【摘要】：軟巖大變形一直是困擾隧道工程界的一個(gè)重要問題,尤其是在軟巖隧道變形機(jī)理方面,由于軟巖巖性和工程地質(zhì)條件的復(fù)雜性,通過傳統(tǒng)的理論分析和經(jīng)驗(yàn)判斷不足以準(zhǔn)確的掌握圍巖的變形機(jī)制和變形規(guī)律,進(jìn)而提出有效的變形控制措施。本文以“濱綏線牡丹江至綏芬河段擴(kuò)能改造工程”的興源隧道為依托,以軟巖隧道大變形為背景,采用現(xiàn)場應(yīng)力及變形監(jiān)控量測、理論分析和有限元計(jì)算相結(jié)合的手段來分析隧道的大變形機(jī)理,并通過數(shù)值模擬手段對比分析優(yōu)選出最優(yōu)的變形控制措施。最后通過突變理論來分析隧道施工過程中的極限位移,并根據(jù)計(jì)算結(jié)果運(yùn)用當(dāng)前工程界普遍使用的三級管理機(jī)制對隧道圍巖變形控制基準(zhǔn)進(jìn)行分級,提出了不同埋深下隧道的變形控制基準(zhǔn)。論文的主要工作和成果如下:(1)結(jié)合現(xiàn)場監(jiān)控量測數(shù)據(jù)分析興源隧道變形與支護(hù)受力之間的相互作用關(guān)系和特征。分析結(jié)果表明,圍巖變形持續(xù)時(shí)間長,具有很強(qiáng)的流變性;受軟弱夾層及巖層走向、傾向的影響,圍巖變形和支護(hù)受力表現(xiàn)出明顯的不對稱性。(2)通過將現(xiàn)場監(jiān)控量測分析與工程地質(zhì)資料相結(jié)合,得出興源隧道圍巖大變形屬于圍巖巖性控制類型,地層巖性、高地應(yīng)力、軟弱夾層和地下水是圍巖產(chǎn)生大變形的重要影響因素,其變形機(jī)理是高地應(yīng)力下軟巖的塑性流變、圍巖的彎曲變形以及夾層的軟化共同作用的結(jié)果。(3)根據(jù)軟巖大變形機(jī)理分析的研究結(jié)果,有針對性的提出了不同的變形控制措施,并通過有限元數(shù)值模擬手段分別對每種變形控制措施進(jìn)行優(yōu)選,如采用不同臺階長度、不同開挖進(jìn)尺、不同臺階高度、不同鎖腳錨管以及不同縱向連接形式等。最終通過比選得出最優(yōu)變形控制措施,宜采用5 m臺階長度、0.5 m開挖進(jìn)尺、3.5 m臺階高度、上臺階采用下斜30°鎖腳錨管、中臺階采用下斜15°鎖腳錨管、縱向連接則采用14號槽鋼。(4)通過對尖點(diǎn)突變理論的應(yīng)用,分別計(jì)算不同應(yīng)力釋放率下隧道洞周關(guān)鍵點(diǎn)的塑性應(yīng)變值,然后利用突變判據(jù)?來尋找塑性應(yīng)變的突變點(diǎn),從而確定圍巖變形突變所對應(yīng)的應(yīng)力釋放率,并以此作為圍巖變形的極限狀態(tài)。通過計(jì)算得出,當(dāng)應(yīng)力釋放率達(dá)到70%時(shí),圍巖穩(wěn)定性發(fā)生突變,進(jìn)入塑性流動階段,當(dāng)應(yīng)力釋放率在45%與70%之間時(shí),圍巖處于塑性發(fā)展階段,而在此之前圍巖尚處于彈性變形階段。(5)根據(jù)極限位移解答,以70%應(yīng)力釋放率為基準(zhǔn),運(yùn)用當(dāng)前工程界普遍使用的三級管理機(jī)制對隧道圍巖變形控制基準(zhǔn)進(jìn)行分級,建立了不同埋深(50 m、100 m、150m)情況下的隧道圍巖變形控制基準(zhǔn)。
[Abstract]:Large deformation of soft rock has always been an important problem in tunnel engineering, especially in the deformation mechanism of soft rock tunnel, because of the complexity of soft rock lithology and engineering geological conditions. Through the traditional theoretical analysis and empirical judgment, it is not enough to grasp the deformation mechanism and deformation law of the surrounding rock accurately, and then put forward the effective deformation control measures. Based on the Xingyuan Tunnel in the Mudanjiang-Suifenhe Section of the Binsui-Sui-Sui Line and the large deformation of the soft rock tunnel, the field stress and deformation monitoring and measurement are adopted in this paper. The large deformation mechanism of tunnel is analyzed by the combination of theoretical analysis and finite element calculation, and the optimal deformation control measures are selected by comparing and analyzing the numerical simulation method. Finally, the ultimate displacement in tunnel construction process is analyzed by catastrophe theory. According to the calculation results, the control datum of surrounding rock deformation of tunnel is classified by using the three-level management mechanism commonly used in the current engineering field. The deformation control datum of tunnel under different depth is put forward. The main work and achievements of this paper are as follows: (1) the relationship and characteristics between deformation and supporting force of Xingyuan tunnel are analyzed based on field monitoring and measurement data. The results show that the deformation of the surrounding rock is of long duration and has a strong rheological property. Under the influence of weak interlayer, rock strike and tendency, the deformation of surrounding rock and supporting force show obvious asymmetry. (2) through the combination of on-site monitoring and analysis with engineering geological data, It is concluded that the large deformation of surrounding rock of Xingyuan tunnel belongs to the controlling type of surrounding rock lithology, formation lithology, high in-situ stress, weak interlayer and groundwater are the important influencing factors of large deformation of surrounding rock, and its deformation mechanism is plastic rheology of soft rock under high in-situ stress. (3) according to the research results of the mechanism analysis of large deformation of soft rock, different deformation control measures are put forward according to the results of the joint action of the bending deformation of surrounding rock and the softening of interlayer. Each deformation control measure is optimized by means of finite element numerical simulation, such as adopting different step length, different excavation length, different step height, different locking anchor pipe and different longitudinal connection forms, etc. Finally, the optimal deformation control measures can be obtained by comparing and selecting the optimal deformation control measures: 5 m step length, 0.5 m excavation scale, 3.5 m step height, 30 擄downward slope locking anchor pipe for upper step and 15 擄lock pin anchor pipe for middle step. Longitudinal connection adopts 14 # channel steel. (4) through the application of cusp catastrophe theory, the plastic strain values of the key points around the tunnel under different stress release rates are calculated respectively, and then the catastrophe criterion is used. In order to find the mutation point of plastic strain, the stress release rate corresponding to the sudden deformation of surrounding rock is determined, which is regarded as the limit state of the deformation of surrounding rock. The results show that when the stress release rate reaches 70%, the stability of the surrounding rock changes abruptly and enters the plastic flow stage. When the stress release rate is between 45% and 70%, the surrounding rock is in the plastic development stage. Before this, the surrounding rock is still in the elastic deformation stage. (5) according to the limit displacement solution, according to the 70% stress release rate as the benchmark, the control datum of tunnel surrounding rock deformation is classified by using the three-level management mechanism commonly used in the current engineering circles. The deformation control datum of tunnel surrounding rock with different buried depth (50m, 100m, 150m) is established.
【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】：2015
【分類號】：U455.4

【共引文獻(xiàn)】

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本文編號：2454591