挖沟埋管是浅海海底管道的常用铺设方法，该方法能够有效降低海底管道被破坏的风险。为了进一步研究挖沟机在硬质黏土中的射流开沟规律，采用自行设计的一套适用于破碎硬质黏土的射流开沟的室内模型试验设备，开展了淹没条件下的固定射流模型试验，测量了不同射流条件下的产生的沟的深度和宽度，研究了土体强度、靶距和流速对固定射流开沟效果的影响。试验结果表明，靶距和土体强度固定时，破土深度随着流速的增加以对数规律增加，破土宽度随流速增加线性增加；在40 kPa的土体中，沟的宽度随靶距增加而增加，在80 kPa的土体中，沟的宽度随靶距增加而减小。明确了对于40KPa和80KPa的破土条件。上述研究成果可为海底管道挖沟时挖沟机的选择提供科学的依据。
Trenching and burying is a common laying method for shallow submarine pipelines, and the method can effectively reduce the risk of submarine pipelines being damaged. In order to further study the jet trenching of submarine hydraulic trencher in stiff clay, a jet trenching system that suitable for breaking stiff cohesive bed was designed, and a series of fixed jet model tests under submerged condition were carried out. The shape, depth, and width of scour hole under different jet conditions were measured, and the effects of clay strength, target distance and jet velocity on the scour hole were studied. The results show that the depth of hole increases logarithmically with increase in jet velocity under constant target distance and clay strength, and the width of hole increases linearly with increase in jet velocity. For low strength (40 kPa) clay, the width of hole increases with increase in target distance, while for high strength (80 kPa) clay, the width of hole decreases with increase in target distance.