本文選題：大直徑鋼護筒嵌巖樁 + 試驗研究��； 參考：《重慶交通大學(xué)》2015年博士論文

【摘要】：本文結(jié)合國家科技支撐計劃《三峽水庫常年回水區(qū)航運工程建設(shè)關(guān)鍵技術(shù)研究(2011BAB09B01)第4專題“深水碼頭嵌巖樁基礎(chǔ)承載性狀及設(shè)計技術(shù)研究”,依托重慶港果園作業(yè)區(qū)二期擴建工程,通過室內(nèi)單樁物理模型對比試驗、碼頭鋼護筒嵌巖樁基的系列數(shù)值模擬分析并借助相應(yīng)的物模試驗成果驗證,對內(nèi)河框架碼頭鋼護筒嵌巖樁基在豎向和水平力作用下的受力性狀、鋼護筒與混凝土界面特性分別進行了研究,獲得的主要研究成果如下:(1)根據(jù)大小比尺單樁對比試驗結(jié)果,在豎向荷載作用下,鋼護筒嵌巖樁工作性狀與一般嵌巖樁大致相同;在水平荷載作用下,鋼護筒嵌巖樁與普通嵌巖樁失效模式不同,普通嵌巖樁破壞面傾斜且在地基表面附近,鋼護筒嵌巖樁破壞面水平,且橫穿鋼管底部。(2)在水平荷載作用下,受壓側(cè)鋼護筒-混凝土界面粘結(jié)較好,受拉側(cè)界面發(fā)生滑移;拉應(yīng)力顯著大于壓應(yīng)力,結(jié)構(gòu)受力狀態(tài)較差。(3)大直徑鋼護筒嵌巖單樁由于側(cè)阻力增加,垂直承載能力提高,樁嵌巖深度增加,但承載能力增加不大,護筒嵌巖深度的經(jīng)濟合理嵌深大約為(1~2)D(D為樁徑);鋼護筒能增加水平承載力,減少位移,可減小樁身拉應(yīng)力及縮小拉應(yīng)力區(qū)域,鋼護筒段抗彎能力顯著增加,但在護筒底端有突變。(4)框架碼頭排架中各鋼護筒嵌巖樁均呈現(xiàn)樁頂位移最大、巖面處接近零,各樁位移基本相同且明顯小于無鋼護筒情況;最大負彎矩在樁頂、最大正彎矩在巖面處,巖面以上段明顯大于無鋼護筒情況,嵌巖段變化不大,最大彎矩出現(xiàn)在后列樁;剪力在橫撐處有突變、嵌巖段反向,最大剪力也出現(xiàn)在后列樁;嵌巖段軸力上下兩端小、中間大,最大軸力出現(xiàn)在前列樁。(5)巖體彈性模量大,鋼護筒嵌巖樁位移小;粘聚力和內(nèi)摩擦角變化,對嵌巖樁樁身位移和彎矩影響不大。(6)框架碼頭排架中樁基與岸坡的施工順序和岸坡填筑方式對鋼護筒嵌巖樁的工作性狀有明顯影響,先填筑岸坡(岸坡穩(wěn)定)后施工樁基可大大減少樁基位移和內(nèi)力,分層填筑好于一次填筑,高岸坡、陡岸坡更應(yīng)先填筑后成樁。(7)碼頭水位增高,排架中各鋼護筒嵌巖樁的位移、彎矩、剪力均增加;水位降幅和降速變化,對后兩列樁的位移和軸力、對前列樁的橫向力影響較大。(8)依據(jù)前述試驗和數(shù)值分析,綜合考慮了嵌固深度、巖體模量、樁徑、水平荷載作用點位置、巖體性質(zhì)和結(jié)構(gòu)重要性等多方面因素影響,提出了大直徑鋼護筒嵌巖樁嵌固深度簡化計算公式,經(jīng)與實際工程對比,吻合較好,可供軟質(zhì)巖中大直徑鋼護筒嵌巖樁基水平承載力的設(shè)計計算時參考。
[Abstract]:Combined with the National Science and Technology support Plan < Research on key Technologies in the Construction of Shipping Engineering in the perennial backwater area of the three Gorges Reservoir (2011BAB09B01), the fourth special topic, "Research on bearing behavior and Design Technology of Rock-socketed pile Foundation in Deep Water Wharf", is presented in this paper.Based on the second phase expansion project of Chongqing Port Orchard Operation area, the series of numerical simulation analysis of the rock-socketed pile foundation of the steel retaining tube of the wharf and the verification of the corresponding physical model test results are carried out through the comparative test of the physical model of the single pile in the laboratory.In this paper, the mechanical behavior of the rock-socketed pile foundation of the inland river frame wharf under the action of vertical and horizontal forces and the characteristics of the interface between the steel guard and the concrete are studied separately. The main research results obtained are as follows: 1) according to the results of comparison test of single pile with size scale,Under vertical load, the working behavior of steel retaining tube rock-socketed pile is approximately the same as that of general rock-socketed pile, and under horizontal load, the failure mode of steel-protected barrel rock-socketed pile is different from that of ordinary rock-socketed pile, and the failure surface of common rock-socketed pile is inclined and near the ground surface.Under the action of horizontal load, the interface between steel retaining tube and concrete in compression side is bonded well, slip occurs in the interface of tension side, and the tensile stress is significantly larger than the compressive stress.The stress state of the structure is poor. (3) because of the increase of lateral resistance, the vertical bearing capacity and the depth of rock socketed pile are increased, but the bearing capacity is not increased.The economical and reasonable depth of the rock-socketed depth of the retaining tube is about 1 / 2 / D as the diameter