地质构造和地形对N.Barton岩质评定系数Q值的影响分析

挪威岩土所Barton等人给出的岩质评定系数Q值计算式,从岩体的完整性、结构面发育程度、地下水和地应力的影响等方面,全面地反映了岩体的工程地质状况和水文地质状况,定量地反映了围岩质量的好坏,但对宏观地质构造及地形地貌的影响考虑相对较少。文章通过理论分析和数值计算,提出了三个修正系数,即褶皱影响系数Kfo、断层影响系数Kfa以及地形影响系数Ktf,并针对具体工程给出了相应的取值范围,对Q值进行了修正,反应了工程地质构造、地形地貌对Q值的影响程度,使其表达更为准确。

老年性痴呆早期诊断的“评定系数”测示研究

当前社会人口已趋向老龄化,老年病发生率日渐增多。老年性痴呆无论对家庭或社会危害均大,其发病率在美国约占65岁以上老年人口的8.9％～10.6％,病因多为Alzheimer氏病形式;日本的发病率为7.2％～8.6％,多为血管性痴呆的表现形式。

花亭湖风景区旅游环境承载力的研究

花亭湖是国家4A级风景区,因人们对旅游环境日益恶化的关注,文章从花亭湖的实际出发在广大专家的帮助下,建立了花亭湖旅游环境承载力指标体系,然后测算出各指标所占的权重,再具体测算出各指标值并标准化为相应的评定系数。在此基础上对花亭湖旅游环境承载力作了综合评价,并分析得出花亭湖风景区属于轻度弱载状态,接近适载状态;各具体指标分别对环境承载力作了贡献和制约。针对所评价的情况提出一些建议。

现代生态农业综合效益评价体系实证研究——以江苏常州地区为例

从现代生态农业的经济效益、生态效益和社会效益影响关键因素入手,借鉴已有生态农业评价指标体系研究成果,运用层次分析法和系统分析方法(AHP),构建了三个层次共17个具体指标的区域性现代生态农业综合效益评价指标体系。根据常州市2011-2013年现代生态农业发展情况,通过数据获取、确定不同年份评定系数、构造判断矩阵确定指标权重、计算综合效益评定系数等科学方法,对常州地区现代农业综合效益进行分析和评价。

综合评价法的再探索——兼与孟令杰同志商榷

拜读了贵刊1987年第一期刊载的孟令杰同志《综合评分方法探索》一文(以下简称孟文)有所启发,特借贵刊与孟令杰同志共同探讨。 孟文运用现代数学方法对我国传统的综合评分方法进行更深入的研究,但我觉得孟文对综合评分方法的修正仍有待完善之处,任何一种技术经济分析方法应尽可能求精求简。

Bus transit travel time reliability evaluation based on automatic vehicle location data

In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed and evaluated based on automatic vehicle location （AVL） data. Based on the statistical analysis of the bus transit travel time, six indices including the coefficient of variance, the width of travel time distribution, the mean commercial speed, the congestion frequency, the planning time index and the buffer time index are proposed. Moreover, a framework for evaluating bus transit travel time reliability is constructed. Finally, a case study on a certain bus route in Suzhou is conducted. Results show that the proposed evaluation index system is simple and intuitive, and it can effectively reflect the efficiency and stability of bus operations. And a distinguishing feature of bus transit travel time reliability is the temporal pattern. It varies across different time periods.

对黑龙江垦区农业可持续发展的评价

一、农业可持续发展评价指标体系的建立 1、计算各指标评定系数. Yit=Cit/Cio(当i为正作用指标时)式中:Yit-第i项指标在第t年的评定系数……

Three-dimensional analysis of slopes reinforced with piles

Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.

A new double reduction method for slope stability analysis

The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.

Shank Selection for Disc-Ripper

The new sustainable tillage system needs new machines which are the combination of well accepted disc harrow and cultivator or chisel/ripper. To find the type of ripper shank we have done a research program with 7 different shape and size tools. The geometrical parameters were determined in laboratory, the performance （loosening effect, depth etc） and draft requirements were measured on loamy soil stubble field （the speed range： 2.5-7.5 krrdh）. Developing a combined evaluation system-based on performance and draft data-to select the most favorable shank type for our condition was found one which has the following features： the size of the point： rake angle = 25°, length = 240 mm, width = 80mm; the equation of the shank curve： y = axb, where a = 2-3.5 and b = 0.04-0.05.

Development of slope mass rating system using K-means and fuzzy c-means clustering algorithms

Classification systems such as Slope Mass Rating(SMR) are currently being used to undertake slope stability analysis. In SMR classification system, data is allocated to certain classes based on linguistic and experience-based criteria. In order to eliminate linguistic criteria resulted from experience-based judgments and account for uncertainties in determining class boundaries developed by SMR system,the system classification results were corrected using two clustering algorithms, namely K-means and fuzzy c-means(FCM), for the ratings obtained via continuous and discrete functions. By applying clustering algorithms in SMR classification system, no in-advance experience-based judgment was made on the number of extracted classes in this system, and it was only after all steps of the clustering algorithms were accomplished that new classification scheme was proposed for SMR system under different failure modes based on the ratings obtained via continuous and discrete functions. The results of this study showed that, engineers can achieve more reliable and objective evaluations over slope stability by using SMR system based on the ratings calculated via continuous and discrete functions.

Study on scattering correction in fast neutron tomography at NECTAR facility

Fast neutron tomography has been established as an inspection and detection tool at the NECTAR facility at the FRM-II reac- tor. Scattered neutrons from the object become a major disturbance and bring in artifacts and deviations in reconstruction re- suits, especially for hydrogenous material object. In this article, an iterative scattering correction method for fast neutron to- mography was proposed. In each loop of iteration the scattering component of the projections will be simulated by Mon- te-Carlo program MCNPX based on the previous reconstruction result and then it will be subtracted from original projections. The differences between scattering components at different perspectives were quantitatively evaluated and an average scatter- ing component image was used for all projections finally. Smooth and uniform slices with more clear edges were obtained and the new reconstructed attenuation coefficients are quite close to the real one compared to the results without scattering correc- tion, in which case the relative error of the reconstructed attenuation coefficients is about 10%-30%.