摘要
根据土力学关于地基承载力等课题的基本假定,土的抗剪强度指标是描述均匀土体平均强度趋势的参数,统计时应计算其一定空间范围的均值及其均值方差,因而有必要将随机场理论引入抗剪强度指标的统计方法,并考虑土性指标的自相关性及互相关性。以抗剪强度指标的传统统计方法为基础,结合随机场理论,提出抗剪强度指标的随机场统计方法,在抗剪强度指标统计时既考虑单个指标的自相关性,又考虑指标之间的互相关性;并且不必分别研究c,tan的自相关函数及互相关函数,而是通过回归直接得到其均值方差,使计算大为简化。最后,通过天津新港的工程算例,进一步说明用此统计方法得到的可靠度指标与工程的实际安全程度相对应,且较传统的统计方法更为合理。
In the reliability analysis of foundations,one of the most important problems is how to choose the reasonable statistical method for shear strength indexes of soils. According to the basic assumption of some topics in the soil mechanics,the indexes of shear strength are the parameters describing the trend of average strength of homogenous soils. The mean values and variance of local spatial averaging of soil properties should be used in the reliability analysis. So it is necessary to introduce the random field theory into the statistics for shear strength indexes and to consider the auto-correlation and cross-correlation of the shear strength indexes of soils. The stochastic statistical methods for shear strength indexes are presented based on the traditional statistical methods. Both the auto-correlation of the individual index and the cross-correlation between the indexes can be considered when using the methods. In addition,there is no need to study the auto-correlation function and cross-correlation function of c and tan respectively. The variance of spatial averaging of c and tan can be obtained directly through regression. The process of calculation will be simplified by this means. Finally,by calculating an example of engineering in Tianjin Port,it is proven that the reliability indexes calculated by the stochastic statistical methods agree well with the reliability of practical engineering.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第S1期3040-3046,共7页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50379034)
教育部高等学校博士学科点专项科研基金资助课题(20020056012)
关键词
土力学
抗剪强度指标
随机场
可靠度
相关性
soil mechanics
shear strength indexes
random field
reliability
correlation
