【摘要】：巖石的時效力學(xué)特征及其破壞行為一直以來是土木水利工程及其相關(guān)領(lǐng)域中非常重要且異常復(fù)雜的研究課題之一。工程實(shí)踐和相關(guān)研究表明，在許多情況下，巖石工程的破壞與失穩(wěn)不是在開挖形成以后立即發(fā)生，巖體的應(yīng)力和變形是隨時間變化發(fā)展和不斷地調(diào)整的，趨于穩(wěn)定往往需要延續(xù)一個較長的時間，如時滯性巖爆、時效大變形等。巖體的這類變形破壞現(xiàn)象往往與脆性巖石在復(fù)雜應(yīng)力條件下的時效變形破裂規(guī)律和細(xì)觀演化機(jī)理有著密切關(guān)系，，但關(guān)于脆性巖石時效變形破裂細(xì)觀演化機(jī)理的研究尚處于起步階段，需要借助新的技術(shù)手段和理論方法進(jìn)一步深化認(rèn)識。鑒于此，本文在錦屏一級大理巖室內(nèi)試驗的基礎(chǔ)上，借助三維顆粒流計算理論，引入BPM模型、PSC模型和超級單元clump技術(shù)，在構(gòu)建基于礦物形顆粒狀的大理巖細(xì)觀力學(xué)模型的基礎(chǔ)上，對不同應(yīng)力水平和應(yīng)力強(qiáng)度比以及不同分級條件下大理巖的時效力學(xué)特性進(jìn)行研究，識別了脆性巖石時效變形破裂規(guī)律和細(xì)觀演化機(jī)理。 本文的研究工作主要集中在如下幾個方面： 1．給出了PSC模型的三維計算理論，該理論是以三維顆粒流細(xì)觀平行粘結(jié)模型和線彈性斷裂力學(xué)理論為基礎(chǔ)，通過引入指數(shù)型細(xì)觀內(nèi)應(yīng)力驅(qū)動的損傷速率，形成具有應(yīng)力腐蝕顆粒破裂時間效應(yīng)的細(xì)觀平行粘結(jié)時效模型，用于描述巖石細(xì)觀層面上的時效破裂。 2．對巖石瞬態(tài)和時效細(xì)觀力學(xué)參數(shù)進(jìn)行了敏感性分析，深入研究了這些細(xì)觀力學(xué)參數(shù)對宏觀力學(xué)響應(yīng)及蠕變變形破壞的影響。結(jié)果表明：宏觀彈性模量主要受顆粒彈性模量、平行粘結(jié)彈性模量、顆粒法切向剛度比、平行粘結(jié)法切向剛度影響，宏觀峰值強(qiáng)度取決于平行粘結(jié)強(qiáng)度，1、2控制著蠕變斷裂時間t f，巖石是否發(fā)生蠕變?nèi)Q于a。 3．基于三維顆粒流理論，通過引入BPM模型、PSC模型和超級單元clump技術(shù)，并依據(jù)錦屏一級地下廠房大理巖的SEM礦物成份檢測結(jié)果，建立了基于礦物形顆粒狀的大理巖細(xì)觀結(jié)構(gòu)模型，在對細(xì)觀力學(xué)參數(shù)敏感性分析的基礎(chǔ)上，根據(jù)室內(nèi)瞬態(tài)壓縮試驗和流變試驗結(jié)果以及巖石細(xì)觀力學(xué)參數(shù)識別方法，確定了大理巖的瞬態(tài)和時效細(xì)觀力學(xué)參數(shù)，構(gòu)建了大理巖的時效細(xì)觀力學(xué)數(shù)值模型。 4．基于大理巖時效細(xì)觀力學(xué)數(shù)值模型，對不同應(yīng)力水平和應(yīng)力強(qiáng)度比條件下大理巖進(jìn)行了單級加載蠕變數(shù)值試驗，研究了應(yīng)力水平和應(yīng)力強(qiáng)度比對大理巖時效變形破裂的影響規(guī)律及其細(xì)觀演化機(jī)理。結(jié)果表明：應(yīng)力水平控制著巖石的長期應(yīng)力強(qiáng)度比；圍壓增加，巖石時效變形和破裂效應(yīng)降低，失穩(wěn)破壞時間延長或不失穩(wěn)；應(yīng)力強(qiáng)度比增加，巖石時效變形和破裂效應(yīng)增加，破裂時間縮短。上述結(jié)果顯示，隨著圍壓或者應(yīng)力強(qiáng)度比的增加，巖石細(xì)觀時效演化機(jī)理本質(zhì)上表現(xiàn)為張性裂紋擴(kuò)展控制機(jī)制和剪切裂紋摩擦控制機(jī)制相互作用，此減彼增逐步過渡。 5．對大理巖進(jìn)行了不同分級加載條件下蠕變數(shù)值試驗，對比研究了分級數(shù)對巖石蠕變變形和時效破裂的影響規(guī)律。結(jié)果表明：分級數(shù)增加，巖石時效變形和破裂效應(yīng)下降，時效破裂時間延長。
[Abstract]:The time-dependent mechanical characteristics and failure behavior of rock have always been one of the most important and complex research topics in civil engineering and related fields. Engineering practice and related research show that in many cases, the failure and instability of rock engineering do not occur immediately after excavation, but the stress and deformation of rock mass are The deformation and failure phenomena of rock mass are often closely related to the law of time-dependent deformation and fracture and the mechanism of micro-evolution of brittle rock under complex stress conditions, but about brittle rock. In view of the fact that the study on the meso-evolution mechanism of aging deformation and fracture is still in its infancy and needs to be further deepened by means of new technical means and theoretical methods, this paper introduces BPM model, PSC model and super-unit clump technology to construct the foundation on the basis of the laboratory test of Jinping first-grade marble and the theory of three-dimensional particle flow calculation. Based on the microscopic mechanical model of mineral-like granular marble, the aging mechanical properties of marble under different stress levels, stress-strength ratios and grading conditions are studied. The aging deformation and fracture laws and microscopic evolution mechanism of brittle rock are identified.
