Large-scale field testing of resin injection as a ground improvement method for mitigation of seismic liquefaction

Large-scale field testing was conducted to investigate the effectiveness of injected expanding resin for mitigation of liquefaction potential beneath existing structures. This method densifies sands and non-plastic silts hence reducing or eliminating the triggering of liquefaction. The stiffness of the injected soil mass is increased not only as a result of an increase in soil density, but through the formation of hard veins and sheets of resin. Test panels were constructed at three sites located within the Christchurch “Red Zone” which liquefied extensively during the 2010-2011 Canterbury earthquakes. The soils were assessed using CPT, VS/VP, and DMT to assess the effects of the resin on the density and stiffness of the soils. This paper describes the construction of the test panels and the testing methodology, and presents the test results which show that significant improvements in both soil density and stiffness, along with a corresponding reduction in liquefaction triggering potential, were achieved.