信息化设计施工在机场高填方边坡工程中的应用     

王睿  邱存家  刘宏 《地质灾害与环境保护》2010,21(2):109-112

信息化设计施工是一种动态的设计施工方法,通过施工过程中的施工信息,掌握工程岩土体的工作状态,从而调整优化初始设计施工方案。本文分析了机场高填方边坡的主要施工信息,提出了信息化设计施工的工作模式,并以西南某机场扩建工程为例,介绍了机场高填方边坡信息化设计施工的实际工程应用。这种设计施工模式在实际工程中取得了较好的应用效果。  相似文献   

A nonlinear time-lag differential equation model for predicting monthly precipitation     

Peng Yongqing  Yan Shaojin  Wang Tongmei 《大气科学进展》1995,12(3):319-324

This paper investigates the nonlinear prediction of monthly rainfall time series which consists of phase space con-tinuation of one-dimensional sequence, followed by least-square determination of the coefficients for the terms of the time-lag differential equation model and then fitting of the prognostic expression is made to 1951-1980 monthly rainfall datasets from Changsha station Results show that the model is likely to describe the nonlinearity of the an-nual cycle of precipitation on a monthly basis and to provide a basis for flood prevention and drought combating for the wet season.  相似文献   

A comparison of methods for the inversion of airborne gravity data   总被引：2，自引：2，他引：0  

B. Alberts  R. Klees 《Journal of Geodesy》2004,78(1-2):55-65

Four integral-based methods for the inversion of gravity disturbances, derived from airborne gravity measurements, into the disturbing potential on the Bjerhammar sphere and the Earths surface are investigated and compared with least-squares (LS) collocation. The performance of the methods is numerically investigated using noise-free and noisy observations, which have been generated using a synthetic gravity field model. It is found that advanced interpolation of gravity disturbances at the nodes of higher-order numerical integration formulas significantly improves the performance of the integral-based methods. This is preferable to the commonly used one-point composed Newton–Cotes integration formulas, which intrinsically imply a piecewise constant interpolation over a patch centered at the observation point. It is shown that the investigated methods behave similarly for noise-free observations, but differently for noisy observations. The best results in terms of root-mean-square (RMS) height-anomaly errors are obtained when the gravity disturbances are first downward continued (inverse Poisson integral) and then transformed into potential values (Hotine integral). The latter has a strong smoothing effect, which damps high-frequency errors inherent in the downward-continued gravity disturbances. An integral method based on the single-layer representation of the disturbing potential shows a similar performance. This representation has the advantage that it can be used directly on surfaces with non-spherical geometry, whereas classical integral-based methods require an additional step if gravity field functionals have to be computed on non-spherical geometries. It is shown that defining the single-layer density on the Bjerhammar sphere gives results with the same quality as obtained when using the Earths topography as support for the single-layer density. A comparison of the four integral-based methods with LS collocation shows that the latter method performs slightly better in terms of RMS height-anomaly errors.  相似文献   

Central Configurations of the Symmetric Restricted 4-Body Problem     

Martha Alvarez-Ramírez  Joaquín Delgado 《Celestial Mechanics and Dynamical Astronomy》2003,87(4):371-381

We consider the symmetric planar (3 + 1)-body problem with finite masses m ₁ = m ₂ = 1, m ₃ = µ and one small mass m ₄ = . We count the number of central configurations of the restricted case = 0, where the finite masses remain in an equilateral triangle configuration, by means of the bifurcation diagram with as the parameter. The diagram shows a folding bifurcation at a value consistent with that found numerically by Meyer [9] and it is shown that for small > 0 the bifurcation diagram persists, thus leading to an exact count of central configurations and a folding bifurcation for small m ₄ > 0.  相似文献   

Geoid determination using one-step integration   总被引：1，自引：1，他引：0  

P. Novák 《Journal of Geodesy》2003,77(3-4):193-206

A residual (high-frequency) gravimetric geoid is usually computed from geographically limited ground, sea and/or airborne gravimetric data. The mathematical model for its determination from ground gravity is based on the transformation of observed discrete values of gravity into gravity potential related to either the international ellipsoid or the geoid. The two reference surfaces are used depending on height information that accompanies ground gravity data: traditionally orthometric heights determined by geodetic levelling were used while GPS positioning nowadays allows for estimation of geodetic (ellipsoidal) heights. This transformation is usually performed in two steps: (1) observed values of gravity are downward continued to the ellipsoid or the geoid, and (2) gravity at the ellipsoid or the geoid is transformed into the corresponding potential. Each of these two steps represents the solution of one geodetic boundary-value problem of potential theory, namely the first and second or third problem. Thus two different geodetic boundary-value problems must be formulated and solved, which requires numerical evaluation of two surface integrals. In this contribution, a mathematical model in the form of a single Fredholm integral equation of the first kind is presented and numerically investigated. This model combines the solution of the first and second/third boundary-value problems and transforms ground gravity disturbances or anomalies into the harmonically downward continued disturbing potential at the ellipsoid or the geoid directly. Numerical tests show that the new approach offers an efficient and stable solution for the determination of the residual geoid from ground gravity data.  相似文献   

