淹没式移动射流对黏性底床开沟试验研究

以试验方法研究双喷式射流结构对软质黏性底床上可沉降管道移动射流开挖规律。通过黄土、高岭土、水泥配置低剪切强度试验黏土，揭示喷嘴射流速度、喷嘴平移速度对冲坑特征尺寸影响规律。以边界层剪应力分析冲坑形态变化，并引入低射流靶距下反映侵蚀能力强度的回归侵蚀特征值Z进行无量纲化分析。结果表明：双喷式垂直射流形成的冲坑断面轮廓具有中心对称性，移动射流形成的冲坑纵向剖面线具有几何相似性。冲坑特征尺寸随射流速度呈近似线性变化，随喷嘴平移速度增加呈减小趋势。剪切强度增加使得黏土抗侵蚀能力增强，冲坑稳定断面曲线由V形向U形逐渐过渡变化。

Experimental study on mobile jet impingement on cohesive bed for submergence-induced channel formation

This study experimentally investigates the variation patterns of mobile jet excavation on soft cohesive bed with a dual-nozzle jet structure. Low shear strength clay specimens of loess, kaolin, and cement are prepared, elucidating the influence of nozzle jet velocity and nozzle translation velocity on scour pit dimensions. The morphological changes of craters are analyzed based on boundary layer shear stress, and a dimensionless erosion characteristic value Z, reflecting erosion intensity under low jet-target distances, is introduced for regression analysis. Results indicate that craters formed by vertically impinging dual jets exhibit a centrally symmetrical cross-sectional profile, and the longitudinal profile of craters formed by mobile jets demonstrates geometric similarity. The scour pit dimensions show an approximate linear increase with jet velocity and a decreasing trend with increasing nozzle translation velocity. The increase in shear strength enhances the clay’s resistance to erosion, leading to a gradual transition of the stable crater cross-sectional curve from V-shaped to U-shaped.