CE5617 - Advanced Geotechnical Engineering Assignment - Brunel University London

Assignment Task

1. Objectives

This assignment aims to help students to understand the fundamental principles of geotechnical designs, such as earthwork, retaining structures, and foundations, when developing a design concept (or taking the idea from the imagination to creating a feasible solution).

Other objectives of this design coursework include:

• To develop students’ ability to apply the principles of preliminary and detailed design for a civil engineering project;
• To develop students’ ability in holistic design of civil engineering projects;
• To balance different design priorities and meet the economic, social and environmental challenges of the changing world.

2. Project information

The background information of two geotechnical projects are provided, and the students are required to complete the designs for the two projects. In the following introduction, only indicative design model and parameters are given, while students may receive customized design parameters.

3. Earth retaining wall design

The client has proposed to cut a slope to construct a building. The local slope geometry is shown in Figure 1. You are required to design a retaining wall of appropriate shape to support the remaining excavated slope. The slope and backfill material is composed by a topsoil sand layer (indicated as SAND in the figure), and a stiff overconsolidated clay layer. All the soils parameters are provided in Table 1. The ground water level (GWL) is 1 m below the excavated ground. A variable surcharge pk = P kPa acts behind the wall on slope that rises at an angle β = 10° to the horizontal.

i) Design the structure according to Eurocode 7 – Design Approach 1 considering all the relevant ultimate limit states. You need to consider both short- and long-term conditions. In undrained conditions, adhesion can be taken as 2/3 of the clay undrained strength. Given that there is ground soil in front of the wall, the client requires that you account for the stabilising thrust due to the passive resistance developed by the ground in the design to keep costs down. In doing so you need to comply with EC7 requirements on making allowance for potential excavation works in front of the wall during the lifetime of the wall.

ii) Just after one year after the construction of the wall, you are contacted by the client informing you that due to a revision of the national seismic zonation, the area where the wall is built is now classified as a seismic area. This implies that there is now the additional requirement that the wall is to be able to withstand an earthquake producing horizontal seismic accelerations up to 0.1g. The client asks you if putting in place dewatering measures to lower the ground water level below the wall base would suffice to guarantee the stability of the wall. If not he would like to know what measures can be put in place to make the wall compliant with the new requirement. Discuss the options available. For full marks, calculations demonstrating that your proposed solution is adequate to guarantee the required performance of the retaining structure are required. To this end, all the relevant ultimate limit states indicated by EC7 Design Approach 1 need to be considered. It is recommended you employ the pseudo-static approach. You can neglect any hydrodynamic effect induced by the earthquake on the water.

4: foundation design

The client has the plan to construct an industrial building. The ground has a 37 m thick deposit composed by a top layer of granular soil, 5 m thick, and a layer of overconsolidated clay (OCR = 3.5) overlying a hard stratum. The ground water level (GWL) is 3 m below ground surface (see Figure 2).

i) You are required to design an appropriate foundation to support a permanent vertical load of 2 MN and a variable vertical load of P MN. The allowable settlement is 10 cm. Soil parameters are shown in Table 2. In undrained conditions, adhesion can be taken as 2/3 of the clay undrained strength.

1) Check the bearing resistance in accordance with Eurocode 7 Design Approach 1.

2) In addition, determine the immediate and consolidation settlements under the centre of the foundation by dividing the ground in 4 layers.

ii) After a few years from construction, a wealth fund has bought the factory and decided to change the production line. Due to several new heavy machineries to be hosted in the factory, there is now the possibility that a significant moment may be applied onto the foundation. The client wants to know what is the maximum moment that the foundation can safely withstand to assess whether the factory can host the proposed new production line. To keep costs down, you want to allow for one or more rows of piles to work in tension (if pile foundation has been used). Calculations are to be carried out according to Eurocode 7 Design Approach 1.

iii) Discuss what problems may arise for piles working in tension and what mitigation measures could be undertaken.

This CE5617 – Engineering has been solved by our PHD Experts at My Uni Paper.