水射流冲埋砂质海床土体数值模拟

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振动与冲击 ›› 2019, Vol. 38 ›› Issue (13) : 253-260.

论文

水射流冲埋砂质海床土体数值模拟

池寅1，时豫川1,吴海洋2,苏洁3,余敏1，卢秋如1

作者信息 +

Numerical simulation for water jet flushing sandy seabed soil

CHI Yin1， SHI Yuchuan1, WU Haiyang2, SU Jie3, YU Min1， LU Qiuru1

Author information +

文章历史 +

摘要

基于SPH-FEM耦合算法，利用ANSYS/LS-DYNA软件建立水射流与海床土体的2D模型，研究水射流冲埋砂质海床土体的过程，分析冲埋过程中的应力波特性及喷射压力和砂质海床土体物理力学指标对冲埋速率的影响规律。结果表明：应力波在海床土体内部沿水射流中心线方向形成，且在扩散过程中能量不断耗散，应力最大值在水射流中心线与海床土体表面接触点处。喷射压力越大，冲埋速率越快，同一时刻的冲埋深度随喷射压力的增大呈线性增长；对于具有相同密实度的砂质海床土体，冲埋速率随剪切模量的增大而降低，且水射流速度越大，剪切模量的影响越显著；对于细砂类砂质海床土体，冲埋速率随内聚力和内摩擦角的增大呈线性下降的趋势；土体孔隙率对冲埋速率的影响较小。通过与参考文献中侵蚀深度的对比，证明数值模型的准确性。通过对数值模拟结果进行拟合，得到冲埋深度与时间的关系式，可作为不同海床土体条件下选择合适喷射压力的参考。

Abstract

Here, based on the SPH-FEM coupled algorithm, 2D models for water jet and seabed soil were established using the software ANSYS/LS-DYNA to study the process of water jet flushing sandy seabed soil, and analyze influence laws of stress wave characteristics, injection pressure and physical and mechanical indexes of sandy seabed soil on flushing rate. The results showed that stress wave inside seabed soil is formed along the center line of water jet, its energy is dissipated continuously in diffusion process, the maximum stress is at the contact point between water jet center line and seabed surface; the larger the injection pressure, the faster the flushing rate, flushing depth at the same time instant increases linearly with increase in injection pressure; for sandy seabed soil with the same compactness, flushing rate drops with increase in soil’s shear modulus, the larger the water jet velocity, the more significant the influence of shear modulus; for fine sandy seabed soil, flushing rate drops linearly with increase in sand’s cohesion and internal friction angle; soil porosity has smaller influence on flushing rate; compared with the depth of invasion published in literature, the correctness of the numerical model is verified; the relation expression between flushing depth and time is obtained through fitting numerical simulation results, and it can provide a reference for choosing a proper injection pressure under different seabed soil conditions.

导出引用

池寅1，时豫川1,吴海洋2,苏洁3,余敏1，卢秋如1. 水射流冲埋砂质海床土体数值模拟[J]. 振动与冲击, 2019, 38(13): 253-260

CHI Yin1， SHI Yuchuan1, WU Haiyang2, SU Jie3, YU Min1， LU Qiuru1. Numerical simulation for water jet flushing sandy seabed soil[J]. Journal of Vibration and Shock, 2019, 38(13): 253-260

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