本文選題：巖爆 + 聲發(fā)射��； 參考：《北京科技大學》2015年博士論文

【摘要】：近幾年隨著我國公路、鐵路等基礎設施建設的大力發(fā)展,在隧道建設中巖爆災害時有發(fā)生,隨著洞室埋深的不斷增加,深部巖體的復雜力學形為也越顯突出,伴之而來的工程地質(zhì)問題也越來越多。因此開展公路隧道脆性巖體巖爆機理與模擬方法的研究具有重要的意義。 本文以張(家口)石(家莊)高速公路黑石嶺隧道為項目背景,進行實地調(diào)查、巖石聲發(fā)射Kaiser效應地應力量測、室內(nèi)巖石力學試驗、室內(nèi)巖爆模擬試驗、聲發(fā)射能量及時頻分析、數(shù)值模擬等方法,分析了公路隧道脆性巖體在埋深不足250m時巖爆發(fā)生的機制,并建立了二維圓形隧道圍巖力學行為的連續(xù)-離散耦合分析模型,從宏-細觀角度深入開展不同圍壓條件下圓形隧道圍巖變形破壞機理研究,本論文取得的主要研究成果如下： (1)區(qū)域工程地質(zhì)環(huán)境調(diào)查及影響因素分析。通過對隧道隧址區(qū)的地層、構(gòu)造、水文、地質(zhì)條件及活動斷裂的分布情況進行調(diào)查,認為巖爆至少與以下各因素有關：地應力和圍巖巖性、巖體結(jié)構(gòu)、地質(zhì)構(gòu)造、不連續(xù)面性狀、工程埋深、巖體工程的規(guī)模和形狀、工程布置、開挖等因素。 (2)地應力測量及分析。現(xiàn)場采集巖樣進行了巖石聲發(fā)射Kaiser效應地應力試驗,測得3個測點的原始地應力值,確定了工程區(qū)地應力的量級大小。得到3個測點的最大主應力值均超過20MPa,得出了主應力沒有隨埋深增加而逐漸增大的變化趨勢的結(jié)論,并結(jié)合工程現(xiàn)場巖體結(jié)構(gòu)及尺寸效應和室內(nèi)巖爆模擬實驗,求得了巖爆的臨界深度為202米。 (3)現(xiàn)場采集巖石試樣進行室內(nèi)巖石力學試驗,測定巖石物理力學參數(shù)。通過利用中國礦業(yè)大學(北京)研發(fā)的深部巖爆過程模擬試驗系統(tǒng),進行巖爆破壞模式及發(fā)生機制分析,獲得了堅硬白云巖受力并發(fā)生巖爆破壞全過程的應力應變、聲發(fā)射及破壞特征等屬性,并利用傅里葉變換和Gutenberg-Richter關系式對巖樣聲發(fā)射能量及頻譜特征進行分析和b值擬合,發(fā)現(xiàn)巖樣在發(fā)生破壞時b值出現(xiàn)且呈降低趨勢,在180kHz(175-210kHz)高頻段的幅值與應力峰值變化相對應且大部分都滿足b值關系式,聲發(fā)射能量較多的巖樣,巖爆發(fā)生時破壞也較為嚴重。 (4)基于顆粒流理論,通過平行黏結(jié)模型和光滑節(jié)理模型相結(jié)合再現(xiàn)礦物顆粒的不規(guī)則構(gòu)造,并重現(xiàn)了脆性巖石的力學特性試驗如抗拉、單軸壓縮及不同圍壓下的三軸壓縮試驗,表明了GBM顆粒流模型能模擬抗壓與抗拉強度比大于10的脆性材料破裂,能真實反映脆性巖石變形破壞的全過程。 (5)卸載巖爆PFC數(shù)值模擬結(jié)果表明,根據(jù)應力環(huán)境的變化,卸載巖爆試驗進程可分為平靜期、局部顆粒彈射期、發(fā)展期及最終爆發(fā)期等4種狀態(tài),瞬時巖爆發(fā)生時的顆粒黏結(jié)破裂機制以張拉型為主、剪切型破裂為輔,宏觀表現(xiàn)為端部碎裂、中部彈射剝落特征。模擬試驗再現(xiàn)了不同應力狀態(tài)下的巖樣細觀破裂過程及機制,為巖爆產(chǎn)生的判別與驗證提供了有效手段,為巖爆試驗研究提供了一種新的有效途徑。 (6)基于有限差分理論及顆粒流理論,建立了二維圓形隧道圍巖力學行為的連續(xù)-離散耦合分析模型,從宏-細觀角度深入開展了不同圍壓條件下圓形隧道圍巖變形破壞機理研究。通過與理論計算、試驗結(jié)果的對比分析,研究表明在低圍壓條件下,當水平圍壓與垂直圍壓相等,相同徑向距離處的圍巖變形量近似相等,均指向圓心。隨著圍壓不斷增大,破裂總數(shù)逐漸增多；在高圍壓條件下,當側(cè)壓系數(shù)K大于1,圍巖破壞主要集中在隧道頂板、底板,當側(cè)壓系數(shù)K小于1,圍巖破壞主要集中在隧道兩幫,破壞形態(tài)均呈“氈帽形”,帽口朝向隧道中心。當側(cè)壓系數(shù)K等于1,圍巖破壞表現(xiàn)出明顯的分區(qū)破裂化現(xiàn)象。 本文在研究過程中,取得了以下創(chuàng)新性成果：(1)建立了一種采用聲發(fā)射波形頻段幅值、能量變化判別巖爆的方法,揭示了聲發(fā)射波形頻段幅值、能量變化與巖爆之間的量化關系；(2)建立了一種基于GBM模型研究脆性巖石破壞力學特征及聲發(fā)射事件識別與定位的方法：(3)建立了隧道圍巖力學行為的連續(xù)-離散耦合分析方法,從宏-細觀角度深入揭示了不同圍壓條件下圓形隧道圍巖變形破壞機理。 本文中的研究方法及相關成果可作為一種新的研究手段為復雜地質(zhì)條件下各類隧道工程問題的科學分析、判別與驗證提供有力支撐。
