*2.1. Test Materials*

The expansive soil used in the study was taken from Nanning, Guangxi, and was off-white. The particle size distribution of the unimproved expansive soil was obtained by taking the expansive soil for particle analysis tests. The particle size distribution of the expansive soils, as shown in Table 1.


**Table 1.** Particle size distribution of expansive soil.

The obtained expansive soil was dried, crushed, adopted 2 mm sieve and a portion of the particles less than 2 mm in diameter was taken for testing. The basic physical properties of the expansive soil were obtained from the tests and are shown in Table 2.



*2.2. Sample Preparation of MICP Improved Expansive Soil*
