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《人民珠江》2016,(1)
为进一步分析边坡开挖加固过程中位移、稳定性和危险滑裂面的变化情况,以弹塑性有限元法为计算工具,对某水库边坡的开挖加固过程进行数值模拟分析,计算考虑了开挖不加固和开挖并及时加固2种情况。计算结果表明:开挖不加固时,边坡整体发生很大位移,开挖完成后安全系数小于1,塑性破坏区贯通内部的软弱夹层,边坡不能保持自身稳定,将沿着软弱夹层发生滑动;开挖并及时加固后,边坡发生位移得到有效控制,安全系数提高141%,软弱夹层内部的塑性区分布范围也大大减少,且锚杆将软弱夹层两侧岩体连接起来,滑裂面往内部发展趋势明显。说明采用的加固措施能有效保证边坡开挖过程中的施工安全,成果对类似边坡工程有一定参考价值。 相似文献
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通过采用地质勘探、测量、现场测试等多种手段,获得大伙房水库输水(二期)工程取水头部竖井高陡边坡开挖范围地质体的基础地质资料,建立能够反映地质体结构特征并具有清晰边界条件的地质模型,综合分析潜在的内外部影响因素,对取水头部竖井开挖边坡的稳定性进行初步定性评价,并对可能的失稳模式作出判断,针对可能的破坏机制,采用相应的边坡稳定分析计算方法,根据计算分析成果,对可能失稳的边坡采取工程加固处理措施。 相似文献
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龙滩水电站右岸航道出口边坡施工期安全监测 总被引:2,自引:2,他引:0
边坡工程由于其地质条件的复杂性和变形机制的多样性,使得对边坡稳定性及其支护效果进行准确的预测和判断存在着很大的难度。而全面的现场监测和分析将为这方面的工作提供强有力的支持。根据龙滩水电站右岸航道出口边坡的监测设计、监测成果和开挖支护情况,分析了各段边坡变形和稳定状况,对加固处理措施和效果进行了初步评价。结果证明,航道出口边坡的监测为边坡工程施工和运行过程的安全提供了可靠的依据,经过一系列的加固措施的实施,边坡呈现比较稳定的状态,但仍需进行进一步的监测和维护。 相似文献
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九甸峡水电站厂房后边坡稳定有限元分析 总被引:1,自引:1,他引:0
采用弹塑性有限元法和强度折减法,对九甸峡水电站厂房后岩体边坡进行稳定性计算分析和评价.根据边坡工程地质条件以及开挖和支护加固过程建立了边坡分级开挖支护的准三维有限元分析模型.模拟了开挖和支护过程,计算分析了开挖完成、支护完成、降雨和地震条件下边坡的应力分布和稳定安全系数.结果表明,该边坡在加固前安全系数小,存在不稳定的可能性,支护加固后边坡的稳定安全系数有较大提高,可满足正常运用要求. 相似文献
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DDA在裂隙岩体边坡工程中的应用 总被引:2,自引:0,他引:2
本文介绍了DDA在裂隙岩体边坡工程中的应用,该边坡靠近大坝的拱座附近,边坡的开挖将影响边坡及大坝的稳定。设计中采用预应力锚索加固边坡。本文介绍了采用DDA方法对原绐边坡和开挖后的边坡进行了计算。这里给出的是计算结果和分析讨论 相似文献
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敖仁军 《水利水电科技进展》2001,21(A01):32-33,42
介绍古洞口水电站溢洪道高边坡的地质条件,通过有限元的计算,评价分析了该边坡的稳定性,并指出在山区狭谷建面板堆面坝,溢洪道的布置对减少边坡开挖量,降低边坡加固处理工程量和节约工程投资都是十分重要的。 相似文献
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青居水电站岩石高边坡稳定分析与加固处理 总被引:3,自引:0,他引:3
四川华能青居水电站是一个以土石方开挖为主的混合式开发电站,土石方开挖总量超过200万m^3,从引水渠,前池到厂房,尾水渠,其开挖边坡高度大多在40m以上,且边坡较陡,地质条件较差,边坡稳定已成为工程的突出问题,经分析计算,决定采用系统砂浆锚杆锚固,边坡挂钢筋网,喷射混凝土支护,施工期加强排水等措施进行加固处理,效果较好。 相似文献
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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。 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
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.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
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. 相似文献