# 倾斜状态下的吸力式基础极限承载力离心试验模拟The Centrifuge Experiments on Maximum Bearing Capacity of the Suction Bucket under the State of Inclination

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To study the mechanism of bearing capacity of a suction bucket, a series of centrifugal tests were designed to investigate the uplift bearing capacity and the entire dynamic process of soil pressure and pore water pressure were monitored as well. Finally, mechanical analysis was carried out for the suction bucket structure, and the calculated bearing capacity was compared with the experi-mental data, and the error was less than 12%. The experiments presented the obvious influence of inclination on the foundation bearing capacity, and it can be used for reference in engineering.

1. 引言

2. 离心机模型试验设计

2.1. 试验土样

Figure 1. Grading curves of soil samples

Table 1. Soil test parameters

2.2. 实验装置

Figure 2. Diagram for monitoring and loading principles in centrifugal model tests

Figure 3. The model box

3. 离心试验结果及分析

3.1. 孔压变化分析

Figure 4. Changes of pore pressure in centrifugal acceleration

Figure 5. The changing process of pore pressure in the suction foundation

3.2. 承载力变化分析

3.2.1. 承载力变化机理分析

Figure 6. History of the vertical displacement in the uplift process of the suction foundation

Figure 7. Force-displacement curve in the process of pulling out of the suction foundation

3.2.2. 承载力计算与试验对比

$F={W}_{P}+{W}_{S}+{T}_{e}+{T}_{S}-{T}_{n}$

Figure 8. Schematic view of forces

4. 结论

1) 离心模型试验中，随着吸力式基础倾斜程度的增加，吸力式基础承载力不断减小，当倾斜程度为5˚时吸力式基础的承载力减小了6%，当倾斜程度为15˚时基础承载力减小了19%。在高速离心还原现场规模状态下，基础承载力受倾斜度的影响较大。

2) 吸力式基础上升过程中，在桶体埋设的左侧、内侧、右侧三个位置的孔压受到扰动，内侧孔压受到扰动情况最为明显，左侧、右侧孔压情况基本相同，三个位置的孔压整体呈上升趋势。

3) 离心模型试验结果表明，吸力式基础在拉拔破坏过程有两种不同状态：当吸力式基础倾斜程度较小时，吸力式基础始终保持匀速上升的状态，吸力式基础以拔出时的荷载值作为极限承载力。当吸力式基础倾斜程度为15˚时，吸力式基础先匀速上升，当到达某一点后，桶体的水平位移突增，并随着拉拔力的增加，水平位移增加愈加明显，吸力式基础则以水平位移的突变点对应的拉拔力作为极限破坏承载力。针对吸力式桶形结构进行力学分析，计算承载力的值与实验数据进行对比，误差在12%以内，基本认为合理。

NOTES

*通讯作者。

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