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21.
贺连顺 《矿产与地质》1992,6(6):420-424
应用层次分析法(Analystical Hierarchy Process,简称AHP法)确定金窝子金矿床合理的工业品位指标。将影响工业品位的因素及各因素间的隶属关系构成系统的多层次分析结构模型,进行层次排序,制订工业品位指标的总目标,通过分析和计算,确定工业品位指标的最佳方案,取得了较满意的结果。  相似文献   
22.
Sinkhole collapse in the area of Maryland Interstate 70 (I-70) and nearby roadways south of Frederick, Maryland, has been posing a threat to the safety of the highway operation as well as other structures. The occurrence of sinkholes is associated with intensive land development. However, the geological conditions that have been developing over the past 200 million years in the Frederick Valley control the locations of the sinkholes. Within an area of approximately 8 km2, 138 sinkholes are recorded and their spatial distribution is irregular, but clustered. The clustering indicates the existence of an interaction between the sinkholes. The point pattern of sinkholes is considered to be a sample of a Gibbsian point process from which the hard-core Strauss Model is developed. The radius of influence is calculated for the recorded sinkholes which are most likely to occur within 30 m of an existing sinkhole. The stochastic analysis of the existing sinkholes is biased toward the areas with intensive land use. This bias is adjusted by considering (1) topography, (2) proximity to topographic depressions, (3) interpreted rock formation, (4) soil type, (5) geophysical anomalies, (6) proximity to geologic structures, and (7) thickness of overburden. Based on the properties of each factor, a scoring system is developed and the average relative risk score for individual 30-m segments of the study area is calculated. The areas designated by higher risk levels would have greater risk of a sinkhole collapse than the areas designated by lower risk levels. This risk assessment approach can be updated as more information becomes available.  相似文献   
23.
提出了关于分块矩阵的广义初等变换这一概念,以此为工具简化了一些复杂矩阵问题的解决方法。  相似文献   
24.
The Non-linear lterative Partial Least Squares(NIPALS)algorithm is used in principal componentanalysis to decompose a data matrix into score vectors and eigenvectors(loading vectors)plus a residualmatrix.N1PALS starts with some guessed starting vector.The principal components obtained by NIPALSdepends on the starting vector;the first principal component could not always be computed.Wold hassuggested a starting vector for NIPALS,but we have found that even if this starting vector is used,thefirst principal component cannot be obtained in all cases.The reason why such a situation occurs isexplained by the power method.A simple modification of the original NIPALS procedure to avoid gettingsmaller eigenvalues is presented.  相似文献   
25.
将投资方、建设者及工程利益方的建设期望与硬性要求具体化,以此形成项目目标,然后根据项目的结构特点对项目目标层层分解,建立工作分解结构(Work Breakdown Structure),二者形成目标矩阵和目标系统,作为工程项目的管理对象,可以让工程项目管理目标明确;对目标系统中的重要目标加强监控,设置对应监管岗位,然后利用PDCA循环实施目标管理,可以尽可能减少目标执行中的偏离。各大目标间管理的动态平衡是目标管理的基本特点。  相似文献   
26.
束缚水饱和度的大小是划分油气层与水层的重要依据之一.在岩石物理实验的基础上,分析影响束缚水饱和度大小的各种因素,利用彼此之间的关系求取束缚水饱和度的大小.以XX盆地低渗储层为例,分析低渗储层束缚水饱和度的特点,建立了束缚水饱和度与孔隙度、渗透率、气柱高度等的模型,应用到实际资料中,检验各种模型的适用性与准确性,取得了较好的效果.  相似文献   
27.
Mohr-Coulomb准则下基于滑动面深度的边坡参数反分析方法   总被引:1,自引:0,他引:1  
孙志彬  杨小礼  张胜 《岩土力学》2014,35(5):1323-1328
利用上限定理与强度折减法,提出了一种新的边坡反分析方法。该方法基于边坡的滑动面形状,不需要位移、应力等监测数据。分析边坡的临界滑动面位置与强度参数的关系,可以发现,当边坡的几何形状、土体重度以及孔隙水压力分布确定,则临界滑动面的形状只与土体黏聚力c、内摩擦角φ的关系式c/tanφ有关,并在此基础上引入边坡的无量纲系数c,λcφ。利用极限分析上限定理与强度折减法,得到了边坡临界滑动面方程,提出了其深度的计算公式,建立了边坡c,λcφ值与滑动面深度的关系。通过已有边坡的反分析实例,验证了方法的正确性和有效性。  相似文献   
28.
