本文關(guān)鍵詞： 大型直剪試驗 高爐礦渣 粉煤灰 顆粒流離散元 力學(xué)特性　出處：《內(nèi)蒙古科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本文采用顆粒流離散元軟件PFC3D作為數(shù)值分析平臺，通過二次開發(fā)的Fish語言建立具有與室內(nèi)試驗相同的簡化模型，，虛擬實現(xiàn)室內(nèi)大型直剪試驗。通過分析試樣宏－細觀參數(shù)間的相關(guān)性，標(biāo)定數(shù)值模型最終的細觀輸入?yún)?shù)，進而對室內(nèi)試驗進行仿真對比。最后，分別從力學(xué)響應(yīng)、能量響應(yīng)以及場的變化三方面研究試驗條件對混合料剪切強度數(shù)值試驗的影響；對經(jīng)驗配合比進行優(yōu)化，并驗證其可靠性，同時選出最優(yōu)配合比。 PFC3D作為研究離散介質(zhì)的一種方法，它能夠準確地模擬高爐礦渣與粉煤灰混合料的直剪試驗過程，試驗結(jié)果可靠性高、周期短且成本低。通過分析顆粒摩擦系數(shù)、剛度比、強度比及半徑因子對峰值強度、初始彈性模量及強度參數(shù)的影響，得到了試樣細觀參數(shù)的有效取值范圍。在此基礎(chǔ)上，標(biāo)定試樣的最終細觀參數(shù)，建立準確的室內(nèi)大型直剪試驗數(shù)值模型�；谝延械臄�(shù)值模型，對混合料試樣共進行了48組大型直剪試驗。試驗中通過改變不同圍壓時的加載速率、孔隙率及粗粒含量，并從力學(xué)響應(yīng)、能量響應(yīng)以及接觸力鏈場的角度進行分析，確定了最佳的加載速率值、孔隙率范圍及最優(yōu)粗粒含量，可為工程應(yīng)用提供借鑒。在對剪切位移場的發(fā)展趨勢和變化規(guī)律分析的基礎(chǔ)上，通過PFC3D中的Fish語言編寫代碼，監(jiān)測沿剪切盒高度設(shè)置的測量球水平位移。經(jīng)計算得到，混合料的剪切帶寬度L=60.75mm，而試樣平均粒徑D30=30mm，即L=2D30。通過對混合料的配合比進行優(yōu)化分析得到，經(jīng)驗配合比5:1具有一定的可靠性但不是最優(yōu)配合比；當(dāng)配合比為4:1時，混合料的力學(xué)響應(yīng)、能量響應(yīng)及接觸力鏈場的結(jié)果最為理想，認為是最優(yōu)配合比。 高爐礦渣作為典型的離散介質(zhì)，其物理力學(xué)特性復(fù)雜，若采用有限元的離散化模型和常規(guī)的室內(nèi)試驗，難以從本質(zhì)上揭示其復(fù)雜的受力特性和損傷機制。因此，本文基于三維顆粒流離散元理論，對高爐渣粉煤灰混合料細觀力學(xué)特性研究具有重要的現(xiàn)實意義和理論價值。
[Abstract]:In this paper, the particle flow discrete element software PFC3D is used as the numerical analysis platform, and the simplified model with the same as the indoor test is established by the second developed Fish language. By analyzing the correlation between the macro and mesoscopic parameters of the samples, calibrating the final mesoscopic input parameters of the numerical model, and then comparing the simulation results of the laboratory tests, the mechanical responses are analyzed. The influence of test conditions on the shear strength of mixture is studied from three aspects: energy response and field change, and the empirical mixture ratio is optimized, its reliability is verified, and the optimal mixture ratio is selected. As a method to study discrete medium, PFC3D can accurately simulate the direct shear test process of blast furnace slag and fly ash mixture. The test results are high reliability, short period and low cost. The influence of strength ratio and radius factor on the peak strength, initial elastic modulus and strength parameters is obtained, and the effective range of meso-parameters is obtained. On the basis of this, the final meso-parameters of the sample are calibrated. An accurate numerical model of large direct shear test was established. Based on the existing numerical model, 48 groups of large direct shear tests were carried out on the mixture samples. The loading rate, porosity and coarse particle content were changed under different confining pressures. From the angle of mechanical response, energy response and contact force chain field, the optimum loading rate, porosity range and coarse-grain content are determined. It can be used as a reference for engineering application. Based on the analysis of the development trend and variation law of shear displacement field, the code is compiled by Fish language in PFC3D to monitor the horizontal displacement of the measuring sphere set along the height of the shear box. The shear band width of the mixture is 60.75mm, and the average particle size of the sample is D3030mm, that is, L2D30mm. Through the optimization analysis of the mixture mix ratio, the empirical mixture ratio of 5: 1 has certain reliability but is not the optimal mix ratio; when the mixture ratio is 4: 1, The results of mechanical response, energy response and contact force chain field of mixture are the most ideal, which is considered to be the optimal mix ratio. As a typical discrete medium, blast furnace slag has complex physical and mechanical properties. If the finite element discretization model and conventional laboratory tests are adopted, it is difficult to reveal the complex mechanical properties and damage mechanism of blast furnace slag in essence. Based on the three-dimensional granular flow discrete element theory, this paper has important practical significance and theoretical value for the study of the meso-mechanical properties of blast furnace slag and fly ash mixture.
【學(xué)位授予單位】：內(nèi)蒙古科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU528

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