Prediction of Bedding Intrusion into Low‐Strength Subgrades

Proper selection of bedding material before construction can prevent loss of money and time due to change orders and sometimes obviate the need for the common remedial practice of overexcavation and replacement with costly granular materials. The bearing capacity and intrusion characteristics of two different types of granular materials, gravel and volcanic clinker, commonly used in northern Arizona as granular bedding materials in pipeline construction, were studied under controlled laboratory conditions. It was determined that the void or area ratio influences the amount of bedding intrusion that occurs in low strength subgrades. Granular bedding materials, such as gravels, were generally found to intrude a low strength subgrade less than coarser bedding materials with relatively higher void or area ratios, such as volcanic clinker.