The influence of a non‐associated flow rule on the calculation of the factor of safety of soil slopes

This paper presents a method that incorporates a non‐associated flow rule into the limit analysis to investigate the influence of the dilatancy angle on the factor of safety for the slope stability analysis. The proposed method retain's the advantage of the upper bound method, which is simple and has no stress involvement in the calculation of the energy dissipation and the factor of safety. Copyright © 2001 John Wiley & Sons, Ltd.     

同震阶变异常的特征与机制分析

本文对徐州地震台JB—72水平摆倾斜仪1988年11月至1989年5月间所记录到的24次同震阶变进行了深入分析,认为:a.造成同震阶变的原因是多方面的,而反应了地球应变场准静态调整的同震阶变才是有价值的价变异常;b.多观测手段的地震台站,同震阶变应该在不止一台仪器上得到响应。     

Fuzzy Fatigue Reliability Analysis of Offshore Platforms in Ice-Infested Waters

1 .IntroductionTheBohaiGulfisinfestedbyiceinthewholewinter,andoffshorestructuresthereexperiencenotonlywind ,waves ,currentsandearthquake ,butalsoiceloadswhicharecomplicatedbecauseofthedynamicinteractionbetweenicesheetsandstructures.Duanetal.( 2 0 0 0 )hadacomprehensivere viewofthelatestadvancesonice inducedvibration ,fatigueandfractureofoffshorestructures ,payingmuchattentiontothedifferencesinicebreakingmodeanddynamicsofstructuresindifferentice in festedwaters .Theypresentedcriticallythelates…     

Response of zooid size in Cupuladria exfragminis (Bryozoa) to simulated upwelling temperatures

We investigate the effect of the temperature–size rule upon zooids of the tropical American bryozoan Cupuladria exfragminis. Results show that mean zooid length, zooid width and zooid area vary significantly between clonal replicates of C. exfragminis kept under different controlled temperature conditions. Significantly larger zooids are produced during times of lowered water temperature that are comparable with the temperatures that occur during seasonal upwelling along the Pacific coast of Panama where the animal lives in abundance. Interpolation of data suggests that a drop of 1 °C causes a 5% increase in zooid size, and that almost all variation in zooid size in natural populations can be explained by temperature. Results are discussed in context of the potential use of zooid size variation in cupuladriid bryozoans to measure the strength of seasonal upwelling in ancient seas by analysing zooid size changes in fossil colonies. The technique of cloning cupuladriid colonies by fragmentation is also discussed with reference to its benefits in experimental studies where genotypes need to be controlled or replicated.     

我国陆上大中型气田分布规律与有利勘探区带优选

“八五”、“九五”期间我国天然气探明储量幅度增长,大中型气田分布规律的深化研究密切关系到天然气储量的增长势头。克拉通盆地下层序古隆起控气理论和上层序非构造圈闭控气机理是克拉通大中型气田富集分布的基本规律,前陆盆地是我国富气盆地类型之一,其冲断带下盘大型造圈闭群、前缘斜坡岩性尖灭区带与浅层次生气藏、前缘隆起上的断块圈闭群等是该类盆地有利的天然气富集区带。依据充分的地质资料,结合我国天然气勘探实际,提     

基于决策树的我国农业数据挖掘分析

决策树是用于分类的常用建模方法。首先对分类的概念和决策树方法分别进行了总体介绍,在此基础上对我国30个省市自治区的乡村劳动力、耕地面积以及农业总产值信息数据进行了挖掘分析,在运用决策树对数据进行分类过程中对连续数据采用聚类分析的方法进行离散化处理,从而避免了原始经验分类方法的主观性。最后,通过上述决策树分类方法,生成我国农业情况的决策树,获得相关空间分类规则,并对其进行分析说明。结果表明,决策树分类方法适合我国农业情况。     

抚顺发电厂变形规律浅析

抚顺发电厂是一座坑口发电厂,受采煤等多种复杂人为及地质因素的影响,厂区发生一系列的变形和破坏.本文基于观测成果对厂区变形规律进行了分析.     

基于规则库和网格算法的土地利用现状图自动数字注记

图形自动注记可极大地提高制图的工作效率。针对土地利用现状图数字注记的特点,本文从地图认知角度出发,建立注记自动配置的规则库,提出面状要素自动注记的一种新的算法——网格法。该算法最大的优点是容易实现、效率高,可方便地解决注记压盖冲突等问题。通过开发一个程序实例,对图斑要素进行了自动数字注记,实验表明95％以上的图形注记效果都较为理想。     

Experimental and numerical studies of rock salt strain hardening

The work presented in this paper comes as part of a research program dealing with the thermomechanical behaviour of rock salt. It aims to study laboratory and in-situ long-term behaviour by means of creep tests with deviator and temperature changes. The laboratory results, using a triaxial multi-stages creep tests, highlighted the strain hardening character of rock salt. Furthermore, the in-situ results, using a borehole dilatometer multi-step creep test, have shown that the drilling is carried out in a weakly stressed pillar. The interpretation of the laboratory results, using the J.LEMAITRE law, did not indicate full agreement with all the test results. As a result a ‘double’ J.LEMAITRE model, which takes into account a double strain hardening variable, has been put forward. The validation of this model on the laboratory creep tests is very satisfactory. Furthermore, the activation energy seems satisfactory to represent the influence of the temperature. The in-situ behaviour modelling is clearly more complex than the modelization based on laboratory tests. In fact, it seems that if the rock salt behaviour is maintained by J.LEMAITRE law, it is necessary to vary with the stress, at least, one of the parameters assumed constant in the basic law.     

土屋铜矿上方覆盖层元素分布规律研究

通过对土屋铜矿上方覆盖层不同层位样品进行分析发现，成矿元素Cu在覆盖层底部靠近基岩的原地风化残积层和地表弱胶结层中富集，而在地衰弱胶结层中又倾向于向两“极”富集，即在最粗粒级和最细粒级含量较高．考虑到采样效率和成本等综合因素，在区域调查中，以采集弱胶结层（5～40cm）、细粒级样品（-160目）为最佳采样介质．