复合加载条件下筒型基础深水防波堤破坏模式及承载性能研究

With the expansion of breakwater buildings and pier to the deep sea area, bucket foundation deep-water breakwater as a new type of engineering structures is being researched and popularized. Currently, there are no specifications or standards of the design calculation method. In this study, bearing capacity of bucket foundation deep-water breakwater under combined loading condition is investigated through numerical simulation, centrifuge model tests and theoretical analysis. Based on the three-dimensional finite element model, failure mechanism of bucket foundation deep-water breakwater under combined loading conditions is evaluated. At the same time, A series of centrifuge model tests are carried out to obtain the failure mechanism of bucket foundation deep-water breakwater under combined loading conditions. A three-dimensional limit analysis method is developed to evaluating the bearing capacity of bucket foundation deep-water breakwater. The three-dimensional failure envelope of bucket foundation deep-water breakwater under combined loading conditions is searched by improved Swipe test procedure, and the control parameters of failure mechanism are calibrated. Accordingly, the failure envelope equation of bucket foundation deep-water breakwater under combined loading conditions is revised and improved. The object of this study is to reveal the stability and bearing capacity characteristics of bucket foundation deep-water breakwater under combined loading conditions, and to provide a theoretical reference for the optimal design and application of bucket foundation deep-water breakwater.

随着防浪建筑物及无掩护码头向深海水域的拓展，筒型基础深水防波堤作为一种新型的港口与海岸工程结构，其设计计算方法目前尚无规范或标准可寻。本项研究将联合运用数值模拟、离心模型试验和理论分析等手段，深入探讨复合加载条件下筒型基础深水防波堤"双排筒基础-地基"体系的承载性能。基于三维有限元数值模型对复合加载条件下筒型基础深水防波堤的失稳模式及地基破坏机理进行评价，并通过离心模型试验进行验证，进而抽象得到复合加载条件下筒型基础深水防波堤地基失稳模式，通过塑性极限分析理论建立筒型基础深水防波堤极限承载力的三维极限分析上限解法。通过变动参数，构建复合加载情况下筒型基础深水防波堤的极限承载力包络面，并标定地基土体破坏模式的控制参数，以修正和完善复合加载情况下筒型基础深水防波堤地基破坏包络面方程。本项目旨在揭示复合加载条件下筒型基础深水防波堤稳定性及地基承载力特性，为该结构的优化设计与应用提供理论参考依据。

对单筒基础结构进行三维竖直极限承载力分析，通过塑性极限分析理论提出了一种单筒基础承载力的三维极限分析上限方法。研究了复合加载条件下单筒基础结构的稳定性，采用基于位移控制的Swipe试验加载方式计算得到不同水平荷载作用点情况下，不同长径比的单筒基础的V-H承载力破坏包络面。进而得到复合加载条件下筒型基础在V-M-H复合加载条件下的三维承载力破坏包络面。进行了筒形基础防波堤承载性能分析，建立筒形基础防波堤三维数值模型，研究了不同荷载下筒型基础防波堤和地基土体的相互作用，地基土体参数以及不同压重对筒型基础防波堤承载力的影响，筒形基础防波堤基础筒竖向、环向路径、筒壁底部以及基础筒底部土压力等问题。最后对筒型基础防波堤地基土体进行离心机模型试验，验证实验结果有效性同时获得不同竖向荷载与地基沉降之间的关系。该研究揭示复合加载条件下筒型基础深水防波堤稳定性及地基承载力特性，为该结构的优化设计与应用提供理论参考依据。