We prove an existence and uniqueness result for the obstacle problem of quasilinear parabolic stochastic PDEs. The method is based on the probabilistic interpretation of the solution by using the backward doubly stochastic differential equation.
"The obstacle problem for quasilinear stochastic PDE’s." Ann. Probab. 38 (3) 1143 - 1179, May 2010. https://doi.org/10.1214/09-AOP507