轴向循环加载条件下人工制备结构性土力学特性  

Mechanical Properties of Artificially Prepared Structured Soils Subjected to Axially Cyclic Loading

作　　者：刘恩龙[1] 罗开泰[1] 

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室水利水电学院,成都610065

出　　处：《北京工业大学学报》2012年第2期180-185,共6页Journal of Beijing University of Technology

基　　金：国家自然科学基金资助项目(51009103)

摘　　要：为探讨结构性土的力学特性和变形机理,对人工制备的弱胶结结构性土样进行了轴向加载—卸载—再加载的三轴压缩试验,分别在围压为25和100 kPa时进行了固结排水和固结不排水压缩试验.结果表明:随着荷载的逐渐增加,结构性土样的结构逐渐弱化,其特性逐渐趋向重塑土的特性;在固结排水条件下,在整个轴向加载—卸载—再加载过程中,结构性土样总体上体积收缩.但在轴向应变较小,颗粒间的胶结保持较完好时,在卸载时会出现局部剪胀或体积收缩不明显,区别与重塑黏土的特性;在固结不排水条件下,产生正的孔压,轴向卸载时,在应变较小的情况下,孔隙压力减小,在应变较大的情况下,孔隙压力增大,且围压大时孔隙压力增加的量值大.To investigate the deformation mechanism and mechanical features of structured soils,triaxial compression tests on weakly bonded structured soils are conducted with the stress paths of axially loading—unloading—reloading.The samples are artificially prepared weakly bonded structured soils,which are tested under consolidation drained（CD） and consolidation undrained（CU） conditions with the confining pressures of 25 and 100 kPa,respectively.It is founded that,with increasing loading,the structured soils will be gradually de-structured and thus tend to behave as the reconstituted soils.Under CD conditions,during the whole axially loading-unloading-reloading processes,the structured samples contract as a whole;however,when the axial strain is smaller,the bonding between the particles remains relative intact and therefore unloading the samples will locally dilate or contract very slightly,which differ from the reconstituted clays.Under CU conditions,the positive pore pressures will occur,and unloading the pore pressures will reduce with the smaller axial strain and increase with the bigger one,having bigger increased values when the confining pressure is bigger.

关 键 词：结构性土 力学特性 轴向循环加载 三轴试验 

分 类 号：X705[环境科学与工程—环境工程]