科学技术与工程
科學技術與工程
과학기술여공정
Science Technology and Engineering
2015年
32期
191-195
,共5页
离散元%颗粒破碎%孔隙率%粗粒土%应力-应变关系
離散元%顆粒破碎%孔隙率%粗粒土%應力-應變關繫
리산원%과립파쇄%공극솔%조립토%응력-응변관계
discrete element method%particle crushing%porosity%coarse-grained%soil stress-strain relationship
为了分析粗粒土的剪切力学特性,采用离散元软件PFC2 D模拟考虑颗粒破碎的粗粒土直剪试验,提供了制备可发生破碎的单颗粒粗粒土试样方法,以及改变离散元试样孔隙率的方法。在不同竖向压力作用下对粗粒土试样模拟直剪试验,分析剪应力、体应变与剪切位移的关系,剪切前后应力状态,剪切后速度分布情况。改变粗粒土试样的孔隙率和颗粒间黏聚力,分析粗粒土剪切强度的影响因素。研究表明,试样先剪缩再剪胀,剪应力峰值、残余强度随着竖向压力的增大而增大。应力场受剪前均匀分布,受剪后分布不均匀。剪切带内外颗粒处于不同的运动状态,剪切带内速度变化梯度较大。在相同竖向压力作用下,剪切强度随孔隙率增大而减小,随黏聚力增大而增大。
為瞭分析粗粒土的剪切力學特性,採用離散元軟件PFC2 D模擬攷慮顆粒破碎的粗粒土直剪試驗,提供瞭製備可髮生破碎的單顆粒粗粒土試樣方法,以及改變離散元試樣孔隙率的方法。在不同豎嚮壓力作用下對粗粒土試樣模擬直剪試驗,分析剪應力、體應變與剪切位移的關繫,剪切前後應力狀態,剪切後速度分佈情況。改變粗粒土試樣的孔隙率和顆粒間黏聚力,分析粗粒土剪切彊度的影響因素。研究錶明,試樣先剪縮再剪脹,剪應力峰值、殘餘彊度隨著豎嚮壓力的增大而增大。應力場受剪前均勻分佈,受剪後分佈不均勻。剪切帶內外顆粒處于不同的運動狀態,剪切帶內速度變化梯度較大。在相同豎嚮壓力作用下,剪切彊度隨孔隙率增大而減小,隨黏聚力增大而增大。
위료분석조립토적전절역학특성,채용리산원연건PFC2 D모의고필과립파쇄적조립토직전시험,제공료제비가발생파쇄적단과립조립토시양방법,이급개변리산원시양공극솔적방법。재불동수향압력작용하대조립토시양모의직전시험,분석전응력、체응변여전절위이적관계,전절전후응력상태,전절후속도분포정황。개변조립토시양적공극솔화과립간점취력,분석조립토전절강도적영향인소。연구표명,시양선전축재전창,전응력봉치、잔여강도수착수향압력적증대이증대。응력장수전전균균분포,수전후분포불균균。전절대내외과립처우불동적운동상태,전절대내속도변화제도교대。재상동수향압력작용하,전절강도수공극솔증대이감소,수점취력증대이증대。
In order to analyze the shear behavior of coarse-grained soil, the discrete elements software PFC2D is used to simulate the direct shear test on coarse-grained soil considering particle crushing.The methods of preparing the crushable coarse-grained soil sample and changing the porosity of the sample are introduced.The direct shear tests are simulated under different vertical pressure, and analyze the relationship between shear stress and shear dis-placement, the relationship between volume strain and shear displacement, the stress state before and after the test and the velocity distribution after the test.The porosity and contact-bonded force are changed to analyze the factors affecting the shear strength of coarse-grained soil.The study shows that shear dilatation occurred after shear con-traction in the test.The peak shear strength and residue strength increases with the vertical pressure increasing.The homogeneous distribution stress field before the test changes into the inhomogeneous distribution after the test.The particles in the shear band are in different motion state, and the gradient of velocity is large.Under the same vertical pressure, the shear strength decreases with the porosity increasing and increases with the contact-bonded force increasing.