In Japan, there are some cases of re-construction of inverted-arch because heaving has been continuing after the passing of many years and the secure of road user is lost. In these cases, it isn’t permitted to block road and one traffic lane must be kept. Therefore, factors of inefficiency are earth-retaining wall for securing one traffic lane and conversion of water drainage. So we introduce thecombination of portable-type earth-retaining and precast gutters which have strength for retaining the roadbed. From this, excavation and earth-retaining, conversion of water drainage are carried out at the same time, and the process is shortened. These effects are confirmed on actual test in Utsu Tunnel which is national road tunnel already unused because of damage from heaving. In regard to stability of tunnel structure, significant variations haven’t been measured from stress and displacement measurement during re-construction. |