倒Y形竖井联系测量   总被引：1，自引：0，他引：1  

曾燕  王利群  唐记城 《现代测绘》2008,31(3)

介绍在小直径竖井联系测量中取消联系三角形,改用单根钢丝定点,全站仪引测高程的施测方法。  相似文献   

Some Results on the Spatial Breakdown Point of Robust Point Estimates of the Variogram     

R. M. Lark 《Mathematical Geosciences》2008,40(7):729-751

The effect of outliers on estimates of the variogram depends on how they are distributed in space. The ‘spatial breakdown point’ is the largest proportion of observations which can be drawn from some arbitrary contaminating process without destroying a robust variogram estimator, when they are arranged in the most damaging spatial pattern. A numerical method is presented to find the spatial breakdown point for any sample array in two dimensions or more. It is shown by means of some examples that such a numerical approach is needed to determine the spatial breakdown point for two or more dimensions, even on a regular square sample grid, since previous conjectures about the spatial breakdown point in two dimensions do not hold. The ‘average spatial breakdown point’ has been used as a basis for practical guidelines on the intensity of contaminating processes that can be tolerated by robust variogram estimators. It is the largest proportion of contaminating observations in a data set such that the breakdown point of the variance estimator used to obtain point estimates of the variogram is not exceeded by the expected proportion of contaminated pairs of observations over any lag. In this paper the behaviour of the average spatial breakdown point is investigated for cases where the contaminating process is spatially dependent. It is shown that in two dimensions the average spatial breakdown point is 0.25. Finally, the ‘empirical spatial breakdown point’, a tool for the exploratory analysis of spatial data thought to contain outliers, is introduced and demonstrated using data on metal content in the soils of Sheffield, England. The empirical spatial breakdown point of a particular data set can be used to indicate whether the distribution of possible contaminants is likely to undermine a robust variogram estimator.  相似文献   

抓“热点”、解“难点”，依法行政搞矿管     

邓宗智 《四川地质学报》1994,(3)

原达县地区是全省矿业活动最频繁的地区之一,也一度成了全省有名的“采煤混战”大区。近几年来,以《矿产资源法》为指针,抓住“重点”,调处“热点”,解决“难点”,以点带面,加强矿管行政执法工作,促进了全区矿业秩序的全面好转,矿业生产也相应得到健康发展。矿业产值占全区工业总产值的１５％左右,是全区的一大支柱产业,有力地促进了地方经济的发展。  相似文献   

DEM高程基准转换方法及应用     

李月华  孙超 《北京测绘》2021,35(2):217-221

随着数字高程模型(DEM)在电力行业的广泛应用,电力地图需求部门对数字高程模型的要求越来越高。针对在数字高程模型生产中,电力业主方提供的立体模型高程基准不统一的问题,本文提出了基于特征数据的DEM基础转换方法。该方法在进行DEM制作过程中采用先采集特征数据,后转换特征数据高程基准的方式,实现了DEM成果的高程基准的转换,并进行了实验验证。结果表明,通过对比转换前后的DEM成果位置精度,验证了该方法的正确性。  相似文献   

自重湿陷性黄土地区桩基设计探讨          下载免费PDF全文

徐建红 《探矿工程》2006,33(9):7-8

根据自重湿陷性黄土的特点、《湿陷性黄土地区建筑规范》（GB50025—2004）和《建筑桩基技术规范》（JGJ94—94）中关于桩基设计的对比分析，通过自重湿陷性黄土场地工程实例分析计算，依据负摩擦产生的机理——中性点理论，论述了自重湿陷性黄土场地中桩基设计应考虑中性点，而不应全部计入负摩阻的观点。  相似文献   

