【摘要】：級配碎石是典型的散體材料,具有明顯的顆粒性結(jié)構(gòu)特征、非線性力學(xué)特性及較大的變異性,物理力學(xué)特性復(fù)雜,采用連續(xù)介質(zhì)力學(xué)理論和常規(guī)的室內(nèi)試驗(yàn)難以從本質(zhì)上揭示其復(fù)雜的物理力學(xué)特性、變形及破壞機(jī)理,本論文以此為背景開展級配碎石三維動三軸數(shù)值試驗(yàn)方法及其應(yīng)用研究。本文通過新“generate”邏輯生成試件,采用球體和平行粘結(jié)模型模擬邊界條件與三段壓實(shí)方法模擬成型,構(gòu)建了級配碎石動三軸數(shù)值試驗(yàn)?zāi)Ｐ�。對比引用文獻(xiàn)數(shù)據(jù)和本文試驗(yàn)結(jié)果,證明了PFC5.0-3D軟件模型的可靠性;通過分析室內(nèi)動三軸試驗(yàn)和數(shù)值試驗(yàn)結(jié)果,證明了數(shù)值試驗(yàn)方法的可靠性。通過長期加卸載循環(huán)數(shù)值試驗(yàn),建議加卸載次數(shù)至少為200次;通過真實(shí)顆粒形狀和球體分別進(jìn)行動三軸數(shù)值試驗(yàn),結(jié)果表明采用球體無法全面分析材料結(jié)構(gòu)-力學(xué)特性,模擬結(jié)果誤差較大,推薦采用真實(shí)顆粒形狀進(jìn)行數(shù)值試驗(yàn)研究。根據(jù)上述確定的模型參數(shù)和試驗(yàn)條件進(jìn)行數(shù)值試驗(yàn)研究,得到如下主要結(jié)論:(1)根據(jù)單檔料粒徑試驗(yàn)確定橡膠球?qū)雍衽c頂墻最大運(yùn)動速率(1e1m/s),并分析微力學(xué)參數(shù)對級配碎石動三軸數(shù)值試驗(yàn)的影響,結(jié)果表明:選取彈性模量在30GPa~40GPa、摩擦系數(shù)在0.4~0.6范圍內(nèi)的集料試驗(yàn)結(jié)果較好。(2)顆粒組成對級配碎石永久變形的影響分析得出:19~26.5mm及16~19mm粒徑主要作為骨架顆粒,體積分?jǐn)?shù)應(yīng)控制在55%~65%之間;4.75mm粒徑作為填充顆粒,體積分?jǐn)?shù)應(yīng)控制在20%~25%之間;13.2mm和9.5mm粒徑作為過渡顆粒,體積分?jǐn)?shù)控制應(yīng)在20%以內(nèi)。(3)總結(jié)分析動三軸數(shù)值試驗(yàn)級配碎石永久變形的細(xì)觀特征,揭示了級配碎石永久變形的機(jī)理,細(xì)觀特征因素基于級配碎石永久變形影響程度重要性的排序?yàn)?空隙率及微應(yīng)力應(yīng)變顆粒接觸(接觸力接觸數(shù)量)顆粒運(yùn)動(速度矢量顆粒平移與轉(zhuǎn)動位移矢量顆粒坐標(biāo))顆粒結(jié)構(gòu)能量響應(yīng)。
[Abstract]:Graded crushed stone is a typical granular material with obvious granular structure characteristics, nonlinear mechanical properties and large variability, and complex physical and mechanical properties. It is difficult to reveal its complex physical and mechanical properties, deformation and failure mechanism by using continuum mechanics theory and conventional laboratory tests. In this paper, the three-dimensional dynamic triaxial numerical test method of graded crushed stone and its application are studied in this paper. In this paper, the new "generate" logic is used to generate the specimen, and the boundary conditions and the three-stage compaction method are simulated by using the spherical and parallel bonding models, and the dynamic triaxial numerical test model of graded crushed stone is constructed. The reliability of the PFC5.0-3D software model is proved by comparing the reference data with the experimental results in this paper, and the reliability of the numerical test method is proved by analyzing the results of the indoor dynamic triaxial test and the numerical test. It is suggested that the loading and unloading times should be at least 200 times through the long-term cyclic loading and unloading tests, and the dynamic triaxial numerical tests on the real particle shape and the sphere are carried out respectively. The results show that the material structure and mechanical properties can not be fully analyzed by using the sphere. Because the error of simulation results is large, it is recommended that the real particle shape be used for numerical test. According to the above determined model parameters and experimental conditions, The main conclusions are as follows: (1) according to the single particle size test, the thickness of rubber ball layer and the maximum velocity of movement (1e1m/s) of the top wall are determined, and the effect of micromechanical parameters on the dynamic triaxial test of graded crushed stone is analyzed. The results show that when the elastic modulus is in the range of 30 GPA and 40 GPA and the friction coefficient is in the range of 0.4 ~ 0.6, the experimental results are better. (2) the effect of particle composition on the permanent deformation of graded macadam is analyzed. The results show that the particle size of 16~19mm is mainly used as skeleton particle. The volume fraction should be controlled between 55% and 65% and the particle size of 4.75 mm should be used as the filling particle, and the volume fraction should be controlled between 20% and 25% as the transition particle, and the particle size of 9.5mm should be controlled between 20% and 25%. The control of volume fraction should be within 20%. (3) the characteristics of permanent deformation of graded crushed stone in dynamic triaxial numerical test are summarized and analyzed, and the mechanism of permanent deformation of graded crushed stone is revealed. The order of meso-characteristic factors based on the importance of permanent deformation of graded crushed stone is: void rate and microstress strain particle contact (contact force contact number) particle motion (velocity vector particle translation and rotational displacement vector) Particle coordinates) the energy response of particle structure.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：U414

