摘要
从陕西泾阳泾河南塬11个新近发生和临滑的黄土滑坡不同深度位置采取原状土样,根据滑坡所处的地质环境和灌溉水诱发条件,按不同应力水平和不同含水率情况,分别对滑带黄土和古土壤进行了三轴蠕变实验和直剪蠕变实验,获得了该类滑带土的蠕变特性:蠕变形变均包含等速蠕变、加速蠕变和蠕变破坏3个阶段,但从加速蠕变到蠕变破坏均历时短暂;滑带土均表现为塑性破坏特征;滑带土发生蠕变破坏时对应的应变量ε基本在10%以下,随着含水率的增加,蠕变破坏相应的应变量也随之降低;而直剪蠕变在不同含水率下的破坏应变量都在4%以内;历时(t>0 min)的应力–应变等时曲线族几乎为一束曲线簇,均具有"归一化"现象,反映出该区滑带土具有良好的一致的蠕变变形特性。讨论了滑带土蠕变特性与边坡失稳时间预报模型之间的内在联系,为黄土滑坡的临滑预报作了实验研究和理论探讨。
Soils at different depths are sampled from 11 recent or apt-to-be landslides located in Jingyang County along the Jinghe River.Considering their geological environment and irrigation conditions,triaxial creep tests and direct shear creep tests on these undisturbed soil samples separately under different stress levels and moisture contents are performed to study their creep property.The findings are as follows： the creep deformation consists of 3 stages,namely,constant speed creep,acceleration creep and creep rupture,and the period from the acceleration creep to the creep rupture is significantly short;the rupture of the soil in sliding zone is characterized by plastic destruction;the corresponding strain capacity ε of the creep rupture is basically below 10%,and with the increase of the moisture content,ε of the creep rupture accordingly decreases;the results of destruction strain capacity by the direct shear creep tests under different moisture content conditions are all below 4%;and the stress-strain isochronic curves under time（t0 min） are nearly a bunch of series of curves and exhibit a ＂normalization＂ phenomenon,demonstrating that the soil in this sliding zone has consistent creep characteristics.The intrinsic relationship between the creep property and the prediction model of slope failure is also discussed.Experimental studies and theoretical discussions are given for forecasting loess landslides.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2010年第7期1023-1028,共6页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(40772181)
关键词
黄土滑坡
蠕变特性
三轴蠕变试验
剪切蠕变试验
失稳时间预测
loess landslide
creep property
triaxial creep test
direct shear creep test
forecast of slope failure
