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1.
新浇大体积混凝土安全爆破振动控制标准   总被引:5,自引:0,他引:5  
高鸣安 《人民长江》1998,29(4):12-13
在清江隔河岩工程的现场,就爆破振动对新浇大体积混凝土的影响进行了试验研究。根据大量的产测资料提出了新浇大体积混凝土安全爆破质点振动速度新的控制值。按照这些控制值,在隔河岩工程的施工中对爆破振动进行了控制。  相似文献   

2.
本文结合辽宁省清河水库溢洪道闸墩控制爆破拆除施工,从方案选择、爆破试验、爆破参数、爆破振动监测以及减震措施等方面论述了控制爆破施工技术,供混凝土拆除工程借鉴.  相似文献   

3.
根据新浇筑基础混凝土基础面上的安全质点振动速度控制标准,以及瑞利(Rayleigh)波作用下安全质点峰值振动速度计算式,分析了爆破荷载特性、新浇混凝土强度、混凝土初始应力应变状态、岩石物理力学特性对新浇混凝土爆破安全标准的影响,研究结论为完善新浇混凝土爆破安全标准提供参考意见.  相似文献   

4.
大坝溢流面受冻融破坏,表面裂缝、剥蚀、脱空是病险水库的常见现象。在大黑汀水库除险加固工程中,采取挖除20cm混凝土,新浇40cm厚混凝土的全断面补强方法,对溢流面进行修补处理。旧混凝土的开挖、新老混凝土接合面处理、裂缝防治等是薄层大面积溢流面混凝土修补设计和施工的关键技术问题。本工程采用微差控制爆破新技术、无机界面胶和聚丙烯纤维网新材料等,可供类似工程借鉴。  相似文献   

5.
狮子坪水电站大坝基础混凝土防渗墙是我国目前最深的混凝土防渗墙,最大墙深达100m。为保证基础防渗墙与坝体防渗心墙的连接质量,工程上对防渗墙施工导墙和超浇部分进行了控制爆破拆除和爆破后声波无损检测,检测结果表明控制爆破是成功的。  相似文献   

6.
为确保爆破引起的振动不会对临近新浇砼产生不利影响,通过对新浇砼跟踪监测以及对爆破振动衰减规律的测试分析,找到了爆破振动控制方法.然后,针对临近新浇砼因地制宜地采取了控制单响药量、调整孔网参数、实施预裂爆破等有效的爆破控制方法,确保新浇砼爆破振动的安全性,从而保证工程施工质量.  相似文献   

7.
三峡临时船闸及升船机基础为前震旦花岗岩,岩体硬而脆,给开挖爆破造成困难,且施工中又要保护中隔墩岩体的整体稳定又要使新浇混凝土不受爆破震害。监理技术人员对控制爆破技术进行了深入的研究,制定开挖方案,确定爆破参数,审核爆破设计,检查重要部位的装药结构及起爆网络,完成了开挖任务。  相似文献   

8.
徐成光 《四川水力发电》1998,17(1):37-38,39
本文介绍了四川南充东西关水电站闸坝工程1号泄洪闸下游齿槽新浇混凝土附近的石方沟槽控制爆破实例,可供爆破同仁参考。  相似文献   

9.
通过采用浅孔控制爆破施工方法,对天花板水电站坝基揭露的f11、f15两个较大断层进行了拉槽开挖置换混凝土处理,现场采用严格的控制爆破施工工艺,有效地保护了已浇混凝土及坝基岩石的完整性,电站投产运行后,大坝运行安全稳定.  相似文献   

10.
公伯峡电站厂房基础开挖与厂房砼浇筑平行施工中,在控制爆破方法、爆破规模、一次允许最大起爆药量的同时,对新浇砼面和基础岩石进行了爆破地震波质点振动速度监测,并对不同爆破条件下,新浇砼和基础岩石上的振动衰减规律作了测试.实测成果为工程质量控制提供了依据.  相似文献   

11.
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   

12.
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   

13.
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。  相似文献   

14.
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   

15.
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。  相似文献   

16.
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   

17.
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。  相似文献   

18.
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。  相似文献   

19.
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).  相似文献   

20.
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   

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