LNG卸料管道穿堤布置方案的设计

中海石油气电集团有限责任公司

CNOOC Gas & Power Group

:LNG 接收站防波堤、海堤的堤顶需通行车辆,因此LNG 卸料管道穿越防波堤、海堤是其设计的难点,同时LNG 的低温特性使其不能采用顶管、埋地敷设等常规管道的穿越方案。借鉴美国、日本采用海底和地下涵洞连接码头和储罐工程的实践经验,提出LNG 卸料管道“堤顶箱涵”过堤方案:通过在堤顶道路设置钢筋混凝土箱涵,使LNG 卸料管道在同一标高内平顺通过海堤,箱涵两侧设置4%坡道,满足平交道路车辆通行要求。实例应用结果表明:该方案既不影响堤顶道路通行和堤身稳定,又能保证LNG 接收站工艺管道的正常运行及检修。同时,通过核算海堤的防潮设计水位,“堤顶箱涵”不影响海堤的防潮功能,可为面临同类问题的LNG 接收站管道穿堤设计提供参考。

It is a technical challenge how the LNG unloading pipelines crosses breakwaters or seawalls while vehicle traffic requirements are satisfied. Moreover, the conventional pipeline crossing program (e.g. pipe jacking and underground laying) is not applicable to the LNG pipelines due to their low-temperature characteristics. In this paper, a seawall crossing program of “box culvert on crown” was proposed for LNG unloading pipelines in reference to the engineering practices of connecting docks and tanks through undersea and underground culverts in the US and Japan. Under this program, a reinforced concrete box culvert is set up on either side of the seawall so as to guarantee the LNG unloading pipelines to run through the seawall smoothly at the same elevation, and 4% ramps are prepared on both sides of the box culvert so as to meet the requirements of level crossing traffic. Field application shows that this program ensures the normal operation and maintenance of process pipelines in LNG receiving terminals, with no effect on the traffic conditions at the crown and the stability of the levee. The designed damp-proof water level of the seawalls was recalculated. Furthermore, the damp-proof capacity of the seawall is not affected. This program of “box culvert on crown” provides a reference for LNG receiving terminals with similar problems in the seawall crossing design of pipelines.