灌溉诱发非饱和黄土破坏的实际应力路径可近似为净法向应力和偏应力均不变，而基质吸力逐渐减小的吸湿破坏过程。为研究非饱和黄土在吸湿过程中的应变特性，以泾阳南塬 Q3马兰黄土为研究对象，从非饱和土角度出发，开展了控制不同基质吸力下(初始含水率)的非饱和黄土的吸湿特性试验研究。研究表明，试样在持续稳定的主应力作用下，随着基质吸力的减小土样发生变形破坏，整个变形过程中没有破坏剪切面；进一步研究发现，土样从塑限含水率到液限含水率之间，土样对水的敏感性很强。即当含水率增大到塑限含水率之后，应变快速发展，其变形特性解释了该地区 Q3黄土强的湿陷特性以及浅层滑坡和崩塌的频发的原因。最后，对于同一种土，其基质吸力与应变的变化关系曲线是类似的，曲线的差别可能是由于土样之间的差异及仪器的误差等因素造成的。%Actual stress path of the unsaturated loess caused by the damage of irrigating induced can be approximated as normal stress and deviatoric stress remains unchanged,while the process of gradually reducing of matrix suction. In order to research the strain characteristics of unsatu-rated loess under wetting conditions,the Q3 Loess in the Southern Tableland of Jingyang County has been taken as the research object,and the experimental research on hygroscopic properties of unsaturated loess under the control of different hygroscopic properties of the matrix suction (ini-tial water content)has been carried out from the angle of the unsaturated soil. The results show that,the deformation and failure are happened in the soil samples under a steady primary stress with the decrease of the matrix suction,but no damage shear surface occursin the whole deforma-tion process;the further research suggests that soil samples have strong water sensitivity from the plastic limit water content to liquid limit water content.When the water content increases to the plastic limit water content,the strain is developed rapidly,which reveals the strong collaps-iblecharacteristics of Q3 loess and the causes of shallow landslide and avalanche. Finally,for the same soil,the change curves of its matric suction and strain are similar,their differences in the curve may be caused by the differences of soil and the errorbetween the instruments that made by human factors.
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