An Empirical Equation for Predicting Penetration Depth into Soft Sediments

The design and use of kinetic energy marine sediment penetrators require a capability for predicting penetration depth. A natural test target of soft saline clay deposits was chosen for its similarity to marine sediments, and 35 instrumented penetrator tests were conducted. An equation was developed to fit the data with an accuracy of approximately ± 15%. The equation includes penetrator mass and diameter, impact velocity, and an index of sediment penetrability. The marine sediment equation is similar in form to a soil penetration equation previously developed. The only sediment related term in the equation is the index of penetrability, which must be estimated from information ranging from a general description to detailed physical properties of the soft sediment. The equation is applicable to very soft saturated clay or soft marine sediments.