Experimental Studies on Extraction of Modified Suction Caisson (MSC) in Sand by Reverse Pumping Water
Experimental Studies on Extraction of Modified Suction Caisson (MSC) in Sand by Reverse Pumping Water
复制标题
反抽水提取砂中改性吸力沉箱（MSC）的实验研究
DOI：
10.1007/s13344-021-0024-1
复制
发表时间：
2021
影响因子：
1.6
通讯作者：
李大勇
中科院分区：
文献类型：
--
作者：
黄凌昰（指导的博士生）;张雨坤;李大勇
抽吸式沉箱可以通过反向抽水的方式进行抽吸，但由于其土-结构相互作用特性的显著差异，不能视为逆向安装过程。本文首先进行了模型试验，研究了改进型抽吸式沉箱（MSC）和常规抽吸式沉箱（RSC）在砂土中反向抽水的抽采行为。研究了安装方式（抽吸式或顶升式）和反抽速率对反抽水超压变化的影响。研究发现，不论是RSC还是MSC都不能完全从砂土中提取出来。当抽采位移达到最大时，吸力沉箱内砂土的水力梯度达到临界值，导致渗流破坏。最大抽采排量随反泵排量的增大而减小。在相同的反向泵送速率下，采用抽吸方式安装的RSC和MSC的最终采出排量低于采用顶升方式安装的RSC和MSC。MSC的最终抽提位移与相同内室长度的RSC的抽提位移几乎相等。基于力平衡理论，提出了一种估算最大抽拔位移的方法。实践证明，该方法能合理地预测最大抽采位移和相应的超压。
A suction caisson can be extracted by applying reverse pumping water, which cannot be regarded as the reverse process of installation because of the dramatically different soil-structure interaction behavior. Model tests were first carried out in this study to investigate the extraction behavior of the modified suction caisson (MSC) and the regular suction caisson (RSC) in sand by reverse pumping water. The effects of the installation ways (suction-assisted or jacking installation) and the reverse pumping rate on the variations of the over-pressure resulting form reverse pumping water were investigated. It was found that neither the RSC nor the MSC can be fully extracted from sand. When the maximum extraction displacement is obtained, the hydraulic gradient of the sand in the suction caisson reaches the critical value, leading to seepage failure. In addition, the maximum extraction displacement decreases with the increasing reverse pumping rate. Under the same reverse pumping rate, the final extraction displacements for the RSC and MSC installed by suction are lower than those for the RSC and MSC installed by jacking. The final extraction displacement of MSC is almost equal to that of the RSC with the same internal compartment length. Based on the force equilibrium, a method of estimating the maximum extraction displacement is proposed. It has been proved that the proposed method can rationally predict the maximum extraction displacement and the corresponding over-pressure.