋550．00段隧洞（下层剩5 m尚未开挖）的边顶拱进行了衬砌混凝土浇筑，加固后，洞室的变形得到了有效控制。     

水工隧洞混凝土衬砌施工地下水控制技术

山西中部引黄工程泵站工程引水隧洞在开挖过程中曾出现多次渗涌水现象,在开挖过程中进行了相应的灌浆等处理,但在混凝土浇筑时围岩仍有较多渗水,使引水隧洞衬砌混凝土施工难度大、风险高。通过采用"堵排结合"施工的技术原则,加强仓内渗水引排,总结经验,优化施工工序,使混凝土开裂渗水得到有效控制,混凝土工程总体达到优良等级。     

水工隧洞衬砌混凝土渗水裂缝处理研究

水工地下隧洞衬砌混凝土为满足抗冲耐磨要求,一般其设计标号高、水泥用量大,同时因基岩硬度大、弹性模量高等原因,导致该类混凝土即使采用低温混凝土浇筑,其最高温度也超过允许标准。在隧洞衬砌混凝土浇筑形成后,结构混凝土由于受到内外温差所引起的温度应力影响,会因不均匀收缩而出现裂缝,特别是在地下水位较高的隧洞会出现垂直于水流方向的有一定水压的环向渗水裂缝。为处理这类渗水裂缝问题,在施工过程中采用高渗透改性环氧浆材,并采用打斜孔埋管和无损贴嘴灌浆的灌浆施工工艺方法,裂缝处理的效果满足设计的质量要求。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。