本文選題：隧道式錨碇 + 承載力�。� 參考：《西南交通大學(xué)》2015年碩士論文

【摘要】：近些年來,隨著我國交通建設(shè)的快速發(fā)展,大跨徑懸索橋已廣泛運(yùn)用于高山峽谷地區(qū)道路建設(shè)中,隧道式錨碇作為懸索橋的一種重要錨固形式,其承載力及其影響因素是隧道式錨碇工程設(shè)計的基礎(chǔ)。因此本文依托瀘定大渡河懸索橋隧道錨工程,對隧道式錨碇承載力的計算方法和影響因素進(jìn)行了分析,主要研究工作如下：1)運(yùn)用MIDAS-GTS軟件建立了包含隧道式錨碇、下穿公路隧道、主墩以及山體的三維地質(zhì)模型,通過FLAC3D有限差分軟件模擬了瀘定大渡河懸索橋隧道式錨碇在超張拉、極限超張拉、加卸載循環(huán)張拉以及圍巖長期強(qiáng)度四種典型工況下圍巖的變形、錨碇與圍巖界面上正應(yīng)力和摩阻力的分布規(guī)律、塑性區(qū)分布以及破壞模式,得出瀘定大渡河懸索橋隧道式錨碇的極限承載力為7倍的設(shè)計纜力,錨碇系統(tǒng)的破壞模式為沿錨碇與圍巖界面的剪切破壞,圍巖長期強(qiáng)度和加卸載循環(huán)張拉工況下錨碇圍巖變形均為毫米級,塑性區(qū)分布范圍較少,錨碇系統(tǒng)承載性能良好。2)通過三維數(shù)值分析,得到了當(dāng)錨碇圍巖強(qiáng)度降低為原來的60%、50%、40%時的塑性區(qū)分布特征,提出在隧道錨碇圍巖強(qiáng)度較低時,有可能發(fā)生剖面上下非對稱的組合式破壞模式。3)采用極限平衡法分別推導(dǎo)了界面剪切破壞和組合式破壞時的錨碇承載力的近似理論計算公式,其中界面剪切破壞理論計算結(jié)果與數(shù)值模擬結(jié)果誤差為2%。利用組合式破壞模式理論公式計算了在圍巖強(qiáng)度分別降為原來的100%、70%、60%、50%、40%時錨碇系統(tǒng)承載力和不同纜力作用下系統(tǒng)的安全儲備。4)通過三維數(shù)值模擬,對隧道式錨碇承載力的影響因素進(jìn)行了分析,主要包括圍巖彈性模量、錨碇軸向傾角、長度及放大角,得出錨碇系統(tǒng)承載力分別隨這4個量的增加而呈不同程度的非線性增大的規(guī)律；在此基礎(chǔ)上考慮錨碇主要影響因素的可改變性對瀘定大渡河懸索橋隧道式錨碇原設(shè)計的合理性進(jìn)行了分析,并將原設(shè)計優(yōu)化為：錨碇軸向傾角β=40。,錨碇長度L=50m,錨碇放大角α=-3.6。。本文的研究工作可為大噸位懸索橋隧道式錨碇的設(shè)計計算提供指導(dǎo)與參考。
[Abstract]:In recent years, with the rapid development of traffic construction in our country, long-span suspension bridges have been widely used in the road construction in high mountains and canyons. Tunnel Anchorage is an important anchoring form of suspension bridges. Its bearing capacity and its influencing factors are the foundation of tunnel Anchorage engineering design. Therefore, based on the Anchorage project of the Dadu River suspension Bridge, this paper analyzes the calculation method and influencing factors of the bearing capacity of the tunnel Anchorage. The main research work is as follows: 1) using MIDAS-GTS software to establish the tunnel including tunnel Anchorage and underpass highway tunnel. The 3D geological model of main pier and mountain is simulated by FLAC3D finite difference software. The tunnel Anchorage of Dadu River suspension Bridge in Luding is overstretched and the limit is overstretched. The deformation of surrounding rock under four typical conditions of loading and unloading cyclic tension and long-term strength of surrounding rock, the distribution of normal stress and friction at the interface of Anchorage and surrounding rock, the distribution of plastic zone and the failure mode, It is concluded that the ultimate bearing capacity of tunnel Anchorage of Dadu River suspension Bridge in Luding is 7 times of the design cable force, and the failure mode of Anchorage system is shear failure along the interface between Anchorage and surrounding rock. The long-term strength of surrounding rock and loading and unloading cyclic tension condition are all millimeter grade, the distribution range of plastic zone is less, and the load-bearing capacity of Anchorage system is good. 2) through three-dimensional numerical analysis, the deformation of surrounding rock is of millimeter grade, and the distribution range of plastic zone is relatively small. The distribution characteristics of plastic zone are obtained when the strength of the surrounding rock of the Anchorage decreases to 60% and 40% respectively, and it is put forward that when the strength of the surrounding rock of the tunnel Anchorage is low, The combined failure mode. 3) the ultimate equilibrium method is used to deduce the approximate theoretical formulas of the bearing capacity of the Anchorage in the case of interfacial shear failure and combined failure, respectively. The error between the calculated results of interfacial shear failure theory and that of numerical simulation is 2. By using the combined failure mode theory formula, the safety reserve of the Anchorage system under the action of bearing capacity and different cable forces of the Anchorage system has been calculated by three-dimensional numerical simulation. The factors affecting the bearing capacity of tunnel Anchorage are analyzed, including elastic modulus of surrounding rock, axial inclination angle, length and magnification angle of the Anchorage. The results show that the bearing capacity of Anchorage system increases with the increase of these four quantities respectively. On this basis, the rationality of the original design of the tunnel Anchorage of the Luding Dadu River suspension Bridge is analyzed considering the variability of the main influencing factors of the Anchorage, and the original design is optimized as follows: Anchorage axial inclination 尾 40., Anchorage length 50 m, Anchorage magnification angle 偽 -3.6.. The research work in this paper can provide guidance and reference for the design and calculation of tunnel Anchorage of large tonnage suspension bridge.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U448.25;U443.24

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本文編號：1995517