Abstract
The considered section where was between two faults of the decomposed granite expanded upward. The section was the dark gray decomposed granite that mainly consisted of biotite. The outer side of two faults was the white decomposed granite that mainly composed of quartz and feldspar. The direction of a relative expansion of the portion pinched between two faults was about 51-degree slant upper part, and the amount of displacement was a maximum of about 26 mm. For the predictions, the elasto-plastic FE analysis based displacement control was con-ducted. The relative displacement obtained by FE analysis was almost agree with the actual relative displacement. X-ray diffraction was performed on two kinds of decomposed granites. The kaolinite and mica were contained rich in the dark gray decomposed granite. The quartz, potassium feldspar and plagioclase were contained rich in the white decomposed granite. The kaolinite and mica in the dark gray decomposed granite were a weak combination of minerals. For this rea-son, it was found that the larger expansion may be caused by cutting. On the other hand, as the quartz was a stable mineral, no expansion may be appeared, and the white de-composed granite was a less amount of expansion induced by cutting.
