地震作用对琼州海峡海缆路由区海底稳定性影向的分析
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摘要
以琼州海峡的北海—临高段海缆路由为例,利用计算对比的方法,分析了地震作用下,路由区3m以浅海底土液化或滑移的可能性,评价了路由区海底的稳定性。结果发现,在地震烈度为Ⅶ度的地震作用下,砂性土海底的地震剪应力平均值(0.86kPa,1.72kPa和2.57kPa)小于砂性土的液化剪应力(1.60kPa,3.20kPa和4.81kPa);粘性土海底的地震剪应力平均值(1.25kPa,2.49kPa和3.74kPa)小于粘性土的抗滑剪应力平均值(4.07kPa,4.61kPa和4.49kPa),路由区海底稳定性良好;在地震烈度为Ⅷ度的地震作用下,砂性土海底的地震剪应力平均值(1.73kPa,3.45kPa和5.12kPa)大于砂性土的液化剪应力;粘性土海底的地震剪应力平均值(2.49kPa,4.98kPa和7.47kPa)除表层外,大于粘性土的抗滑剪应力,路由区海底会发生失稳破坏。
The liquefaction and slippage of sediment are calculated and analyzed under seismic actions along the route area of cable between Beihai City and Ligao County. Then, seabed stability is analyzed in the area. Conclusion is as follows: the seabed stability is all right when seism intensity is Ⅶ.The reason is that the average values of seismic shear stress ( 0.86 Kpa, 1.72 kPa and 2.57 kPa ) are less than the values of liquefying shear stress ( 1.60 Kpa, 3.20 kPa and 4.81kPa ) in the sandy seabed, and the average values of seismic shear stress ( 1.25 kPa, 2.49 kPa and 3. 74 kPa ) are less than the values of cohesion shear stress ( 4.07 Kpa, 4.61 kPa and 4.49 kPa ) in the clay seabed. The seabed stability is destroyed when seism intensity is Ⅷ. The reason is that the average values of seismic shear stress ( 1.73 kPa, 3.45 kPa and 5.12 kPa ) are bigger than the values of liquefying shear stress in the sandy seabed, and the average values of seismic shear stress ( 2.49 kPa, 4.98 kPa and 7.47 kPa ) are bigger than the values of cohesion shear stress in the clay seabed.
The liquefaction and slippage of sediment are calculated and analyzed under seismic actions along the route area of cable between Beihai City and Ligao County. Then, seabed stability is analyzed in the area. Conclusion is as follows: the seabed stability is all right when seism intensity is Ⅶ.The reason is that the average values of seismic shear stress ( 0.86 Kpa, 1.72 kPa and 2.57 kPa ) are less than the values of liquefying shear stress ( 1.60 Kpa, 3.20 kPa and 4.81kPa ) in the sandy seabed, and the average values of seismic shear stress ( 1.25 kPa, 2.49 kPa and 3. 74 kPa ) are less than the values of cohesion shear stress ( 4.07 Kpa, 4.61 kPa and 4.49 kPa ) in the clay seabed. The seabed stability is destroyed when seism intensity is Ⅷ. The reason is that the average values of seismic shear stress ( 1.73 kPa, 3.45 kPa and 5.12 kPa ) are bigger than the values of liquefying shear stress in the sandy seabed, and the average values of seismic shear stress ( 2.49 kPa, 4.98 kPa and 7.47 kPa ) are bigger than the values of cohesion shear stress in the clay seabed.
引文
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[4]周晶,李昕等.地震时海底悬跨管道动力特性试验研究[J].水利学报,2003,1,12-16.
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[6]詹文欢,钟建强等.华南沿海地质灾害[M].北京:科学出版社,1996,91-98.
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