海洋平台射流辅助沉桩试验研究

为探寻海洋石油平台桩基高效的建设方法,针对停锤后打桩困难甚至出现拒锤现象,提出高压水射流辅助沉桩的技术设想,并设计了海洋平台射流辅助沉桩模型试验装置,测试了6种不同形状喷嘴产生的射流对土塞表面的作用力。同时,通过对土体内应力分布状态进行数值模拟,得到6种喷嘴射流作用下土塞内的最大应力和最小应力,验证了模型试验结果。结果表明海洋平台桩基建设过程中,采用高压水射流辅助沉桩提高桩基建设效率是完全可行的,且6种喷嘴中等变速型喷嘴有限喷距最长,作用在土塞表面中心处的压力也最大。研究结果为海洋平台射流辅助沉桩原理样机采用等变速喷嘴试制提供了重要依据。

High-pressure Water Jet to Assist Pile Driving for Offshore Platform

In the pile foundation construction for offshore oil platform, pile drilling becomes difficult after hammer stops and even repelling of hammering occurs. To explore efficient approach of pile construction, we present a technical proposal of driving pile by high-pressure water jet, and design apparatus for model test. Forces generated by jets with six different nozzles acting on the soil plug are tested, and the stress distributions in the soil are numerically simulated. The maximum and minimum stresses in the soil plug under jet forces are obtained, and model test results are verified. Results showed that it is feasible to improve pile construction efficiency by employing high pressure water jet. Among the six different nozzles, nozzle with iso-variable velocity could generate the longest limited jet distance and in the meantime the largest force on the soil plug surface center. This research provides basis for the preparation of model machine.