A shape recognition technique for hydraulic applications

SURFACE STRUCTURES:HYDRAULIC STRUCTURES Dispersive soils are widely distributed in South Africa and are derived from a variety of rock types. They are commonly found in regions where the annual rainfall is less than 850 ram. In some parts of South Africa dispersive soils have to be used for the construction of earth dams since no other soil material is available. Several failures of earth dams due to piping have occurred in South Africa, most taking place on first filling of the reservoir. However, if an earth dam containing dispersive soils is properly constructed, with filters, an impervious core and correctly compacted, then it should perform satisfactorily. A case history of a failure of a dam is provided which illustrates some of these points. (from Authors) 957292 Fleedwaters threaten to topple India's dams S. Kumar, New Scientist, 146(1975), 1995, p9. A leaked memo from the World Bank has suggested that many of India's dams are under threat from severe floods because of underestimation of calculated peak flOod discharges in their design. While reviewing 25 dams needing repairs, engineers have recalculated the scale of the flooding. In each case, these figureswere greater than those used in the original designs. The risks posed by these dams and the consequences of their failure are discussed. The lack of emergency plans for coping with the aftermath of a dam burst is also criticized.(P.M.Taylor) 957293 Barrage of fire P. Reynolds, International Water Power & Dam Construction, 47(3), 1995, pp 52-53. In December 1994, the Federal Energy Regulatory Commission (FERC) issued its policy statement on its authority in relation to hydropower project decommiP~ioning at reficensing. The FERC policy states that it has the authority, on a case-by-case basis, to order the removal of a dam at the owner's expense, together with environmental improvement measures. The implications of this policy statement for the hydropower industry are discussed. The case history of the Edwards Dam in Maine is described. (P.M.Taylor)

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deployed in a field monitoring programme. This installation examined impact pressures, concrete strains and wave climate on a rubble mound breakwater in Jersey. The pattern recognition technique has been applied post-logging to evaluate its usefulness. Besides its use in recognising wave impact events it is hoped that the pattern recognition approach will be of wider benefit in identifying events in hydraulic data. (Authors)

957296 Simulations of wave iatentction with e e ~ t a l stmetnr~ M. R. A. Van Gent & H. A. H. Petit, in: Hydroinformatics '94. Proc. 1st international conference, Delft, 1994. Voi. 1, ed A. Verwey & others, (Balkema), 1994, pp 141-146. Simulations and applications with two numerical models for wave interaction with various types of c~astal structures are presented. Both models are able to simulate individual breaking waves on impermeable and permeable structures such as breakwaters. One of the models is also capable of simulating the reshaping process of dynamically stable stru~ures such as berm-type breakwaters and gravel beaches.

(Authors)

957297 Saving the s a n ~ of time M. Rose, Surveyor, 182(5337), 1995, pp 16-18. An innovative system is being used for the rebuilding of a beach at Newquay. This will protect the vulnerable old sea wall at a fraction of the cost of conventional solutions. The Danish-invented Beach Management System is described. This system solves the problem of permanently wet sands, which cause frictionalinstabilities and beach erosion, by the installation of a perforated drainage system buffed in the beach. This lowers the water table and encourages sand accretion. The cost of the system at Newquay was £170 000 and is the first time the system has been used in the UIC (S.E.Brown)

957294 Arching in piled embankments B. K. Low, S. K. Tang & V. Choa, Journal of Geotechnical Engineering - ASCE, 120(11), 1994, pp 1917-1938.

957298 Rock, stock & Bambk M. Winney, New Civil Engineer (NCE), 1125, 1995, pp 24,26.

Model tests and theoretical analysis were performed to investigate the arching in embankments on soft ground supported by piles with cap beams and geotextiles. The capbeam-and-geotextile combination may alleviate the uneven surface settlements that sometimes occur in embankments supported by piles with individual square caps. Equations and charts were developed to show the parameters affecting the tension in the geotextile and to assess the effect of geotextile on load transfer. Theoretical solution showed reasonable agreement with experimental results for cases with no geotextile but only partial agreement for cases with geotextile. (from Authors)

A scheme to protect a 40-year-old sea wall on the north Kent coast involves a beach recharge operation and the constnmtion of 14 rock groynes. Granite for the rock armouring, wastage material from a Norwegian quarry, is unloaded from a barge on every possible tide, while a floating stockpile is kept just offshore. The mooring is specially designed to withstand storm conditions. Continuous reballastingis vital to keep the barges levels as the rock is transferred. (P.M .Taylor)

Hydraulic structures 957295 A shape recognition technique for hydraulic applications A. M. Van & J. P. Davis, in: Hydroinformatics '94. Proc. 1st international conference, Delft, 1994. Vol. 2, ed A. Verwey & others, (Balkema), 1994, pp 699-704. This paper describes a comparison of pattern recognition and conventional techniques for the identification of wave impact events. The conventional technique used has been successfully R M M S 32/7--K

957299 Reconstruction of the flood damaged Nero viaduct Inverness W. R. Scott, Proceedings- ICE: Transport, 111(2), 1995, pp 135-137. This technical note deals with the reconstruction of the Ness viaduct in Inverness. The des~ption of the masonry viaduct and its foundations, previous scour protection measures, the inspection regime and the cause of collapse has unfortunately not been included, due to ongoing legal action. The background design and construction of the new bridge and how, by close client/consultant/contractorrelationship,the extremely tight timescale was met are described. (Author)