基于侧振减阻的吸力式基础沉贯纠偏机制与试验研究

With the increasing exploitation of marine resources in the deep-water zone of the South China Sea, more effective station-keeping systems are required to limit the motion of floating structures and the installation of anchor systems is much more difficult. Many studies have focused on the research of anchoring performance and application of suction buckets in deep-water sea. Suction-installed foundations are one of the most promising types of foundation, since the industry demands reusable platforms offshore in the exploitation of petroleum and natural gas with rapid construction and more vertical uplift capacity. As a new type of anchor foundation, there are so many problems about the vertical installation of suction buckets due to the complex ocean wave current and seabed geological conditions. Based on our patents and Pu tracing technology, a set of experimental facility will be developed to observe the microcosmic behavior of soil around suction buckets during local cyclic vibration on the bucket wall by a series of model tests, and to monitor the dynamic variation of pore pressure in the soil body simultaneously, revealing the mechanism of righting suction bucket with initial leaning angle. Combining theories of soil dynamics and particle flow, the effect of local cyclic vibration parameters on the righting rate of leaning bucket can be quantified and the microcosmic mechanism of development of soil heave in the bucket can be verified accordingly. A set of integral patented technology with proprietary intellectual property rights will be concluded in this project, which is of great importance to reveal anchoring mechanism and new technology development. Therefor this research program has important theoretical value and practical significance.

随着我国油气开采步入南海深水区，海上采油平台的深水锚泊系统承载性能要求更高，安装难度也更大，吸力式基础以其可重复利用、施工快、竖向承载力大而得到广泛关注。作为新型锚泊基础形式，吸力式基础应用于海洋深水区的安装难题亟待解决。复杂多变的海洋波流环境、海床地质条件使得吸力式基础难以垂直贯入海床，严重影响其承载功能。结合申请人专利技术，针对局部振动液化对吸力式基础沉贯过程中的纠偏内在机理，研制其细观模拟实验装置，开展系列模型试验，再现周围土体孔隙水压力在纠偏过程中的动态演化过程，并基于细观力学与同位素Pu示踪技术，结合土动力学理论和颗粒流理论揭示局部振动控制性参数对桶形基础纠偏速率的影响规律，以及土塞形成细观机理与纠偏机制，确立有效的桶形基础贯入自动纠偏技术。通过本项目研究，为深海吸力式基础的垂直沉贯提供一套完整的、拥有自主知识产权的专利技术，对锚泊承载机理与新技术开发具有重要理论价值与现实意义。

随着我国油气开采步入南海深水区，海上采油平台的深水锚泊系统承载性能要求更高，安装难度也更大，吸力式基础以其可重复利用、施工快、竖向承载力大而得到广泛关注。作为新型锚泊基础形式，吸力式基础应用于海洋深水区的安装难题亟待解决。本项目的研究目标是针对复杂多变的海洋波流环境、海床地质条件下吸力式基础难以垂直贯入海床的现实技术难题，基于课题组专利技术与研制的细观模拟实验装置，开展系列模型试验，研究了局部振动液化对吸力式基础沉贯过程中的纠偏内在机理，并进一步分析了该机理作用下的吸力式基础沉贯纠偏技术关键控制参数，为吸力式基础更广泛的成功应用提供理论支撑和实践指导。本项目主要完成了五大部分研究内容：（一）成功研制了吸力式基础沉贯装置，可模拟再现吸力式基础在水平地基的贯入机理以及在倾斜地基的倾斜发生、发展机制；（二）成功研制了吸力式基础抗拔承载试验装置，可模拟再现吸力式基础在上拔过程中的承载特性和土体表现机制；（三）吸力式基础沉贯过程中发生倾斜的产生因素分析与倾斜机制研究；（四）吸力式基础沉贯过程中的倾斜纠偏影响因素分析与纠偏机制研究；（五）吸力式基础在倾斜状态下的承载性能研究。