Using Tabu Search Algorithm to Study the Groutability of Permeation Grouting with Microfine Cement Grout
Date Issued
2010
Date
2010
Author(s)
Lien, Tsung-Hsun
Abstract
In this study, 240 sets of field data were collected and analyzed to evaluate the groutability by using two methods, namely the conventional formula with relative particle size ratio and the tabu search algorithm (TS). The accuracy of the conventional formula method ranged from 45% to 68%, i.e., this method can not be successfully used to predict the groutability. Tabu search algorithm used four factors：the effective soil particle size ,(d10), the soil particle size ,(d15), the microfine cement partical size ,(D85) and the microfine cement partical size ,(D95) to redefine the groutability limits of the conventional empirical formula. These factors were used to establish a suitable prediction formula which can predict the groutability of permeation grouting with microfine cement grout to the sandy silt soils with high fines content in Taiwan. From the obtained results, it was found that the microfine cement could grout to the sandy silt soils while N1>2 and N2>1, and the prediction formula showed a better forecast ability with an accuracy as high as 90.83%.
Aside from these, in order to realize the parameter uncertainty, this study used bootstrap method to carry out uncertainty analysis. The results revealed that the mean values and the standard deviations of 1000 bootstrap samples of the groutability limits fit the results derived from tabu search algorithm model. It indicated that the parameter uncertainty can be neglected and the prediction formula is feasible.
In this study, the permeation grouting experiments were also conducted in the laboratory. The water-to-cement ratio were controlled to be 3.34, 4.0 and 4.65, which were the same as the value used in the field. The slag content of the microfine cement was 50% and five different contents of fines, namely, 0%, 10%, 20%, 30% and 40%, were used. Using the data obtained from the permeation grouting experiments, the prediction formula were verified and its accuracy reached 80%.
According to the results of this study, the conventional formula method could not be successfully used to predict the groutability of the permeation grouting with microfine cement grout to sandy silt soils. However, using tabu search algorithm to construct the prediction formula by redefining the groutability limits showed its superiority and practicality.
Subjects
tabu search algorithm (TS)
groutability
microfine cement
permeation grouting
bootstrap method
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