You have been given a report analysing the stresses around a 40m by 4m rectangular excavation (stretching 100m in the out-of-plane dimension). The excavation was at a depth of 1800m and was modelled using a 2D plane strain finite element code. The model used a region of 320m horizontally by 60m vertically. The top and bottom boundaries were fixed in x and y displacements, while left and right boundaries were fixed in x displacement. The model used an in situ field-stress 20 MPa vertically and 10 MPa horizontally.
Sketch the above model clearly labelling relevant information. Discuss the accuracy of the model and the specific steps you would take to improve it.
Please fix the following input errors:
