| dc.description.abstract | Abstract
In this research, the horizontal variability of standard penetration test N values (SPT-N), the fines content, the depth of groundwater table, and the depth of Sabkha are discussed in terms of the spatial variability through semivariance and semi-variogram. According to the results of semivariance and semi-variogram, the corresponding unknown values in the study areas are estimated within range and sill by Kriging method. There are total 193 boring logs at the construction site. It is about 8 km in length and 3 km in width. The soil boring depths are in the range of 10 to 30 meters. Since the construction site locates in a deserted area, the subsurface condition is mostly silty and clayey sands. In this research, there are the discussions of applicability and restrictions considering various ground improvement techniques. Various ground improvement techniques are suggested through the estimated geotechnical values by Simple Kriging. In this study, the variability of semivariance and parameters in the semivariogram was also investigated by randomly choosing a given number of soil borings from the database. The selected number of borings are 30, 50, 70 and 90, respectively. The main findings are (1) the range of SPT-N values is 572 m, the range of the fines content is 673 m, the range of the depth of groundwater is 516m, and the range of the depth of Sabkha is 342m. (2) When the number of borings decreases, the coefficients of variation of the estimated values such as the sill, and range in the semivariogram increase. (3)Based on the assumption that areas with SPT-N values of 15 or larger blows do not need ground improvement, the areas that do not need ground improvement is about 80%. With other geotechnical parameters such as the ground water level depth, percent of fine contents and depth of Sabkha, it was estimated that area needing roller compaction is about 1.5%, the areas using dynamic compaction is about 0.07%, the areas using rapid impact compaction is about 4.5%,and the areas using stone column is about 14%. The percentage of ground improvement technique is influenced mostly by the variance of the depth of Sabkha.
Key words: Semivariance、Semi-variogram 、Kriging、ground improvement technique、R-Squared | en_US |