The objective of this demonstration is to validate the GeoPoncelet model originally developed under SERDP project MR19-1277 and currently being refined through SERDP project MR23-3855. The GeoPoncelet model can predict the depth of burial (DoB) of full-scale unexploded ordnance (UXO) under field conditions. The effort is structured as a series of phased milestones designed to progressively transition the model from the current controlled lab-scale experiments onto increasingly more realistic field scenarios. Initial tests will validate the model against stable projectiles impacting vertically into prepared soil beds. Subsequent phases will introduce increasing complexity: first by replacing prepared soils with natural in situ soils; next, using realistic ogive-nose projectiles and replicas of common military munitions prone to instability; and finally simulating oblique impacts on natural test beds with shallow standing water where asymmetric entry forces, interface effects, and complex penetration trajectories are expected. This incremental, risk-informed approach will maximize the probability of success across a range of operational conditions from the most ideal to the most challenging. In parallel, two important secondary goals will be pursued: (1) evaluating established time-domain electromagnetic technology for locating impact-buried munitions, and (2) strengthening collaborations between academic investigators operating in a 6.1 research environment and Department of War personnel working in applied facility management.

The technology is encapsulated in a physics-informed, site-specific semi-empirical model for predicting soil penetration. Complex geological site conditions are realistically incorporated by using field cone penetration tests (CPT) conducted at sites of interest. The technology is implemented as a spreadsheet tool, known as the Projectile Penetration Prediction Tool (3PT), which takes as inputs the characteristics of the munition and data from CPT to predict the DoB with associated uncertainty. The model has demonstrated excellent accuracy in laboratory experiments for normal impact across a wide range of projectile shapes, including realistic ogival noses, under both stable and unstable trajectories, in cohesive and non-cohesive soils, and in wet and dry conditions. An ongoing funded effort is extending the model to account for non-normal impacts and for estuary environments. In the last two years, the experimental and modeling effort has been documented in over 18 refereed technical publications. However, the model has not yet been validated in full-scale field tests, nor for impact speeds exceeding 200 m/s.

The potential presence of UXO poses serious operational risks in formerly used defense sites (FUDS) as well as active ranges and war zones. Such hazards also delay closure and transition of impacted sites to civilian use. Remediating these zones necessitates accurate knowledge of the DoB of UXO, which can vary significantly due to complex soil and ballistic conditions, along with their associated uncertainties. Also, the Underwater Munition Expert System approach to underwater mobility of UXO hazard evaluation starts from an initial estimate of DoB. The 3PT methodology will meet both needs and will, moreover, permit cost-effective remediation of FUDS and base alignment and closure objectives. (Anticipated Project Completion - 2029)