Two phase flow in FLAC

i use two-phase flow option in FLAC 8.0 version to simulate carbon dioxide injection into the deep ground undersea floor.
When the “udcoe” is initialized to 0 in my model, all the results seem reasonable except the displacement of the ground. The displacement of the ground above the injection point has an unreasonably large uplift (1e11 meters), while an unreasonably large settlement is observed below the injection point.
When the “udcoe” is initialized to 1.0 in my model, the displacement of the ground seem reasonable. But the pore pressure for both saline and CO2 near the injection point is negative after the injection of CO2.
i have attahed my code. Hope somebody can help me check the problem.
new_1_model.dat (39.7 KB)
new_2_gravity.dat (3.9 KB)
new_3_injection.dat (975 Bytes)

Xiongyu, we have received your follow-up questions via flacsupport email, we are now checking your model and will get back to you soon. Thanks for your patience.