Based on the variational approach for pile groups embedded in soil modeled using a load-transfer curve method, a practical method was conducted to estimate the settlement of symmetric pile group supported embankments....Based on the variational approach for pile groups embedded in soil modeled using a load-transfer curve method, a practical method was conducted to estimate the settlement of symmetric pile group supported embankments. The working mechanism of composite foundations improved by rigid or semi-rigid columns is analyzed by this method. Under equivalent strain conditions, the pile-soil stress ratio approaches the pile-soil modulus ratio up to a limited value of pile stiffness （Rm〈10）; in the subsequent stages of high pile stiffness （Rm〉10）, a further increase in the pile-soil modulus ratio cannot lead to a significant increase of stress transferred to the columns in composite foundations. The major influencing factor of the stress concentration from soil to pile in a high pile-soil modulus ratio is the padding stiffness. For the composite foundation improved by cement mixing columns, the effective column length is about 15 to 20 m and it is a more economical and effective design when the column length is less than 15 m.展开更多
A series of 2D model tests were conducted to assess the foundation stability of composite vertical breakwaters. In this paper, the results from the experimental study are presented conjointly with a formula to estimat...A series of 2D model tests were conducted to assess the foundation stability of composite vertical breakwaters. In this paper, the results from the experimental study are presented conjointly with a formula to estimate the stability number of foundation, which is the most important parameter for evaluation of foundation stability of such structures. The influences of wave height, wave period and the berm width on the stability of compo^ite breakwaters with different armor stone sizes were investigated. Forty-five tests were performed to cover the influences of these parameters. According to the present research, berm width is a significant parameter concerning erosion of armor foundation. As the berm width increases, the amount of berm erosion decreases. Comparisons are made between results of present study and the estimated stability number proposed by Kimura et al. （1994）, which is extension of Tanimoto formula. Results show that the later formula underestimates the stability number. However, by applying an enhancement factor about 1.7 meters to Kimura et al. formula, results correlated with the present experimental results..展开更多
文摘Based on the variational approach for pile groups embedded in soil modeled using a load-transfer curve method, a practical method was conducted to estimate the settlement of symmetric pile group supported embankments. The working mechanism of composite foundations improved by rigid or semi-rigid columns is analyzed by this method. Under equivalent strain conditions, the pile-soil stress ratio approaches the pile-soil modulus ratio up to a limited value of pile stiffness （Rm〈10）; in the subsequent stages of high pile stiffness （Rm〉10）, a further increase in the pile-soil modulus ratio cannot lead to a significant increase of stress transferred to the columns in composite foundations. The major influencing factor of the stress concentration from soil to pile in a high pile-soil modulus ratio is the padding stiffness. For the composite foundation improved by cement mixing columns, the effective column length is about 15 to 20 m and it is a more economical and effective design when the column length is less than 15 m.
文摘A series of 2D model tests were conducted to assess the foundation stability of composite vertical breakwaters. In this paper, the results from the experimental study are presented conjointly with a formula to estimate the stability number of foundation, which is the most important parameter for evaluation of foundation stability of such structures. The influences of wave height, wave period and the berm width on the stability of compo^ite breakwaters with different armor stone sizes were investigated. Forty-five tests were performed to cover the influences of these parameters. According to the present research, berm width is a significant parameter concerning erosion of armor foundation. As the berm width increases, the amount of berm erosion decreases. Comparisons are made between results of present study and the estimated stability number proposed by Kimura et al. （1994）, which is extension of Tanimoto formula. Results show that the later formula underestimates the stability number. However, by applying an enhancement factor about 1.7 meters to Kimura et al. formula, results correlated with the present experimental results..