of the pile, and the steel tube can increase the horizontal bearing capacity, reduce the displacement, reduce the tensile stress of the pile and reduce the area of the tensile stress, and the bending resistance of the steel pipe can be increased significantly.However, there is a sudden change at the bottom of the retaining tube. 4) in the bent frame of the frame wharf, the pile top displacement is the largest, the rock face is near zero, the displacement of each pile is basically the same and obviously smaller than that of the steel retaining tube, and the maximum negative bending moment is on the pile top.The maximum positive bending moment is at the rock face, the above section is obviously larger than the case of no steel retaining tube, the rock socketed section has little change, the maximum bending moment appears in the back row pile, the shear force is abrupt at the horizontal brace, the rock socketed section is reverse, the maximum shear force also appears in the back row pile.The axial force of rock socketed segment is small in both ends and middle, and the maximum axial force appears in the front row pile. 5) the elastic modulus of rock mass is large, the displacement of rock-socketed pile in steel retaining tube is small, the cohesive force and the angle of internal friction change,The construction sequence of pile foundation and bank slope in the frame wharf and the filling mode of bank slope have obvious influence on the working behavior of the rock-socketed pile with steel retaining tube. The influence of the displacement and bending moment of the rock-socketed pile body is not significant on the construction sequence of the pile foundation and the bank slope in the frame wharf.The displacement and internal force of pile foundation can be greatly reduced by first filling bank slope (bank slope stabilization) and then construction pile foundation. The layered filling is better than the first filling, and the high bank slope and steep bank slope should be filled first and then become pile. 7) the water level of the wharf is increased, and the displacement of the rock-socketed piles of each steel retaining tube in the row frame is increased.Bending moment and shear force increase, water level decrease and velocity drop change, the displacement and axial force of the latter two piles and the transverse force of the front row pile are greatly affected.) according to the above test and numerical analysis, the embedded depth, the modulus of rock mass and the diameter of pile are considered synthetically.Based on the influence of many factors, such as the position of the action point of horizontal load, the nature of rock mass and the importance of structure, a simplified formula for calculating the embedded depth of large diameter steel retaining tube socketed pile is put forward, which is in good agreement with the actual engineering.It can be used as a reference for the design and calculation of horizontal bearing capacity of large diameter steel pipe socketed pile foundation in soft rock.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：U656.1

【參考文獻】

相關(guān)期刊論文 前5條

1 鄧方明;何光春;;岸坡對庫區(qū)碼頭樁基變形影響分析[J];水運工程;2009年11期

2 張明義,鄧安福;樁-土滑動摩擦的試驗研究[J];巖土力學(xué);2002年02期

3 盧廷浩,鮑伏波;接觸面薄層單元耦合本構(gòu)模型[J];水利學(xué)報;2000年02期

4 茜平一,陳曉平;無粘性土中水平荷載樁的地基土極限水平反力研究[J];土木工程學(xué)報;1998年02期

5 殷宗澤，朱泓，許國華;土與結(jié)構(gòu)材料接觸面的變形及其數(shù)學(xué)模擬[J];巖土工程學(xué)報;1994年03期

，

本文編號：1752913