Experimental Analysis of Desiccation Crack

A laboratory investigation on a scaled model of a landACT: l ti n a scaled o l f ­ fill liner was conducted to provide data regarding the occurrence l i e e and extent of desiccation cracking of prototype liners. The crack t t of desi t e li rs. intensity factor, CIF, was introduced as a descriptor of the extent of t f , , as i tr as f the extent of surficial cracking. CIF is defmed as the ratio of the surface crack l ing. IF is ed s surf area A, to the total surface area of the clay liner, At. A computer c, to the total surface area of the clay liner, At. aided image analysis program was used to determine CII' values i s F from scanned photographs of the desiccation process. The variation t raphs of e desiccation process. he variation of the CII' was related to duration of drying and measured soil F ti f il moisture suctions. The soil of this investigation experienced significant cracking, i i t ing, with crack widths approaching 10 mm in the first drying cycle and ro le a penetration through the entire 16 cm thickness. Crack propagation t r the entire 16 c thickness. rac pr was limited to a very intense period of the desiccation process. ver intense period of the desicc t s. Nearly 90 percent of the crack development occurred during a 19­ t ccurred during a ­ hour time period, although the total duration of the desiccation , d r ti of t desi cycle was approximately 170 hours. The soil moisture suction le as r i ately 0 urs. il i t r t changed by only 2 bars during the period of rapid crack growth, ly r ri t peri f r i r r t , although it changed by more than 40 bars during the period of re t peri reduced growth. (KEY TERMS: soil liners; clays; desiccation cracks; geo-environ­ S: soil li ­ mental engineering.)