~gA

832218

832219

A numerical analysis based on Blot's theory of elastic wave propagation in a saturated porous medium has been developed to predict the poten- tial for liquefaction due to buried charges, such as those used in construction blasting. The analytical results are compared to a case his- tcry in which a test blasting progrsmm~ was con- ducted at a construction site. The case his- tC~y, which yielded data on pcrevater press1~re charges and particle velocities, is briefly discussed. Auth.

Crushing and grinding

POINT LOAD-D~FOR~ATION RELATIONSHIPS AND DESIGN OF JAW CRUS~ PLATES DOwdlng~ C H; Lytw~shyn, G Powder Tech~ol, V31, 1982, P2"~'-286

Point load-defc~tion-failure (PDF) relation- ships were determined by point loading various sizes of materials: comcrete mc~tar, two lime- stones, amphiholite and taconite. These results together wlth a ram~rical model of the swing plate of a Jaw crusher w~'e used in a study to decrease enec'gy consumption durimg crushlr~.

Cutting

PRACTICAL EVALUATION OF SOME COAL-Cb~ING THEC~IES USI~ A CONTINUOUS MIN~

Roxborough, F F; Pedroncelli, E J Min Engr, V142, N252 , Sept 19@2, P1~5-156

Cutting tests were carried out at several coal mine sites using a fully instrtm~nted continuous miner which ~lowed variations in pick spacing and shape, drmm speed, and depth of cut. Results showed that cutting efficiency imlroved r~m~rk- ably when operating at a large depth of cut, and that the optimmn spacing of the picks was bet- ween I and 2 times the deFth of cut. This agreed well with laboratc~V a~ the~etical findings.

Rock and Soil Improvement Techniques See also: 83209~, 832180

832220 E~IMENTAL COMPARISON OF THE FILTRATION CHARACTERISTICS OF CON~ON FABRICS UNDER DYNAMIC LOADIq~. TECHNICAL NOTE

Salter, R J Oeotechnique, V32, R~, Dec 1982, F392-3~6

Tests were carried out on I woven ard 3 non- woven fabrics to assess their fil~ratlon charac- teristics when placed between a granular st~b- base and vsrious cohesive soils.

832221 FILTER CRITERIA FOR GEOTEXTILES: RFI.k~ANGE AND USE

Lawson, C B J Geotech Er~T 6 Div ASCE, V108, NGTIO, Oct

1982, P1300-1317

The general requirements for filters, granular amd geotextile I in one-dlrectior~ flcw applications and the relevant geotextile properties affecting good filtration perform- ar~e (pare size and water permeability) are presented. An application involving the speci-

fication and performance evaluation of a geo- textile for an internal filter in an earth dam, constructed on flyash, where large hydraulic heads were anticipated at the fly~sh-geotextile interface, validated the use of existing geo- textile filter criteria.

832222 EX~YENCE IN PLASTIC FILTER APPLICATION Batereau, C; Markert, T; Welzin, K Proc lOth International Conference on Soil

Mechanics and Foundation Engineering, Stockholm, 15-19 June 1981, V1, P379-382. Publ Rotterdam: Ao A. Balkema, 1981

The use of plastic filters (high-polymeric tex- tile materials) instead of conventional earth filters is discussed.

Bolts and anchors

832223 D ~ CODE SHEDS LIGHT ON GROUND ANCHORS • Dadson, J New Civ Er~, NSI0, 30 Sept 1982, P12-13

A brief report on Britain's first draft anchar- age code.

83222~ ROOF PINNING - RATE OF THE ART Sinkha, A K Min Engr, V142, N25~, Nov 1982, P279-281

It is comclmied from a review of recent develop- merits that roof pins (roof bolts with a pointed end) can be installed in coal measm:e rocks of medium to low hardness.

832225 ROCK BOLTS - THE SA~'~.'I'f PINS OF ~D ROCK TUNNELLING

Wallis, S Tunn Tunnlg, Vl~, Ng, Oct 1982, P23-26

A survey of rock bolts, anchors and anchoring resins presently available.

832226 PREDICTION OF ANCHOR HOLDING POWER BY SCALE ~ s (IN ~E~)

Habib, P; Luong, M P; Le Tirant~ P Proc lOth International Conference on Soil

Mechanics and Foundation E~gineerirg, Stockholm, 15-19 June 1981, V1, P133-136. Publ Rotterdam: A. A. Balkema, 1981

Similitude effects are examined in anchor tests with scale models using sand and clay.

832227 CRACK INITIATION AROUND PRESTRESSED ROCK BOLTS WiJk, G Swedish Detonic Research Foundation report

DS 1982:7, 22 July 1982, 16P

The stress fields in the rock in the immediate vicinities of the ends of prestressed rock bolts are considered. In particular the tensile stresse that are likely to initiate cracks are studied. A fracture mechanics analysis shows that if cracks are initiated they will normally not extend more than a few borehole diameters and will cause negligible reduction of the tensile force in the rock bolts. It is suggested that the cracks can be considerably extended by blasting activities in the neighbourhood and accordimgly cause loss of bolt tension. If so retensioning of the rock bolts is quite meaningle s s •