Influence of Vetiver Root System on Mechanical Performance of Expansive Soil: Experimental Studies

Table 2

Expansive force test results.

Height	Category	Density (g·cm^−3)	Water content (%)	Root content (g·1000 cm^−3)	Growth period (d)	Expansive force (kPa)
0∼5 cm	Pure soil	1.97	17.0	—	—	73.3
	Root-soil	1.96	17.3	1.467	90	44.5
		1.92	17.2	1.283	90	50.9
		1.95	16.9	3.133	180	30.2
		1.92	16.7	3.667	180	28.2
5∼10 cm	Pure soil	1.78	17.6	—	—	58.2
	Root-soil	1.76	17.8	0.983	90	31.3
		1.73	17.8	1.170	90	28.3
		1.78	17.1	2.267	180	14.1
		1.74	17.6	2.083	180	16.6
10∼15 cm	Pure soil	1.66	18.6	—	—	26.8
	Root-soil	1.65	18.5	0.583	90	12.0
		1.62	18.2	0.650	90	11.9
		1.63	18.2	1.706	180	3.9
		1.62	18.6	1.467	180	5.1
15∼20 cm	Pure soil	1.97	19.5	—	—	62.3
	Root-soil	1.98	19.1	0.444	90	45.2
		1.96	18.8	0.517	90	41.5
		1.97	19.4	0.983	180	21.4
		1.93	18.9	0.867	180	22.6
20∼25 cm	Pure soil	1.78	19.7	—	—	53.6
	Root-soil	1.74	19.5	0.383	90	28.5
		1.72	19.8	0.317	90	30.7
		1.77	19.8	0.653	180	19.0
		1.74	20.1	0.517	180	20.5
25∼30 cm	Pure soil	1.65	20.8	—	—	23.3
	Root-soil	1.65	20.3	0.217	90	12.2
		1.68	20.5	0.184	90	14.6
		1.67	20.7	0.451	180	7.2
		1.65	21.0	0.434	180	5.8