發(fā)布時間：2018-02-21 06:50

  本文關(guān)鍵詞： 錨碇隧道 圍巖穩(wěn)定 振動速度 圍巖損傷 掌子面縱向間距　出處：《西南交通大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隧道式錨碇在公路懸索橋建設(shè)中得到越來越多的重視,其施工質(zhì)量要求也越來越嚴格。錨碇隧道是利用隧道圍巖體對錨塞體的作用平衡拉力,因其具有變截面、小凈距等工程特點,因此,對錨碇隧道圍巖的完整性和穩(wěn)定性要求更高。鉆爆法是隧道開挖的主要手段,所以研究開挖爆破作用下錨碇隧道圍巖穩(wěn)定性具有重要意義。本文結(jié)合雅康高速大渡河特大懸索橋雅安岸錨碇隧道爆破施工項目,分別利用現(xiàn)場監(jiān)測和數(shù)值計算方法分析隧道圍巖穩(wěn)定性,歸納出具有實踐意義的結(jié)論,以指導(dǎo)類似隧道工程的施工建設(shè)。本文研究內(nèi)容和取得成果具體如下:根據(jù)錨碇隧道的工程特點,基于上臺階掘進爆破施工現(xiàn)場監(jiān)測數(shù)據(jù),研究分析先行洞迎爆側(cè)的振速峰值、振動頻率、振動衰減規(guī)律,并用圍巖變形數(shù)據(jù)驗證隧道圍巖穩(wěn)定性。由分析結(jié)果可知,后行洞爆破施工時,先行洞迎爆側(cè)最大振動速度由掏槽孔爆破引起;為保證各微差爆破段相互獨立,各段延遲時間應(yīng)大于最大振速的振動持續(xù)時間;振動速度峰值以后行洞掌子面平行斷面處為中心向前后方隨距離的增大表現(xiàn)為衰減趨勢,且掌子面后方振速峰值衰減速度大于掌子面前方;振動衰減規(guī)律不滿足薩道夫斯基公式;先行洞拱頂沉降為11.5mm,沉降速率最大值為1.5mm/d,后行洞拱頂沉降為8mm,沉降速率最大值為2mm/d,均滿足安全要求,圍巖穩(wěn)定性較好。本文利用ANSYS/LS-DYNA軟件建立與工程實際相符的數(shù)值模型,巖石損傷的質(zhì)點峰值振速臨界值選取30cm/s,計算周邊孔爆破時圍巖的損傷范圍。由計算結(jié)果可知,隨質(zhì)點與炮孔壁的距離增大,質(zhì)點振速峰值迅速衰減,距離超過20cm之后,衰減幅度明顯減小。30cm處的質(zhì)點振速峰值為33cm/s,35cm處的質(zhì)點振速峰值為28cm/s,則可以推測周邊孔爆破產(chǎn)生的圍巖損傷范圍在33cm左右。為分析各因素對隧道圍巖穩(wěn)定性的影響,本文利用有限元軟件以控制變量法模擬討論了埋深、凈距、隧道斷面尺寸、先后洞掌子面縱向間距等工況。分別得到以下結(jié)論:隧道處于淺埋狀態(tài)時,隨埋深增大,則先行洞迎爆側(cè)拱腰位置的振速會隨之減小,當(dāng)埋深增加到20m后,振動速度基本不再變化;凈距越大,振動速度越小;斷面尺寸對先行洞迎爆側(cè)拱腰處的振動速度基本沒有影響;先后洞掌子面間距變化對先行洞迎爆側(cè)振速峰值的影響不明顯,掌子面前方圍巖受影響范圍在15m以內(nèi),掌子面后方圍巖受影響范圍在7m以內(nèi)。同時,還分析了掌子面縱向間距對先行洞拱頂沉降的影響,得出結(jié)論:前三施工步對先行洞拱頂沉降影響最大,且間距越小,前期沉降量越大,占總沉降量的比例也越大;隧道施工對圍巖拱頂沉降影響范圍在12m左右,為保證工程安全,本工程先后洞掌子面縱向間距取15m。
[Abstract]:Tunnel Anchorage is paid more and more attention to in the construction of highway suspension bridge, and its construction quality requirement is more and more strict. Because of the characteristics of engineering such as small clear distance, the integrality and stability of surrounding rock of Anchorage tunnel are required higher. The drilling and blasting method is the main method of tunnel excavation. Therefore, it is of great significance to study the stability of surrounding rock of Anchorage tunnel under the action of excavation blasting. This paper combines with the blasting construction project of Ya-an Anchorage Tunnel of Yakang Expressway Dadu River suspension Bridge. The stability of surrounding rock of tunnel is analyzed by field monitoring and numerical calculation, and the conclusions of practical significance are concluded. In order to guide the construction of similar tunnel projects, the research contents and achievements are as follows: according to the engineering characteristics of Anchorage tunnel, based on the monitoring data of blasting construction, the peak value of vibration velocity on the blasting side of the first tunnel is studied and analyzed. Vibration frequency, vibration attenuation law, and surrounding rock deformation data are used to verify the stability of tunnel surrounding rock. In order to ensure that each millisecond blasting section is independent of each other, the delay time of each segment should be greater than the vibration duration of the maximum vibration velocity, and after the peak value of vibration velocity, the center of the parallel section of the palm face of the tunnel will show a attenuation trend with the increase of the distance. The