[Abstract]:In recent years, with the development of the highway and railway infrastructure construction in China, the rock burst disaster occurred in the tunnel construction. With the continuous increase of the depth of the cave, the complex mechanics shape of the deep rock mass is also more prominent, and more and more engineering geological problems are accompanied by it. Therefore, the mechanism of rock burst in the brittle rock mass of the highway tunnel is carried out and the mechanism of rock burst is carried out. The study of simulation method is of great significance.
Based on the project background of the heshiling tunnel of the Zhang (Jiazhuang) stone (Jiazhuang) Expressway, this paper carries out a field investigation, the rock acoustic emission Kaiser effect stress measurement, the laboratory rock mechanics test, the indoor rock burst simulation test, the acoustic emission energy time frequency analysis, the numerical simulation and so on, to analyze the rock of the highway tunnel brittle rock when the buried depth is less than 250m. The mechanism of explosion occurred and the continuous discrete coupling analysis model of the mechanical behavior of the two dimensional circular tunnel surrounding rock was established. From the macro meso angle, the deformation and failure mechanism of the surrounding rock under different confining pressure was studied. The main achievements of this paper are as follows:
(1) investigation of regional engineering geological environment and analysis of influencing factors. Through the investigation of the formation, structure, hydrology, geological conditions and distribution of active faults in tunnel and tunnel sites, it is considered that rock burst is at least related to the following factors: geostress and rock lithology, rock structure, geological structure, discontinuities, engineering burial depth, rock engineering Size and shape, engineering layout, excavation and other factors.
