Analysis of Changes in the Micromorphology of Sandstone Joint Surface under Dry-Wet Cycling

Table 2

Microstructure parameters of joint surface under dry-wet cycling.

Number of dry-wet cycles (n)	Maximum surface peak height, Sp (mm)	Maximum surface valley depth, Sv (mm)	Maximum height of contour, Sz (mm)	Arithmetic mean deviation, Sa (mm)	Height mean square root, Sq (mm)	Slope mean square root, Sdq	Expand interface area ratio, Sdr (%)
0	2.0045	3.4423	5.4468	0.5170	0.6651	0.2612	5.2461
1	1.9678	3.3534	5.3212	0.5133	0.6590	0.2557	5.1803
3	1.9123	3.2345	5.1468	0.5092	0.6523	0.2525	5.0877
5	1.8812	3.2012	5.0824	0.5075	0.6501	0.251	5.0534
8	1.8623	3.1821	5.0444	0.5062	0.6492	0.2495	5.0244
12	1.8434	3.1667	5.0101	0.5050	0.6478	0.2481	4.9878
16	1.8290	3.1523	4.9813	0.5046	0.6466	0.2464	4.9745
20	1.8245	3.1456	4.9701	0.5042	0.6461	0.2458	4.9578

Note. 0 in the table represents the initial state, as explained below.