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  本文選題：被動樁 + 邊載作用�。� 參考：《東南大學(xué)》2015年碩士論文

【摘要】：非對稱荷載是橋梁樁基工程中常見的工況,如單側(cè)堆載或大開挖等,當(dāng)?shù)乇硐麓嬖诹魉苄攒浲翆訒r,非對稱荷載容易導(dǎo)致軟土側(cè)向流動,對基樁產(chǎn)生附加的側(cè)向土壓力,影響上部結(jié)構(gòu)的穩(wěn)定性,因此對此類樁(即被動樁)的工作機(jī)理的研究尤為重要。由于被動樁的受力性狀復(fù)雜,目前國內(nèi)外尚無統(tǒng)一的、精確度高的分析模型,較常見的被動樁分析方法有懸臂樁法、地基梁法等,無一例外均對樁土相互作用關(guān)系做了簡化,而簡化的方式和模型直接決定了計(jì)算結(jié)果的可靠度。本文采用的是分段耦合的分析方法,將被動樁按其受力性狀分為上部自由段、流塑土層被動段以及主動段三部分分別建立數(shù)學(xué)模型,得到的解答根據(jù)分界面連續(xù)性原理采用矩陣相乘的方法進(jìn)行耦合,得到樁身的內(nèi)力位移解答。將計(jì)算過程編寫了Fortran程序,并對錫張高速和南京某橋梁兩個工程案例做了計(jì)算分析驗(yàn)證。本文完成的主要工作如下：(1)基于被動樁的實(shí)際受力性狀,推導(dǎo)了梁和地基梁在不同工況時的內(nèi)力位移解答,其中地基梁根據(jù)軸力的不同假設(shè)分別給出了軸力不變時的解析解答和考慮軸力變化時的冪級數(shù)解答。(2)根據(jù)不同工況,采用兩套方法對被動樁進(jìn)行解答。當(dāng)考慮土體分層時,被動段和主動段按土層分段,各段均采用地基抗力常系數(shù)模型的解析解法；當(dāng)考慮主動段土體屈服時,采用“m”法冪級數(shù)解答。(3)給出了樁臺基礎(chǔ)及各類邊界條件下橋梁樁基的內(nèi)力解答。(4)基于兩個典型的橋梁被動樁失穩(wěn)工程案例,利用本文所述的方法進(jìn)行計(jì)算驗(yàn)證,得到的結(jié)果與實(shí)測數(shù)據(jù)吻合較好。
[Abstract]:Asymmetric load is a common condition in bridge pile foundation engineering, such as unilateral heaped load or large excavation. When there is fluid-plastic soft soil layer under the local surface, asymmetric load can easily lead to lateral flow of soft soil and generate additional lateral earth pressure on foundation pile. The stability of superstructure is affected, so it is very important to study the working mechanism of this kind of pile (passive pile). Because of the complex mechanical behavior of passive pile, there is no unified and accurate analysis model at home and abroad. The common methods of passive pile analysis are cantilever pile method, foundation beam method, etc., without exception, the pile-soil interaction relationship is simplified. The simplified method and model directly determine the reliability of the calculation results. In this paper, a piecewise coupling analysis method is used to divide the passive pile into three parts: the upper free section, the passive section of the fluid-plastic soil layer and the active section according to its mechanical properties. The solution is coupled by matrix multiplication according to the principle of interface continuity, and the solution of internal force displacement of pile body is obtained. The Fortran program is written, and the two engineering cases of tin Zhang high speed and Nanjing bridge are analyzed and verified. The main work accomplished in this paper is as follows: (1) based on the actual mechanical behavior of the passive pile, the solutions of the internal force displacement of the beam and the foundation beam under different working conditions are derived. According to the different assumptions of axial force, the foundation beam gives the analytical solution for the invariant axial force and the power series solution for considering the variation of the axial force. (2) according to different working conditions, two sets of methods are used to solve the passive pile. When delamination of soil is considered, the passive and active segments are divided according to the soil layer, and the analytical solution of the constant coefficient model of soil resistance is adopted in each segment, and when the active section of the soil is considered to yield, The solution of internal force of pile foundation and bridge pile foundation under all kinds of boundary conditions is given by using "m" method power series solution. (4) based on two typical examples of bridge passive pile instability engineering, the method described in this paper is used to verify the calculation. The results are in good agreement with the measured data.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U443.15

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