Model tests have been carried out using an apparatus with several trap doors, to examine an earth pressure distribution patterns during shield driving execution and the redistribution by the succeeding change of load conditions. The present paper describes the load distribution on lowering trap doors measured by the apparatus, to get vertical load distribution pattern on trap doors and the load distribution by surface loading after lowering a trap door. The typical arching pattern of load and the load concentration on the area adjacent to the lowered trap door have been obtained Further, the anaiytical results by FEM are in relatively good agreement with the test results.