Mini Zone Load Test

Using our CPT equipment and a bit of lateral thinking, we’ve developed a system for undertaking mini zone load tests. At our customer’s request, and with a view to fulfilling verification requirements of structural fill under NHBC Chapter 4.6, the system allows simulation of a reinforced strip foundation via a test beam loaded in stages up to a constant load of 120kPa while measuring displacement and, crucially, the development and dissipation of excess porewater pressures directly underneath the test beam under constant load. The ability to measure excess porewater pressure development allows us to assess if the test is drained or undrained (here drained) and, if the latter, assess primary consolidation as well as creep settlement to allow a reasonable extrapolation of the short-term test over a longer time horizon.

The system could also be used simply as part of a site investigation to measure bearing capacity / load-settlement response for shallow foundations directly. Another application might be for construction platform verification – for example, it is straightforward to offset the contact plate to impose a non-uniform pressure distribution like that under the tracks of a piling rig or crane, giving a fairer reflection of the loading conditions that the platform would be actually subjected to.