本文關(guān)鍵詞： 剛性樁復(fù)合地基 承載性狀 尺寸效應(yīng) 切線模量法 變形協(xié)調(diào) 沉降控制　出處：《武漢大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：剛性樁復(fù)合地基由于沉降小、樁身質(zhì)量可靠、施工速度快,在工程建設(shè)中應(yīng)用越來越廣泛,對(duì)沉降變形的可控性已使其在高層建筑中的應(yīng)用越來越多。為揭示剛性樁復(fù)合地基承載性狀,科技工作者對(duì)此作了大量研究,有力地推動(dòng)了剛性樁復(fù)合地基理論的發(fā)展。但目前仍存在一些問題值得進(jìn)一步探討,如：不同尺寸基礎(chǔ)下剛性樁復(fù)合地基樁土受力性狀有何規(guī)律,工程中用單樁復(fù)合地基或多樁復(fù)合地基載荷試驗(yàn)進(jìn)行檢測(cè)時(shí),其與實(shí)際基礎(chǔ)下復(fù)合地基受力性狀存在什么差異；剛性樁復(fù)合地基沉降計(jì)算采用經(jīng)驗(yàn)系數(shù)修正法還不盡如意,尚需通過研究化經(jīng)驗(yàn)為理論等,都需進(jìn)一步深入研究,以更好地認(rèn)識(shí)剛性樁復(fù)合地基的作用機(jī)理。 為此,本文通過室內(nèi)模型試驗(yàn)及理論分析開展了系列研究,以獲得對(duì)剛性樁復(fù)合地基受力性狀的一些深入認(rèn)識(shí)。具體工作如下： (1)針對(duì)剛性樁復(fù)合地基承載性狀受基礎(chǔ)尺寸大小影響的問題,從地基附加應(yīng)力分布與基礎(chǔ)尺寸關(guān)系以及地基極限承載力與基礎(chǔ)尺寸關(guān)系入手進(jìn)行了分析。介紹了切線模量法的計(jì)算理論并提出了應(yīng)用該理論解決復(fù)合地基尺寸效應(yīng)問題的方法； (2)為研究剛性樁復(fù)合地基承載性狀受基礎(chǔ)尺寸影響的規(guī)律,利用自主設(shè)計(jì)的模型箱試驗(yàn)裝置,在4個(gè)不同尺寸的壓板下分別進(jìn)行了地基土載荷試驗(yàn)、復(fù)合地基載荷試驗(yàn)以及單樁荷載試驗(yàn)等相關(guān)模型試驗(yàn),獲得了一套載荷試驗(yàn)測(cè)試資料； (3)針對(duì)模型試驗(yàn)成果,對(duì)剛性樁復(fù)合地基的樁土承載性狀以及不同尺寸壓板復(fù)合地基承載性狀的差異進(jìn)行了分析,揭示了以下規(guī)律：在基底應(yīng)力相同和置換率相同時(shí),復(fù)合地基沉降隨壓板尺寸增大而增大,樁土應(yīng)力比隨壓板尺寸增大而增大,樁分擔(dān)的荷載隨壓板尺寸增大而增大； (4)在以上研究的基礎(chǔ)上,針對(duì)剛性樁復(fù)合地基檢測(cè)方法確定承載力的問題,對(duì)復(fù)合地基承載力的評(píng)估提出了新的建議,即除了進(jìn)行單樁和單樁復(fù)合地基載荷試驗(yàn)外,尚應(yīng)進(jìn)行樁間土載荷試驗(yàn),先利用樁土組合疊加計(jì)算模型方法獲得試驗(yàn)壓板下復(fù)合地基的p-s曲線,再用復(fù)合地基試驗(yàn)結(jié)果進(jìn)行檢驗(yàn),然后利用切線模量法計(jì)算實(shí)際基礎(chǔ)下地基土的p-s曲線,與單樁載荷試驗(yàn)的p-s曲線疊加獲得實(shí)際基礎(chǔ)下剛性樁復(fù)合地基的p-s曲線,利用該曲線可以對(duì)復(fù)合地基承載能力進(jìn)行科學(xué)合理的評(píng)估； (5)在分析樁土變形協(xié)調(diào)機(jī)制、樁土荷載傳遞力學(xué)性狀以及共同作用理論的基礎(chǔ)上,利用切線模量法建立了一套按沉降控制的剛性樁復(fù)合地基設(shè)計(jì)計(jì)算的系統(tǒng)方法,該方法考慮了樁土變形協(xié)調(diào)和樁土荷載傳遞性狀。通過工程實(shí)例驗(yàn)證,該方法可較好反映實(shí)際基礎(chǔ)下復(fù)合地基承載性狀； (6)利用某CFG剛性樁復(fù)合地基工程實(shí)例,驗(yàn)證了本文提出的剛性樁復(fù)合地基承載力評(píng)估方法和復(fù)合地基設(shè)計(jì)計(jì)算系統(tǒng)方法的合理性和可靠性。同時(shí),實(shí)際工程數(shù)據(jù)與模型試驗(yàn)數(shù)據(jù)所揭示的剛性樁復(fù)合地基承載性狀規(guī)律是一致的； (7)研究了有褥墊層復(fù)合地基的樁土共同作用性狀,褥墊層厚度及變形模量在常規(guī)值范圍內(nèi)變化時(shí),分析揭示了褥墊層厚度及變形模量對(duì)復(fù)合地基樁土應(yīng)力比有影響,但對(duì)復(fù)合地基總沉降的影響不大。
[Abstract]:Because of the rigid pile composite foundation settlement is small, reliable pile quality, fast construction, in the construction of more and more widely, the controllability of settlement has made it more and more applications in high-rise buildings. In order to reveal the bearing behavior of rigid pile composite foundation, the work of science and technology have made a lot of research effectively to promote the development of the theory of rigid pile composite foundation. But there are still some problems worthy of further study, such as different sizes under the foundation of the rigid pile soil pile composite foundation bearing capacity to any rules, detected