A new method for computing rigorous upper bounds on the limit loads for one‐, two‐ and three‐dimensional continua is described. The formulation is based on linear finite elements, permits kinematically admissible velocity discontinuities at all interelement boundaries, and furnishes a kinematically admissible velocity field by solving a non‐linear programming problem. In the latter, the objective function corresponds to the dissipated power (which is minimized) and the unknowns are subject to linear equality constraints as well as linear and non‐linear inequality constraints. Provided the yield surface is convex, the optimization problem generated by the upper bound method is also convex and can be solved efficiently by applying a two‐stage, quasi‐Newton scheme to the corresponding Kuhn–Tucker optimality conditions. A key advantage of this strategy is that its iteration count is largely independent of the mesh size. Since the formulation permits non‐linear constraints on the unknowns, no linearization of the yield surface is necessary and the modelling of three‐dimensional geometries presents no special difficulties. The utility of the proposed upper bound method is illustrated by applying it to a number of two‐ and three‐dimensional boundary value problems. For a variety of two‐dimensional cases, the new scheme is up to two orders of magnitude faster than an equivalent linear programming scheme which uses yield surface linearization. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
29.
Sulfur speciation and concentration in geothermal water are of great significance for the research and utilization of the water resources. In most situations, it is necessary to determine the total sulfur in geothermal water. In this study, the method was established for the determination of determining total sulfur content — the inductively coupled plasma-atomic emission spectrometry (ICP-AES), with the wavelength of 182.034 nm selected in spectral line of sulfur. It was identified that the optimal working conditions of the ICP-AES instrument were 1 200 W for high frequency generator power 9 mm for vertical observation height, 0.30 MPa atomizer pressure, and 50 r/min analytical pump speed. The matrix interference of the method was eliminated by the matrix matching method. Using this method, sulfur detection limit and minimum quantitative detection limit were 0.028 mg/L and 0.110 mg/L, respectively, whilst the linear range was 0.0–100.0 mg/L. The recovery rate of sample was between 90.67% and 108.7%, and the relative standard deviation (RSD) was between 0.36% and 2.14%. The method was used to analyze the actual samples and the results were basically consistent with the industry standard method. With high analysis efficiency, the method has low detection limit and minimum quantitative detection limit, wide linear range, good precision and accuracy, and provides an important detection method for the determination of total sulfur in geothermal water.  相似文献   
30.
朱学亮  邵生俊  沈晓钧  邵帅  刘小康 《岩土力学》2022,43(10):2735-2743
黄土边坡中竖直裂隙的发育往往会对边坡稳定产生影响。相对于平面应变机制,建立三维破坏机制下边坡稳定性分析方法更能接近实际边坡失稳情况。基于塑性极限分析上限法,考虑预先存在竖直裂隙的三维黄土边坡不同破坏机制(坡面破坏、坡脚破坏和坡底破坏),建立能量平衡方程及其无量纲临界高度值γH/c表达式,采用随机搜索法得到了临界高度的上限解。分析了约束宽度、边坡坡度、内摩擦角以及裂隙深度对三维竖直裂隙黄土边坡临界高度值的影响。结果表明:对于坡脚破坏机制,临界高度值随着裂隙深度的增加而减小,减小至临界裂隙深度 (δ /H)min后,裂隙深度的增加不再影响临界高度值;临界裂隙深度随着坡度β 的增大而增大,随着内摩擦角φ 的增大而减小。当约束宽度B/H<0.8时,大多数破坏机制为坡面破坏。当约束宽度B/H=0.8、内摩擦角φ =10° 及约束宽度B/H=0.6、内摩擦角φ =15° 时,边坡的破坏从坡面破坏机制逐渐过渡到坡脚破坏机制。存在竖直裂隙的黄土边坡比完整边坡具有更小的临界高度,约束宽度及内摩擦角会对三维黄土边坡破坏机制产生影响。  相似文献   
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