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李燦;邱紅勝;張志華;;基于PFC3D的粗粒土三軸試驗(yàn)細(xì)觀參數(shù)敏感性分析[J];武漢理工大學(xué)學(xué)報(交通科學(xué)與工程版);2016年05期

2 劉寶;蘇謙;PHAM Duc Phong;白皓;LAM Thi Huyen Hanh;;不同含水狀態(tài)級配碎石臨界動應(yīng)力及變形規(guī)律研究[J];鐵道學(xué)報;2016年06期

3 郭寅川;王禮根;申愛琴;顧聘聘;;動載作用下級配碎石基層瀝青路面力學(xué)分析[J];公路交通科技;2016年01期

4 王啟云;張家生;鄧國棟;孟飛;吳波;;高速鐵路路基粗粒土B組填料剪脹特性的大型三軸試驗(yàn)研究[J];鐵道科學(xué)與工程學(xué)報;2015年04期

5 張東;黃曉明;田飛;;級配碎石動三軸試驗(yàn)離散元模擬[J];公路交通科技;2014年12期

6 鄧國棟;張家生;王啟云;石熊;王佳;;高速鐵路粗粒土填料動力參數(shù)試驗(yàn)研究[J];鐵道科學(xué)與工程學(xué)報;2014年02期

7 褚福永;朱俊高;殷建華;;基于大三軸試驗(yàn)的粗粒土剪脹性研究[J];巖土力學(xué);2013年08期

8 高井望;徐佩華;黃潤秋;袁中凡;;DEM擬合級配碎石材料大三軸試驗(yàn)的顆粒粗糙度效應(yīng)研究[J];工程地質(zhì)學(xué)報;2013年04期

9 孟飛;張家生;胡奇凡;陳曉斌;王啟云;;粗粒土體變規(guī)律大型三軸試驗(yàn)研究[J];水利水電技術(shù);2013年06期

10 蔣應(yīng)軍;李思超;王天林;;級配碎石動三軸試驗(yàn)的數(shù)值模擬方法[J];東南大學(xué)學(xué)報(自然科學(xué)版);2013年03期

相關(guān)博士學(xué)位論文 前4條

1 馬士杰;粒料基層設(shè)計方法與永久變形控制指標(biāo)研究[D];東南大學(xué);2015年

2 李，

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