peak attenuation velocity of the square vibration velocity behind the palm is larger than that of the front of the palm, and the law of vibration attenuation is not satisfied with the Sadolski formula. The settlement of the arch roof of the first hole is 11.5mm, the maximum settlement rate is 1.5mm / d, the settlement of the dome is 8mm and the maximum rate of settlement is 2mm / d. all of them meet the safety requirements and the stability of surrounding rock is good. In this paper, the numerical model, which is in accordance with the engineering practice, is established by using ANSYS/LS-DYNA software. The critical value of peak particle velocity of rock damage is 30 cm / s to calculate the damage range of surrounding rock during blasting. The results show that with the increase of the distance between particle and hole wall, the peak value of particle vibration velocity rapidly attenuates, and when the distance exceeds 20cm, the damage range of surrounding rock is calculated. The attenuation amplitude is obviously reduced. The peak value of particle vibration velocity at 33cm / s-1 35cm is 28 cm / s, and the damage range of surrounding rock caused by peripheral hole blasting is about 33cm. In order to analyze the influence of various factors on the stability of tunnel surrounding rock, the attenuation amplitude is obviously reduced. In this paper, the finite element software is used to simulate and discuss the conditions of buried depth, net distance, tunnel section size and vertical spacing of tunnel face by using the control variable method. The conclusions are as follows: when the tunnel is in shallow burying state, the buried depth increases with the tunnel depth. Then the vibration velocity of the arch at the side of the first hole will decrease, when the buried depth increases to 20 m, the vibration velocity will not change basically, the larger the net distance, the smaller the vibration velocity. The cross section size has no effect on the vibration velocity of the arch waist of the blasting side of the antecedent tunnel, and the change of the space between the face surfaces of the successive holes has no obvious effect on the peak value of the vibration velocity of the front side of the tunnel, and the influence range of surrounding rock in front of the front face of the tunnel is less than 15m. At the same time, the influence of the longitudinal distance of the face on the settlement of the arch roof of the antecedent tunnel is analyzed. It is concluded that the first three steps of construction have the greatest influence on the settlement of the arch roof of the leading cave, and the smaller the distance, the smaller the distance between the first three construction steps. The larger the pre-settlement, the greater the proportion of the total settlement, the influence range of tunnel construction on the settlement of surrounding rock arch is about 12m, in order to ensure the safety of the project, the longitudinal distance between the face of the tunnel and the face of the tunnel is 15m.
【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】：2017
【分類號】：U455.6;U451.2

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