海洋平台桩基安装过程对土阻力的影响分析

提高桩基可打入性预测的精度一直是海洋工程界普遍关心的问题。影响桩基可打入性分析结果的因素有很多,很多学者对此进行了研究,但受到各种因素的限制,对于打桩过程的影响鲜有涉及。针对某海域现场两根试验桩的实测数据、室内试验数据和现场CPT结果,采用波动方程方法对在砂土中进行打桩时的打桩过程对打桩土阻力(SRD)的影响进行了研究。分析结果显示:在砂土中,即使桩径达到2.438m仍然可以形成闭合的土塞；相同土质条件下,打桩过程中不同的锤击能量导致了不同的锤击数,并进一步产生了SRD的差异,这说明打桩所导致的侧阻退化程度与打桩过程有关。CPT方法用于评价砂土中打桩的SRD的精度优于传统方法。在本次试验条件下,对于形成土塞的情况,ICP方法的计算结果偏小。

Analysis of pile driving process influence on the Soil Resistance to driving

The pile drivability prediction is one of the important problem concerned by the marine engineers. Many factors effect the results of pile drivability analysis and many researchers have made some works on it, but the influence of pile driving process on it is rarely involved. Based on the in situ tests of two piles, CPT results and the results from indoor tests, the influence of pile driving process on soil resistance to driving in the sand was studied by wave equation method. The analysis results show that the soil plug could form in the pile even if pile diameter is 2.438m when pile driving in sand; Under the same soil condition, different impact energy in driving leads to the difference of blow counts and then the difference of SRD. This means that the degradation of pile friction caused by pile driving is related to the pile driving process. The CPT based methods used to evaluate the accuracy of SRD in sand is better than the traditional methods. In this analysis, the calculation results of the ICP method is smaller in the case of soil plug closure.