海上风电宽浅式筒型基础地基承载力极限分析及试验研究

发布时间：2018-01-31 03:35

本文关键词： 海上风电宽浅式筒型基础地基承载力破坏模式极限分析模型试验　出处：《天津大学》2014年博士论文　论文类型：学位论文

【摘要】：海上风电基础在正常工作状态下不仅要承受自重产生的竖向荷载,还承受括波、浪、流等因素引起的水平荷载及由上部发电机组受风力作用产生的巨大的弯矩荷载。大直径宽浅式筒型基础作为是一种新型的海上风电基础,在能够有效的承受上述荷载的同时又具有施工方便,建造成本低等优点。但因其自身具有较大的直径,并在基础边缘有一定深度的筒壁,使得该型基础在竖向、水平及弯矩荷载作用下的地基破坏模式不同于圆形浅基础,也不同于相同高径比的圆形墩式基础。针对大直径宽浅式筒型基础的地基承载力问题进行研究,其主要的研究内容及创新性成果如下:(1)针对海上风电基础的受力特点研制了一套基础三自由度加载装置。围绕筒型基础的地基承载力问题进行了1g条件下的竖直向、水平向及弯矩承载力单向加载试验,并通过试验观测,获得了筒型基础单向加载条件下的地基破坏模式。(2)综合模型试验与数值分析结果,引入了竖直向土体破坏率,用于表征筒内土体的破坏程度,提出了基于Meyerhof公式和Terzaghi公式的两种筒型基础地基竖向承载模式,并采用极限分析理论建立了机动场,求解了宽浅式筒型基础竖向承载力的上限解。(3)结合块体极限分析上限规划法与基于柱坐标的有限元下限规划法,提出了基于柱坐标的块体极限分析下限规划法,并由此建立了宽浅式筒型基础下限解的目标函数,等式约束条件,和不等式约束条件。通过编程求解了宽浅式筒型基础地基竖直向承载力的下限解。(4)建立了与水平向承载力模型试验相对照的数值分析模型,模拟得到了水平荷载作用下的地基破坏模式,提出了适用于宽浅式筒型基础在水平荷载作用下的地基失稳模式。引入了水平向土体破坏率,用于表征筒内土体的破坏程度,建立了机动场,求解了宽浅式筒型基础地基水平向承载力的上限解。(5)建立了与抗弯模型试验相对照的数值分析模型,模拟得到了弯矩荷载作用下地基的破坏模式,提出了适用于宽浅式筒型基础在弯矩荷载作用下的地基失稳模式。引入了抗弯土体受压率,用于表征筒内土体参与抵抗弯矩的程度,建立了机动场,求解了宽浅式筒型基础地基抗弯承载力的上限解。
[Abstract]:Under the normal working condition, the offshore wind power foundation not only bears the vertical load caused by self-weight, but also bears the wave and wave. The large diameter wide shallow cylindrical foundation is a new type of offshore wind power foundation which is caused by the horizontal load caused by the flow and the huge moment load caused by the wind force on the upper generator set. At the same time, it has the advantages of easy construction and low construction cost. However, because of its large diameter and a certain depth of cylinder wall at the edge of the foundation, this type of foundation is vertical. The failure mode of foundation under horizontal and moment loads is different from that of circular shallow foundation and circular pier foundation with the same ratio of height to diameter. The bearing capacity of large diameter wide shallow cylindrical foundation is studied. Its main research contents and innovative results are as follows: 1). According to the stress characteristics of offshore wind power foundation, a three-degree-of-freedom loading device is developed. The vertical bearing capacity of cylindrical foundation is studied under the condition of 1g. Through the unidirectional loading test of horizontal and bending moment bearing capacity, the comprehensive model test and numerical analysis results of failure mode of foundation under unidirectional loading condition of cylindrical foundation are obtained. The vertical soil failure rate is introduced to characterize the failure degree of the soil in the tube. Two vertical bearing modes of the cylindrical foundation are proposed based on the Meyerhof formula and the Terzaghi formula. The upper limit solution of vertical bearing capacity of wide and shallow cylindrical foundation is obtained by using the limit analysis theory. The upper limit programming method of block limit analysis and the finite element lower bound programming method based on cylindrical coordinates are solved in combination with the upper limit programming method of block limit analysis and the finite element lower bound programming method based on cylindrical coordinates. The lower limit programming method for block limit analysis based on cylindrical coordinates is proposed, and the objective function, equality constraint condition, of the lower bound solution of wide and shallow cylindrical foundation is established. By programming the lower limit solution of vertical bearing capacity of wide and shallow cylindrical foundation, a numerical analysis model compared with horizontal bearing capacity model test is established. The failure mode of foundation under horizontal load is obtained, and the failure mode of foundation under horizontal load is put forward, and the failure rate of horizontal soil is introduced. In order to characterize the failure degree of soil in the tube, the maneuvering field is established, and the upper limit solution of horizontal bearing capacity of the wide and shallow cylindrical foundation is solved. (5) the numerical analysis model compared with the bending model test is established. The failure mode of foundation under bending moment load is obtained, and the failure mode of foundation under bending moment load is put forward, and the compression rate of bending soil is introduced. In order to characterize the degree of resistance of soil in the tube to bending moment, the maneuvering field is established, and the upper limit solution of bending bearing capacity of wide and shallow cylindrical foundation is solved.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU476.1;TM614

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