型钢截面形式对型钢混凝土闸墩承载能力的影响研究

发布时间：2018-07-01 19:01

本文选题：型钢混凝土 + 闸墩　；参考：《广西大学》2014年硕士论文

【摘要】：水利水电工程泄水建筑物中的闸墩是支撑并保证弧形闸门在所受水推力等荷载作用下安全运行的关键结构。随着我国水利水电事业的发展,超大型水电站相继开工建设,泄水建筑物下泄流量不断增加,相应的工作水头不断加大,闸墩所受荷载同样不断增大。受枢纽布置、投资等因素的制约,闸墩尺寸不可能不受限制的增加,常规的钢筋混凝土闸墩的刚度和承载能力已很难满足闸墩可靠运行的要求。因此,很有必要寻求一种新型闸墩结构,确保弧形闸门在大推力作用下能可靠运行。本文根据型钢混凝土的特点,提出了在闸墩内用型钢代替常规筋混凝土闸墩的扇形钢筋的新型型钢混凝土闸墩结构,并开展了型钢截面形式对型钢混凝土闸墩承载能力的影响研究。本文结合拟建的实际工程,采用有限元法对普通钢筋混凝土闸墩和型钢混凝土闸墩建立非线性有限元模型,并对两种结构型式的闸墩模型施加相同的荷载和边界位移条件。通过两种闸墩的对比分析,从闸墩位移,牛腿支座附近拉应力减小的趋势,抑制裂缝开展的效果,和极限承载能力的大小共同论证了型钢混凝土闸墩的合理性。本文研究了T型钢,H型钢,槽型钢,箱型钢在型钢混凝土闸墩的适用性,研究了型钢截面形式对型钢混凝土闸墩承载能力的影响,得出了如下结论：(1)以两侧闸门挡水工况下的设计荷载为基础荷载进行超载计算,得出配置T型钢闸墩的极限承载力最高,为4.5倍正常运行设计荷载,H型钢混凝土闸墩、箱型钢混凝土闸墩和槽型钢混凝土闸墩的的极限承载力均小于T型钢闸墩,极限承载力较T型钢混凝土闸墩分别减小了3.78%、7.33%和20.44%。从极限承载力来看,T型截面型钢更适合于型钢混凝土闸墩。(2)通过闸墩位移分析得出,不同截面形式的型钢混凝土闸墩整体变形规律相近。牛腿支座及下游的墩体出现向下游的相对变位,且墩尾上侧出现较大的沿闸墩高度方向的变位。在正常运行工况下,T型钢、H型钢、箱型钢、槽钢混凝土闸墩最大位移分别为0.91mm、0.87mm、0.93mm、 0.87mm。(3)从闸墩的裂缝分布和发展来判断,型钢形式对混凝土开裂和裂缝的发展影响不明显,当荷载为正常荷载的0.58倍时,配置了T型钢、H型钢、箱型钢和槽型钢的闸墩均在牛腿支座受力面与墩体相交两角点首先开裂。随着荷载的增加,牛腿支座受力面与墩体相交处开裂并向牛腿支座后方发展。(4)T型钢、H型钢、槽型钢、箱型钢混凝土闸墩墩体内型钢在加载过程中沿型钢布置方向(向下游)位移增加,其中在墩体与牛腿支座内型钢交接处变形最大。沿墩厚方向,墩体与牛腿支座内型钢交接处变位以及变形最大。(5)T型钢、H型钢、槽型钢、箱型钢混凝土闸墩内型钢首达屈服时的荷载分别为2.9、2.75、2.83、2.67倍正常运行工况设计荷载,极限荷载分别为4.5、4.33、3.58、4.17倍正常运行工况设计荷载,表明槽型钢混凝土闸墩延性最差。
[Abstract]:The piers in the drainage structures of water conservancy and hydropower projects are the key structures to support and ensure the safe operation of the arc-shaped gates under the action of water thrust and other loads. With the development of water conservancy and hydropower industry in China, superlarge hydropower stations have started construction one after another, the discharge under the discharge structure is increasing, the corresponding working head is increasing, and the load on the pier is also increasing. Restricted by the layout of the hub and investment, the size of the pier can not be increased without restriction. The stiffness and bearing capacity of the conventional reinforced concrete pier are difficult to meet the requirements of reliable operation of the pier. Therefore, it is necessary to seek a new type of pier structure to ensure the reliable operation of arc gate under the action of large thrust. According to the characteristics of steel reinforced concrete, a new type of steel reinforced concrete pier structure is proposed in this paper, in which section steel is used to replace the sector steel bar of conventional reinforced concrete pier. The influence of section form on the bearing capacity of SRC pier is studied. In this paper, the nonlinear finite element model of the common reinforced concrete pier and the steel reinforced concrete pier is established by finite element method, and the same load and boundary displacement conditions are applied to the two types of pier models. Through the comparative analysis of the two kinds of piers, the rationality of the SRC pier is demonstrated from the displacement of the pier, the decreasing tendency of tensile stress near the bracket support, the effect of restraining the crack development, and the size of the ultimate bearing capacity. In this paper, the applicability of T-section H-shaped steel, grooved steel and box steel in steel reinforced concrete pier is studied, and the influence of section form on the bearing capacity of steel reinforced concrete pier is studied. The conclusions are as follows: (1) based on the design load under the condition of water retaining on both sides of the gate, the ultimate bearing capacity of the T-shaped steel pier is the highest, which is 4.5 times the normal operating load of the H-shaped steel concrete pier. The ultimate bearing capacity of box steel concrete pier and slot steel concrete pier is smaller than that of T section steel pier, and the ultimate bearing capacity is 3.787.33% and 20.44% less than that of T section steel concrete pier, respectively. According to the ultimate bearing capacity, the T-section steel is more suitable for the steel reinforced concrete pier. (2) through the displacement analysis of the pier, it is concluded that the integral deformation law of the steel reinforced concrete pier with different sections is similar. The corbel support and the lower pier body appear the relative displacement to the downstream, and the upper side of the pier tail appears the bigger displacement along the height direction of the pier. Under normal operating conditions, the maximum displacements of T section steel, box steel and channel concrete pier are 0.91mm / 0.87mm / 0.93mm and 0.87mm / m respectively. (3) judging from the crack distribution and development of the pier, the shape of section steel has no obvious influence on the crack and crack development of concrete. When the load is 0.58 times of the normal load, the T-section H-section steel is arranged, and the gate piers of the box steel and the slot section are first cracked at the two corners of the corbel bearing surface and the pier body. With the increase of load, the interface between the bearing surface of the corbel bearing and the pier is cracked and developed to the rear of the corbel support. (4) T-section steel and grooved steel, During the loading process, the internal steel displacement of box steel concrete pier increases along the direction of section steel arrangement (downstream), in which the deformation is greatest at the junction of section steel between the pier and the corbel support. Along the direction of the thickness of the pier, the displacement and deformation of the section steel in the interface between the pier and the corbel support is the greatest. (5) the load of the section head in the T section steel bar, the slot section steel and the box steel concrete sluice pier reaches yield when it reaches the yield time, respectively, when the load is 2.79 / 2.75 / 2.83 / 2.67 times the normal operating condition design load, The ultimate load is 4.35 ~ 4.33 ~ 3.58 ~ 4.17 times the design load under normal working condition, which indicates that the ductility of the slotted steel reinforced concrete pier is the worst.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV33;TV662.2

【参考文献】