内河高桩码头大直径桩基长期工作特性研究
发布时间：2018-10-22 14:57
【摘要】：为克服内河码头建设中大水位差对施工的影响,钢护筒-钢筋混凝土结构桩基已经广泛应用于内河高桩码头工程实践。本文结合交通运输部建设科技项目“在役高桩码头结构整体安全性评估技术”,依托重庆果园港码头结构二期工程,通过室内模型试验及理论分析的方法,对大直径钢护筒-钢筋混凝土桩的承载性能及长期工作性能进行研究,主要的研究内容及相关的研究结论为:(1)结合果园港码头二期工程,完成了模型设计。开展了6组不同参数的模型桩基的承载力试验研究。研究发现:对于D/δ≥20薄壁钢护筒-钢筋混凝土桩基,在应力水平低于0.45的轴向荷载作用下,钢护筒与内部钢筋混凝土的纵向应变大小基本相同,此时钢护筒对内部钢筋混凝土的约束作用并不明显,而在应力水平高于0.45的轴向荷载作用下,钢护筒将对钢筋混凝土施加侧向约束作用。此侧向约束作用可延缓微裂缝的开展,从而增强桩基的延性及极限承载能力;钢护筒对核心混凝土的侧向约束作用随钢护筒厚度的增加而增大;(2)对不同钢护筒厚度下的钢护筒-钢筋混凝土模型桩基的横向纯弯构件性能进行研究。研究发现:对于长细比L/D小于8的模型桩,在三分点加载方式下,相比于钢筋混凝土模型桩基,钢护筒的存在可有效增大破坏时的跨中挠度,避免脆性破坏;同时,钢护筒的存在可极大提高此类构件的极限弯矩。(3)对钢护筒-钢筋混凝土模型桩基在长期荷载作用下核心混凝土徐变规律进行了研究,主要变量参数为钢护筒厚度。并将试验结果与混凝土徐变理论模型计算结果比较,研究发现:在应力水平低于0.45的轴向荷载作用下,钢护筒-钢筋混凝土构件核心混凝土的徐变规律与混凝土结构徐变规律相同,均是前期发展较快而后期发展逐渐缓慢;钢护筒-钢筋混凝土桩的徐变值及徐变系数均小于同龄期时理论计算值且钢护筒厚度越大,同龄期下混凝土的徐变值越小;(4)与混凝土典型徐变模型的比较发现,在应力水平低于0.45的轴向荷载作用下,采用混凝土徐变的MC90模型计算的结果与试验结果偏差相对较小。同时,用有限元软件LINK3D对长期性能进行数值模,结果与试验结果较为吻合。
[Abstract]:In order to overcome the influence of large water level difference on the construction of inland river wharf, the pile foundation of steel tube-reinforced concrete structure has been widely used in the engineering practice of inland river high pile wharf. In this paper, combined with the construction of science and technology project of Ministry of Communications and Transport, "overall safety assessment technology of in-service high pile wharf structure", relying on the second phase of Chongqing Orchard Port structure Project, through indoor model test and theoretical analysis method, The load-bearing performance and long-term working performance of large-diameter steel sheet-reinforced concrete pile are studied. The main research contents and related conclusions are as follows: (1) combined with the second phase of Orchard Port Wharf, the model design has been completed. The bearing capacity of six groups of model pile foundations with different parameters was studied. It is found that the longitudinal strain of steel retaining tube and internal reinforced concrete is basically the same when the stress level is less than 0.45 for D / 未 鈮，
本文编号：2287484
[Abstract]:In order to overcome the influence of large water level difference on the construction of inland river wharf, the pile foundation of steel tube-reinforced concrete structure has been widely used in the engineering practice of inland river high pile wharf. In this paper, combined with the construction of science and technology project of Ministry of Communications and Transport, "overall safety assessment technology of in-service high pile wharf structure", relying on the second phase of Chongqing Orchard Port structure Project, through indoor model test and theoretical analysis method, The load-bearing performance and long-term working performance of large-diameter steel sheet-reinforced concrete pile are studied. The main research contents and related conclusions are as follows: (1) combined with the second phase of Orchard Port Wharf, the model design has been completed. The bearing capacity of six groups of model pile foundations with different parameters was studied. It is found that the longitudinal strain of steel retaining tube and internal reinforced concrete is basically the same when the stress level is less than 0.45 for D / 未 鈮，
本文编号：2287484
本文链接：https://www.wllwen.com/kejilunwen/shuiwenshuili/2287484.html
