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1.
结合太平驿水电站拦河闸的抗冲耐磨设计,介绍了钢板,钢轨,花岗岩条石,硅粉混凝土用在不同过流部位的设计布置和施工要求。 相似文献
2.
在建筑工程的设计过程中,建筑物室内外临空处经常会遇到安全防护的问题。护栏底部有宽度大于或等于0.22m,且高度低于或等于0.45m的部位称为可踏部位。设计者在设计护栏可踏部位时,应从实际使用角度出发,为确保安全,区分建筑种类,并考虑不同人体的需要,慎重研究后再加以规定,以满足对现代建筑使用性、针对性、安全性的要求。 相似文献
3.
三峡工程左厂(Ⅱ)A标段为大坝混凝土浇筑和金属结构的安装,按坝体不同部位、高程及用途的不同,布置了EL.82m、EL120m两座大型施工栈桥,施工栈桥通过优化设计,严密的施工组织设计,严格的质量控制,合理的移梁方案,并经荷载试验验证,完全能达到规范和设计要求,满足三峡工程施工的需要。 相似文献
4.
大梁水库是万家寨引黄工程中的一座调节水库,主坝为黄土砂砾石混合坝,坝基渗漏、湿陷变形是设计和施工中的主要问题。坝基处理采用开挖回填和侵水压实相结合的处理方案,对不同部位采用不同的处理措施。心墙部位开挖基槽后回填黄士,心墙上下游部位坝基依靠施工期砂砾料和反滤料填筑中的洒水和上游回填前抽蓄洪水入灌以及运行期采用初期控制水库蓄水位等途径进行浸水预压处理,以期逐渐完成地基上固结。笔者认为,大坝可分为四期填筑,用4年时间施工,使坝体缓慢浸水预压,沉陷团结。 相似文献
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6.
主要介绍三板溪水电站对外公路沿线桥梁改造加固设计的思路,根据不同的桥型、不同的改造加固部位详细介绍了沿线11座桥梁的改造加固方法。 相似文献
7.
黑河水利枢纽溢洪洞工程混凝土施工过程中,由于采用C50高标号混凝土及掺用HF外加剂,加之施工工艺不尽完善等各种原因造成了不同程度的质量缺陷和隐患,针对这些缺陷黑河施工指挥部组织了专业施工队伍,根据不同的部位,不同的缺陷类型,采用了不同的处理方法和不同的材料进行了消缺处理,满足了设计要求,为同类工程的混凝土缺陷处理积累了经验。 相似文献
8.
本文介绍了大坝施工混凝土质量的评价系统软件的设计思路和设计成果。它利用现代计算机技术和应用模糊数学理论评价混凝土重力坝和拱坝单块和整体的质量。在采用模糊综合评价工程质量中,对不同工艺环节,对坝体不同部位,鉴于其质量要求的差异应赋予不同的权重,在权重的取值上采用了专家调查排序,定量转化的方法是比较适宜的。在程序设计中,评价数学模型采用了BASIC程序,访膜块通过*TXT文件实现了与整个大坝混凝土质量微机管理系统的接口及数据传递。操作运行方便灵活。 相似文献
9.
小浪底土石坝反滤设计 总被引:1,自引:0,他引:1
阐述了小浪底土石坝反滤设计的原则,方法和成果。设计中,根据大坝防渗体的结构特点设置了多种反滤。按各个部位反滤的工作条件和重要性,将反滤分为关键性反滤和非关键性反滤。对这两类不同性质的反滤采用了不同的设计原则和方法。对于关键性反滤着重强调在防渗体发生集中漏时应不致于产生渗透破坏而危及大坝安全,而对于非关键性反滤则根据不同情况进行适当简化。根据料场砂卵石级配特点和反滤设计要求,综合利用筛分料和轧制料改 相似文献
10.
根据隧洞实际开挖揭示出的地质条件和设计图示的隧道地质构造,在施工中,结合不同的工程部位和不同的地质条件,采取超前锚杆、超前管棚、钢筋拱架等不同的临时支护技术措施。同时,在临时支护的施工中,控制好施工工艺、把好质量关,对保证不良地质地段围岩的稳定和施工安全、确保施工进度,取得了良好的效果。 相似文献
11.
