Temporary and permanent supports 831179 ROADWAY ~ IN THIN SEAMS U S I ~ CONCRETE BLOCKS OF LIMITED YIELDING CAPACITY (IN CZECH) Peknlk, J Vedeckovyzk Uhelr~ U~t~v Zprava, N195 , 1981, PI-30 Describes ur~ergrouni tests on two types of block made of cement, fly ash, sawdust and water. The blocks have a high bearing capacity.
831180 O B S ~ A T I O N S OF CAUSES FOR BRFAEDOWN OF FRAME SUPPORTS IN MINEs (IN RUSSIAN) S~prumenko, A N Izv Vyssh Uchebn Zaved, Gorn Zh, N9, Sept
198o, ~5-29 Records of support failures in drifts in several coal mines have been collected and used to obtain an empirical probability distribution. An approximate theoretical probability distribution has also been determined using Pearson's criterion. Using this the probability of failure for various cases can be calculated.
The L S Wood No 3 coal mine, Redstone, Colerado, USA is to be used to demonstrate the ~-w multilift lor~wall mining technique of mining thick seams. The seam will be extracted in two lifts, with a 5-foot matural partition of coal left between the upper and lower lifts. Proper selection of face supports is critical to the success of this ~roJect. Specifications were defined far the roof supports, ani it was concluded that the supports selected must provide full coverage, yield at the legs, and have a 60-iuch push-out cantilever that can be set at any position under full load. A Hemscheidt two-leg shield was Judged as the best q-~l~fied candidate and ~as selected for the multi-lift trial.
831186 DESIGN AND OPERATION OF POWERED AND ENTRY SUPPORTS Hutchinson, T L Proc let Conference on Ground Control in Mimlmg, Morgantown, 27-29 July 1981, F201208. Publ Mc~gantown: West Virgimia University, 1981 Discusses the overall design of a mining system, irmluding support design.
831181 STUDY OF LOAD D I S T E I ~ O N ON THE CANOPY OF
SUPPORTS (ZN C'~X~SS)
Shi Yuanwei Coal Sci Technol, NI2, Dec 1981, P23-27 Laboratc~y measurement of the vertical component of the farce on a canopy is described. It is shown that the method of calculation us,~lqy used is inaccurate. From u~lergroumd measurements it is shown that the loads on the front and rear parts of the canopy are different. A statistical method of calculation produces similar results. Modifications to support structure and design parameters are suggested.
831182 PERFORMANUE TESTS OF ~
SUPPORTS (IN CHINESE) Zhao Hengshan Coal Sci Technol, NI0, Oct 1981, P19-22
831183 R E ~ T I ~ HIGH ROOF FALLS Chlumecky, N Proc Ist Conference on Groumd Control in Mining, Morgantown, 27-29 July 1981, PI16131. Publ Mc~gantown: West Virginia University, 1981 The rehabilitation of high roaf fall cavities (floor-to-roof height greater than 12ft) is a serious problem. The use of steel arch canopies is an effective method of reducing the hazards durirg rehabilitation work amd virtually eliminates st~sequent malnter.ance costs. 83118~ DESIGN OF SHIELD SUPPORTS FOR THE US COAL MINING INDUS~!~Y Peacock, A Proc let Conference on Ground Control in Mining, Morgantown, 27-29 July 1981, P17~185. I ~ i Mc~gantown: West Virginia University, 1981 Reviews the development a~d construction of shield supports in the USA. Shield selection is then discussed. 831185 SUFPC~T ~ R C T I O N FOR THE MULTI-LIFT MININO METHOD Goode, C A; Jaspal, J S; Barczak, T M Proc 1st Conference on Grouni Control in Mining, Mc~gantown, 27-2 9 July 1981, P186200. Publ Mc~gantown: West Virginia University, 1981
831187 EFFECT OF GROtqIU4ATER FLOW ON THE STABILITY AND DESIGN OF RETAINED EXCAVATIONS Kaiser, P K; Hewitt, K J Can Geoteeh J, VI9, N2, May 1982, P139-153 Numerical models (finite element), simplified models, amd comparison with observations from a case histc~y have been used to investigate the effect of grour~water flow on the design of deep excavations. The influence of seepage on the ~ater load, the earth pressures amd the piping and bulk heave potential are considered. special eml~hasis is placed on evaluating the significance of bourdary condition asst~ptions, soil anisotz'opy amd soil stratification. It is concluded that it is unreasonable to base the d e r ign on the assmmption of isotro~ic, homogeneous soil conditions.
Geological factors of importance in underground excavations See also: 831108
Influence of dynamic loads due to explosions or earthquakes 831!88 VIBRATION CAUSED BY UNDEBGRfN/ND CONS'fRUCTION New, B M In: T u r ~ l i m g 82, Proceedings af %~he International Sympoeit~, Brighton, 7-11 J u ~ 1982, F217-229. PuBl London: IMP, 1982 Considers the effects of machine (continuous) and blastimg (transient) induced vibrations durirg turmallimg in urbam areas. Measurements from a n~nber of sites are given with a discussion of current 'damage' criteria.
Surface Structures 831189 CRI'Aw2%IA FOR SK'fTLEMENT OF TANKS Mart, W A; Ramos, J A; Lambe, T W J Geoteeh E z ~ Div ASCE, VI08, N ~ , 1982, FI017-I039