深井降水条件下的高边坡土石围堰稳定性分析

Stability analysis of high earth-rock cofferdam under the condition of deep-well dewatering

在深厚透水层地区,可采用无止水帷幕土石围堰结合深井降水技术在临海环境中创造干地施工条件。为研究深井降水对围堰稳定性的影响,依托埃及苏赫纳第二集装箱码头工程,运用GeoStudio软件,分析降水井正常运行时的高边坡土石围堰的渗流分布规律及边坡稳定性。建立不同目标降水位与整体边坡最小安全系数的关系曲线,并与集水明排工况下的围堰稳定性进行对比。结果表明:1)渗流在向陆侧发展的过程中受降水井控制作用明显,围堰坡脚不产生渗流逸出点,稳定性可以满足要求。2)当目标降水位升高时,围堰稳定性呈降低趋势。3)当目标降水位降至一定深度后,浸润线达到一定埋深,围堰稳定性几乎不受渗流影响,稳定系数不再增加。4)分析结果可以为类似工程提供合理的围堰设计思路。

In the area with a thick permeable stratum,the dry condition construction under the coastal environment can be achieved by combination of earth-rock cofferdam without water-proof curtain and deep-well dewatering technology.In order to study the influence of deep-well dewatering conditions on the stability of cofferdams,this paper analyzes and discusses the seepage distribution and slope stability of high earth-rock cofferdam during the operation of dewatering wells by GeoStudio based on Egypt port of Sokhna Container Terminal Basin 2 Project.It is established that the relationship curve between different target dewatering levels and the minimum safety factor of the overall slope stability,and compare with the stability of the cofferdam under the condition of open drainage of water collection.The results show that:1)The seepage is obviously controlled by the dewatering well in the process of developing towards the land side.As there is no seep point in the toe of the cofferdam,the stability can meet the safety requirements.2)When the target dewatering level rises,the stability of the cofferdam tends to decrease.3)When the target dewatering level falls to a certain depth,the phreatic line reaches a certain depth,and the stability of the cofferdam is almost not affected by seepage while the stability coefficient no longer increases.4)The analysis results can provide a reasonable design approach for similar projects.