波浪与盾构施工耦合作用对新建海堤稳定性影响机理研究

Fully utilizing ocean space and developing island infrastructure construction are extremely important to the development of the marine economic of China. Unfortunately, marine soft soil has high sensitivity and strong structure and its strength and stiffness will decrease significantly by external disturbance. Moreover, the safety and stability of constructed buildings will be seriously affected. On the background of the shield tunnel for large coastal power plants water intakes underground crossing newly-biult seawall, a method of combining laboratory test, model test, theoretical modeling with numerical analysis is used in this subject. . Firstly, the laboratory tests such as shear wave velocity tests, one-dimensional compression tests, static and dynamic triaxial tests on the natural and disturbed soft soil are carried out to study the mechanical property of the marine soft soil under the coupled disturbed state. According to the test results, the static and dynamic constitutive models considering disturbance of marine soft soil are established. . Secondly, on basis of the proposed constitutive models, three dimensional numerical simulations are carried out to model the process of a shield tunnel underground crossing the newly-built sea dike. Moreover, the mechanism of the coupled disturbance on the stablility of the newly-built sea dike is obtained by combing with the model test results. . Finally, the stability calculation model of the newly-built sea dike considering the disturbance and the optimization design method of the shield construction parameters are proposed. The implement of this subject will enrich and develop the constitutive theory and calculation method of marine soft soil under complex disturbed state. Moreover, it can proved scientific theory basis for the design and construction of the infrastructure construction. the anti-slide design in the practical engineering. Therefore, the project has important scientific significance and application value.

充分利用海洋空间，大力开展海岛基础设施建设，对于我国发展海洋经济具有重大意义。然而，海洋软土灵敏度高、结构性强，在外界扰动下其强度和刚度将显著降低，严重影响已建构筑物的安全和稳定性。本项目以沿海大型电厂输水隧道盾构施工穿越新建海堤处理技术为背景，采用室内试验、模型试验、理论建模和数值模拟相结合的方法，对原状和扰动海洋软土开展剪切波速、一维压缩和动、静三轴等试验，研究波浪与盾构施工耦合作用下海洋软土的物理力学特性，建立考虑耦合扰动作用的软土本构模型；在此基础上开展波浪作用下盾构穿越新建海堤的三维数值模拟，结合模型试验结果，揭示波浪与盾构施工耦合作用对新建海堤稳定性扰动影响机理；并提出考虑扰动效应的新建海堤三维稳定性计算方法。本项目的完成将大大地丰富和发展复杂扰动条件下海洋软土本构理论与计算技术，为海岛基础设施设计和施工提供必要的科学依据，具有重要的科学意义和应用价值。

充分利用海洋空间，大力开展海岛基础设施建设，对于我国发展海洋经济具有重大意义。然而，海洋软土灵敏度高、结构性强，在外界扰动下其强度和刚度将显著降低，严重影响已建构筑物的安全和稳定性。本项目以沿海大型电厂输水隧道盾构施工穿越新建海堤处理技术为背景，采用室内试验、理论建模和数值模拟相结合的方法，分析波浪荷载和盾构施工荷载的特性，开展了考虑盾构施工引起土体损失和波浪荷载作用下主应力轴连续循环旋转的空心圆柱扭剪试验研究，提出了统一的扰动函数表达式，结合宁波轨道交通的十字板剪切试验资料，预测了扰动状态下软土的力学参数，开发了考虑扰动影响的土体本构模型计算程序。根据波浪作用下盾构穿越海堤的现场试验和有限元模拟结果，分析了海堤地基的变形产生机理与变化规律，揭示盾构施工和波浪荷载耦合作用对新建海堤稳定性的扰动机理；最后基于边坡稳定性计算理论和智能优化技术，建立考虑扰动影响的海堤三维可靠性计算模型。本项目的丰富和发展了复杂扰动条件下海洋软土本构理论与计算技术，可在海岛基础设施设计和施工得到推广应用。