随着海洋油气安全标准提高，海底管道后保护挖沟面临复杂地质带来的效率与成本挑战。传统喷射式挖沟法在硬质土、岩礁区效率低下。本文结合涠洲北部某浅水区域海底管道后保护工程，系统介绍了动力定位船搭载大型犁式挖沟机的作业实践，重点分析了该犁式挖沟机针对松散砂土、强风化玄武岩等复杂地质的适应性，阐述了基于土壤剪切强度的挖沟拖力预判方法及实际作业中的动态控制策略，通过对比理论拖力曲线与实际作业数据，验证了参数预设的有效性。本文还总结了浅水低能见度环境下的监控方案、线缆管理及应急弃置等关键技术措施，为类似浅水、复杂地质条件下的海底管道后保护挖沟作业提供了可借鉴的技术方案与数据参考。

With the increasing safety standards for offshore oil and gas， the efficiency and cost challenges of trenching for submarine pipeline protection are becoming more complex due to varying seabed substrates. Traditional jet trenching methods are inefficient in hard soil and rocky reef areas. This paper systematically introduces the operational practices of a dynamically positioned vessel equipped with a large plough-type trencher for a pipeline protection project in a shallow-water area in northern Weizhou. It focuses on analyzing the adaptability of this plow-type trenching machine to complex geological conditions ranging from loose sandy soil to strongly weathered basalt. The study elaborates on a trenching drag force prediction method based on soil shear strength and the dynamic control strategies implemented during actual operations. By comparing the theoretical drag force curve with field operational data， the effectiveness of parameter presetting is validated. This paper also summarizes key technical measures such as monitoring solutions， cable management， and emergency abandonment in shallow water with low visibility conditions， providing technical solutions and data references for post-protection trenching operations of submarine pipelines in similar shallow water and complex geological environments.