1、英文原文Effect of grout properties on the pull-out load capacity of fully groute rock boltA. Klc, E. Yasar*, A.G. CelikDepartment of Mining Engineering, C ukurova University, 01330 Balcal, Adana, TurkeyReceived 30 October 2001; received in revised form 30 April 2002; accepted 24 May 2002AbstractThis pap
2、er represents the result of a project conducted with developing a safe, practical and economical support system for engineering workings. In rock engineering, untensioned, fully cement-grouted rock bolts have been used for many years. However,there is only limited information about the action and th
3、e pull-out load capacity of rock bolts, and the relationship between boltgrout or groutrock and the influence of the grout properties on the pull-out load capacity of a rock bolt. The effect of grout properties on the ultimate bolt load capacity in a pull-out test has been investigated in order to e
4、valuate the support effect of rock bolts. Approximately 80 laboratory rock bolt pull-out tests in basalt blocks have been carried out in order to explain and develop the relations between the grouting materials and untensioned, fully grouted rock bolts. The effects of the mechanical properties of gr
5、outing materials on the pull-out load capacity of a fully grouted bolt have been qualified and a number of empirical formulaehave been developed for the calculating of the pull-out load capacity of the fully cement-grouted bolts on the basis of the shear strength, the uniaxial compressive strength o
6、fthe grouting material, the bolt length, the bolt diameter, the bonding area and the curing time ofthe grouting material.Keywords: Rock bolt; Grouting materials; Bolt pull-out load capacity; Bolt geometry; Mortar1. IntroductionIn rock engineering, rock bolts have been used to stabilise openings for
7、many years. The rock bolting system may improve the competence ofdisturbed rock masses by preventing joint movements, forcing the rock mass to support itself (Kaiser et al., 1992). The support effect of rock bolt has been discussed by many researchers(e.g. Hyett et al., 1992; Ito et al., 2001; Reich
8、ert etal., 1991 and Stillborg, 1984). Rock bolt binds together a laminated, discontinued, fractured and jointed rock mass. Rock bolting not only strengthens or stabilizes ajointed rock mass, but also has a marked effect on therock mass stiffness (Chappell, 1989). Rock bolts perform their task by one
9、 or a combination of several mechanisms. Bolts often act to increase the stress and the frictional strength across joints, encouraging loose blocks or thinly stratified beds to bind together and act as a composite beam (Franklin and Dusseault, 1989). Rock bolts reinforce rock through a friction effe
10、ct,through a suspension effect, or a combination of two.For this reason, rock bolt technique is acceptable forstrengthening ofmine roadway and tunnelling in all type ofr ock (Panek and McCormick, 1973).Generally rock bolts can be used to increase the support of low forces due to the diameter and the
11、 strength ofthe bolt materials. They enable high anchoring velocity to be used at closer spacing between bolts.Their design provides either mechanical clamping or cement grouting against the rock (Aldorfand Exner,1986).Anchorage system ofr ock bolt is normally made of solid or tube formed steel inst
12、alled untensioned or tensioned in the rock mass (Stillborg, 1986). Rock bolts can be divided into three main groups according to their anchorage systems (Franklin and Dusseault, 1989; Aldorf and Exner, 1986; Hoek and Wood, 1989;Cybulski and Mazzoni,1989). First group is the mechanically anchored roc
13、k bolts that can be divided into two groups:slit and wedge type rock bolt, expansion shell anchor.They can be fixed in the anchoring part either by a wedge-shaped clamping part or by a threaded clamping part. Second group is the friction-anchored rock bolts that can be simply divided into two groups
14、: split-set and swellex. Friction-anchored rock bolts stabilise the rock mass by friction ofthe outer covering ofbolt against the drill hole side. The last group is the fully grouted rock bolts that can also be divided into two groups: cement-grouted rock bolts, resin grouted rock bolts.A grouted ro
15、ck bolt (dowel) is a fully grouted rock bolt without mechanical anchor, usually consisting of a ribbed reinforcing bar, installed in a drill hole and bonded to the rock over its full length (Franklin and Dusseault, 1989). Special attention should be paid to cement-grouted bolts and bolts bonded (glu
16、ed, resined) by synthetics resins for bolt adjustment. Grouted bolts fix the using of the coherence of the sealing cement with the bolt rod and the rock for fastening the bolts.Synthetic resin (resined bolt) and cement mortar (reinforced-concrete bolt) can be used for this type rock bolt.These bolts may be anchored in all type of rock.Anchoring rods may be manufactured of several materials such as ribbed steel rods, smooth steel bars, cable bolts and other s
