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Software Tutorials
Homogeneous Embankment Dam Analysis (Part 1 of 3)
This FLAC 8.1 tutorial demonstrates how to establish the stresses in the dry embankment prior to the formation of the upstream reservoir.
Plotting 3D Isosurfaces
This tutorial demonstrates how you can add isosurfaces to your 3D Itasca model plots.
FLAC3D 6.0 Interactive Model Pane
Technical Papers
Numerical Evaluation of Effectiveness of Drainwells in Dewatering Overburden at Surface Coal Mines
Typical sedimentary sequences overlying coal seams consist of interbedded sandstones, siltstones, shales, and rider coal seams.
Formulation and Application of a Constitutive Model for Multijointed Material to Rock Mass Engineering
This paper presents the formulation of a constitutive model to simulate the behavior of foliated rock mass. The 3D elastoplastic constitutive model, called Comba, accounts for the presence of arbitrary orientations of weakness in a nonisotropic elastoplastic matrix.
Tunnelling and reinforcement in heterogeneous ground – A case study
Abstract
A case study of tunnelling in heterogeneous ground conditions has been analysed. The case involves a tunnel excavated in mixed-face conditions, where the main host material was rock, but for a distance of about 30 m, the tunnel had to be driven through a thick layer of soil, primarily moraine and sandy soil materials.During tunnel drifting, a "chimney" cave developed through the soil layer, resulting in a surface sinkhole.This case was analysed using a three-dimensional numerical model with the FLAC3D software code, in which the soil stratigraphy and tunnel advance were modelled in detail. Tunnel and soil reinforcement in the form of jet grouting of the soil, pipe umbrella arch system, bolting, and shotcreting, was explicitly simulated in the model. The studyaimed at comparing model results with observations and measurements of ground behaviour, and to replicate the major deformation pattern observed. The modelling work was based on a previous generic study in which various factors influencing tunnel and ground surface deformations were analysed for different cases of heterogeneous ground conditions.Model calibration was performed through adjusting the soil shear strength. The calibration provided a qualitatively good agreement with observed behaviour. Calculated deformations on the ground surface were in line with measured deformations, and the location of the tunnel collapse predicted by the model. The installed tunnel reinforcement proved to be critical to match with observed behaviour. Without installed pipe umbrella arch system, calculated deformations were overestimated, and exclusion of jet grouting caused collapse of the tunnel. These findings prove that, in particular, jet grouting of the soil layer was necessary for the successful tunnel advance through the soil layer.