摘要
在改进的非饱和土三轴仪上运用3级持续加荷固结排水试验法,对小浪底水库1#滑坡体非饱和土的强度特性进行了三轴试验,研究了目前在非饱和土的试验研究中极少关注的试样轴向变形过大(即剪破)和剪胀对非饱和土基质吸力、抗剪强度及各特征关系的影响。结果表明:高密实度试样通过升高负孔隙水压力数值这样的内部应力调整来抵消受剪时的剪胀趋势,这个过程将增大试样的基质吸力,并对试样强度有增强作用;剪胀对抗剪强度的影响类似于饱和土,总体上对之产生负影响;多级试验中试样的提前剪破将降低后续围压下试验测得的抗剪强度,并在最终计算中得到比真实值更大的黏聚力和更小的内摩擦角,剪破后的后续围压试验测得的抗剪强度接近残余抗剪强度。
Strength characteristics of unsaturated soil of the landslide #1 in Xiaolangdi Reservoir are studied by using consolidation drainage test method with three-level continuous loading on the improved triaxial test instrument. The attention to the influences of oversized axial deformation （namely shear destruction） and shear expansion on the experimental sample of unsaturated soil is less paid in many present studies. The influences of shear destruction and shear expansion of experimental sample on matrix suction, shear strength and various characteristic relations of unsaturated soil are comprehensively analyzed. The results indicate high compactness samples counteract the trend of shear expansion by internal stress adjustment as increased negative pore water pressure, the matrix suction and strength of sample will increase in this process, and the influence of shear expansion on shear strength is similar with that on saturated soil. Furthermore, the shear destruction of sample in advance in multi-level test reduces the shear strength of the test within follow-up confining pressure, and more cohesive force and less internal friction angle than true values are obtained; the shear strength of the test within follow-up confining pressure after shear destruction is close to the residual shear strength.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2009年第3期640-644,共5页
Rock and Soil Mechanics
基金
河南省高等学校创新人才培养工程项目及河南省高校杰出科研人才创新工程项目(HAIPURT)(No.2005KYCX015)
科技部科研院所社会公益研究专项<大型水库土质库岸崩滑机理及其防治研究>(No.2005DIB3J054)
关键词
非饱和土
三轴试验
轴向变形
剪胀
基质吸力
抗剪强度
unsaturated soil
triaxial test
axial deformation
shear expansion
matrix suction
shear strength
