本文選題：隧道 + 樁�。� 參考：《北京交通大學(xué)》2017年碩士論文

【摘要】：本文研究了城市地區(qū)隧道與現(xiàn)有樁基之間的相互作用。文章采用了空洞理論和有限元理論進(jìn)行了分析。文章提出了一種利用圓孔擴(kuò)張理論估算靜壓樁承載力的方法,并對(duì)相關(guān)機(jī)理進(jìn)行了說(shuō)明。對(duì)模型參數(shù)進(jìn)行了研究,以評(píng)估其對(duì)樁端承載力的影響。結(jié)果表明,靜壓樁的安裝會(huì)對(duì)地層初始?jí)毫Ξa(chǎn)生影響,且隨著與樁端彈塑性界面距離的增大而減小,并且樁端承載力的增加與土壤的粘聚力、摩擦角和密度有關(guān)。提出了一種利用簡(jiǎn)化空腔收縮理論估算隧道樁端損失量對(duì)樁端承載力影響的方法,并對(duì)相關(guān)機(jī)理進(jìn)行了說(shuō)明。對(duì)樁-隧之間的相互作用進(jìn)行了參數(shù)分析,結(jié)果表明,根據(jù)隧道與樁端的相對(duì)位置,隧道體積的損失可以造成樁端承載力的提高或減小。采用PLAXIS進(jìn)行了二維數(shù)值模擬分析。重點(diǎn)分析了隧道開(kāi)挖對(duì)現(xiàn)有靜壓樁的土體運(yùn)動(dòng)和應(yīng)力的影響,并與分析結(jié)果進(jìn)行了比較。隧道會(huì)造成樁端壓力和拉力的減小,這取決于樁基礎(chǔ)相對(duì)于影響區(qū)的位置。對(duì)于位于影響范圍內(nèi)的樁基礎(chǔ),樁主要受拉力,這是由于樁與周圍土體之間的相對(duì)運(yùn)動(dòng)引起的。空腔理論和有限元分析都表明當(dāng)有限元分析中Xp12.5m或者空腔理論Xtp11m時(shí),拉應(yīng)力會(huì)增加。隨著隧道與樁的分離導(dǎo)致的壓應(yīng)力的發(fā)展規(guī)律也驗(yàn)證了這兩種分析結(jié)果。壓縮力通常要比極限承載力小。對(duì)地層深度的研究結(jié)果也表明,隨著深度的增加qb,vl/qb的值也在增加。深度也會(huì)影響各向同性圍巖的壓力�？梢圆捎靡粋�(gè)關(guān)于圍壓的函數(shù)對(duì)地層摩擦角和膨脹角進(jìn)行分析。對(duì)于工況3,這兩種方法(空腔理論和有限元法)也都驗(yàn)證了隧道的大小對(duì)樁端承載力的影響,qb,vl/qb的數(shù)值隨著隧道半徑的增大而減小,隧道的半徑也會(huì)影響圍巖擾動(dòng)區(qū)的大小(隨著隧道半徑增大而增大)。
[Abstract]:The interaction between tunnels and existing pile foundations in urban areas is studied in this paper. The cavity theory and finite element theory are used to analyze the problem. In this paper, a method of estimating the bearing capacity of static pile by using the theory of circular hole expansion is put forward, and the related mechanism is explained. The model parameters are studied to evaluate the effect of the model on the bearing capacity of pile tip. The results show that the static pile installation will affect the initial formation pressure and decrease with the increase of the distance between the pile end and the elastic-plastic interface, and the increase of the pile end bearing capacity is related to the cohesive force, friction angle and density of the soil. A method is proposed to estimate the influence of pile end loss on pile end bearing capacity by using simplified cavity contraction theory, and the related mechanism is explained. The parameter analysis of pile-tunnel interaction shows that according to the relative position of tunnel and pile end, the loss of tunnel volume can increase or decrease the bearing capacity of pile end. The two-dimensional numerical simulation was carried out by PLAXIS. The influence of tunnel excavation on the soil movement and stress of the existing static pile is analyzed, and the results are compared with those of the analysis. The pressure and tension at the end of the pile are reduced by the tunnel, which depends on the position of the pile foundation relative to the affected area. For the pile foundation which is located in the influence area, the pile is mainly subjected to tensile force, which is caused by the relative motion between the pile and the surrounding soil. Both cavity theory and finite element analysis show that tensile stress increases when Xp12.5m in finite element analysis or Xtp11m in cavity theory. With the separation of tunnel and pile, the development of compressive stress also verifies the two analytical results. The compression force is usually smaller than the ultimate bearing capacity. The results of the study on the formation depth also show that the value of qbnvl / qb increases with the increase of the depth. The depth also affects the pressure of isotropic surrounding rock. A function on confining pressure can be used to analyze the angle of friction and expansion. For working condition 3, both of these two methods (cavity theory and finite element method) also verify the influence of tunnel size on the bearing capacity of pile end. The numerical value of QB / vl / qb decreases with the increase of tunnel radius. The radius of the tunnel will also affect the size of the surrounding rock disturbance zone (increasing with the increase of the radius of the tunnel).
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U455;TU473.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 楊敏;孫慶;李衛(wèi)超;馬亢;;Three-dimensional finite element analysis on effects of tunnel construction on nearby pile foundation[J];Journal of Central South University of Technology;2011年03期

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本文編號(hào)：2005310