Study on Hygroscopic Swelling and Dehumidification Cracking Characteristics of Expansive Soil under Acid Rain and Cyclic Drying-Wetting

Table 2

The expansion rate of the sample under different conditions.

Cyclic drying-wetting/times	Swelling rate (%)
	pH = 3	pH = 7	Difference between the two
1	19.4	15.6	3.8
4	24.5	19.6	4.9
Growth rate	26.3%	25.6%	28.9%