耙吸式挖泥船在疏浚过程中主要采用机械切削方式将海床土体耙松，其土体切削阻力形成机制一直是疏浚技术改进的关键科研问题之一。针对海床土体切削阻力的形成机制，应用自行研制的耙齿切削土体监测装置，对黄骅港粉土进行了耙齿切削试验。试验可直观再现和测试土体被耙齿切削的动态过程及其孔隙水压力演化规律，结果显示，土体在耙齿切削过程中，由于土体在短时间内发生挤压、剪切变形，外部水体难以完成内外流体的交换，致使其土体因剪胀效应而孔隙水压力骤减（甚至成为负压），土体有效应力骤升，使得切削阻力成倍增加。

In the trailing suction hopper dredging, mechanical cutting methods are widely used to loosen the hard sedimented soil on the seabed. It is of great importance to find some effective techniques for higher soil loosening efficiency, so it is a key issue to study the mechanism of soil cutting resistance. A new experimental setup with monitoring system was developed in the tests to represent whole cutting process of the bed soil by a prototype draghead tooth. The experiments were conducted to investigate the large deformation / failure process and the pore water pressure response at the tooth-soil interface during the draghead tooth cutting of the fine sandy soil from Huanghua port, close to coast of the Bohai Sea in North China. The experimental results show that the intact soil ahead of the rake teeth was squeezed, cut and subjected to shear deformation. In the much short time of soil cutting process, the effective stress and deformation of the soil should be considered under undrained condition; and the pore water pressure decreased significantly due to the effect of soil shear dilation. The soil cutting resistance of the draghead tooth came from the increased effective soil stress which resulted from the significant decrease of the pore water pressure in the soil.