發(fā)布時間：2018-06-02 21:28

  本文選題：預(yù)應(yīng)力錨索 + 高地應(yīng)力��； 參考：《蘭州交通大學(xué)》2014年碩士論文

【摘要】：毛羽山隧道為軟弱圍巖且埋深較大，并處于極高地應(yīng)力環(huán)境下，且松動圈范圍較大，普通的錨桿長度不足以穿越松動區(qū)錨固到穩(wěn)定巖體中，這使得傳統(tǒng)的錨噴支護(hù)不能充分發(fā)揮作用，嚴(yán)重影響施工進(jìn)度并存在較大的安全隱患。針對上述的特點(diǎn)，選用預(yù)應(yīng)力長錨索配合錨噴混凝土的支護(hù)結(jié)構(gòu)來測試對大變形的改善情況。本文以蘭渝鐵路毛羽山隧道的預(yù)應(yīng)力長錨索試驗(yàn)段為背景，圍繞錨索對大變形的控制情況展開下列研究。 （1）在隧道12m和18m長錨索試驗(yàn)段中各選一個監(jiān)測斷面作為研究對象，分別從圍巖變形、圍巖壓力、接觸壓力和錨索受力等四個方面進(jìn)行研究分析，得到了圍巖的變形和應(yīng)力應(yīng)變的規(guī)律，以及二次襯砌受力情況。 （2）采用FLAC3D軟件對12m和18m長錨索試驗(yàn)段，以及將12m長錨索布設(shè)在18m長錨索位置處的換布設(shè)位置段的隧道施工過程進(jìn)行數(shù)值模擬，分析得出隧道變形、圍巖應(yīng)力和接觸應(yīng)力隨施工空間變化的規(guī)律。 （3）通過毛羽山隧道預(yù)應(yīng)力長錨索試驗(yàn)段現(xiàn)場實(shí)測變形、圍巖壓力和初支與二次襯砌接觸壓力與數(shù)值模擬中的結(jié)果比較分析，綜合評選變形控制效果，選擇最優(yōu)的錨索施作方案。 主要研究成果： （1）預(yù)應(yīng)力長錨索是一種“主動”的支護(hù)形式，對圍巖的變形能更容易控制，且12m和18m的錨索長度都可以穿過6m左右的圍巖表層松動區(qū)范圍，將表層松動的巖塊錨固到深層未擾動的穩(wěn)定巖體中，充分利用未擾動體的穩(wěn)定性加固隧道洞室。 （2）通過對現(xiàn)場圍巖位移和應(yīng)力值分析，得出預(yù)應(yīng)力長錨索試驗(yàn)段隧道的變形和應(yīng)力規(guī)律：各測點(diǎn)的位移量、圍巖壓力、接觸壓力的測量值受隧道三臺階施工工序的影響較大，有較長時間波動，其增大期較長，累積總量大，且還出現(xiàn)左右不對稱的情況。12m長錨索試驗(yàn)段監(jiān)控?cái)嗝娴墓绊斃鄯e沉降量為371mm，上臺階收斂值為438mm，中臺階收斂值為347mm，下臺階收斂值為269mm；18m長錨索試驗(yàn)段監(jiān)控?cái)嗝娴墓绊斃鄯e沉降量為296mm，上臺階收斂值為387mm，中臺階收斂值為340mm，下臺階收斂值為279mm。當(dāng)在預(yù)應(yīng)力錨索施作后，施作部位的控制變形效果較明顯，可以減小累積變形量，，且能有效的減小二次襯砌的受力情況。 （3）通過12m和18m兩個長錨索試驗(yàn)段及換布設(shè)位置段的三維數(shù)值模擬對比分析得出，12m長錨索試驗(yàn)段的支護(hù)結(jié)構(gòu)在中臺階和下臺階收斂值比18m長錨索試驗(yàn)段約減小30%；18m長錨索試驗(yàn)段在拱頂沉降方面比12m長錨索試驗(yàn)段減小約15%，在上臺階水平收斂控制上減小約20%；換布設(shè)位置段在拱頂沉降控制方面比18m長錨索試驗(yàn)段略差5%。18m長錨索試驗(yàn)段的預(yù)應(yīng)力錨索布設(shè)形式對上拱部的變形、圍巖y應(yīng)力和接觸應(yīng)力都有較好地控制，換布設(shè)位置段控制效果略差于18m長錨索試驗(yàn)段控制效果；12m長錨索試驗(yàn)段的支護(hù)結(jié)構(gòu)對墻中范圍控制效果較好。
[Abstract]:The Maoyu Mountain Tunnel is a weak surrounding rock with a large buried depth and is in the extremely high ground stress environment, and the loosening circle is large. The common anchor rod length is not enough to be anchored to the stable rock mass through the loose zone. This makes the traditional bolting and shotcrete support can not play a full role, seriously affect the progress of construction and there are larger safety risks. According to the above characteristics, the support structure of prestressed long anchor cable combined with shotcrete is selected to test the improvement of large deformation. Based on the test section of long prestressed Anchorage cable in Maoyushan Tunnel of Lanyu Railway, the following research is carried out around the control of large deformation of anchor cable. 1) in the 12m and 18m long cable test section of the tunnel, a monitoring section is chosen as the research object, and the deformation of surrounding rock, the pressure of surrounding rock, the contact pressure and the force of anchor cable are studied and analyzed, respectively, from four aspects: deformation of surrounding rock, pressure of surrounding rock, contact pressure and force of anchor cable. The law of deformation, stress and strain of surrounding rock and the stress of secondary lining are obtained. FLAC3D software is used to simulate the tunnel construction process of 12m and 18m long cable test section, and the section of 12m long anchor cable placed at the position of 18m long anchor cable, and the tunnel deformation is obtained by numerical simulation. The variation of surrounding rock stress and contact stress with construction space. 