防沉板基础在软黏土地基上的抗拔特性试验研究  

Experimental investigation on uplift behaviors of mudmats on soft clay

作　　者：王靖 韩聪聪[1] 刘君[1] 孔宪京[1] WANG Jing;HAN Cong-cong;LIU Jun;KONG Xian-jing(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《岩土工程学报》2022年第11期2097-2105,F0003,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51890915,51979035)。

摘　　要：防沉板基础通常用于支撑海底结构。当位于软黏土海床表面的防沉板基础受到上拔荷载时,基底-海床土界面会产生吸力。吸力可提高基础的稳定性,但同时也增加了基础的回收难度,因此需对基底吸力进行充分研究。通过一系列室内模型试验,研究位于均质土和轻微超固结土表面的防沉板基础的抗拔承载特性,考虑的影响因素有上拔速度、土强度、土的非均质度系数以及固结度。模型基础底部装有若干孔压传感器,用来研究基底吸力形成、发展和消散规律以及基础底部不同位置处吸力的分布情况。结果表明,防沉板基础的抗拔承载力由基底吸力提供,净抗拔力和平均吸力随上拔速度增加而增加,非均质度系数和固结度对抗拔承载力有显著影响。离基底中心越近,吸力越大且消失越晚,因此基础中心是降低基底吸力的最佳开孔位置。The subsea mudmats are usually used to support subsea structures. When the mudmat, located on the surface of soft clayey seabed, is subjected to uplift loads, the suction force is generated at the mudmat-soil interface. The suction is beneficial in improving the stability of the mudmat, but is disadvantageous in retrieving the mudmat. Therefore, it is necessary to investigate the invert suction systematically. A series of model tests are conducted to investigate the uplift capacity of the mudmat resting on the homogeneous or lightly overconsolidated clay. The factors influencing the uplift capacity are investigated, including the uplift velocity, the soil strength, the soil heterogeneity and the degree of consolidation. Several pore pressure transducers are installed at the invert of the model mudmat to measure the generation, development, distribution and dissipation of the pore water pressure. The test results show that the uplift capacity of the mudmat is provided by the invert suction. Meanwhile, the results show that the uplift capacity and the average suction at the invert of the mudmat the increase with increasing uplift velocity, heterogeneity and degree of consolidation. In addition, it is found that the suction near the centre of the mudmat invert is greater and disappears later than that at the margin. In order to reduce the invert suction through perforating, the optimal position of perforations should be set at the centre of the mudmat.

关 键 词：防沉板 抗拔承载力 基底吸力 超孔隙水压力 黏土 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]