荔湾3-1气田管线路由海底峡谷段斜坡稳定性分析  

SLOPE STABILITY ANALYSIS OF SUBMARINE CANYON AREA ALONG PIPELINE ROUTE OF LIWAN3-1 GASFIELD

作　　者：修宗祥[1,2] 刘乐军[1] 李西双[1,3] 解秋红[1,3] 李家钢 胡光海[1] 

机构地区：[1]国家海洋局第一海洋研究所,青岛266061 [2]大连理工大学海岸和近海工程国家重点实验室,大连116024 [3]国家海洋局海洋沉积与环境地质重点实验室,青岛266061 [4]中海油研究总院,北京100027

出　　处：《工程地质学报》2016年第4期535-541,共7页Journal of Engineering Geology

基　　金：国家自然科学基金青年基金项目(41206058);国家科技重大专项子课题(2011ZX05056-001-02);国家重点实验室开放基金(LP1514);中央级公益性科研院所基本科研业务费专项资金项目(GY0213G25)资助

摘　　要：针对南海荔湾3-1气田管线穿过的海底峡谷区6个典型斜坡剖面,分别采用有限元强度折减法和极限平衡法开展斜坡稳定性分析,模型考虑了土层强度随深度的变化。计算结果对比表明,有限元强度折减法与极限平衡法分析结果一致,其中与Spencer法结果最接近,稳定系数相对误差小于3.5%。重力作用下各斜坡基本处于相对稳定状态,峡谷中下部土强度较低且坡度较高的局部区域接近临界状态,峡谷头部因坡度相对较小且土体强度相对较大,其斜坡稳定系数相对较高。地震水平加速度能够明显降低该区斜坡的稳定系数,且随着加速度值的增大滑动深度逐渐变大。当水平加速度达到0.2g时峡谷中下部区域大部分会发生滑动。海底地形坡度和土层强度是影响峡谷区斜坡稳定性的主要因素,且稳定系数与滑动面对局部坡度和强度分布较为敏感,合理的稳定性评价依赖于精确的地形数据与土层力学参数。The finite element strength reduction method and limit equilibrium method are used respectively for the slope stabilities of six typical profiles in the submarine canyon area where the submarine pipeline of Liwan3 - lgasfield is laid along its seabed. The soil strength characteristic of increase in depth is considered in the slope stabilities models. The comparison result shows that finite element strength reduction method and limit equilibrium method present consistent results. The stability factors obtained by the finite element strength reduction method are most closed to those of the Spencer method, with a relative error of less than 3. 5%.All the slopes are basically stable, although some local areas in the middle and lower parts of the canyon with low soil strength and high slope are close to the critical state. The slopes in the upper canyon area have relatively higher stability factors than those in the other areas. The horizontal seismic acceleration can reduce the slope stability factor greatly, and the sliding depth usually increases with the acceleration. When the horizontal acceleration is 0. 2g , most slopes in the middle and lower parts of the canyon would fail. The submarine slope angle and the soil strength are the mainly factors which control the slope stability in the canyon area. The stability factor and sliding depth are sensitive to the local slope angle and the strength distribution of the soil. A reasonable slope stability assessment result is dependent onthe accuracy of terrain data and soil mechanics parameters.

关 键 词：荔湾3-1气田 海底峡谷 海底滑坡 稳定性 

分 类 号：P694[天文地球—地质学]