In the last two decades, the global economy and population have been growing steadily. Due to these global trends the demand for dredging, trenching and deep sea mining activities have grown dramatically. In these engineering practices, underwater excavation is one of the major procedures which involves complicated physics. In dredging, operations with clamshell buckets in saturated cohesive soils often leads to a decreased production due to the highly adhesive properties of these soils. And, in offshore wind farm installation operations, the vulnerable power cables transporting the generated energy must be buried a couple of meters under the seabed for their protection, so trenching in saturated cohesive soils becomes indispensable.

Miedema has developed "The Delft Sand, Clay and Rock Cutting Model", in which several sets of equations are derived for each type of seabed soil. In the scenario of clay cutting, both the cohesion and adhesion should be known as the input parameters. However, very few information is available to define the relation between cohesion and adhesion. Yet, it is of great importance to get a better understanding of the relationship between cohesive and adhesive forces, because the large surfaces on dredging tools can generate a lot of resistance; limiting production for materials with increasing adhesion.
First, literature is reviewed to get a better understanding into the relevant soil mechanical properties and cutting theories. Existing models for the adhesion factor, which is defined as the ratio between the adhesion or stickiness of a cohesive soil and its cohesion or internal shear strength, are analyzed and new models for the adhesion factor are constructed.

To validate these new models, a new dedicated test setup is constructed with the help of the National Engineering Research Center for Dredging Technology and Equipment based in Shanghai, China. Tests are performed on two different cohesive soils (clays) to obtain the adhesion and cohesion of the samples. Furthermore, the test data is analyzed and the data is used to validate the models.

Finally, the obtained relation between the adhesion and cohesion is implemented in a numerical discrete element model for clay cutting. Two models are constructed to validate the properties of the numerical clay sample, after which the full cutting model is validated using existing experimental data obtained by Chijiiwa and Hatamura . With this validated cutting model, it is now possible to simulate the cutting force on more complicated geometries.