The research work in this paper is mainly concentrated on the following aspects:
1. A three-dimensional computational theory of PSC model is presented. Based on the three-dimensional particle flow parallel bond model and the linear elastic fracture mechanics theory, a meso-parallel bond aging model with stress corrosion particle rupture time effect is developed by introducing an exponential damage rate driven by internal stress. The breakdown of age at the level of perception.
2. Sensitivity analysis of rock transient and time-dependent meso-mechanical parameters is carried out, and the effects of these parameters on macro-mechanical response and creep deformation and failure are studied in depth. The results show that the macro-elastic modulus is mainly affected by the elastic modulus of particles, the elastic modulus of parallel bonding, the tangential stiffness ratio of particles, and the tangential rigidity of parallel bonding. The macroscopic peak strength depends on the parallel bond strength, 1,2 controls the creep fracture time t f, and whether the rock creeps depends on a.
3. Based on the theory of three-dimensional particle flow, by introducing BPM model, PSC model and super-unit clump technology, and according to the results of SEM mineral composition test of marble in Jinping I underground powerhouse, a micro-structure model of marble with mineral shape and granular shape is established. Based on the sensitivity analysis of micro-mechanical parameters, and according to the indoor transient state, the micro-structure model of marble is established. The results of compression test and rheological test as well as the identification method of rock micro-mechanical parameters are used to determine the transient and time-dependent micro-mechanical parameters of marble, and the time-dependent micro-mechanical numerical model of marble is constructed.
4. Based on the numerical model of marble aging micro-mechanics, the creep numerical tests of marble under different stress levels and stress-strength ratios were carried out under single-stage loading. The effects of stress levels and stress-strength ratios on the aging deformation and fracture of marble and its micro-evolution mechanism were studied. The results show that with the increase of confining pressure or stress-strength ratio, the evolution mechanism of rock aging is essentially the same. It is shown that the tensile crack growth control mechanism interacts with the shear crack friction control mechanism, and the change is gradual.
5. The creep numerical tests of marble under different staged loading conditions are carried out, and the effects of stages on creep deformation and time-dependent fracture of rock are studied comparatively.
【學(xué)位授予單位】：長江科學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU45

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