油气管道沉管技术在珠三角淤泥质地层中的应用

摘要

珠海中山天然气管道沿线多为淤泥质地层，由于较深的淤泥质土层导致管道上浮及水土流失，致使管道埋深不足，影响到管道自身安全及周围土地的耕种。对于油气管道埋深不足，首先应根据地形条件及管道自身情况确定是否可以采用沉管技术，其次根据地质条件、水文情况及技术水平合理选择沉管施工方法。由于油气长输管道输送介质的压力较高，沉管施工过程中存在较大的风险，因此必须合理设计沉管管道的开挖长度、纵断面挠度及支撑座间距，管道强度经校核应满足要求。实践表明，在珠三角淤泥质地层沉管过程中必须充分考虑淤泥对沉管的影响，采取合理的沉管施工步骤和排水措施，才能保证沉管的顺利进行。%The stratums along the Zhuhai-Zhongshan gas pipeline are mostly muddy lay-ers,since the deep muddy layers lead to the floating of the pipeline and the losing of the soil, the buried depth of the pipeline is not enough, which has affected not only the pipeline its own safety,but also the farming land around.For the insufficient depths of oil and gas pipe-lines, firstly, we should determine whether we can use immersed tube technology according to the conditions of terrains and pipelines, secondly, we should choose a reasonable im-mersed tube construction method, which is based on geological conditions, hydrologic re-gime and technical level. Due to the high pressure of the transporting medium in oil and gas pipelines, there is a big risk during the construction process of the immersed tube, there-fore, the excavation length, the profile deflection and the support seat pitch of the pipelines must be designed reasonably, and the strength checking of the pipelines must meet the re-quirements. The practice shows that the impact of the muddy layers on the pipelines must be fully considered during the immersed tube process in the muddy layers of the Pearl River Del-ta area, and reasonable construction steps and drainage measures should be taken in order to ensure the smooth progress of the immersed tube.