粗粒土三轴制样过程中的颗粒破碎特性
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摘要
粗粒土在制样和加载的过程中常常会发生破碎,目前大多数室内试验研究均集中在对粗粒土加载过程中破碎特性的描述,而忽视了其制样过程中颗粒破碎的影响。为此,采用2种不同级配的粗粒土分层击实制样,分析其在不同相对密度条件下的制样破碎特性。研究发现:粗粒土在制样过程中存在一定程度的颗粒破碎现象,较大颗粒破碎较为显著;但无论初始级配如何,粗粒土制样过程中的颗粒破碎率都随着制样相对密度的增大而增大。
Particle breakage of granular material often inevitably occurs during both sample preparation and loading stages. However, main attention is usually paid to the laboratory assessment of the particle breakage behaviour of samples under loading, where the impact of particle breakage during sample preparation is often ignored. Therefore, an attempt was made to evaluate the breakage behaviour of granular materials with two different gradings during sample preparation. Layered compaction method was used to prepare triaxial samples of rockfill with different relative densities. It is found out that there is particle breakage during sample preparation exists. Larger sized particles appear to break more than that of the smaller ones. Regardless of the initial gradings, the particle breakage extent increases with an increase of the relative density.
Particle breakage of granular material often inevitably occurs during both sample preparation and loading stages. However, main attention is usually paid to the laboratory assessment of the particle breakage behaviour of samples under loading, where the impact of particle breakage during sample preparation is often ignored. Therefore, an attempt was made to evaluate the breakage behaviour of granular materials with two different gradings during sample preparation. Layered compaction method was used to prepare triaxial samples of rockfill with different relative densities. It is found out that there is particle breakage during sample preparation exists. Larger sized particles appear to break more than that of the smaller ones. Regardless of the initial gradings, the particle breakage extent increases with an increase of the relative density.
引文
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[2] YU F.Particle Breakage and the Critical State of Sands[J].Géotechnique,2017,67(8):713-719.
[3] XIAO Y,LIU H,CHEN Q,et al.Particle Breakage and Deformation of Carbonate Sands with Wide Range of Densities During Compression Loading Process[J].Acta Geotech,2017,12(5):1177-1184.
[4] Einav I.Breakage Mechanics—Part I:Theory[J].J Mech Phys Solids,2007,55(6):1274-1297.
[5] DE BONO J,MCDOWELL G.Particle Breakage Criteria in Discrete-Element Modelling[J].Géotechnique,2016,66(12):1014-1027.
[6] COOP M,SORENSEN K,FREITAS T B,et al.Particle Breakage During Shearing of a Carbonate Sand[J].Géotechnique,2004,54(3):157-163.
[7] SUN Y,ZHENG C.Breakage and Shape Analysis of Ballast Aggregates with Different Size Distributions[J].Particuology,2017,35:84-92.
[8] MCDOWELL G R,LI H.Discrete Element Modelling of Scaled Railway Ballast Under Triaxial Conditions[J].Granular Matter,2016,18(3):1-10.
[9] XIAO Y,LIU H,DING X,et al.Influence of Particle Breakage on Critical State Line of Rockfill Material[J].Int J Geomech,2015,16(1):4015031.
[10] LACKENBY J,INDRARATNA B,MCDOWELL G,et al.Effect of Confining Pressure on Ballast Degradation and Deformation Under Cyclic Triaxial Loading[J].Géotechnique,2007,57(6):527-536.
[11] 中华人民共和国水利部.土工试验规程:SL237—1999[S].北京:中国水利水电出版社,1999:38-40.
[12] MARSAL R J.Large Scale Testing of Rockfill Materials[J].J Soil Mech Found Div,1967,93(2):27-43.