Reference no: EM132732608

CEN4000-N Advanced Geotechnics - Teesside University

Assignment - The use of soil nailing methods for enhancing the stability of cutting slopes.

Assignment Title: ‘The use of soil nailing methods for enhancing the stability of cutting slopes.'

This assignment is designed to enable you to use geotechnical modelling techniques used in industry and academia for designing soil nailed slopes. You will also be able to improve your understanding of soil-structure interactions in modern pieces of civil engineering infrastructure.

Brief:
The A19 highway is an important piece of civil engineering infrastructure in the north east of England. The highway is 200km long with 2 lanes (in both directions), which connects Middlesbrough with other major cities across the region, including Newcastle upon Tyne and York. Due to increased numbers of road users on the A19 causing congestion and long delays at peak rush hours around Middlesbrough, the decision was made to widen the highway from 2 lanes to 3 lanes in both directions between Norton (A1027) and Wynyard (A689). This section of the A19 is located just north of Middlesbrough, as shown on Figure 1.

For the Norton - Wynyard section of the A19, the highway runs within a cutting where slopes range between 3m and 8m in height and have a general inclination of 21o (from horizontal). The slopes are largely covered with vegetation, with no signs of instability present.

To accommodate the widening of the A19 highway, the easiest option would be to purchase additional land from local farmers. However, this was dismissed by the Client as it is very expensive. Hence, engineering solutions need to be developed to enable highway widening within the land already owned. Very basic ground investigations have been undertaken along the Norton - Wynyard section of the A19, where boreholes have been drilled from the crests (top) of the slopes using conventional cable percussive rigs. Figure 2 shows the geometry of the existing slope profile and information about the local groundwater levels. A borehole log has been produced (Figure 3), which summarises the ground conditions present.

Part 1: Modelling the existing slope

You have been employed as a geotechnical design consultant to carry out a numerical investigation that aims to understand the stability of the existing slopes. However, your Client did not want to pay for geotechnical laboratory testing on samples collected from the borehole. Hence, you will need to use your own knowledge and refer to literature for providing assumed values for soil properties (e.g. unit weight, strength).

The first half of your report (worth 40% of the ICA mark) requires you to present a numerical stability analysis (SLS, EC7 DA1C1 (ULS1) and DA1C2 (ULS2)) of the existing slope using appropriate tables, images and statistics (including Factors of Safety, driving and resisting forces), their interpretation and discussion for your SLOPE/W model(s). In your analyses, you should also consider the implications of surcharge loads associated with highway traffic and local engineering structures. Please clearly state any assumptions you have made for your analyses (e.g. loadings, material design parameters) and the technical reasoning.

Part 2: Proposed soil nailed slope design

In order to accommodate the construction of the widened A19 highway, numerous engineering options are available and have been reviewed. One of the Client's preferred solutions is to use soil nails for reinforcing a steeper slope design. The reprofiled slope that has been proposed is shown in Figure 4.

The second half of your report (worth 60% of the ICA mark) will require you to produce a soil nail design for the proposed steeper slope under SLS, EC7 DA1C1 (ULS1) and DA1C2 (ULS2) design conditions. Ensure that you present your raw calculations for individual rows of soil nails. Make effective use of tables, images and statistics to interpret and discuss your SLOPE/W models. Clearly state any assumptions that you have made for your analyses and the technical reasoning.

Learning outcomes and instructions:
This assignment will focus on assessing learning outcomes 1, 4 and 5 as detailed in the module handbook and specification documents:
Personal & Transferable Skills
1) Communicate complex professional issues to specialist and non-specialist audiences.
2) Demonstrate numerical and computer skills that are commensurate with the demands of civil engineering profession.
3) Demonstrate IT skills that are commensurate with the demands of research and scholarship in the civil engineering profession.
4) Innovatively apply IT practical skills at a professional level utilising a specialist software.
Research, Knowledge and Cognitive Skills
5) Demonstrate a comprehensive and critical understanding of the mathematical and computer techniques and methodologies appropriate to geotechnical design and be able evaluate its relevance in wider non civil engineering contexts.
6) Demonstrate originality in the application of knowledge together with a practical understanding of how established techniques of research are used to interpret geotechnical data as well as understanding the inherent limitations of methods and data and their effects on design and other disciplines.
7) Integrate and synthesise diverse technical knowledge evidence, ideas theory and practice to solve technical problems and adapt these into the design process to produce an appropriate and adaptable geotechnical design.
8) Make reasoned conclusions on the basis of incomplete data and use the data to produce innovative designs that demonstrate comprehensive understanding of the design process.
Professional Skills
9) Act autonomously in planning and implementing civil engineering tasks.

Attachment:- Advanced Geotechnics.rar