GEOGUIDE 1 GUIDE TO RETAINING WALL ... - HKU Libraries

314.3.2 Design Calculation ModelsA design calculation model generally consists of two elements :(a) a method of analysis, often based on a theoretical approachincluding simplifications, and(b) if necessary, a modification to the results of the analysis toensure that the results of the calculation are either accurateor err on the side of safety.Where an unconventional theory is to be used, or where a conventional theory is tobe applied in an untried situation, the uncertainty in the applicability of the design calculationmodel should be assessed. Whenever possible, the method of analysis should be calibratedagainst observations of field performance of previous similar designs, load tests or morereliable analysis.Design calculation models are given in Chapters 9 to 11 for the checking of limitstates for various types of retaining walls.4.3.3 Loadings, Geometric and Geotechnical Parameters(1) General. Some general guidance is given in the following Sections. Specificguidance on the selection of values of geotechnical parameters for design, and on theevaluation of various types of loadings, viz. earth pressures, surcharge (and seismic) andwater loads, is given in Chapters 5, 6, 7 and 8 respectively. Where appropriate, parametricstudies of the effect of a variable loading or parameter should be carried out.(2) Loadings and Load Combinations. For each design situation, concentrated ordistributed loads which may result in forces acting on the retaining wall should be evaluated.The common types of direct loads are :(a) weights of soil, rock and water,(b) earth pressures,(c) free water and ground water pressures,(d) seepage forces, and(e) surcharge and seismic loads.Indirect loadings that need to be tolerated by the retaining wall should also beconsidered and, where appropriate, their magnitudes should be determined. These includeloadings arising from :(a) geological factors, e,g. creep of slope masses, solution ofsoluble rock and collapse of sinkholes in cavernous rock,(b) conceivable man-made activities* e.g. dewatering,excavation, tunnelling and blasting, and