(2) geostress measurement and analysis. The in-situ stress test of rock acoustic emission Kaiser effect was carried out on the site. The original in-situ stress values of the 3 points were measured and the magnitude of the stress in the engineering area was determined. The maximum principal stress values of the 3 measured points were more than 20MPa, and the main stress did not gradually increase with the increase of the depth of the buried depth. The critical depth of rockburst is 202 meters, according to the conclusion of the project and combined with the rock mass structure and size effect and the indoor rock burst simulation experiment.
(3) the rock specimens were collected on the site to carry out the laboratory rock mechanics test and determine the rock physical and mechanical parameters. By using the deep rock burst simulation test system developed by the China University of Mining and Technology (Beijing), the rock burst failure mode and the mechanism were analyzed, and the stress and strain of the hard dolomite were obtained and the rock burst was damaged. The characteristic of emission and destruction characteristics, and the analysis of acoustic emission energy and spectrum characteristics of rock samples by Fourier transform and Gutenberg-Richter relation and b value fitting, it is found that the b value appears and decreases when the rock sample is destroyed. The amplitude value of the 180kHz (175-210kHz) high frequency section corresponds to the variation of the peak stress peak and most of which satisfy the B. In the case of rock samples with higher energy of acoustic emission, the failure of rock burst is more serious.
(4) based on the theory of particle flow, the irregular structure of mineral particles is reproduced by the combination of parallel bonding model and smooth joint model, and the mechanical properties of brittle rocks, such as tensile, uniaxial compression and three axial compression tests under different confining pressure, are reproduced, which shows that the GBM particle flow model can simulate the brittleness of compression and tensile strength greater than 10. The rupture of material can reflect the whole process of brittle rock deformation and failure.
(5) the numerical simulation results of unloaded rock burst PFC show that, according to the change of stress environment, the process of unloading rock burst test can be divided into 4 states, such as calm period, local particle ejection period, development period and final outbreak period, and the mechanism of particle bond rupture when instantaneous rock burst occurs is tensioning, shear fracture is supplemented, and macro performance is end fragmentation. The simulation test reproduces the mesoscopic fracture process and mechanism of rock samples under different stress states, which provides an effective means for the identification and verification of rock burst, and provides a new effective way for rock burst test.
(6) based on the finite difference theory and the particle flow theory, a continuous discrete coupling analysis model of the mechanical behavior of the surrounding rock of a two-dimensional circular tunnel is established. From the macro meso angle, the deformation and failure mechanism of the surrounding rock of a circular tunnel under the conditions of different confining pressure is carried out. The comparison analysis of the experimental results and the theoretical calculation shows that the low confining pressure is shown. Under the condition that the horizontal confining pressure is equal to the vertical confining pressure, the surrounding rock deformation at the same radial distance is approximately equal and points to the center. As the confining pressure increases, the total number of fracture increases gradually. Under the condition of high confining pressure, when the lateral pressure coefficient K is greater than 1, the failure of the surrounding rock is mainly concentrated on the tunnel roof, and the bottom plate, when the lateral pressure coefficient is less than 1, the failure of the surrounding rock is main. The two groups are concentrated in the tunnel. The damage forms are all felt "felt cap" and the cap and mouth face the center of the tunnel. When the lateral pressure coefficient K equals 1, the destruction of the surrounding rock shows a distinct division and fracture phenomenon.
In the course of the study, the following innovative achievements have been obtained: (1) a method of using the amplitude of acoustic emission wave band and energy change to distinguish rock burst is established. The amplitude of acoustic emission wave band and the quantitative relation between energy change and rock burst are revealed. (2) a GBM model is established to study the mechanical characteristics of brittle rock failure. The methods for identifying and locating acoustic emission events are: (3) a continuous discrete coupling analysis method is established for the mechanical behavior of tunnel surrounding rock. The deformation and failure mechanism of surrounding rock under the conditions of different confining pressure is deeply revealed from the macro meso angle.
The research methods and related achievements in this paper can be used as a new research means for scientific analysis of various tunnel engineering problems under complex geological conditions, and a strong support for discrimination and verification.
【學位授予單位】：北京科技大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：U451.2

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