This report is the first in a series of three required under a Contract between the Transport and Road Research Laboratory (TRRL) and Geotechnical Consulting Group (GCG). This report (Report 1) reviews the methods available to numerically model multiple tied-back retaining structures. The scope of the study includes both reinforced earth (inextensible reinforcement) and anchored earth retaining walls. The theoretical basis of the finite element method (FEM) is briefly described and the capabilities of the finite element package ICFEP (Imperial College Finite Element Program) are outlined. The modelling of reinforced earth in two-dimensional analysis is discussed. Techniques with discrete modelling of the reinforcement and alternative formulations with a composite 'equivalent homogeneous material' are reviewed. The preferred method of modelling is identified. The relevance to the modelling of anchored earth of the methods used for reinforced earth and ground anchors is evaluated. The optimal method of modelling anchored earth is developed and simplified methods are presented. The aspects of the design and construction which can be incorporated into numerical analysis are discussed. The importance of these variables to the performance of a structure is compared with the provision to account for them in current design methods. Conclusions are drawn of the importance of finite element analysis in design and back-analysis of multiple tied-back earth retaining structures. There are two appendices to this report: (A) finite element solution techniques; and (B) example of results from finite element analysis.

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