膨胀土强度特性的研究进展

Research Progress on Strength Characteristics of Expansive Soils

膨胀土地区的工程灾害问题日益严峻,其本质是膨胀土强度的变化而造成的。研究表明:膨胀土的黏土矿物类型和含量是影响膨胀土强度的关键内在因素,蒙脱石的有效含量对其影响最大。含水量与密度都会影响土体强度,对于膨胀土而言,含水量的影响更为明显。膨胀土自身的胀缩性与超固结性使得其强度劣化。干湿循环与裂隙研究结合紧密,干湿循环过程中产生的裂隙是强度劣化的直接原因,土体强度随干湿循环次数增加而逐渐降低。在非饱和土理论和土体结构的各向异性两个方面有待深入研究。

The engineering disaster in the expansive land area is becoming more and more serious.The results show that the types and contents of clay minerals in expansive soils are the key internal factors affecting the strength of expansive soils,and the effective content of montmorillonite has the greatest influence.Both water content and density can affect soil strength,and the influence of water content is more obvious for expansive soil.The strength of expansive soil is degraded due to its expansion and shrinkage and over-consolidation.The study of dry and wet cycles is closely combined with that of fractures.The cracks generated in the process of dry and wet cycles are the direct cause of strength deterioration,and the soil strength decreases gradually with the increase of dry and wet cycles.The theory of unsaturated soil and the anisotropy of soil structure need to be further studied.