【作者】 司建辉；

【导师】 陈尧隆； 简政；

【作者基本信息】 西安理工大学 ， 水工结构工程， 2009， 博士

【摘要】 预应力闸墩作为大型弧型闸门的支承结构,在水利水电工程中得到了广泛应用。然而,当前预应力闸墩普遍拉锚系数偏大,结构形式不尽合理,在锚索预应力及巨大弧门推力的共同作用下,闸墩锚块内应力状态复杂且应力值大。为了使锚块内部的应力得以释放,近年来,各种新型空腔预应力闸墩在实际工程中得到了应用,也形成了初步的计算理论及方法,但在空腔位置、大小和形状的确定上,尚未做出深入细致的研究；锚头部位混凝土承受巨大的预应力作用,研究其极限承载力究竟是多少对预应力吨位的选择具有重要的学术价值。本文以实际工程为背景,研究一种新型的闸墩结构型式—空腔结构颈缩式预应力闸墩,采用大型有限元结构分析软件ABAQUS对其在不同荷载工况作用下进行模拟,并对锚块中空腔的位置、大小以及形状进行优化,从而找到合理的空腔锚块结构形式,并运用精细有限元弹塑性分析方法对锚头部位混凝土极限承载力进行了研究。用ABAQUS建立预应力闸墩的三维有限元模型,研究各种工况及荷载组合下的预应力闸墩及锚块的应力状态,分析锚块内的应力分布情况,通过与非预应力闸墩、简单锚块式预应力闸墩、颈缩式预应力闸墩进行对比研究,对空腔结构预应力闸墩的结构型式进行评价；研究开槽锚块预留空腔在不同厚度下的应力分布,研究空腔位置向上下游移动对应力分布的影响,通过分析确定在给定工况和荷载组合下,锚块的最佳空腔厚度和空腔位置；研究非矩形空腔布置的可行性,采用矩形外接拱形结构来代替矩形空腔,对四种起拱高度方案进行分析研究,并根据计算结果找出最合理的方案；对锚索永存张拉吨位进行优化,以提高锚索预压效果,降低拉锚系数；对锚头部位混凝土进行精细有限元弹塑性分析,得到其极限承载力。通过本文的研究,对新型空腔结构颈缩式预应力闸墩的应力分布和结构优化进行了深入分析,研究成果为新型弧门支撑结构预应力闸墩的设计提供了理论上的指导和工程实际应用价值。更多还原

【Abstract】 Pre-stressed pier is used as supporting structure of large-scale arc-type gates, which has been widely applied in hydraulic engineering. However, the pull-anchor coefficient is generally too high in the present pre-stressed piers, the structure is not reasonable. The stress in a pre-stressed pier is quite complicated and the stress is very high due to the combined action of the pre-stress of anchor cable and the huge thrust of arc-gate. To release the stress in an anchor block, various new cavity pre-stressed piers have been applied, formulating some computation theory and method. However, no detailed work has been reported in determining the position, size and shape of a cavity. The pre-stress in the concrete part of an anchor head is enormous, and the limit bearing capacity is very important for choosing a pre-stress tonnage.A new pier structure is studied in the present work---cavity structure necking pre-stressed pier. The finite analysis software ABAQUS has been utilized to simulate different load conditions, optimizing the position, size and shape of the cavity in anchor blocks in order to search for a reasonable cavity pier structure,In addition, the refined finite element elasto-plastic analysis has been conducted to investigate the limit bearing capacity in the concrete part of an anchor head Three-dimensional finite element model has been built by using ABAQUS to investigate the stress status in a pre-stressed pier and pier block under different load conditions and to analyze the stress distribution in the anchor block, appraising the structure of a cavity structure necking pre-stressed pier by comparing with the non-pre-stressed pier, simple anchor pre-stressed pier and necking pre-stressed pier. The stress distribution in the slotted anchor reservation cavity has been studied for different thicknesses, and the effect of the cavity position on the stress distribution is also investigated. The optimal thickness and position of the cavity is determined at a given working condition and load condition. The feasibility of non-rectangle cavity layout has been analyzed. Replacing the rectangle cavity with the rectangle circumscribed arched structure, and four camber heights are studied to search for the optimal one. The perpetuation tension tonnage of an anchor cable has been optimized in order to improve the preloading effect of the anchor cable. The limit bearing capacity is obtained by using the refined finite element elasto-plastic analysis on the concrete in the anchor head part.The present work gives detailed analysis on the stress distribution of new cavity structure necking pre-stressed piers and on structure optimization, which provides some guidance for designing a new arc-gate supporting structure pre-stressed pier.更多还原