19A
8]-179 EKP~I]4ENTAL RETAINING WALL FACILITY - LATERAL STRESS ~ASUR~4ENTS WITH SAND BACKFILL Carder, D R; P~cock, R G; Murray, R T Transport & Road Research Lab lab report 766, 1977 Discusses the construction of 2 pilot scale retaining walls, 2m high and over 6m long, built to study the pressures and deformations during and after completion of earth filling o~er~tions behind the walls. Experiments Using sand have shown that significant residual lateral stresses are produced by the compaction of sand behind the wall, and that very small translations of the wall away from the soil are sufficient to develop the fully active condition of the sand. Peak lateral thrusts were measured. Tests with cohesive soils are planned. Avail: TRRL, Old Woklngham Road, Crowthorne, Berks, UK
Influence of dynamic loads due to explosions or earthquakes 781180 GEOTECHNICAL DESIGN ASPECTS FOR LARGE GRAVITY RD~AINING STRUCTURES UNDER SEISMIC LOADING Thompson, C D; ~nery, J J Can Geotech J, V13, N3, Aug 1976, P231-242 Simplified procedures for evaluating the liquefaction potential of sands and silts are presented, and some guidelines for sensitive clays are discussed. Since hydraulic fill is often used remedial measures end specifications to avoid liquefaction of backfills are described. Conservative earth pressure parameters are given for areas exposed to tsunamis, end these may be employed for initial assessment of potential problems from offshore earthquakes. The various geotechnieal aspects considered must be closely related to other design factors such as seismic exposure, earth pressures, and allowable short-term safety factors.
Comminution of Rocks T81181 DRILLING AND BLASTING SYMPOSIUM: HOW TO DRILL ROTARY BLASTHOLES FASTER AND CHEAP~q AND SEE WHAT YOUR ROCK MEASURES ON THE DRILLABILITY INDEX World Min, V30 , N5, Nay 1977, P54-57 Briefly reports on papers presented at the International Drilling and Blasting Technology Symposium, Houston, March 1977. Topics covered include: effectiveness of big blast holes, a new drillability index, use of conical reamers, big hole developments end activities, new experimental drills.
Rock fracture under dynamic stresses See also: 781019
781182 FRACTURE OF ROCKS BY AN I~4PACT LOAD Voitsekhovska~, F F; Voitsekhovskii, B V Sov Min Sci, Vl2, N4, July-Aug 1976, P391-394 Discusses the Use of impact rock breaking tools and how the cost per unit volume of broken rock can be reduced.
Drilling 781183 UNIQUE CORE DRILLING TECHNIQUE World Min, V30, NIO, Sept 1977, P85 Briefly reports the drilling of a 80ram borehole beneath the potash bed at Boulby Mine, Yorkshire. The 3 deflections from the horizontal hole into the potash seam were made as the hole was deepened, and the information gained was Used in the planning of future intersection points. The hole of total length 1480m was drilled through halite, sylvinite, anhydrite, shale and marl. 781184 SHELL'S HIGH-DATA-RATE DRILLING TELEMEYRY SYSTem4 PASSES FIRST TEST Denison, E B Oil Gas J, V75, N24, 13 June 1977, P63-66 Describes the Shell electric telemetry system and discusses a recent test in which a 510Oft hole was drilled and data obtained on surveysteering, pressure, temperature and acceleration along 3 orthogonal axes. 781185 AIR DRILLING, PART 1. AIR OR GAS CIRCULATION CAN SLASH DRILLING TIME. PART 2. AMOCO'S EKPESI~CE GIVES RIGHT AIR-DRILLING TECHNIQUES Hook, R A; Cooper, L W; Payne, B R Oil Gas J, V75, N25, 20 June 1977, P86-94, and V75 , N26, 27 June 1977, P160-174 781186 FIVE WELiS TEST HIGH PRESSURE DRILLING Deily, F H; Heilhecker, J K; Maurer, W C Oil Gas J, V77, N27, 4 July 1977, P74-81 Discusses the test progrsalne in which penetration rates in sand end shale sections of the wells could be increased by 55-60 per cent by using high pressures and extended nozzle bits. These advantages were achieved at depths of 3000-6000ft. 781187 SIGMALOG TELLS PRESSURE, POROSITY WHILE DR ILLING Gerard, R E Oil Gas J, V75, N31, 1 Aug 1977, P99-103 Discusses the Use of the Sigmalog to derive values for pore pressure and porosity from penetration rate and other drilling parameters. 781188 HYDRAULIC P~CUSSIVE ROCK DRILLS - A PROVED CONCEPT IN TUNNELLING Ottosson, L; Cameron, T I Paper to Tunnelling '76 conference, London, 1-5 March, 1976, P277-285, disc P310-316 Case histories from mining and civil engineering tunnelling experiences with hydraulic percUssive rock drills and their associated hydraulically operated support systems and rigs are discussed, end mention is also made of the raining progTammes provided for operating personnel as well as for the maintenance of this new equipment.