【摘要】：為克服內(nèi)河碼頭建設(shè)中大水位差對施工的影響,鋼護筒-鋼筋混凝土結(jié)構(gòu)樁基已經(jīng)廣泛應(yīng)用于內(nèi)河高樁碼頭工程實踐。本文結(jié)合交通運輸部建設(shè)科技項目“在役高樁碼頭結(jié)構(gòu)整體安全性評估技術(shù)”,依托重慶果園港碼頭結(jié)構(gòu)二期工程,通過室內(nèi)模型試驗及理論分析的方法,對大直徑鋼護筒-鋼筋混凝土樁的承載性能及長期工作性能進行研究,主要的研究內(nèi)容及相關(guān)的研究結(jié)論為:(1)結(jié)合果園港碼頭二期工程,完成了模型設(shè)計。開展了6組不同參數(shù)的模型樁基的承載力試驗研究。研究發(fā)現(xiàn):對于D/δ≥20薄壁鋼護筒-鋼筋混凝土樁基,在應(yīng)力水平低于0.45的軸向荷載作用下,鋼護筒與內(nèi)部鋼筋混凝土的縱向應(yīng)變大小基本相同,此時鋼護筒對內(nèi)部鋼筋混凝土的約束作用并不明顯,而在應(yīng)力水平高于0.45的軸向荷載作用下,鋼護筒將對鋼筋混凝土施加側(cè)向約束作用。此側(cè)向約束作用可延緩微裂縫的開展,從而增強樁基的延性及極限承載能力;鋼護筒對核心混凝土的側(cè)向約束作用隨鋼護筒厚度的增加而增大;(2)對不同鋼護筒厚度下的鋼護筒-鋼筋混凝土模型樁基的橫向純彎構(gòu)件性能進行研究。研究發(fā)現(xiàn):對于長細比L/D小于8的模型樁,在三分點加載方式下,相比于鋼筋混凝土模型樁基,鋼護筒的存在可有效增大破壞時的跨中撓度,避免脆性破壞;同時,鋼護筒的存在可極大提高此類構(gòu)件的極限彎矩。(3)對鋼護筒-鋼筋混凝土模型樁基在長期荷載作用下核心混凝土徐變規(guī)律進行了研究,主要變量參數(shù)為鋼護筒厚度。并將試驗結(jié)果與混凝土徐變理論模型計算結(jié)果比較,研究發(fā)現(xiàn):在應(yīng)力水平低于0.45的軸向荷載作用下,鋼護筒-鋼筋混凝土構(gòu)件核心混凝土的徐變規(guī)律與混凝土結(jié)構(gòu)徐變規(guī)律相同,均是前期發(fā)展較快而后期發(fā)展逐漸緩慢;鋼護筒-鋼筋混凝土樁的徐變值及徐變系數(shù)均小于同齡期時理論計算值且鋼護筒厚度越大,同齡期下混凝土的徐變值越小;(4)與混凝土典型徐變模型的比較發(fā)現(xiàn),在應(yīng)力水平低于0.45的軸向荷載作用下,采用混凝土徐變的MC90模型計算的結(jié)果與試驗結(jié)果偏差相對較小。同時,用有限元軟件LINK3D對長期性能進行數(shù)值模,結(jié)果與試驗結(jié)果較為吻合。
[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，

本文編號：2287484