常用围岩分类方法对某深埋隧洞的适用性分析   总被引：3，自引：0，他引：3  

葛华  王广德  石豫川  寇佳伟  单治钢  周春宏 《中国地质灾害与防治学报》2006,17(2):44-49

某深埋隧洞局部地应力高达42 MPa,局部外水压力高达10 MPa,具有高地应力、高外水压力的特点。一般认为,最大主应力大于20 MPa属于高地应力,外水压力远大于1 MPa为高外水压力。采用Q系统、RMR分类、水电规范HC分类、国标BQ分类等4种常用围岩分类方法对该隧洞进行了围岩分类。分类结果表明,高地应力条件下,Q系统的适用性较好,RMR分类、HC分类、BQ分类适用性均差。4种分类方法在高外水压力条件下的适用性均差。出现上述现象的主要原因有:Q系统通过最大切向应力与岩石抗压强度的比值σθ/σc的大小,反映高地应力对围岩类别的影响。故其在高地应力条件下的适用性较好;RMR分类没有考虑高地应力对围岩类别的影响。其分类结果在高地应力区特别是岩爆段偏高;HC分类在高地应力区简单地采用降级的方法。其分类结果误差较大;BQ分类对岩石强度过于敏感。其分类结果在高地应力区过于保守。这4种方法均未考虑高外水压力对围岩类别的影响。论文提出了一种“归一化方法”,可以对不同分类方法分类结果进行相互比较。  相似文献   

Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery   总被引：5，自引：0，他引：5  

徐涵秋 《中国地质大学学报(英文版)》2006,17(2):146-150,157

INTRODUCTIONMultitemporal satellite i magery has long beeninvolvedin the detection of changes occurringin nat-ural ecosystems . The accuracy of the result largelyrelies onthe consistency of at mospheric andillumina-tion conditions of the multitemporal i mages used.However ,the date and seasonal variations resultingin different at mospheric and illumination effects usu-ally cause errors in change detection results . Accord-ingly ,pre-processing of multitemporal i magery usingabsolute or re…  相似文献   

 卫星影像的云雾检测及干扰去除     

徐逸祥  朱子豪  刘英毓 《国土资源遥感》2006,17(3):23-28

云雾检测及去除是光学遥感图像处理的难题。厚云雾因具高反射特性，可通过阈值的设定将其检测并去除； 薄云因混有地物 光谱特性而较难检测，需先对影像做相对辐射校正处理，再将影像由RGB转换成HIS彩色模型，并假设薄云雾的加入等于白色颜料的加 入，即仅改变光谱的亮度或饱和度值，色相并无改变，藉此，可用多时段方式检测。实践证明，在HIS系统中可简化薄云雾的检测准 则，大大提高自动化检测云雾的可能性。  相似文献   

基于归一化高光谱位置变量的干叶片生化组分分析     

沈艳  牛铮  缪启龙  徐永明 《南京气象学院学报》2006,29(6):833-838

利用实测干叶片生化组分和高光谱反射率数据，提出了基于面积归一化的高光谱位置变量一阶导数极值法提取生化组分的新思路。结果表明：该方法能较好地提取叶片全氮、纤维素、木质素和淀粉含量，尤其是对纤维素、木质素和淀粉含量的反演精度有了提高。研究还表明：该方法在提取全氮、纤维素、木质素含量时，能有效剔除土壤影响，但是在提取淀粉含量时，效果不够理想。  相似文献   

Coordinates for perturbed keplerian systems with axial symmetry     

Sebastián Ferrer  Bruce R. Miller 《Celestial Mechanics and Dynamical Astronomy》1992,53(1):3-10

A coordinate system is defined on the phase space of a perturbed Keplerian system after the mean anomaly has been averaged out, for the purpose of explaining how eliminating the longitude of the ascending node reduces the orbital space to a two-dimensional sphere in case the system admits an axial symmetry. Concomitantly, on the submanifold of direct osculating ellipses, the CDM variables are replaced by functions which form the basis of a Poisson algebra isomorphic to the Lie algebra so(3) of the rotation group SO(3); furthermore, in these variables, the doubly reduced phase flow appears like a rotation of the reduced phase space.  相似文献   

基于MM5模式的站点降水预报释用方法研究   总被引：15，自引：5，他引：15       下载免费PDF全文

陈力强韩秀君  张立祥 《气象科技》2003,31(5):268-272

对MM5模式输出产品解释应用，建立县级站点定量降水MOS预报模型。方案为将影响辽宁降水的天气模型归纳为动力诊断模型，从中构造出多个能够较全面反映降水模型特征的综合物理因子；根据站点降水的气候分布特征，对偏态分布的降水量进行正态化处理，处理方案为首先将降水量划分为有雨和无雨两档，然后对有雨样本进行分级、开4次方处理，经分析对比降水量经过正态化处理后建立的预报模型优于未经处理的模型。运用统计方法建立站点降水预报模型，该模型分为晴雨预报模块和雨量预报模块。通过2001和2002年夏季业务试运行表明，该模型对降水有较强的预报能力，较原模式预报水平有一定改进。  相似文献   

