基于滑移线法的黏土海床中浅基础固结承载力分析

doi:10.16183/j.cnki.jsjtu.2022.468

上海交通大学学报 ›› 2024, Vol. 58 ›› Issue (7): 1047-1056.doi: 10.16183/j.cnki.jsjtu.2022.468

基于滑移线法的黏土海床中浅基础固结承载力分析

李志坚¹^,², 廖晨聪¹^,²(), 张璐璐¹^,², 叶冠林¹^,²

1.上海交通大学海洋工程国家实验室,上海 200240
2.上海市公共建筑和基础设施数字化运维重点实验室,上海 200240

收稿日期:2022-11-21 修回日期:2023-01-24 接受日期:2023-03-09 出版日期:2024-07-28 发布日期:2024-07-26
通讯作者: 廖晨聪,副教授,博士生导师;E-mail: billaday@sjtu.edu.cn.
作者简介:李志坚(1998-),硕士生,主要从事海底浅基础承载力方面的研究.
基金资助:
国家自然科学基金(52279106);上海市晨光计划(20CG15);上海市教委科研创新计划(2021-01-07-00-02-E00089)

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

LI Zhijian¹^,², LIAO Chencong¹^,²(), ZHANG Lulu¹^,², YE Guanlin¹^,²

1. State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
2. Shanghai Key Laboratory for Digital Operation and Maintenance of Buildings and Infrastructure, Shanghai 200240, China

Received:2022-11-21 Revised:2023-01-24 Accepted:2023-03-09 Online:2024-07-28 Published:2024-07-26

摘要/Abstract

摘要：

为评估海底浅基础服役过程的承载力时变规律,推导了预载作用下黏土海床完全固结后的不排水抗剪强度分布,利用滑移线法给出了应力特征线方程并求解出浅基础固结承载力,研究了预载比、土体不均匀性、有效内摩擦角和基础尺寸对浅基础固结承载力的影响.结果表明:浅基础固结承载力的相对增长幅度和预载比近似呈线性关系,由土体不均匀因子和有效内摩擦角共同决定,不受基础尺寸的影响.通过与水土耦合有限元分析结果进行比较,对所提方法的准确性进行了严格的验证,表明了该方法的有效性.最后,根据有限元结果分析了滑移线解的误差来源,发现孔压计算差异是导致固结承载力预测结果产生误差的主要原因.该滑移线解可快速准确地预估浅基础固结承载力的增长规律,为海底浅基础的优化设计提供重要参考.

关键词: 黏土海床, 浅基础, 固结承载力, 滑移线法, 预载作用

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

中图分类号:

TU471.8

李志坚, 廖晨聪, 张璐璐, 叶冠林. 基于滑移线法的黏土海床中浅基础固结承载力分析[J]. 上海交通大学学报, 2024, 58(7): 1047-1056.

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

基于滑移线法的黏土海床中浅基础固结承载力分析

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

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