Influence of Soil Heterogeneity on the Ground Deformations Above the Heading of a Shallow Tunnel: Centrifuge Modeling

Abstract

In order to understand the influence of soil heterogeneity on ground deformation in front of a tunnel, a group of centrifuge tests on a two-dimensional spatial arrangement of three soils were carried out. These tests included three different geometries of the front of the tunnel in terms of the length uncoated. Thus, for the manufacture of soil, a mixture of kaolin and bentonite in three different proportions was used to obtain the correct set values of liquid limit. These values sought to simulate the spatial variability of the property of liquid limit for a typical clay from the Savannah Formation in Bogota. Thus, a method was employed to simulate random fields in order to generate different embodiments, which required to determine the average, the standard deviation and the correlation length, as well as the size of the space discretization. Finally, a comparison was made between the physical models when using heterogeneous soils and using an average value of liquid limit. Also, a number of homogeneous models allowed the evaluation of the ground surface settlement between the three soils used