内蒙古地震台网与呼和浩特遥测台网ML震级的归一化研究     

樊星  薛峰 《地震地磁观测与研究》1997,18(6):35-38

对内蒙古地震台网和呼和浩特遥测地震台网测定的近震震级ＭＬ的偏差进行了统计研究，结果表明；两者之间的ＭＬ震级标度基本一致。由于ＭＬ震级公式本身的不均匀性，对于网外地震，遥测台网ＭＬ震级需加适量校正值。  相似文献   

Radiometric normalization of overlapping LiDAR intensity data for reduction of striping noise     

Wai Yeung Yan  Ahmed Shaker 《International Journal of Digital Earth》2016,9(7):649-661

Airborne LiDAR data are usually collected with partially overlapping strips in order to serve a seamless and fine resolution mapping purpose. One of the factors limiting the use of intensity data is the presence of striping noise found in the overlapping region. Though recent researches have proposed physical and empirical approaches for intensity data correction, the effect of striping noise has not yet been resolved. This paper presents a radiometric normalization technique to normalize the intensity data from one data strip to another one with partial overlap. The normalization technique is built based on a second-order polynomial function fitted on the joint histogram plot, which is generated with a set of pairwise closest data points identified within the overlapping region. The proposed method was tested with two individual LiDAR datasets collected by Teledyne Optech's Gemini (1064?nm) and Orion (1550?nm) sensors. The experimental results showed that radiometric correction and normalization can significantly reduce the striping noise found in the overlapping LiDAR intensity data and improve its capability in land cover classification. The coefficient of variation of five selected land cover features was reduced by 19–65%, where a 9–18% accuracy improvement was achieved in different classification scenarios. With the proven capability of the proposed method, both radiometric correction and normalization should be applied as a pre-processing step before performing any surface classification and object recognition.  相似文献   

Arsenic and other Trace Metals in Sediments from the Kara Sea and the Ob and Yenisey Estuaries, Russia     

D.H. Loring  S. Dahle  K. Naes  J. Dos Santos  J.M. Skei  G.G. Matishov 《Aquatic Geochemistry》1998,4(2):233-252

Major (Al and Fe), minor (Mn) andtrace (As, Cd, Co, Cr, Cu, Hg, Li, Mo, Ni, Pb, Sb, Vand Zn) metals along with material of grain size<63 m, TOC and TN have been determined insediment grab and core samples from the Kara Sea, andthe Ob and Yenisey estuaries, Russia. Surprisingly,the levels of trace metals, with the exception of As,were much lower than was anticipated from speculativereports of extensive contamination in the Arcticmarine areas adjacent to the Siberian coastline ofRussia. Lithium normalization indicates that theabundance and distribution of the metals, with theexception of As and Mo, are controlled by theaccumulation of their fine grained aluminosilicatehost minerals at sites determined by hydrodynamicconditions in the Kara Sea and in the estuaries. Metallevels in the Kara Sea and the Ob and Yeniseyestuaries, except for some anomalous As, Cu and Nivalues, are close to natural baseline levels of otherEurasian Arctic shelf sediments. High levels of As,however, occur in surface and subsurface sediments.The accumulation of As, as well as Mo, can beattributed to the post-depositional diagenetic effectsof Fe-Mn cycling both at and near the sediment waterinterface. Subsurface As and Fe maxima and minimasuggest alternating oxic and anoxic water conditionsduring post-glacial rises in sea level. In contrast tothe results from the adjacent Pechora Sea, in the KaraSea there is no correlation between the levels of Asand radionuclides in the sediments.  相似文献   

The use of mantle normalization and metal ratios in the identification of the sources of platinum-group elements in various metal-rich black shales   总被引：10，自引：0，他引：10  

Jan Pašava  Sarah-Jane Barnes  Anna Vymazalová 《Mineralium Deposita》2003,38(6):775-783

It has been shown that Ni/Cu versus Pd/Ir and Cu/Ir versus Ni/Pd ratios, as well as mantle-normalized metal patterns can be successfully used to evaluate the effects of partial melting, crystal fractionation and sulfide saturation in mafic and ultramafic rocks. Platinum-group element (PGE) enrichments occur in Zn-, Cu- and Ni-rich black shales in a number of geological settings. These facies are generally associated with the development of continental rift structures, both without significant volcanic activity (examples in Canada, China, Finland and Poland) and with volcanic activity (Czech Republic and Namibia). Using the same element ratios as were used in mafic igneous rocks, it is evident that metal-rich black shales associated with volcanic rocks reflect the fractionation of PGEs in volcanogenic facies. It is further concluded that, in metal-rich black shales in which distributions of Ni and Cu have been altered by various processes, the Cu/Ir versus Ni/Pd and Ni/Cu versus Pd/Ir ratios plots are applicable for determination of the source of PGEs only after careful evaluation of Ni and Cu enrichments.Editorial handling: A. Brown, D. Lentz  相似文献