Presently, the water resources across the world are being continuously depleted. It is essential to find sustainable solutions for this shortage of water. Rainwater harvesting is one such promising solution to this problem. This paper presents a new GIS-based methodology to identify suitable locations for rainwater harvesting structures using only freely available imageries/remote sensing data and data from other sources. The methodology has been developed for the semi-arid environment of Khushkhera-Bhiwadi-Neemrana Investment Region (KBNIR) in Alwar district of Rajasthan. For identifying locations suitable for rainwater harvesting structures, the layers of surface elevation (ASTER-DEM), landuse/landcover, soil map, drainage map and depression map are used and further analyzed for their depression volume, and availability of surface runoff using Soil Conservation Service - Curve Number (SCS-CN) method. Based on the proposed criteria total seven locations were identified, out of which two locations are excellent; three locations are good, (if provisions of overflow structure are made for them) and two locations are not suitable for rain water harvesting. The total rainwater harvesting potential of the study area is 54.49 million cubic meters which is sufficient to meet the water requirements if harvested and conserved properly. This methodology is time-saving and cost-effective. It can minimize cost of earthwork and can be utilized for the planning of cost effective water resource management. 相似文献
12.
《水动力学研究与进展(B辑)》2014,26(1):122-128
Multi-scale properties of Reynolds stress in decaying turbulence in a wind tunnel with high Reynolds number are investigated. Two filtering techniques i.e., the zeroth-order and first-order detrending methods are applied to the two velocity components, where the local mean value (resp. local linear trend) is removed in the former (latter) technique. Some basic statistics for thirty measurements show that the variation is very large at first two locations and relatively small at last two locations. Moderately good power law is found for the mean value of local Reynolds stress at last three measurement locations with scaling exponents approximately being 1.0 and a dual power law exists for the mean value of standard deviation of local Reynolds stress at all four measurement locations with scaling exponents being 0.53 and 0.58 for zerothand first-order filtering respectively. Present results about local Reynolds stress are useful to build and evaluate the model of sub-grid Reynolds stress in large eddy simulations. 相似文献
13.
《Journal of Great Lakes research》2020,46(5):1331-1339
Constructed and restored wetlands can be effective sinks for particulate and dissolved phosphorus (P) if properly managed, but identifying suitable P retention wetland locations remains challenging. From a landscape perspective, Soil and Water Assessment Tool (SWAT) models identify locations within target watersheds with high nutrient loads that exhibit appropriate site characteristics and hydrodynamics. However, soil properties vary at the field scale, dictating the capacity of wetland systems to remove P and ultimately determining if a given wetland will operate as a sink or source of P over time. Land ownership and site access further complicate identification of P retention wetland locations. As a result, optimization and identification of P retention wetland locations requires analysis at both 1) watershed and 2) field scales, and 3) public engagement. In response, a survey effort linked SWAT model results that identified locations with target watersheds with field soil P storage capacity data and interested landowners. Results suggest that several locations recommended for their high SWAT-predicted P loading and landowner interest were in fact not well suited for project implementation due to soil P saturation and legacy P constraints. These findings highlight the need to couple watershed models with field scale soils analysis to identify locations for P retention wetlands in order to avoid unintended P release. Additionally, increased collaboration with social scientists and others familiar with public engagement strategies is needed to improve outreach activities targeting regional water quality improvements. Practical applications for nutrient retention wetland site selection are also discussed. 相似文献
14.
Dynamic Optimal Monitoring Network Design for Transient Transport of Pollutants in Groundwater Aquifers 总被引:2,自引:2,他引:0
Optimal groundwater pollution monitoring network design models are developed to prescribe optimal and efficient sampling locations
for detecting pollution in groundwater aquifers. The developed methodology incorporates a two dimensional flow and transport
simulation model to simulate the pollutant concentrations in the study area. Different realizations of the pollutant plume
are randomly generated by incorporating the uncertainty in both source and aquifer parameters. These concentration realizations
are incorporated in the optimal monitoring network design models. Two different objectives are considered separately. The
first objective function minimizes the summation of unmonitored concentrations at different potential monitoring locations.
