Numerical Modelling and Geotechnical Monitoring of an Anchor Wall System for a Deep Excavation in Lima Conglomerate

Abstract

The city of Lima is located in an area where the soil is mainly composed of coarse granular material known as Lima conglomerate. It is characterized by having good geomechanical properties from a civil engineering point of view. However, there has always been some difficulty in obtaining the necessary parameters, basically because of the lack of laboratory equipment. On the other hand, the city has played a key role in the country's economic growth over the last two decades, where many new and modern buildings have taken place which in turn include the construction of several basements as part of them. In this regard, the Anchor Wall system (Sort of a combination of Diaphragm wall and Soil Nailing) has shown a good performance during the excavation phase, taking advantage of the quite good geotechnical characteristics of this alluvial gravel deposit. This research aims at determining the soil parameter in an indirect way, it means that the real lateral displacements, obtained by geotechnical monitoring in a given project, will be compared with that output data obtained by a previous numerical simulation. It is worth mentioning that the first input data used in the computational stage was based on a proper collection of information about the predominant soil in Lima. The results show coherence between the horizontal displacements seen in-situ with that obtained by The Finite Element Method (FEM); thus contributing to the geomechanical characterization of Lima Conglomerate. Last but not least, the safety and efficiency of this technology were proven once again during the project monitoring.