APPLICATION OF SPATIAL AVERAGE METHOD TO ESTIMATION OF SCALE OF FLUCTUATION OF SOIL INDEXES
GUO Linping1,2, XU Wenxiang3, YANG Aiwu1, LIU Xiaoqiang4
1. Key Laboratory of Soft Soil Engineering Character and Engineering Environment of Tianjin, Tianjin Chengjian University, Tianjin 300384;
2. CCCC Tianjin Port Engineering Institute, Ltd., Key Laboratory of Port Geotechnical Engineering, Ministry of Communications, PRC, Key Laboratory of Geotechnical Engineering of Tianjin, Tianjin 300222;
3. Tianjin Architecture Design Institute, Tianjin 300074;
4. Tianjin Research Institute for Water Transport Engineering, Tianjin 300000
Like most other soil layers, spatial variability of soil indexes also exists in the clayey layers. Such characteristic mainly results from geologic processes like deposition, diagenesis, et al. Determination of the scale of fluctuation is the key to know spatial variability of soil indexes. Therefore, this paper aims to analyze spatial variability of indexes of clayey soil in Nanjiang Port in Tianjin. It summarizes the spatial average method and its improved method at first. Combining geology data, the improved spatial average method is employed to analyze the scale of fluctuation of a typical soil layer in Tianjin Port in the vertical direction. The regional representative values are obtained, which are of high value on risk assessment in geotechnical engineering and determination of exploratory engineering intervals. In addition, the Bayesian inference is also discussed to revise the scale of fluctuation. Its results indicate that the Bayesian inference is much more reasonable. Furthermore, the scale of fluctuation of the mud and silt clay layer can be guidance for selection of sampling locations, and also valuable to reliability analysis of geotechnical engineering.
. APPLICATION OF SPATIAL AVERAGE METHOD TO ESTIMATION OF SCALE OF FLUCTUATION OF SOIL INDEXES[J]. Journal of Engineering Geology, 2017, 25(6): 1424-1429.
Bao C G. 1985. The Bayesian inference and its application in Sanxia[J]. Yangtze River, 1:46~52,59.
Degroot D J,Baecher G B. 1994. Estimating autocovariance of in-situ soil properties[J]. Journal of Geotechnical Engineering, 119 (1):147~166.
Guo L P,Yang A W,Yan S W,et al. 2016. Estimation of random field characteristic parameters of soil layers at Tianjin Port[J]. Journal of Engineering Geology, 24 (1):130~135.
Li J P,Shu X,Ding S J. 2003. Discussion on characteristic parameter of self-correlation of soil index and its determining principle[J]. Journal of Tongji University, 31 (3):287~290.
Li X Y,Xie H. 2000. Numerical studies and statistic analysis on correlation distances of soil character parameters[J]. Rock and Soil Mechanics, 21 (4):350~353.
Li X Y. 2001. Spatial probabilistic characteristics of geotechnical parameters and probability analysis of consolidation of soft clay ground[D]. Hangzhou:Zhejiang University.
Lin J,Cai G J,Zou H F,et al. 2015. Assessment of spatial variability of Jiangsu marine clay based on random field theory[J]. Chinese Journal of Geotechnical Engineering, 37 (7):1278~1287.
Lumb P. 1966. The variability of natural soils[J]. Canadian Geotechnical Journal, 3 (2):74~97.
Terzaghi K. 1943. Theoretical soil mechanics[M]. New York:John Wiley and Sons.
Vanmarcke E H. 1977. Probabilistic modeling of soil profiles[J]. Journal of the Geotechnical Engineering Division, 103 (11):1227~1246.
Vroumenvelder T,Calle E. 2003. Measuring spatial correlation of soil properties[J]. Heron, 5 (4):297~311.
Yan S W, Zhu H X, Liu R, et al. 2007. Study on methods for estimating correlation distance of soil layers[J]. Rock and Soil Mechanics, 28 (8):1581~1586.
Yan S W,Guo L P,Cao Y H. 2014. Regularity of determination of reduction function of variance in reliability analysis in geotechnical engineering[J]. Rock and Soil Mechanics, 35 (8):2286~2292.
Yan S W,Guo L P. 2015. Calculation of scale of fluctuation and variance reduction function[J]. Transaction of Tianjin University, 21 (1):41~49.
Zhang J Z,Miao L C,Lin F,et al. 2014. Statistical analysis of correlation distances of lacustrine sedimentary soils in central region of Jiangsu Province[J]. Journal of Engineering Geology, 22 (2):348~354.
Zhu D F,Gao D Z. 2003. Space statistical characteristics analysis of smooth stochastic field of soil characteristics[J]. Rock and Soil Mechanics, 24 (3):455~457,462.