膨胀土是一种吸水膨胀、失水收缩,具有较大胀缩变形能力的高塑性粘性土。即使在一定的荷载作用下,它仍然具有胀缩变形能力。在膨胀土分布的地区建造房屋或构筑物,若不采取必要的措施,就会导致产生裂缝和损坏。汉中盆地内膨胀土分布较广,因此研究它具有现实意义。 Expansive soil is a kind of high plasticity clay which absorbs water, expands and shrinks, and has large capacity of expansion and contraction. Even under a certain load, it still has the capacity of expansion and contraction. Construction of houses or structures in areas where expansive soils are distributed can result in cracks and damage unless the necessary measures are taken. The expansive soil in the Hanzhong Basin is widely distributed, so it is of practical significance to study it.