膨胀土裂隙发育与土体状态的关系研究

Study on Relationship between Fissure Development and State of Soil in Expansive Soil

不同状态的膨胀土在干湿循环下裂隙发育的最终程度不同。为寻求应力状态、膨胀力与最终裂隙发育程度的关系,取样自云南文山盆地普者黑机场区域膨胀土,进行荷载状态下干湿循环等试验。试验结果:膨胀土最终裂隙发育程度与所受载荷关系密切,单位面积裂隙长度平均值由5 k Pa载荷下的15. 32 mm/cm^2减少至40k Pa载荷下的10. 56 mm/cm^2;相同载荷作用下,单位面积裂隙长度平均值与膨胀力呈正相关,由土样膨胀力12. 76 k Pa对应的9. 78 mm/cm^2增至土样膨胀力39. 52 k Pa对应的11. 39 mm/cm^2。表明膨胀土最终裂隙发育程度受载荷制约,并与自身膨胀力有关,而裂隙展布则受含水率梯度分布影响。

The degree of fissure development of expansive soil under different wetting cycles is different.In order to find out the relationship between stress state,expansive force and the development degree of final cracks,the expansive soils from Puzhehei Airport in Wenshan Basin,Yunnan Province,were sampled and tested under dry-wet cycling.The results show that the ultimate crack development degree of expansive soil is closely related to the load.The average crack length per unit area decreases from 153.17 mm/10 cm^2 under 5 kPa load to 105.58 mm/10 cm^2 under 40 kPa load.Under the same load,the average crack length per unit area is positively correlated with the expansive force,and the expansive force of soil sample is 12.76.KPa corresponding to 97.83 mm/10 cm^2 increased to 39.52 kPa of soil sample swelling force corresponding to 113.91 mm/10 cm^2.The results show that the ultimate crack development degree of expansive soil is restricted by load and is related to its own expansive force,while the crack distribution is affected by water content gradient distribution.