Studies of earth shielding effect to direct dark matter searches at the China Jinping Underground Laboratory

Dark matter direct detection experiments mostly operate at deep underground laboratory. It is necessary to consider shielding effect of the earth, especially for strongly interacting massive particle dark matter. We analyzed and simulated the earth shielding effect for dark matter at the China Jinping Underground Laboratory (CJPL) with a simulation package, CJPL Earth Shielding Simulation code (CJPL_ESS) which is applicable to other underground locations. The further constraints on the $\chi$-N cross-section exclusion regions are derived based on the studies with CDEX experiment data.