喷冲系统降低自升式平台拔桩阻力的试验研究

发布时间：2018-12-14 02:56

【摘要】：自升式作业平台作为我国勘探开采海洋油气资源的重要装备被广泛应用。在其寿命周期内，自升式平台需要多次移动位置。移动之前需要进行拔桩作业，拔桩过程可能因地质条件复杂而费时费力。如何有效降低拔桩阻力成为海洋工程界一个急需解决的技术难题。同时我国海域辽阔，不同海域之间地质情况可能差别巨大，目前我国对不同海域进行了许多地质勘探工作，积累了大量丰富的资料。但由于这些工作隶属于不同的工程项目，资料比较分散，查阅起来困难。因此，开发一个方便检索查阅的地质资料的信息系统成为一项有意义的工作。本文以埕岛海域为例，通过收集，整理地质资料，使用HTMLworkshop软件编制了一套地质信息查询系统。详细介绍查询系统编制流程。从系统制作前期的准备工作到创建项目、目录、索引文件以及最后的系统设置工作都进行详细说明。本系统可实现数据的访问、查询、检索，能够极大的加快工作效率。这为今后建立更加全面的海域地质信息查询系统提供了思路。喷冲拔桩作为降低拔桩阻力的手段在自升式平台中普遍应用，但其对降低拔桩阻力的有效性一直受到海岸工程界的质疑。为了研究喷冲系统的工作机理及其工作的有效性，本文通过小比尺的桩靴模型喷冲拔桩试验证明了喷冲系统对降低拔桩阻力效果明显。为喷冲系统在实际工程中的应用提供了理论支持。通过合理的理论假定，给出拔桩过程中需要的桩靴上部土体的重力、桩周土体侧摩阻力、桩底土体吸附力的推导过程并得出简化计算公式。通过变换地质条件、喷冲压力、桩靴埋置深度进行喷冲拔桩试验。通过试验结果分析可知，桩靴上下同时喷冲时拔桩阻力可以降低30%-50%，效果非常明显。另外，经过试验证明喷冲系统内喷冲压力的增大不会无限制的降低最大拔桩力。其理想状况为喷冲压力增加至桩靴底部土体吸附力消失，此时拔桩阻力为最小。但随着喷冲压力的增大会带来系统方面问题，，需要综合考虑。
[Abstract]:As an important equipment for exploration and exploitation of offshore oil and gas resources, jack-up platform is widely used in China. In its life cycle, the jack-up platform needs to move multiple times. It is necessary to pull out piles before moving, which may be time-consuming and laborious because of the complex geological conditions. How to effectively reduce the pile pulling resistance has become a technical problem urgently needed to be solved in the field of marine engineering. At the same time, the sea area of our country is vast, and the geological conditions of different sea areas may differ greatly. At present, China has carried out a lot of geological exploration work on different sea areas and accumulated a great deal of rich data. But because these works belong to different projects, the data are scattered, so it is difficult to consult. Therefore, the development of a convenient retrieval of geological information system has become a meaningful work. Taking Chengdao sea area as an example, a geological information query system is developed by collecting and arranging geological data and using HTMLworkshop software. Detailed introduction of query system compilation process. From system preparation to create project, directory, index file and final system setup are described in detail. The system can achieve data access, query, retrieval, can greatly speed up the work efficiency. This provides the train of thought for the establishment of a more comprehensive sea geological information query system in the future. As a means of reducing pile pulling resistance, jet punching pile is widely used in jack-up platform, but its effectiveness in reducing pile pulling resistance has been questioned by coastal engineering circles. In order to study the working mechanism and the effectiveness of the jet punching system, this paper proves that the ejection system has obvious effect on reducing the pile pulling resistance through the pile-boot model ejection test with small scale. It provides theoretical support for the application of jet impact system in practical engineering. On the basis of reasonable theoretical assumptions, the paper gives the derivation process of the gravity of the upper soil, the friction of the soil around the pile, and the adsorption force of the soil on the bottom of the pile, which are needed in the process of pile pulling, and obtains a simplified calculation formula. By changing the geological conditions, jet pressure and the depth of the pile boots, the test of spouted pile pulling was carried out. The test results show that the resistance of pulling pile can be reduced by 30-50 when the pile boots are ejected at the same time, and the effect is very obvious. In addition, it is proved that the increase of jet pressure will not reduce the maximum pile pulling force without limitation. The ideal condition is that the pressure of jet punching is increased to the bottom of the pile shoe, and the adsorption force of the soil is disappeared, and the resistance of pulling pile is the minimum. However, with the increase of jet pressure, it will bring system problems, which need to be considered comprehensively.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P742

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