Uniaxial Compression of Synthetic, Poorly Consolidated Granular Rock with a Bimodal Grain-size Distribution

The failure behaviour of poorly cemented sands at a borehole wall using laboratory tests

“…Therefore, by increasing the sand grain size it is possible to obtain a higher strength mixture for a certain w c value. This confirms the findings by other researchers [15,12,16] who used different ranges of w c to create cementedsand specimens. Also, the level of compaction improved with the increase of the δ up to a certain level and thus the cementing agent could suture more sand particles in a unit volume.…”

“…For preparing poorly cemented sands in laboratory conditions a wide range of values have been suggested by different researchers [12][13][14][15]. Kongsukprasert [15] used a maximum of w c ¼ 2.5% of Portland cement, whereas Saidi et al [12] used 9-18%. In addition, Gueguen and Palciauskas [11] stated that the minimum w c is reached at δ ¼ 1.5.…”

“…The specimen contains three separate phases sand, cement and macro-porosity larger than the sand grain size [17]. According to Saidi et al [12], minimum macro-porosity is achieved when δ is around 1-3. Also, based on the collected samples from the drilling site, the cured mixture should be weak enough to allow sand particles to debond when the surface is scratched with a finger nail.…”

“…Portland cement type II (specific gravity, G s ¼ 3.15 g/cm 3 ) was used for preparing the TWHC specimens based on previous studies on the mechanical properties of weakly cemented sands [12]. For preparing poorly cemented sands in laboratory conditions a wide range of values have been suggested by different researchers [12][13][14][15].…”

Shear failure analysis of a shallow depth unsupported borehole drilled through poorly cemented granular rock

“…Saidi et al (2003) showed that Portland cement is a suitable cementing agent for simulating poorly bonded specimens. A wide range of cement contents (2.5 % ≥ w c ≥ 18 %) for producing poorly cemented synthetic sandstone has been suggested in different works (Alsayed, 2002;Saidi et al, 2004;Saidi et al, 2003;Younessi et al, 2013;Kongsukprasert, 2003). For instance, Kongsukprasert (2003) used a maximum of 2.5% of Portland cement to prepare poorly cemented gravel specimens, while Saidi et al (2004) used 9-18%.…”