Geostatistical modelling of geotechnical properties in the context of a tunneling project: Application to the Grand Paris Express project (France)

• Published in: Expanding Underground - Knowledge and Passion to Make a Positive Impact on the World pp. 301 - 309
• Main Authors: Lacherade, L., Marache, A., Denis, A., Halfon, I., Closset, L., Rohmer, J., Quesnel, F.
• Format: Book Chapter
• Language: English
• Published: United Kingdom CRC Press 2023; Taylor & Francis Group
• Edition: 1
• Subjects: Grand Paris; Cross Variograms; Variogram Models; Geological Strength Index; Overburden; Total Horizontal Stress; Nugget Effect; Spatial Variability; Pf; Geostatistical Modelling; Kriging Standard Deviation; OK; Above Ground; Pressuremeter Tests; Tunnel Alignment; Grand Paris Express; BIM Model; Pressuremeter Modulus; Auxiliary Variable; Interpolation Results; Du Grand Paris; SEM; Homoscedasticity Hypotheses; SCL; Coarse Limestone
• DOI: 10.1201/9781003348030-37

In the context of underground construction projects, the knowledge of the urban subsoil is of major importance. This article focuses on the development of a 3D geostatistical modelling of the pressuremeter tests applied on a section of the Grand Paris Express. The spatial variability of the geotechnical behavior is studied through a comparison between deterministic geostatistical methods: ordinary kriging and collocated cokriging. They both give quite similar results but collocated cokriging is definitely more accurate. This study also shows that large-scale underground projects are an ideal setting for the application of such 3D modelling. This chapter focuses on the development of a 3D geostatistical modelling of the pressuremeter tests applied on a section of the Grand Paris Express. Within the framework of this tunneling project, extensive investigation campaigns were carried out and a wide variety of geotechnical tests were performed. After introducing the study site and the data of interest, the chapter describes the methodological process leading to the creation of a 3D geostatistical model. The data processing and sectorisation of the tunnel line were briefly described in order to show the stages are very important phase in the modelling process. The aim of sectorisation is to divide the Coarse Limestone into several sectors with homogeneous geotechnical characteristics, validated from statistical criteria, and to model each sector individually. The geostatistical modelling is conducted on each sector independently with the use of two deterministic methods: Ordinary Kriging and Collocated CoKriging.