How We Created the Reconstructions (Part 2)

The geographic location and layout of the ancient earthworks found in Ohio are largely known, although the earthworks themselves may not be visible today (i.e.Romain and Burks 2008; Lynott 2009). The original  height and cross sectional geometries of the earthworks, however, have not been extensively analyzed (i.e. Bernardini 2004). For this reason, we ran a multitude of geotechnical engineering models of different slope stability conditions to estimate potential geometries of the earthworks based on the surrounding soil properties (Busch 2011). Estimates of the original height of the earthworks were then back calculated given the width of the embankments, rate of erosion, bearing capacity, and maximum slope configurations.

Table 1. List of the most common engineering issues related to earthworks (Kerisel 2005).

Table 2. Relationship between soil properties and their effect on the soil fabric.

Equation 1. The basic equation of slope stability.

 

 Figure 1. Illustration of the basic equation of slope stability.

Figure 2. Classification of the soils surrounding the Hopewell site based on 

the USDA-NRCS (2010) Soil Report  and Johnston’s (1975) engineering characteristics of Ohio soils

Figure 3. Cross-section of different earthwork geometries, ground water conditions, and 

subsurface soil properties, as an example of the models run in the analysis.

Figure 4. Example of  the output of the slope stability analysis from the Rocscience Slide 2010 program. Results indicated that the bearing capacity was the driving force behind slope geometry and stability.