378A

current practices and the amenability of the problem to physi- cal modelling. Scale effects, boundary effects, and the concept of modelling of models are examined. Limitations of physical modelling are discussed. Centrifuge equipment and particular problems for which it is suitable are described.

Geological factors of importance in surface structures

916372 Problem of quality control and selection of armourstone Clark, A P; Palmer, J S Q J Engng Geol V24, N1, 1991, Pl19-122

Rock for armourstone must meet criteria for fabric and block size, shape, and integrity. Two case examples are described, the Whitby coast protection scheme and the A55 coast road, where effective quality control was not applied at the quarry of armourstone origin, and substandard or out of specification rock was delivered, only to be rejected. The necessity to fully take into account discontinuity orientation and spacing at the quarrying stage, to avoid over/under sizing or supply of rocks containing discontinuities, is emphasised.

916373 Some experiences in investigating problematic soils Ray, S; De, P K Proc Indian Geoteclmical Conference, 1989, Geotectmiques of Problematic Soils and Rocks, Visaklmpatnam, 14-16 December 1989 V1, P197-200. Publ New Delhi: Sarita Prakashan, 1989

Soils become 'problematic' due to ignorance or inadequate experience or care taken at design, site investigation, or labo- ratory testing stages. Three case histories illustrate common errors. The first describes bridge foundations where the field investigations were undertaken in a casual manner and boreholes for cast in situ piles could not be completed in very loose soils. The second describes a well project where the client did not take notice of advice from soil consultants. The third covers preloading of a building site where difficulties in form- ing sand drains in stiff clay were underassessed.

916374 Engineering geology related to groundwater flow. Determination, impermeubilization, supply Ewert, F K Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 II2, Pl109-1142. Publ Rotterdam: A A Balkema, 1990

An overview is presented of paths of water flow in rocks (water routing) and their modelling. The impact of ground- water flow on surface and underground structures is examined. Examples are presented considering sealing of per- meable reservoir slopes, influence of a reservoir on natural groundwater flow, influence of groundwater level on the lat- eral extent of subsoil treatment, effects of geologic structure on seepage, and hydraulic models for simulating seepage and pumping. Grouting processes and the environmental conse- quences resulting from failure to accurately consider ground- water flow are discussed.

916375 Review of progress in engineering geology of water resources and hydroelectric projects in China Chen Deji Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 II2, P1157-1161. Publ Rotterdam." d A Balkema, 1990

Many hydroelectric projects have been successfully completed in complex geological conditions in China in recent years. Basic research into engineering geomechanics has led to improved application of geological modelling, remote sensing and field testing, rock mass classification, drilling in special conditions, and mathematical analysis techniques. Compre- hensive studies have been made on rock masses containing gently dipping weak intercalations. Engineering problems for some projects are described, including foundation treatment, stability of arch abutments, and cutting and stability of steep slopes.

Base courses and pavements

916376 Methods of design. Earthworks on expansive soils in Greece Giannaros, H; Christodoulias, J Proc 2nd International Conference on Foanda~ns and Tunnels, London, 19-21 September 1989 V2, P165-170. Publ Edinburgh: Engineering Technics Press, 1989

Two case studies are presented, widening of a roadway on an expansive base and reconstruction of a failed embankment. The roadway was constructed using a polymer sheet moisture blanket between expansive roadbed and embankment fills. The slope was found to have failed because of expansive content of fine fill materials. Seasonal moisture changes resulted in for- mation of deepening fissures. Remedial measures required excavation of the top 3m of fill, stabilisation of the next 25m with lime,and reconstruction with granular fill.

Foundations

See also: 916078, 916112, 916288, 916352, 916366

916377 Model of soil-pile interaction due to cyclic loading Swinianski, J; Sawicki, A Can Geotech J V28, N1, Feb 1991, Pl1-19

The concept of t-z curves combined with a compaction theory for granular materials is used to study the change in shearing resistance around a shaft under vertical cyclic loading and the subsequent redistribution of loads carried by the shaft and tip of the pile. Predictions of the model are compared to experi- mental data. Qualitative agreement is seen overall, with quan- titative agreement for large scale tests.

916378 Numerical experiments into group effects on the response of piles to lateral loading Brown, D A; Shie, C F Coraput Geotech VIO, N3, 1990, P211-230

Previous work on single piles is extended to develop a three dimensional finite element analysis of response of single or multiple rows of piles to lateral loading. Undrained loading of saturated clay or drained loading of sand can be simulated. Interface elements are used to describe slippage or gapping at the pile-soil interface. Group effects are significantly influ- enced by row position. Group effects diminish as interpile

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