Abstract
This report deals with the shoring design for excavation. In the customary design of shrut-shorting, struts, which bear the whole load, are assumedly never dislocated and no consideration is given to the work sequence of excavation. In the strut design it is examined whether the axial force exceeds the allowable unit stress of member. However, shoring is designed to prevent soil and structures around the excavated site from moving towards the site. Therefore, the deformation as well as the strength of shoring members should be examined. It requires many assumptions and is rather difficult to calculate the deformation of shoring and the displacement of soil and near-by structures. Measured values of the strut axial force and the bending moment of the shoring walls during excavation are shown in Fig. 4.1. They show that the strut axial force remains constant or decreases somewhat with the progress of excavation. The modified dividing method shown in Fig. 3.8 is based on this performance. This report gives a calculation method of shoring in which the excavation sequence and above-mentioned bending moment change of shoring walls are taken into consideration. According to the new method shown in Fig. 3.3 and Fig. 3.4, basically, not only the unit stress of shoring members but also their strain should be examined. Because the soil pressure distribution and shoring model are considerably simplified, the unit stress of shoring members are easily determined. Measured valves and calculated values of shoring wall deformation and bendingmoment are shown in Fig. 4.1 and Fig. 4.2, and both values are highly consistent each other.
