本文關(guān)鍵詞： 土石混合體 細(xì)觀結(jié)構(gòu)力學(xué) 尺度效應(yīng) 三軸試驗(yàn) 精細(xì)結(jié)構(gòu)重建　出處：《清華大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：土石混合體(S-RM)常見于多種淺表生地質(zhì)災(zāi)害以及水利水電工程、道路工程、房屋建筑、礦山開采等領(lǐng)域。其中“土”和“塊石”在粒徑及強(qiáng)度方面均存在很大差異,使得土石混合體的細(xì)觀結(jié)構(gòu)特征對(duì)其宏觀物理力學(xué)性質(zhì)有顯著影響,且與研究尺度密切相關(guān),并具有明顯的非均質(zhì)特性。論文通過物理試驗(yàn)和數(shù)值模擬開展了土石混合體細(xì)觀結(jié)構(gòu)力學(xué)及尺度效應(yīng)的系統(tǒng)研究。結(jié)合實(shí)時(shí)無損的CT掃描技術(shù),開展了土石混合體室內(nèi)三軸試驗(yàn)。研究了含石量、粒度組成、試樣尺度對(duì)其宏觀強(qiáng)度及變形特性的影響,并實(shí)現(xiàn)了對(duì)試樣細(xì)觀結(jié)構(gòu)及其演化過程信息的實(shí)時(shí)獲取。應(yīng)用數(shù)字圖像處理、數(shù)據(jù)庫管理和3D可視化技術(shù),研發(fā)了土石混合體三維細(xì)觀結(jié)構(gòu)重建及分析系統(tǒng)(MSRAS3D),實(shí)現(xiàn)了土石混合體試樣三維細(xì)觀結(jié)構(gòu)模型重建及細(xì)觀結(jié)構(gòu)定量統(tǒng)計(jì)分析,為揭示三軸試驗(yàn)全過程的細(xì)觀結(jié)構(gòu)演化規(guī)律提供了有力手段。在此基礎(chǔ)上,揭示了土石混合體試樣在外荷載作用下內(nèi)部塊石的空間運(yùn)動(dòng)規(guī)律、典型破碎形式和變形局部化現(xiàn)象�；谕潦旌象w重建模型開展了三軸試驗(yàn)的離散元數(shù)值模擬,根據(jù)室內(nèi)試驗(yàn)結(jié)果反演獲得了“土”與“塊石”的顆粒細(xì)觀力學(xué)參數(shù)。應(yīng)用反演計(jì)算參數(shù),采用隨機(jī)生成技術(shù)獲得土石混合體隨機(jī)模型,系統(tǒng)研究了塊石形狀、破碎性能和試樣尺度等因素對(duì)土石混合體宏細(xì)觀力學(xué)行為的影響。基于數(shù)值試驗(yàn)結(jié)果,對(duì)土石混合體剪切破壞過程中內(nèi)部顆粒的空間運(yùn)動(dòng)、顆粒間接觸數(shù)、法向與切向接觸力、細(xì)觀體變等細(xì)觀結(jié)構(gòu)特征的演化規(guī)律進(jìn)行了定量分析,從細(xì)觀層次揭示了粒度組成、塊石形狀及破碎性、試樣尺度等因素對(duì)土石混合體宏觀強(qiáng)度及變形特性的影響機(jī)制。通過論文研究表明:基于室內(nèi)試驗(yàn)中的重建模型和數(shù)值模擬中的隨機(jī)模型量化分析細(xì)觀結(jié)構(gòu)演化規(guī)律,是揭示土石混合體宏細(xì)觀力學(xué)特性的有效手段。土石混合體的細(xì)觀結(jié)構(gòu)特征和“土”、“塊石”的自身性質(zhì),共同影響其力學(xué)行為。變形破壞過程中,內(nèi)部塊石運(yùn)動(dòng)、破碎等引起內(nèi)部細(xì)觀結(jié)構(gòu)的不同調(diào)整,從而影響宏觀強(qiáng)度和變形特性。研究尺度和粒度組成直接決定了塊石在土石混合體力學(xué)響應(yīng)中所發(fā)揮的作用類型;棱角性塊石未破碎時(shí),能通過咬合有效提高強(qiáng)度;由應(yīng)力水平和塊石自身強(qiáng)度決定的破碎性質(zhì),對(duì)土石混合體強(qiáng)度參數(shù)及變形特性均有重要影響。
[Abstract]:RSA (S-RM) is common in a variety of epigenetic geological disasters and water conservancy and Hydropower Engineering, road engineering, building, mining and other fields. The "soil" and "stone" in terms of size and strength are different, the soil rock mixture microstructure has a significant effect on the the physical and mechanical properties, which is closely related with the research scale, and has the obvious characteristics of the heterogeneous system. This paper research meso structure mechanics and scale effect of soil rock mixture through physical experiments and numerical simulation were carried out. Based on the real-time lossless CT scanning technology, carry out the soil rock mixture of the three axis of particle size test. Stone content, composition, effect of specimen size on the macroscopic strength and deformation characteristics, and realizes the real-time acquisition of the sample microstructure and the evolution of information. The application of digital image processing, database management 3D and visualization technology, research and development of earth-rockaggregate three-dimensional structure reconstruction and analysis system (MSRAS3D), the SRM three-dimension meso structure model of meso structure reconstruction and quantitative statistical analysis, provides a powerful means to reveal the whole process of three axis test of meso structure evolution law based. That reveals the spatial movement of SRM under load inside the stone, crushing and deformation localization phenomenon typical form. The reconstruction model of earth rock mixture discrete element numerical simulation based on three axis test, according to the test results of inversion obtained "soil" and "stone" fine particles the concept of mechanical parameters. Calculation parameters are used for inversion of soil rock mixture stochastic model using random generation technology, studied the shape of block stones, crushing performance and specimen size and other factors on the soil rock mixture Influence of macro and meso mechanical behavior. The results of numerical experiments based on the space motion of particles inside the process of destruction of soil rock mixture shear, particle contact number, normal and tangential contact force, meso evolution body change of meso structure were quantitatively analyzed, revealing the fine granularity level from view, the shape of block stones and broken, the influence mechanism of factors on the sample scale and deformation characteristics of soil rock mixture macroscopic strength. Through the study showed that the model of quantitative analysis of stochastic reconstruction model and numerical simulation of indoor test in meso structure evolution based on earth is to reveal the effective means of combination of macro and meso mechanics the characteristics of soil rock mixture. The meso structure characteristics and the "soil", "stone" of their own nature, influence its mechanical behavior. In the process of deformation and fracture, the internal rock movement caused by breaking internal meso node Different adjustment structure, thus affecting the macroscopic strength and deformation characteristics. Research on the scale and size directly determines the type of stone in the role play in the mechanical response of soil rock mixture; angularity stone is not broken, can effectively improve the strength of the occlusion; by nature should be broken stress level and rock strength that of soil rock mixture strength parameters and deformation characteristics have a significant impact.

【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TU411

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