by the single pile composite foundation load or multi pile composite foundation test engineering, with the actual composite foundation what are the differences of the stress characters; calculated by empirical coefficient correction method is not satisfactory settlement of rigid pile composite foundation, is required by research experience for the theory, need further study, to The mechanism of the rigid pile composite foundation is better understood.
Therefore, a series of researches have been carried out through indoor model test and theoretical analysis, in order to get some deep understanding of the behavior of rigid pile composite foundation.
(1) according to the basic size effect of bearing capacity of rigid pile composite foundation, the foundation of additional stress and stress distribution and size based relationship based size and ultimate bearing analyzed. This paper introduces the calculation theory of tangent modulus method and proposed the application of the theory method to solve the problem of size effect of the composite foundation;
(2) as basic size influence study on bearing capacity of rigid pile composite foundation of experimental device of the model box is designed, the foundation loading tests were carried out in 4 different sizes of the plate under the model load test of composite foundation and pile load test, get a load test data;
(3) according to the experimental results, the characters of different sizes and pressure bearing capacity of composite foundation of the difference of the analysis of rigid pile composite foundation pile soil bearing, reveal the following rules: in the same substrate stress and the same replacement ratio, and increases with the increase of plate size settlement of composite foundation pile soil stress ratio with the plate size increases, pile load sharing increases with the increase of plate size;
(4) on the basis of the above research, the rigid pile composite foundation test method to determine the bearing capacity problems, evaluation of bearing capacity of composite foundation and put forward new proposals, which in addition to the single pile and single pile composite foundation loading test, through piles of soil load test should be, by combination of pile and soil model superposition calculation method to obtain the test plate under the P-S curve of the composite foundation and composite foundation test results were examined, and then calculate the P-S curve of foundation soil under the actual basis of using tangent modulus method, and p-s curve superposition pile load test p-s curve was the actual foundation of the rigid pile composite foundation, the curve can be used scientific and reasonable evaluation on the bearing capacity of composite foundation;
(5)鍦ㄥ垎鏋愭々鍦熷彉褰㈠崗璋冩満鍒，

本文編號(hào)：1520515