79A suggested have been applied are described. Three types of cutter head, in line, transverse, and cylindrical, advancing and articulated booms, and water jet assisted cutting, and their particular advantages are considered. Finally, special project requirements are examined.
Rock and Soil Reinforcement and Support
892231 Ten thousand anchorages in rock Barley, A D Ground Engng V21, N7, Oct 1988, P24-35 Use of ground anchors in chalk, mudstones, siltstones, shales and marls, and sandstones is considered using data from a variety of projects. For each rock type, development of construction method, ultimate bond, failure mechanism and working anchorages are considered, and a data table presented showing SPT values, fixed length, diameter, working bond, test bond, ultimate bond and F value for a number of sites. 892232 Stability of rock masses reinforced by passive, fully-grouted rock bolts Sharma, K G; Pande, G N Int J Rock Mech Min Sci V25, NS, Oct 1988, P273-285
See also: 892407 892227 Rock support Hoek, E; Wood, D F Min Mug Oct 1988. P282-287 A comprehensive evaluation of support requirements for underground hard rock mining is presented. Suggested rock support for conditions from good quality rock under low in situ stress to poor quality rock in shear zones is illustrated in tabular form. Active rock reinforcement, the range of bolts, dowels, bars and anchors, and passive support, mesh, straps, shotcrete and steel sets, are illustrated, and areas for their application discussed.
Bolts and anchors 892228 Australian mining - the role of roofbolting Banford, C R Colliery Guard V236, N9, Sept 1988, P315-318 As open pit mine reserves have become depleted, deep longwall mining has assumed increasing importance in Australia. The historical development of roofbolting in Australian pits and currently used methods and equipment are described. Factors which must be taken into account to adapt these practices to British conditions are examined. The role of the strata control group at ACIRL is also described. 892229 Roofbolting for retreat Eaton, J Colliery Guard V236, N9, Sept 1988, P320-322 Key areas where cost reductions are possible in British coal mines are outlined. The mechanism of roadway stability and influences of rock mass strength, stress level and orientation, and size and shape of roadway are considered. The use of active roofbolt support for longwall mining with retreat as a specific economy measure is described. 892230 Ten thousand anchorages in rock Barley, A D Ground Engng V21, N6, Sept 1988. P20-29 An overview of the use, effectiveness and development of rock anchorages, based on data from 10,000 cases, is presented. Fixed anchor dimensions, drilling and flushing methods, borehole alignment, methods to ensure grout tightness of a fixed anchor length, grout and grout mixing, and anchor tendons are considered.
The behaviour of a jointed rock mass with fully grouted passive reinforcements is simulated using the equivalent material approach, which distributes the influence of rock joints as well as rock bolts throughout the rock mass. Properties of the rock material, joint sets and reinforcement sets are discussed, and a finite element program developed to analyse the problem of a jointed rock slope and compute factors of safety against collapse. It is shown that the dilatancy of rock joints and the orientation of rock bolts are the most important factors in determining the effectiveness of passive, fully grouted rock bolts. 892233 Estimation of gain in pillar strength due to bolting: technical note Sheorey, P R lnt J Rock Mecli Min Sci V25, NS, Oct 1988. P321-326 Wilson's theory to define pillar strength in terms of the vertical stress developed in the failed rock zone has been extended to obtain the probable strength of bolted pillars which are intact before bolting. The approach assumes that bolting becomes fully effective only when the pillar is about to fail. Estimation of the triaxial parameter and strength is outlined. 892234 Response of grouted roof bolts to blast loading: technical note Otuonye, F O lnt J Rock Mech Min Sci V25, NS. Oct 1988. P345-349 The transfer of stresses from rock to rock bolt and the bolt's response during blast loading have been studied, using a time series and systems modelling technique, Data Dependent Systems. The technique was applied to signals from strain gauges on a fully grouted resin roof bolt, and signals from accelerometers on the bolt head and roof rock used to examine the roof bolt's response to repeated blast loading. The damping ratios and natural frequencies of modes of vibration can reveal alteration of a bolt's dynamics due to deterioration of the roof rock, and can be used to identify incidence of instability in the roof bolt system. 892235 Uplift testing of model anchors Su, W; Fragaszy, R J J Geotech Engng Div ASCE VII4, N9, Sept 1988, P961-983 Model anchor tests were performed in sand to study uplift behaviour, difference between top and skin resistance, influence of anchor shape and size on uplift capacity, and the difference in the behaviour of anchors with and without free anchor length. Both deep and shallow failure were observed
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