S ec t i o n 7 -P a g e5 May 2013 DYWI ® Drill Self-Drilling Bolt The DYWI ® Drill Self-Drilling bolt is a fully thr eaded hollow bar that initially serves as a drill r od, utilizing a lost bit. The thr ead is made to 15010208. For use in unconsolidated gr ound or other dif fcult gr ound conditions. Excellent for spiling (for e-poling). Bolt is drilled in and gr out is pumped thr ough the center hole with pumpable r esin or cement gr outs. The couplers ar e designed to exceed the ultimate load of the bar by 20 The couplers ar e designed to minimize the loss of drill ener gy . Several drill bits ar e available. Most widely used is the EXX T ungsten carbide chisel bit for handling UCT* up to 12.5N/mm (RQD 100 and up to 50 N/mm (RQD 75. Standar d length is 3m (9ft-10"). Longer lengths ar e available: 4m, 6m *UCT is unconned compr essive str ength DSI Hollow Bar System is typically installed using r otary per cussive drilling. This technique enables high rates of installation, good dir ectional stability and also helps to consolidate the gr out within the bor ehole. Rotation speeds should be suf fcient to cut a true bor ehole (120-150 RPM for soil nails; 100-130 RPM for mini piles), as opposed to displacement of the soil with the drill bit thr ough per cussion and heavy feed pr essur es (driven installation). Drilled bor eholes ensur e enlar ged gr out bodies together with better permeation of the gr out into the surr ounding gr ound. Feed pr essur es on the drill r ods should be r egulated in accor dance with the cutting performance of the drill bit. Simultaneous Drilling and Gr outing Suitable for granular soils and flls. This installation method utilizes a Gr out Swivel, gr out pump and drifter . The technique combines drilling and gr outing as a single operation, ensuring that gr out is placed over the full length of the bor ehole. For gr ound conditions wher e bor ehole collapse is anticipated or wher e subsequent gr out injection down the center of the bar is pr oblematical, simultaneous drilling and gr outing is the pr eferr ed solution. Gr outing pr essur es should be r egulated to maintain cir culation at all times (typically up to 100 psi), with a small amount of gr out r etur n visible at the mouth of the bor ehole. Pr essur es in excess of 100 psi ar e generally only r equir ed for specialist applications (i.e. anchors in cohesive soils or mining applications). The choice of gr out pump varies between applications, but basic r equir ements ar e as follows: a) thor ough mixing of the gr out – to avoid blockages at the drill bit, b) delivery of a continuous volume – to ensur e consistent gr outing, c) maintenance of suf fcient pr essur e. Installation Bar Size R25N R32N R32S R38N R51N Diameter over thr eads [in] / [mm] 0.984 25 1.260 32 1.260 32 1.496 38 2.008 51 Cr oss sectional ar ea of bar a) [in 2 ] / [mm 2 ] 0.378 244 0.614 396 0.756 488 1.111 717 1.455 939 Ultimate Str ength [1000 lbs] 45.0 62.9 80.9 112.4 179.8 Y ield Str ength [1000 lbs] 33.7 51.7 62.9 89.9 141.6 W eight [lbs/ft] / [kg/m] 1.5 2.3 2.3 3.4 2.8 4.1 4.0 6.0 5.6 8.4 Maximum Drilling Depths c) [ft] / [m] 39.4 12 52.5 16 65.6 20 78.7 24 98.4 30 www .dsiundergr ound.com