Why carry out site investigation

Unforeseen ground conditions often have a significant impact on the success of a construction project. Figure 2.1 shows the cost over-run due to ground conditions, as a proportion of tendered price, from a survey of UK highway projects. The time taken to carry out construction can increase considerably, delaying the point at which revenue or other benefits can be obtained to offset the investment. Methods of construction may need to be changed, leading to delays because of the need to redesign, and additional costs due to changes in contracts. The quality of construction components such as foundations may be reduced. The health and safety of construction workers, the public and end-users may be threatened. Unknown environmental land-use factors, for example, the presence of old foundations, archaeological remains, sites of special scientific interest, or contamination of the soil or groundwater, may require significant redesign, thereby delaying or preventing construction. As a result, costs and time for construction completion can escalate, threatening the overall financial viability of the project. Good site investigation can significantly reduce ground-related risk.