3) through the field measurement of deformation, the pressure of surrounding rock, the contact pressure between initial support and secondary lining and the numerical simulation results in the test section of long prestressed Anchorage cable in Maoyushan Tunnel, the optimal anchoring cable construction scheme is selected by synthetically selecting the effect of deformation control. Main findings: 1) Prestressed long anchor cable is a kind of "active" supporting form, which can easily control the deformation of surrounding rock, and the length of 12m and 18m Anchorage cable can pass through the loose zone of surrounding rock surface layer about 6m. The surface loose rock block is anchored to the deep undisturbed stable rock mass, and the stability of the undisturbed rock mass is fully utilized to reinforce the tunnel cavern. 2) by analyzing the displacement and stress of surrounding rock on site, the deformation and stress law of the tunnel in the test section of prestressed long anchor cable is obtained. The displacement of each measuring point, the pressure of surrounding rock and the measured value of contact pressure are greatly affected by the construction procedure of the three steps of the tunnel. There is a long period of fluctuation, and its increasing period is longer, and the accumulative total amount is large. The cumulative settlement of the monitoring section of the 12m long anchor cable test section is 371mm, the convergence value of the upper step is 438mm, the convergence value of the middle step is 347mm, and the convergence value of the lower step is 269mm / 18m long anchor cable test section. The cumulative settlement is 296mm, the convergence value of the upper step is 387mm, the convergence value of the middle step is 340mm, and the convergence value of the lower step is 279mm. When the prestressed anchor cable is applied, the effect of controlling deformation is obvious, which can reduce the amount of accumulated deformation and reduce the stress of secondary lining. Through the comparative analysis of 3D numerical simulation of the test section of 12m and 18m long anchor cable and the section of changing the position of anchor cable, it is concluded that the convergence value of the supporting structure of the test section of 12m long anchor cable is 30 ~ 18m shorter than that of the test section of 18m long anchor cable compared with that of the test section of 18m long anchor cable. The test section of anchor cable is about 15 less than that of 12m long cable test section in the settlement of arch roof, about 20 parts in horizontal convergence control of upper steps, and 5. 18 m long anchor cable test section is slightly less than 18 m long anchor cable test section in settlement control of arch roof in replacement position section The deformation of the upper arch in the form of the prestressed anchor cable in the section, Y stress and contact stress of surrounding rock are well controlled, and the control effect of changing position section is slightly worse than that of 18m long anchor cable test section. The supporting structure with 12m long anchor cable test section has better control effect on the scope of wall.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U451.2

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本文編號：1970261