Prediction of soil deformation beneath temporary airfield matting systems based on full-scale testing

This paper presents results from full-scale evaluations of an aluminum structural mat system with regard to carrying heavy aircraft across graded, but unimproved, soil with California Bearing Ratios (CBRs) of 6, 10, 15, 25, and 100. The objective was to determine relationships among soil deformation rate, the mat’s flexural modulus, the number of applied passes, and the underlying soil’s CBR. Current prevailing performance prediction models for aluminum mat systems are based on full-scale tests using historic aircraft loads over soils having a CBR of 4 that were never validated for soils with higher CBR values. Full-scale test results presented herein demonstrated the inability of current models to accurately predict mat permanent deformation. Strong correlations were found between measured and predicted data across the entire spectrum of soil CBRs. These relationships can be used to noticeably improve the accuracy of performance prediction models. An empirical equation was developed to reasonably predict subgrade deformation for any number of passes and soil CBR for the loading and mat system tested.