A long-term ground movement monitoring system for surcharging works at a new housing development.
The project
GEO-Instruments teams have returned to site for multiple phases of construction
at an ongoing housing development site in Seaton.
Before construction can begin on each phase of the project it’s necessary to
prepare the ground. To help prevent structural damage to the buildings and
infrastructure, the ground must be consolidated to minimise ground movement or
settlement that could occur during or after construction.
The challenge
The main contractor is using a surcharging method to achieve the necessary consolidation and stability of the soil. In this process, the ground is covered with a load (an earth mound) greater in mass than that of the final planned development. This surcharge is left in place for an extended period to allow the soil to compress and settle. Accurate ground movement monitoring is required in order to confirm that the necessary settlement is achieved.
The solution
GEO-Instruments installed a settlement monitoring system in the ground before
the surcharge was placed.
This system consists of nine VW Liquid Settlement plates located around the
surcharged area. The plates are connected via liquid filled tubing to a shared
reservoir installed away from the monitored area.
Each plate is fitted with a vibrating wire pressure transducer that measures
changes in pressure as the plates move relative to the liquid reservoir. The
system then calculates liquid head in millimetres, for a precise measure of
ground movement.
As these instruments use automated data collection, they will measure
continuously, providing an ongoing, complete record of settlement over
time without the need for manual intervention.