This objective function in effect minimizes the probability of not monitoring the pollutant concentrations at those locations
where the probable concentration value is large. Although this probability is not explicitly incorporated in the model, a
surrogate form of this objective is included as the objective function. The second objective function considered is the minimization
of estimation variances of pollutant concentrations at various unmonitored locations. This objective results in a design that
chooses optimal monitoring locations where the uncertainties in simulated concentrations are large. The developed optimization
models are solved using Genetic Algorithm. The variances of estimated concentrations at potential monitoring locations are
computed using the geostatistical tool, kriging. The designed monitoring network is dynamic in nature, as it provides time
varying network designs for different management periods, to account for the transient pollutant plumes. Such a design can
eliminate temporal redundancy and is therefore, economically more efficient. The optimal design incorporates budgetary constraints
in the form of limits on the number of monitoring wells installed in any particular management period. The solution results
are evaluated for an illustrative study area comprising of a hypothetical aquifer. The performance evaluation results establish
the potential applicability of the proposed methodology for optimal design of the dynamic monitoring network for detection
and monitoring of pollutant plumes in contaminated aquifers. 相似文献
15.
《Journal of Great Lakes research》2001,27(4):402-422
Beginning as early as 1976 at many locations, total phosphorus concentrations (TP) were measured weekly in samples collected year-round in the intake water of 18 municipal water treatment plants in Canadian (Ontario) waters of the Laurentian Great Lakes. No consistent long-term trends were evident at two north-shore Lake Superior sampling locations, but there were significant long-term declines in TP measured at all three Lake Huron locations; however, concentrations there have remained relatively constant during the past decade. Declines in TP averaging about 1 μg/L/yr during 1976 to 1990 were prevalent at lower Great Lakes sampling locations and by the early 1990s TP had declined to 15–25 μg/L in Lake Erie and 10–20 μg/L in Lake Ontario. Declines generally levelled out in Lake Ontario after 1990, but TP increased substantially at some Lake Erie locations in the late 1990s. Recent (1996 to 1999) total phosphorus concentrations in north-shore Lake Erie locations in the range of 20 to 30 μg/L were 2 to 3 times higher than at Lake Ontario near-shore locations in the 8 to 11 μg/L range. Rates of decline of TP were generally highest for the March–April period (−1.88, −1.61, and −1.34 μg/L/yr in Lakes Ontario, Erie, and Huron, respectively for 1976 to 1990). The March–April Lake Ontario near-shore rate of TP decline was nearly twice as high as that reported previously for off-shore Lake Ontario (attributed to proximity to P loading sources and to lower net sedimentation losses of P in the near-shore environment). There were substantial declines in chlorophyll-to-TP ratios and in the slopes and Y-intercepts of chlorophyll-TP regressions for both Lake Erie and Lake Ontario following the establishment of dreissenid mussels. 相似文献
16.
This study investigates the relationship between historically observed changes in extreme precipitation magnitudes and temperature (Pex-T relationship) at multiple locations in Canada. The focus is on understanding the behavior of these relationships with regards to key storm characteristics such as its duration, season of occurrence, and location. To do so, three locations are chosen such that they have large amounts of moisture available near them whereas four locations are chosen such that they are located in the land-locked regions of Canada and subsequently have no nearby moisture source available on them. To investigate the effect of different storm durations on Pex-T relationship, storms of durations: 5, 10, 15, 30 min, 1, 2, 6, 12, 24 h are considered. Finally, Pex-T relationship is analyzed separately for summer and winter seasons to quantify the influence of seasons. Results indicate strong influences of storm duration, season of occurrence, and location on observed precipitation scaling rates. Drastic intensification of precipitation extremes with temperature is obtained for shorter duration precipitation events than for longer duration precipitation events, in summers than in the winters. Furthermore, in summertime, increases in the intensity of convection driven precipitation extremes is found highest at locations away from large waterbodies. On the other hand, in wintertime most drastic increases in extreme precipitation are obtained at locations near large waterbodies. These findings contribute towards increasing the current understanding of precipitation extremes in the context of rapidly increasing global temperatures. 相似文献
17.
