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961.
This article derives the closed‐form solutions for estimating the vertical surface displacements of cross‐anisotropic media due to various loading types of batter piles. The loading types include an embedded point load for an end‐bearing pile, uniform skin friction, and linear variation of skin friction for a friction pile. The planes of cross‐anisotropy are assumed to be parallel to the horizontal ground surface. The proposed solutions are never mentioned in literature and can be developed from Wang and Liao's solutions for a horizontal and vertical point load embedded in the cross‐anisotropic half‐space. The present solutions are identical with Wang's solutions when batter angle equals to 0°. In addition, the solutions indicate that the surface displacements in cross‐anisotropic media are influenced by the type and degree of material anisotropy, angle of inclination, and loading types. An illustrative example is given at the end of this article to investigate the effect of the type and degree of soil anisotropy (E/E′, G′/E′, and ν/ν′), pile inclination (α), and different loading types (a point load, a uniform skin friction, and a linear variation of skin friction) on vertical surface displacements. Results show that the displacements accounted for pile batter are quite different from those estimated from plumb piles, both driven in cross‐anisotropic media. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
962.
Many civil infrastructures are located near the confluence of two streams, where they may be subject to inundation by high flows from either stream or both. These infrastructures, such as highway bridges, are designed to meet specified performance objectives for floods of a specified return period (e.g. the 100 year flood). Because the flooding of structures on one stream can be affected by high flows on the other stream, it is important to know the relationship between the coincident exceedence probabilities on the confluent stream pair in many hydrological engineering practices. Currently, the National Flood Frequency Program (NFF), which was developed by the US Geological Survey (USGS) and based on regional analysis, is probably the most popular model for ungauged site flood estimation and could be employed to estimate flood probabilities at the confluence points. The need for improved infrastructure design at such sites has motivated a renewed interest in the development of more rigorous joint probability distributions of the coincident flows. To accomplish this, a practical procedure is needed to determine the crucial bivariate distributions of design flows at stream confluences. In the past, the copula method provided a way to construct multivariate distribution functions. This paper aims to develop the Copula‐based Flood Frequency (COFF) method at the confluence points with any type of marginal distributions via the use of Archimedean copulas and dependent parameters. The practical implementation was assessed and tested against the standard NFF approach by a case study in Iowa's Des Moines River. Monte Carlo simulations proved the success of the generalized copula‐based joint distribution algorithm. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
963.
进行不同温度和不同规格人工养殖的乌苏里江唇(Hemibarbus labeo)耗氧量(MO2)、耗氧率(WO2)和窒息点(SO2)的初步测定。结果表明:水温16-28℃范围内,随着水温的升高,耗氧率、耗氧量和窒息点都表现出增大的变化趋势。温度和耗氧率的回归方程:1龄鱼体重11 g的为WO2=0.0142T-0.0863(R2=0.9617),2龄鱼体重60 g的为WO2=0.0138T-0.1121(R^2=0.97);温度和窒息点的回归方程:1龄鱼体重8 g的为SO2=0.0298T-0.1891(R^2=0.977 8),2龄鱼体重40 g的为SO2=0.048 8T-0.402 5(R^2=0.999 7)。体重20-100 g范围内,水温25℃时,随着体重规格的增大,耗氧量逐渐升高,耗氧率逐渐减小。体重和耗氧率的回归方程为WO2=0.7825W-0.2898(R2=0.947 4),体重和耗氧量的回归方程为MO2=0.7837W0.7097(R^2=0.991 6)。唇鱼的昼夜耗氧率(水温25℃,体重72 g)有一定的变化趋势,早间4-10时耗氧率较高,平均在0.332±0.046 mg/(g.h),午间11-19时中等,在0.287±0.030 mg/(g.h),晚间20-3时较低,在0.251±0.029 mg/(g.h)。  相似文献   
964.
复杂野外地质属性数据的快速采集方法探讨   总被引:3,自引:0,他引:3  
研究、开发计算机辅助填图系统的野外数据采集子系统的关键是要解决快速采集数据的问题。通过编制特别的野外数据录入专用软件 ,把数据库的前端和后端分离 ,使用多数据表单界面录入技术和标准词条的屏幕提示录入技术 ,大量使用组合快捷键 ,采用动态数据模型技术 ,综合集成先进设备和空间坐标的实时自动捕获等方法 ,可以有效提高野外地质数据的采集速度。  相似文献   
965.
甚低频电磁法在河南省竹园铜矿的应用   总被引:9,自引:0,他引:9  
许令兵 《中国地质》2001,28(11):25-28
简要叙述了甚低频电磁法的方法技术,并以河南省西峡县竹园铜矿为例,介绍了甚低频法寻找铜多金属硫化物矿床的显著效果。结合工作效果,对甚低频法的不足之处提出了3点看法。  相似文献   
966.
Kriging with Inequality Constraints   总被引:1,自引:0,他引:1  
A Gaussian random field with an unknown linear trend for the mean is considered. Methods for obtaining the distribution of the trend coefficients given exact data and inequality constraints are established. Moreover, the conditional distribution for the random field at any location is calculated so that predictions using e.g. the expectation, the mode, or the median can be evaluated and prediction error estimates using quantiles or variance can be obtained. Conditional simulation techniques are also provided.  相似文献   
967.
网络环境下测绘数据三库一体化的研究与实践   总被引:5,自引:0,他引:5  
文中利用Oracle 8中的多媒体特性 ,就三库一体化中正射影像数据库、分要素层矢量数据库和格网DEM数据库的建立进行了探讨。主要解决了矢量源数据入库前的组织、DEM数据与ORDimage类型的转换、跨带自动拼接等关键问题  相似文献   
968.
通过对布设在克孜尔水库大坝及库区一等水准点及 GPS监测网多期观测结果的分析 ,对贯穿大坝的 F2 断层近期形变特征进行了初步研究。结果表明 :F2 断层的活动属于新构造继承性运动 ,其水平形变速率大于垂直形变速率 ,并与地震活动存在着一定相关性  相似文献   
969.
The 1300 km long Narmada River flows along a structural lineament, alternating between constricting rocky gorges and rapids, and meandering wide alluvial reaches. Channel forms and processes were studied in a 120 km long section of an alluvial reach. Channel size, shape and bedforms in the Narmada River are related to very large floods which have occurred three times in this century. During such floods the entire 400 m wide channel is utilized and 10–15 m high cliffs on both sides operate as riverbanks. Normally, even the high flows of the south-western monsoon are insufficient to fill the whole channel, and hence their effects are limited to building of discontinuous floodplains between the cliffs and modifying bedforms and bars. A channel-in-channel topography is thus created. The very large floods are also responsible for erosion of the rocky stretches and building of point bars. The river meanders, but its movement is restricted because of (1) rocky gorges and scablands operating as anchor points at intervals, and (2) the presence of high alluvial cliffs which are topped on extremely rare occasions. In spite of being located in a tectonically active zone in a monsoon setting, it is the exceptional high-magnitude floods at irregular intervals which control the form and behaviour of the Narmada River.  相似文献   
970.
在应用各种预报方法作每日的天气预报时,常遇到的各种预报方法的结果不一致的情形,这时需集各预报结果为一体作为群体决策意见,作者介绍了后置群体评价方法在天气预报决策中的具体应用,用该方法进行决策,取得了较理想的效果。  相似文献   
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