Polymer Injection and Liquefaction-Induced Foundation Settlement Mitigation: A Shake Table Testing Investigation

Shake table experiments are conducted to assess the potential of the polymer injection technique as a liquefaction countermeasure. A large 2.9 m high (10 ft) laminar soil container on a 3.9x1.85 m (13x6 ft) shake table is employed. Mitigation of liquefaction-induced settlement for a shallow foundation is explored. In a series of two shake table experiments, the system response is studied first without (baseline) and subsequently with polymer injected into the liquefiable stratum. Each test is densely instrumented to provide insights into the dynamic response of the soil and foundation system. Furthermore, cone penetration tests (CPTs) are performed pre- and postinjection to assess the extent of soil improvement. Strong base excitation is imparted by the shake table, resulting in liquefaction and excessive foundation settlement in the original baseline test. In the second test, with the polymer injection countermeasure, a significant reduction is observed in the tendency for liquefaction and the resulting foundation settlement. After this test, careful excavation provided additional insights into the polymer's configuration within the deposit, increasing overall soil relative density, confinement and creating solidified paths for the shallow foundation load toward the lower, more competent stratum. As such, these mechanisms have the potential to allow for: (1) an increase in soil resistance to liquefaction, and (2) a significant reduction in settlement of overlying shallow foundations.