环形探测仪在深海浅层土中的工作机理研究

Study on Working Mechanism of Toroidal Penetrometer in Shallow Soil in Deepwater

环形探测仪是海洋工程中一种新型的用于描述海底结构物与海床相互作用的原位探测设备。论文建立了环形探测仪工作时剪切地基土的有限元模型,海床地基土采用修正的剑桥模型。分析了探测仪在不同剪切速率下的环向阻力、法向接触力及地基土中超孔压等参数的变化规律,还考虑了埋深和过载比的影响。研究发现,超孔压ΔUN是决定阻力变化的主要因素,其产生与消散的过程与剪切速率、埋深、过载比等因素有关。随着过载比的增加,超孔压从正变为负。

A new type of in-situ detection device named toroidal penetrometer has been developed for describing the interaction between the seabed and the engineering structure on the seabed.In this paper,a finite element model of detecting the operation in the seabed was established using the modified Cam clay model.Variation of the resistance,normal contact force and the excess pore pressure at different shear rates of the toroidal penetrometer was revealed.It is found that the excess pore pressure is the main factor determining the variation of the resistance.Generation and dissipation of the excess pore pressure are related to the shear rate and the over load ratio.As the over load ratio increases,the excess pore pressure will change from positive to negative.