摘要
采用颗粒流方法模拟不同排水条件下砂土的双轴试验,研究了循环荷载作用下松砂渐进破坏过程中配位数、接触方向、粒间接触力的演化规律,应用表征上述量的组构参数研究了砂土的诱发各向异性,探讨了饱和砂土液化、状态转换面产生的微细观机理。研究表明:宏观的液化对应于细观组构上配位数的连续累积丧失和粒间接触力的不断减小,其根本原因在于循环荷载往返过程中,组构各向异性与应力各向异性发展的不匹配。研究成果对于揭示砂土变形的细观机理以及建立砂土的细观力学模型都具有意义。
A series of cyclic biaxial tests on loose sand sunder both drained and undrained conditions with constant amplitudes of strain and stress were performed. The evaluation of micro fabric parameters such as coordinate number, contact orientation and contact forces were studied during the process of failure under cyclic loading. The mechanism of liquefaction and phase transformation was discussed from the viewpoint of micro-mechanism. It was indicated that macroscopic liquefaction was induced due to the cumulative loss of co-ordination number and continuous reduction of contact forces in microscopic fabric. The fundamental reason for sand liquefaction was the incompatibility of fabric and force anisotropies during cyclic loading. The results were valuable for the studies on the micro regularity of sand deformation and the establishment of micro models.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2007年第7期1035-1041,共7页
Chinese Journal of Geotechnical Engineering
关键词
砂土液化
细观组构
循环荷载
诱发各向异性
sand liquefaction
micro-fabric
cyclic loading
induced anisotropy
