Team Profile This dynamic team was assembled for this project by Dr. Fleming within this team is a diverse mix of personalities, experience and nationality. This mix brought together unique mix allowing for dynamic thinking and fresh ideas. The further gain insight to the members of this quartet link to each person’s personal profile is listed below. Just click and further gain insight into our group dynamic. Winbert Charles Hugh-Berk Sinclair Deamon Mayfield Anthony Allard

Problem statement Design a retaining wall for a cut that will be made in embankment of a highway. The client has requested that you provide two designs. i) One with water in the cut as shown below (Fig 1.1) ii) One without the water as shown below (Fig. 1.2) Only one boring has been conducted at the site and the boring log is attached. After you completed the project the client has requested that you visit her alma mater and share your design process and thinking with the civil engineering students. You are unable to attend in person so you choose to submit your thoughts in the form of a letter. The client has asked to see the letter prior to your submission.

Methodology and Theory A retaining wall (or bulkhead) is a structure to provide a barrier to down slope movement of soil, rock, or water. Retaining walls are generally made of masonry: stone, brick, concrete or steel sheet piles. In recent years, railroad ties have been a popular material for these walls. There is a definite science to building retaining walls, but they are often built without proper knowledge of the technology, and so often fail. The most important consideration is that any material behind a retaining wall is attempting to flow down slope due to gravity, and this creates a horizontal soil pressure behind the wall (depending on φ - the angle of internal friction of the material), smallest at the top and increasing toward the bottom. Also any groundwater behind the wall causes a horizontal hydraulic pressure on the wall. In the designing this wall the bore log information was used supplemented by numerous assumptions. The soil exploration revealed a clayey soil type through out the depth of the bore, although of slightly varying properties one soil profile was assumed and a corresponding specific gravity was assumed based on the clayey nature of the soil. Hence the average water content for the profile was found and using the fundamentals of soil mechanics the void ratio and the other soil properties were calculated. The design chosen for the project was a gravity retaining wall with weepholes to reduce the hydrostatic pressure of the water present throughout the backfill. The principal design criteria’s were found using Rankine’s Theory for cohesive soils. Through Rankine’s theory the active pressure on the wall due the backfill was found and from this the vertical and horizontal pressures were derived. Some geometry was used to establish the dimensions of the wall (based on the standard dimensioning criteria for gravity walls) and to establish the sub areas of the wall used in determining the factor of safety. The factors of safety were calculated to determine the feasibility of the design and adjusted to allow for efficiency in both safety and cost. Due to the fact that the theory presented has not covered all the theory for calculating the bearing capacity failure this was compensated by higher levels of safety in overturning and sliding. In both design conditions the characteristics of the backfill remained the same therefore the only the factors of would be affected by the change in conditions above the toe of the wall in the second design condition. The water present above the toe of the wall in the second design condition added a large passive force which resists overturning therefore change in the factor if safety for overturning. The soil around the toe of the wall also now becomes submerged as the water is present above the soil. Factors of safety were calculated for both situations and the appropriate adjustments made to achieve a satisfactory final design.

Calculations

Reflection and Conclusion As future engineers on a design team, and unfamiliar with all the nuances that play a part in the role of more experienced engineers, we tend to rely on our ability to calculate more than we do to problem solve. Though our experiences may be shallow we do recognize that there are many experiences that have been presented itself to be of benefit in the progression of the project at hand. It is truly exciting to begin to experience the big picture of engineering, for so long in the academic process there is an emphasis on individual progress and individual assessment, and we selfishly buy into the notion that this is what our experience will continue to be in the future, not totally understanding the reason behind the team projects we deemed pointless or even irritating at times in earlier courses of our higher education. Although our individual talents and assessment of these talents help to garner our individual paths in our engineering careers, it does not disguise the fact that there is an absolute need for teamwork or a team environment. As there is a need for exposure into the working world of engineering, internships play a major role in the assimilation of what will take place away from the classroom. This is where the lessons begin on being able to adjust to problem solving rather than problem calculating. Understanding that there are no ideal, textbook situations in the field and each design will be different especially when dealing with materials that are non- homogeneous and unpredictable. Drawing from the experiences of those that have been there before, it is necessary to pay attention to their approach to the problem, be it from their assessment of it to the team's preparation to tackle the problem at hand. Individual experiences were drawn on for various elements of the design process. Both in our academic and professional lives experiences were utilized. There is a natural order, where there is the bringing together of minds to get a glimpse of each individual’s grasp of the problem before a solution is even looked at, because there must be a distinct understanding of what faces the design team before any thing is put to paper or any attention is turned to the solution. This is the reason why surveys are done be it for the census bureau or for surveys taken in foundation building, where the survey is in this case come the form of topography and bore logs. Research into projects that have taken place before is vital, since engineering is a science that has been practiced for so many years there is a situation that may be similar to the one of present that can be used to give insight to how the situation may be handled, and since it is not an exact science there may be two or more previous projects that may be the makeup of the project faced with. Taking advantage of our resources is so vital in the engineering practice, and having them on hand is even more beneficial and this is why there are numerous handbooks for use at a moments notice. Faculty and staff at the institutions we attend are part of the resource system because they have trekked the paths that are now under our feet some of them have even designed or built them, so our resources are endless and account for so many of our achievements and disappointments. With the main focus being to design the retaining wall to the specifications given, experiences played a great part in the decision making process. Although experience in actual design of the retaining wall was limited, it was necessary to reflect on other design opportunities in the past be it self-experienced or from the experience of others and realize the factors involved in the planning and outlining of the design project. It is imperative for a good plan of action because time is needed for every aspect of the design process to run smoothly. The need for checks and balances during the design process to ensure that there is no over designing or under-designing to the specifications needed, since this leads to cost and safety issues during the building process. Where a check and on the factors of safety for sliding and overturning are calculated considering all particulars such as soil type, moisture content, water levels, and the size and shape of the wall to be designed. It is also necessary to review the results of similar designs in the past to make certain that the design fits the topography, and all the conditions and the material properties that are presented for the region where the design will finally be constructed. All of these experiences were compressed and utilized in intelligent actions to aid in the final process of design. Previous experiences in Soil mechanics were used to decipher the information provided in the bore logs. Knowledge from engineering economics was used to weigh design elements against build cost and thereby gaining the most appropriate design for the client. Geometry was also used to determine appropriate dimensions for the wall which was further compounded by our experiences in the field of weighing safety with cost. This among many other elements of previous knowledge and experience help greatly improve work dynamic of the group. Group work was especially important to the completion of this task as this enabled a smooth transition throughout the process.

Fig. 1.3 Final dimension of the Gravity retaining wall to be used. Shown is the water table at a height of 6.5 ft from the base of the wall, a backslope angle of 15 degrees.