Strain softening of K0-consolidated Changi sand under plane-strain conditions     

D. Wanatowski  J. Chu 《Acta Geotechnica》2006,1(1):29-42

Experimental results are presented in this paper to study the strain softening behaviour of a marine dredged sand under plane-strain conditions. K₀ consolidated drained and undrained tests were conducted using a new plane-strain apparatus to characterize the strain softening behaviour of the sand under plane-strain conditions. For medium dense specimens, strain softening and shear bands were observed to occur under both drained and undrained conditions. For very loose specimens, no shear bands were observed and critical states were reached within the homogeneous deformation region in both drained and undrained tests. Strain softening was observed to occur at small strain for very loose specimens under undrained conditions. Two types of strain softening, the homogenous softening and banding softening, were identified and the conditions for strain softening were established. The results obtained from this study were compared with the studies by Han and Vardoulakis (Géotechnique 41(1):49–78, 1991), Finno et al. (J Geotech Eng ASCE 122(6):462–473, 1996, Géotechnique 47(1):149–165, 1997) and Mokni and Desrues (Mech Cohes-Frict Mat 4:419–441, 1998).  相似文献   

A Connectivity Index for Discrete Fracture Networks     

C. Xu  P. A. Dowd  K. V. Mardia  R. J. Fowell 《Mathematical Geology》2006,38(5):611-634

Connectivity is an important measure for assessing flow transport in rock, especially through fractures. In this paper, rock fracture systems are modelled by a discrete fracture model simulated by a marked point process. A connectivity index is then introduced to quantify the connectivity between any two points in space. Monte Carlo simulation is used to evaluate the connectivity index for stationary cases and relationships between the connectivity index and the parameters of the discrete fracture model are analysed. The average number of intersections per fracture, X_f, and the fracture intensity, P12 (P32), are calculated and the relationships between these parameters and the connectivity index are investigated, concluding that X_f is the more suitable parameter for the classification of rock mass flow properties. The relationships between the connectivity index and the percolation state of the fractured medium are also discussed. An edge correction is briefly discussed and a practical example is used to demonstrate the method of computing the connectivity index.  相似文献   

SPOT5影像严格几何纠正方法研究   总被引：8，自引：1，他引：8  

宁晓刚  张晓东  胡进刚 《测绘信息与工程》2005,30(1):43-45

根据SPOT卫星的成像原理和特点,讨论了对SPOT5卫星影像按共线方程法进行有控制点的几何纠正的方法,经对关中、陕北和陕南三种地形的影像纠正结果进行对比检验,证明了该方法精度达到了较高水平。  相似文献   

GIS中直线元内插点精度及对误差带的影响   总被引：1，自引：0，他引：1  

魏峰远  邰茜 《测绘学院学报》2005,22(3):232-234

基于误差传播定律，考虑参数r误差影响，推导了线元内插点的精度计算公式，讨论内插点精度对线元误差带的影响，并对影响的结果进行了分析，得到了一些有益的结论。  相似文献   

鄂尔多斯盆地石炭纪中央古隆起形成机制   总被引：1，自引：4，他引：1  

王庆飞  邓军  黄定华  高帮飞  徐浩 《现代地质》2005,19(4):546-550,595

将鄂尔多斯盆地简化为受南北挤压的等厚各向同性弹性薄板模型进行应力—应变场数值模拟,力图揭示鄂尔多斯地区石炭纪出现的细腰状中央古隆起的形成机制。模拟中Z轴方向应变(εz)正值区对应于盆地内部的隆起区,zε正等值线形态对应于隆起形态;单轴挤压条件下,εz正等值线总会呈现沿应力轴方向延伸的细腰状形态;点作用力产生的zε正等值线范围局限,而线作用力产生的εz正值区分布较广。模拟结果表明鄂尔多斯盆地石炭纪细腰状隆起是在南北边界受挤压条件下,应力—应变在盆地内部传递过程中所必然出现的结果,南北向点作用力比南北向线作用力产生的zε等值线形态更接近于鄂尔多斯盆地中央古隆起形态;点作用力可能代表了石炭纪微板块间的点碰撞或者弧—陆碰撞。  相似文献