岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
1期
41-47
,共7页
胞元土体模型%基体%增强颗粒%颗粒尺度效应%三轴抗剪试验
胞元土體模型%基體%增彊顆粒%顆粒呎度效應%三軸抗剪試驗
포원토체모형%기체%증강과립%과립척도효응%삼축항전시험
soil model of cell element%matrix%reinforcing particle%grain size effect%triaxial shear test
土体是一种颗粒介质，其强度与变形特性具有显著的颗粒尺度效应。采用胞元土体模型和三轴抗剪试验分析了土体强度和变形的尺度效应特性。根据土体中不同尺度颗粒间相互作用表现出的聚集和摩擦效应，提出了“基体-增强颗粒”土体胞元模型，胞元体由基体和增强颗粒组成，其中基体由微小土颗粒集成，而增强颗粒为砂粒，宏观土体则简化为由许多胞元体构成的介质。引入广义球应变和广义等效应变，基于应变能导出了考虑颗粒尺度效应的应力-应变关系以及屈服应力计算公式；同时，针对增强颗粒不同粒径和体分比的土体进行一系列三轴不排水抗剪试验，给出了应力-应变和屈服应力尺度效应的测试结果。试验和理论计算结果均表明，土体强度和变形的尺度效应随增强颗粒的体分比增加以及粒径的减小而增强，由此反映出土体强度和变形显著的尺度效应；土体强度和变形尺度效应的理论预测结果与试验具有较好的一致性。
土體是一種顆粒介質，其彊度與變形特性具有顯著的顆粒呎度效應。採用胞元土體模型和三軸抗剪試驗分析瞭土體彊度和變形的呎度效應特性。根據土體中不同呎度顆粒間相互作用錶現齣的聚集和摩抆效應，提齣瞭“基體-增彊顆粒”土體胞元模型，胞元體由基體和增彊顆粒組成，其中基體由微小土顆粒集成，而增彊顆粒為砂粒，宏觀土體則簡化為由許多胞元體構成的介質。引入廣義毬應變和廣義等效應變，基于應變能導齣瞭攷慮顆粒呎度效應的應力-應變關繫以及屈服應力計算公式；同時，針對增彊顆粒不同粒徑和體分比的土體進行一繫列三軸不排水抗剪試驗，給齣瞭應力-應變和屈服應力呎度效應的測試結果。試驗和理論計算結果均錶明，土體彊度和變形的呎度效應隨增彊顆粒的體分比增加以及粒徑的減小而增彊，由此反映齣土體彊度和變形顯著的呎度效應；土體彊度和變形呎度效應的理論預測結果與試驗具有較好的一緻性。
토체시일충과립개질，기강도여변형특성구유현저적과립척도효응。채용포원토체모형화삼축항전시험분석료토체강도화변형적척도효응특성。근거토체중불동척도과립간상호작용표현출적취집화마찰효응，제출료“기체-증강과립”토체포원모형，포원체유기체화증강과립조성，기중기체유미소토과립집성，이증강과립위사립，굉관토체칙간화위유허다포원체구성적개질。인입엄의구응변화엄의등효응변，기우응변능도출료고필과립척도효응적응력-응변관계이급굴복응력계산공식；동시，침대증강과립불동립경화체분비적토체진행일계렬삼축불배수항전시험，급출료응력-응변화굴복응력척도효응적측시결과。시험화이론계산결과균표명，토체강도화변형적척도효응수증강과립적체분비증가이급립경적감소이증강，유차반영출토체강도화변형현저적척도효응；토체강도화변형척도효응적이론예측결과여시험구유교호적일치성。
Soil is a granular medium, and its strength and deformation characteristic behave marked grain size effect. Based on the theoretical model of cell element and triaxial shear tests, the analysis of grain size effect is presented. The matrix-reinforcing particles cell element model of soil is proposed according to cohesion and friction effect of interaction between particles of varying size. The cell element is composed of matrix and reinforcing grain. Many tiny grains are grouped into the matrix and reinforcing grain is a sand grain, so the macroscopic soil is simplified as a medium that consists of a number of cell elements. Introduced the generalized spherical strain and equivalent strain, the stress-strain relation and yielding stress formula are derived from strain energy accounting for the grain size effects. A series of triaxial undrained shear tests are performed for test samples with reinforced particles of different sizes and volumes fractions, and test results of stress-strain curves and yielding stresses are presented on the size effect. The experimental results and theoretical analysis show that the size effect of the strength and deformation of soil is increased with volume fraction raising and decreasing of particle size, which suggests strong size effect. The theoretical prediction of size effect is in good agreement with that of the test.