含溶洞介质地震记录正演     

郑四连  贺振华  黄德济 《物探化探计算技术》2004,26(2):114-117

为了揭示缝洞储层的地震波场特征，运用适合任意倾角且横纵向可变速的波场数值模拟方法(相移加插值)研究了其中一种重要的具有“串珠”状反射特征的地质模型。根据某地区地质特征设计了四个模型，并利用相移加插值的方法对模型进行了正演和偏移，得出了含溶洞介质的地震波场特征的一些有意义的结论和认识。  相似文献   

海底天然气水合物分解与甲烷归宿研究进展   总被引：5，自引：1，他引：5  

陈忠  颜文  陈木宏  王淑红  肖尚斌  陆钧  杨华平 《地球科学进展》2006,21(4):394-400

综述了近年来天然气水合物分解与甲烷归宿等方面的研究成果。天然气水合物的汇聚与地质构造或地层圈闭有关，其溶解受物质转换控制，分解则受热转换控制。水合物释放甲烷的运移方式包括分散式、中心式和大规模排放式。缺氧氧化和耗氧氧化是甲烷在海洋环境中的2种主要转化方式。天然气水合物释放甲烷的最终归宿主要为：①重新形成天然气水合物；②形成化能自养生物群落和沉淀出碳酸盐沉积；③与氧发生氧化后转变为CO2；④直接排放进入到大气中。沉积物中的微构造、化能自养生物群落、自生碳酸盐矿物及其碳氧同位素组成是水合物释放事件的指纹记录。  相似文献   

大比例尺高精度磁测在卡休他他铁(金、钴)矿生产中的应用   总被引：7，自引：0，他引：7  

许东青  白大明  李荣光 《地质与勘探》2006,42(3):76-80

卡休他他铁矿床是20世纪70年代由甘肃省地质六队在内蒙古阿拉善右旗发现的一处中型磁铁矿床,并伴生有钴和金.该矿床由南北2个矿带组成,已由内蒙古庆华集团开采多年.目前正面临资源短缺的局面,为扩大矿山潜在资源,在矿区开展了大比例尺高精度磁测,突出异常细节,可弥补矿床勘探阶段工作比例尺偏小之不足,对提高矿山生产效益,扩大潜在资源量意义重大.文章着重介绍了野外观测技术和室内数据处理方法(磁异常化极、化极向下延拓和交互式二维剖面反演),探讨了地质解释成果在矿山生产中的应用效果.  相似文献   

A STUDY OF DYNAMIC SYSTEM ESTABLISHMENT IN EOF-CONTINUATION PHASE SPACE          下载免费PDF全文

朱育峰  彭永清  严绍瑾  张勤 《Acta Meteorologica Sinica》1996,(1)

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A solution to the downward continuation effect on the geoid determined by Stokes' formula   总被引：2，自引：1，他引：2  

L.E. Sjöberg 《Journal of Geodesy》2003,77(1-2):94-100

 The analytical continuation of the surface gravity anomaly to sea level is a necessary correction in the application of Stokes' formula for geoid estimation. This process is frequently performed by the inversion of Poisson's integral formula for a sphere. Unfortunately, this integral equation corresponds to an improperly posed problem, and the solution is both numerically unstable, unless it is well smoothed, and tedious to compute. A solution that avoids the intermediate step of downward continuation of the gravity anomaly is presented. Instead the effect on the geoid as provided by Stokes' formula is studied directly. The practical solution is partly presented in terms of a truncated Taylor series and partly as a truncated series of spherical harmonics. Some simple numerical estimates show that the solution mostly meets the requests of a 1-cm geoid model, but the truncation error of the far zone must be studied more precisely for high altitudes of the computation point. In addition, it should be emphasized that the derived solution is more computer efficient than the detour by Poisson's integral. Received: 6 February 2002 / Accepted: 18 November 2002 Acknowledgements. Jonas ?gren carried out the numerical calculations and gave some critical and constructive remarks on a draft version of the paper. This support is cordially acknowledged. Also, the thorough work performed by one unknown reviewer is very much appreciated.  相似文献