A novel SON2‐based similarity index and its application for the rationalization of river water quality monitoring network
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In this paper, a novel self‐organizing network (SON) based similarity index and its application for the optimization of sampling locations in an existing river water quality monitoring network (WQMN) is presented. A rationalization of the River Danube WQMN on its stretch through Serbia was performed using the proposed SON2‐based similarity index. A high‐dimensional dataset was used, which is composed of 18 water quality parameters that were collected during the period 2002–2010 at 17 monitoring locations. The SON‐based seasonal classification that divides 12 months into the cold, moderate, and warm seasons was employed, whereas its second application on each seasonal class yielded subclasses that were used to compare the monitoring locations. The obtained SON2‐based similarity index can be utilized for analysing seasonal variations, as well as overall similarities among neighbouring sites. Based on the calculated similarities of locations and characteristics of the River Danube basin a rationalized WQMN, which uses 30% less monitoring sites, has been proposed. 相似文献
18.
Bithin Datta Om Prakash Sean Campbell Gerry Escalada 《Water Resources Management》2013,27(14):4959-4976
This study aims to improve the accuracy of groundwater pollution source identification using concentration measurements from a heuristically designed optimal monitoring network. The designed network is constrained by the maximum number of permissible monitoring locations. The designed monitoring network improves the results of source identification by choosing monitoring locations that reduces the possibility of missing a pollution source, at the same time decreasing the degree of non uniqueness in the set of possible aquifer responses to subjected geo-chemical stresses. The proposed methodology combines the capability of Genetic Programming (GP), and linked simulation-optimization for recreating the flux history of the unknown conservative pollutant sources with limited number of spatiotemporal pollution concentration measurements. The GP models are trained using large number of simulated realizations of the pollutant plumes for varying input flux scenarios. A selected subset of GP models are used to compute the impact factor and frequency factor of pollutant source fluxes, at candidate monitoring locations, which in turn is used to find the best monitoring locations. The potential application of the developed methodology is demonstrated by evaluating its performance for an illustrative study area. These performance evaluation results show the efficiency in source identification when concentration measurements from the designed monitoring network are utilized. 相似文献
19.
Michael J. Millard David R. Smith Eric Obert James Grazio Meredith L. Bartron Colleen Wellington Sara Grisè Sean Rafferty Robert Wellington Shannon Julian 《Journal of Great Lakes research》2009
Presque Isle Bay, Lake Erie, was listed as an Area of Concern (AOC) by the International Joint Commission in part because of the high incidence of external tumor in brown bullheads. Verifying the source of the possible contaminant exposure is critical to addressing the AOC designation. We used telemetry tracking (n = 49 fish) to test the hypothesis that adult bullheads captured within the bay during spawning season do not exit the bay during the post-spawning summer and fall months. We analyzed genetic variation at 15 microsatellite loci for 112 adult fish from 5 locations, 4 inside the bay and 1 outside, in order to test for possible differences. Data from fixed-station receivers suggested fish did not leave Presque Isle Bay during the study period. Predicted locations outside Presque Isle Bay were only 0.1% of all predicted locations and were below the 0.2% error rate based on known manual relocations. However, there was evidence for movement within Presque Isle Bay. Most movement was between Misery Bay or Lagoons and the open bay area. Whereas telemetry results showed tendency for adult site fidelity, genetic results showed no differences among locations, indicating that there is a single panmictic population. Our telemetry data suggest that brown bullheads are likely a useful indicator species for environmental conditions in Presque Isle Bay, since adults likely are retained in the system. 相似文献
20.
高压水除鳞系统中蓄势器对水击防护的特性分析 总被引:1,自引:1,他引:0
针对高压水除鳞系统水击现象,基于特征线法,建立了高压水除鳞系统水击计算的通用数学模型。通过实例,对系统中蓄势器在不同位置对水击的防护特性进行了模拟仿真计算,得到了有无加装蓄势器以及蓄势器安装在不同位置时对水击防护的差异性。分析结果表明:安装蓄势器,并不一定能完全达到防护水击的理想效果。蓄势器的安装位置越靠近管道上游处,则对水击的防护特性越差;相反,越靠近下游处,则对水击的防护特性越好,这将对系统的工程设计具有极其重要的指导意义。 相似文献