發(fā)布時(shí)間：2018-04-25 03:30

  本文選題：列車荷載 + 動(dòng)三軸試驗(yàn)　； 參考：《西南交通大學(xué)》2017年碩士論文

【摘要】：隨著中國(guó)西部大開發(fā)的繼續(xù)深入,西南地區(qū)鐵路的建設(shè)迎來(lái)新的高潮。成昆鐵路復(fù)線米易至攀枝花段,峨眉山至米易段正在如火如茶的建設(shè)中。新建成昆鐵路將穿越我國(guó)四川攀西地區(qū)特有的昔格達(dá)地層。昔格達(dá)地層質(zhì)軟,易風(fēng)化剝落,最顯著的特點(diǎn)是水穩(wěn)性差,遇水軟化崩解呈現(xiàn)流塑性。在既有老成昆鐵路隧道病害調(diào)研中發(fā)現(xiàn),穿越昔格達(dá)地層的隧道均出現(xiàn)大量翻漿冒泥、道床下沉、襯砌裂損等病害,給老成昆鐵路的運(yùn)營(yíng)帶來(lái)極大的安全隱患。本文以國(guó)家自然基金項(xiàng)目“昔格達(dá)組地層高速鐵路隧道圍巖承載能力及災(zāi)變控制技術(shù)研究”為依托,采用文獻(xiàn)調(diào)研、理論分析、室內(nèi)動(dòng)三軸試驗(yàn)、離散-連續(xù)耦合方法的數(shù)值模擬等多種研究手段,探究了列車荷載作用下昔格達(dá)地層隧道基底動(dòng)力響應(yīng)規(guī)律,并提出了昔格達(dá)粘土在循環(huán)荷載下的累積塑性應(yīng)變公式,意在為在建鐵路隧道基底施工提供科學(xué)依據(jù),改善施工工藝,減少后期運(yùn)營(yíng)過(guò)程中因列車荷載反復(fù)作用引起的各種病害,從而節(jié)約大量的后期維護(hù)成本。主要研究工作及結(jié)論如下:(1)通過(guò)多工況的昔格達(dá)粘土動(dòng)三軸試驗(yàn),研究了其在循環(huán)荷載作用下的累積塑性變形、動(dòng)彈性模量、阻尼比的變化規(guī)律,建立了考慮含水率的累積塑性變形模型。研究表明:昔格達(dá)粘土累積塑性變形曲線可分為穩(wěn)定型和破壞型,曲線類型主要受動(dòng)應(yīng)力比和含水率的影響。累積塑性變形隨著動(dòng)應(yīng)力比、靜偏應(yīng)力比、含水率的增大而增大,隨著圍壓和荷載頻率的增大而減小。(2)運(yùn)用試塊沖擊模擬試驗(yàn)驗(yàn)證了 FLAC3D6.0內(nèi)置耦合方案在耦合界面應(yīng)力的連續(xù)性,并基于室內(nèi)三軸剪切試驗(yàn)數(shù)據(jù),分別在FLAC3D和PFC3D中建立三軸剪切試驗(yàn)?zāi)Ｐ?標(biāo)定了昔格達(dá)粘土的細(xì)觀和宏觀參數(shù)。(3)運(yùn)用離散-連續(xù)方法分析了列車荷載作用下昔格達(dá)隧道基底動(dòng)力特性,具體方法是仰拱底部附近區(qū)域采用離散元進(jìn)行模擬,其他區(qū)域連續(xù)介質(zhì)進(jìn)行模擬。研究表明:列車振動(dòng)引起加速度的變化可分為初始加速度和行車中加速度,隨著列車車速增大,初始加速度峰值緩慢增大,行車中加速度峰值顯著增大,且動(dòng)應(yīng)力峰值增大。
[Abstract]:With the further development of China's western region, the railway construction in the southwest region has ushered in a new climax. Cheng-Kun railway line from Miyi to Panzhihua section, Emei Mountain to Miyi section is in the construction of fire as tea. The newly built Kun Railway will cross the Xigeda formation in Panxi area, Sichuan Province, China. Xigeda formation is soft and easy to be weathered and spalling. The most obvious feature is that water stability is poor and water softening disintegration presents flow plasticity. In the investigation and investigation of the tunnel diseases of the existing Laocheng and Kun railway, it is found that a large number of diseases such as mud-breaking, bed sinking and lining damage appear in the tunnels passing through Xigeda, which bring great safety risks to the operation of the Laocheng and Kun Railway. Based on the National Natural Fund project "study on bearing capacity and catastrophe Control Technology of surrounding Rock of High-speed Railway Tunnel in Xigeda formation", this paper adopts literature investigation, theoretical analysis and indoor dynamic triaxial test. In this paper, the dynamic response law of foundation of Xigeda formation tunnel under train load is studied by numerical simulation of discrete-time and continuous coupling method, and the cumulative plastic strain formula of Xigeda clay under cyclic load is put forward. The purpose of this paper is to provide scientific basis for the foundation construction of the railway tunnel under construction, to improve the construction technology, to reduce various diseases caused by repeated train loads in the later operation process, and thus to save a large amount of later maintenance costs. The main research work and conclusions are as follows: (1) through the dynamic triaxial test of Xigeda clay under multiple working conditions, the variation of cumulative plastic deformation, dynamic elastic modulus and damping ratio under cyclic load is studied. A model of cumulative plastic deformation considering moisture content is established. The results show that the cumulative plastic deformation curve of Xigeda clay can be divided into stable type and failure type, which are mainly affected by dynamic stress ratio and water content. The cumulative plastic deformation increases with the increase of dynamic stress ratio, static stress ratio and moisture content. With the increase of confining pressure and load frequency, the test block impact simulation test is used to verify the continuity of the coupled interface stress of the FLAC3D6.0 built-in coupling scheme, and based on the indoor triaxial shear test data, The triaxial shear test models were established in FLAC3D and PFC3D respectively, and the mesoscopic and macroscopic parameters of Xigda clay were calibrated. The dynamic characteristics of Xigeda tunnel foundation under train loads were analyzed by discrete-time continuous method. The concrete method is that discrete element is used to simulate the region near the bottom of inverted arch and continuum medium is used to simulate other regions. The results show that the variation of acceleration caused by train vibration can be divided into initial acceleration and in-train acceleration. With the increase of train speed, the peak of initial acceleration increases slowly, the peak of acceleration increases significantly, and the peak of dynamic stress increases.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U457.2

【參考文獻(xiàn)】

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本文編號(hào)：1799574