The Large-Scale Soil Box: A New Device for Testing the Performance of Buried Pipe

Abstract A new apparatus that measures pipe deflection as a function of simulated overburden stress is described—the large-scale soil box (LSSB). While the LSSB is similar to previous quasi-full scale instruments, it is capable of load testing two pipes simultaneously while monitoring deflection along their crowns. A series of tests were conducted on 24 and 36-in., 10-ft-long pipe sections. Pipe material varied throughout testing; materials included polyvinylchloride (PVC), high-density polyethylene (HDPE), steel, and aluminum. During load application, lasers allowed for deflection curves to be developed for each of the pipes as a function of simulated overburden produced via constrained lift bags. Analysis of the results appeared to indicate that loading in the LSSB is not necessarily uniform. This is likely due to non-uniform soil densities that were present prior to testing even though strict procedures and quality control checks were used prior to each test. Therefore, it would be difficult to use data from a device like this as a comparison against finite element models. However, results from these tests still may be used to assess the relative levels of effect of different pipe types and installation procedures.