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  本文選題：噴射混凝土 + 齡期��； 參考：《石家莊鐵道大學(xué)》2014年碩士論文

【摘要】：隧道施工所采用的噴射混凝土是一種齡期類材料。在噴射混凝土施作完成后，需要幾天甚至是幾十天的時間才能使其強度和彈性模量達到最終值。而目前大多數(shù)設(shè)計者在進行初期支護計算模擬時往往不考慮噴射混凝土這一硬化特性。本文使用FLAC3D軟件通過對噴射混凝土支護參數(shù)進行循環(huán)賦值，實現(xiàn)了初期支護中噴射混凝土支護參數(shù)隨齡期變化的模擬。通過數(shù)值模擬對初期支護中考慮噴射混凝土硬化特性和不考慮噴射混凝土硬化特性兩種情況進行對比分析，得出兩種情況對圍巖的變形和塑性區(qū)的范圍的影響無明顯差別，而兩種情況下初期支護的應(yīng)力相差很大，在隧道初期支護設(shè)計時需要考慮噴射混凝土硬化特性。并以埋深為100m的V級圍巖襯砌為例，通過對比分析，闡述了在初期支護的設(shè)計時考慮噴射混凝土硬化特性可以使得設(shè)計更加合理并且可以避免工程材料的浪費。 對于二次襯砌而言，，合理確定二次襯砌施作時機是保證隧道工程施工階段和長期運營階段安全性的關(guān)鍵。本文使用ANSYS軟件對IV、V級圍巖條件下150m、200m、250m、300m埋深的隧道分別進行數(shù)值模擬計算，通過比較初期支護拱頂相對下沉速度恰滿足鐵路隧道施工規(guī)范時距離開挖掌子面的距離與拱腳水平相對凈空變化速度恰滿足規(guī)范規(guī)定時距離開挖掌子面的距離，得到初期支護拱腳水平相對凈空變化速度先于拱頂相對下沉速度滿足鐵路隧道施工規(guī)范的要求。通過對二次襯砌安全性和抗裂性的檢算，以及與二次襯砌極限變形值的比較，最終得到在不干擾前方隧道開挖支護施工的情況下，二次襯砌的合理施作時機。
[Abstract]:The shotcrete used in tunnel construction is a kind of age material.It takes a few days or even tens of days to reach the final value of the strength and elastic modulus of the sprayed concrete.At present, most designers do not consider the hardening characteristics of shotcrete in the initial support calculation simulation.In this paper, FLAC3D software is used to simulate the variation of shotcrete support parameters with the age of the initial support through the cyclic assignment of the parameters of the shotcrete support.Through numerical simulation, the effects of shotcrete hardening characteristics and not shotcrete hardening characteristics on the deformation of surrounding rock and the range of plastic zone of surrounding rock are analyzed and compared by numerical simulation, and the results show that there is no obvious difference between the two conditions on the deformation of surrounding rock and the range of plastic zone.However, the stress of initial support is very different between the two conditions, and the hardening characteristics of shotcrete should be considered in the design of initial support of tunnel.Taking the V-class surrounding rock lining with a depth of 100m as an example, through comparison and analysis, it is expounded that considering the hardening characteristics of shotcrete in the design of initial support can make the design more reasonable and avoid the waste of engineering materials.For secondary lining, it is the key to ensure the safety of tunnel construction stage and long-term operation stage.In this paper, ANSYS software is used to numerically simulate the tunnel with a buried depth of 250m ~ 300m under the condition of class V surrounding rock.By comparing the relative subsidence speed of the initial supporting arch roof with the distance between the excavation face and the relative clearance speed of the arch foot, the distance from the excavation face to the excavation face is exactly satisfied when the relative subsidence speed of the supporting arch roof meets the construction specifications of the railway tunnel.It is obtained that the relative clearance speed of the arch foot in the initial support is prior to the relative subsidence velocity of the arch roof to meet the requirements of the construction code of the railway tunnel.Through checking and calculating the safety and crack resistance of the secondary lining and comparing with the limit deformation value of the secondary lining, the reasonable timing of the secondary lining can be obtained without interfering with the excavation and supporting construction of the tunnel in front.
【學(xué)位授予單位】：石家莊鐵道大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U455

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