西北地质
西北地質
서북지질
Northwestern Geology
2015年
4期
218-225
,共8页
原状黄土%灌溉%非饱和土%基质吸力%应变
原狀黃土%灌溉%非飽和土%基質吸力%應變
원상황토%관개%비포화토%기질흡력%응변
intact loess%irrigation%unsaturated soil%matrix suction%strain
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。
灌溉誘髮非飽和黃土破壞的實際應力路徑可近似為淨法嚮應力和偏應力均不變,而基質吸力逐漸減小的吸濕破壞過程。為研究非飽和黃土在吸濕過程中的應變特性,以涇暘南塬 Q3馬蘭黃土為研究對象,從非飽和土角度齣髮,開展瞭控製不同基質吸力下(初始含水率)的非飽和黃土的吸濕特性試驗研究。研究錶明,試樣在持續穩定的主應力作用下,隨著基質吸力的減小土樣髮生變形破壞,整箇變形過程中沒有破壞剪切麵;進一步研究髮現,土樣從塑限含水率到液限含水率之間,土樣對水的敏感性很彊。即噹含水率增大到塑限含水率之後,應變快速髮展,其變形特性解釋瞭該地區 Q3黃土彊的濕陷特性以及淺層滑坡和崩塌的頻髮的原因。最後,對于同一種土,其基質吸力與應變的變化關繫麯線是類似的,麯線的差彆可能是由于土樣之間的差異及儀器的誤差等因素造成的。
관개유발비포화황토파배적실제응력로경가근사위정법향응력화편응력균불변,이기질흡력축점감소적흡습파배과정。위연구비포화황토재흡습과정중적응변특성,이경양남원 Q3마란황토위연구대상,종비포화토각도출발,개전료공제불동기질흡력하(초시함수솔)적비포화황토적흡습특성시험연구。연구표명,시양재지속은정적주응력작용하,수착기질흡력적감소토양발생변형파배,정개변형과정중몰유파배전절면;진일보연구발현,토양종소한함수솔도액한함수솔지간,토양대수적민감성흔강。즉당함수솔증대도소한함수솔지후,응변쾌속발전,기변형특성해석료해지구 Q3황토강적습함특성이급천층활파화붕탑적빈발적원인。최후,대우동일충토,기기질흡력여응변적변화관계곡선시유사적,곡선적차별가능시유우토양지간적차이급의기적오차등인소조성적。
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.