Analysis of Consolidated Bearing Capacity of Shallow Foundations Based on Characteristics Method

doi:10.16183/j.cnki.jsjtu.2022.468

Abstract

Abstract:

To evaluate the bearing capacity evolution of subsea shallow foundations during operation, an undrained shear strength distribution of clay seabed following full consolidation due to preloading was deduced. The characteristics method was used to derive the stress characteristics equation and to evaluate the consolidated bearing capacity of shallow foundations. The influence of preloading ratio, soil inhomogeneity, effective internal friction angle, and foundation dimension on the consolidated bearing capacity of shallow foundations was investigated. The result shows that the relationship between the relative gain in the consolidated bearing capacity of shallow foundations and the preloading ratio is approximately linear. Meanwhile, the relative gain in consolidated bearing capacity is jointly determined by soil inhomogeneity and effective internal friction angle and is not affected by the foundation dimension individually. The accuracy and effectiveness of the proposed method were verified by comparing it with the results of soil-water coupled finite element analysis. Finally, possible errors between the characteristics solution and finite element model (FEM) results were analyzed. It was found that the discrepancy in the pore pressure calculation was the main reason for the disparity in the prediction of consolidated bearing capacity obtained by two methods. This characteristics solution can quickly and accurately predict the growth of consolidated bearing capacity of shallow foundations, which provides important reference for the optimal design of subsea shallow foundations.

Key words: clay seabed, shallow foundation, consolidated bearing capacity, characteristics method, preloading

CLC Number:

TU471.8

LI Zhijian, LIAO Chencong, ZHANG Lulu, YE Guanlin. Analysis of Consolidated Bearing Capacity of Shallow Foundations Based on Characteristics Method[J]. Journal of Shanghai Jiao Tong University, 2024, 58(7): 1047-1056.

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数据来源	N_cv
数据来源	ξ=1	ξ=2	ξ=4	ξ=10	ξ=20
本文	6.62	7.59	9.13	12.65	17.39
Gourvenec等^[19]	6.70	7.71	9.24	12.95	—
Martin^[20]	6.61	7.60	9.13	12.66	17.40

参数	取值
初始参考孔隙比,e	1.2
泊松比,μ	0.3
临界状态线线斜率,M	1.2
λ	0.2
κ	0.04
渗透系数,k/(m·s^-1)	4×10^-8
土体饱和重度,γ_sat/(kN·m^-3)	18

ξ	β	ξ	β
1	0.60	6	0.34
2	0.49	8	0.33
4	0.41	10	0.27