Concrete trench ﬁll is often used where strip loads are required to be transferred to relatively shallow depths
through soft material which is capable of standing up, without extra support, for at least a period adequate to cater for the construction sequence to be adopted. The trench ﬁll can embrace requirements for heavy loads going down to rock or light loads on soft sub-strata (see Fig. 9.6).
The requirement for working space within the trench for bricklayers is not a factor in determining the width of excavation with this method. Pouring concrete to within 150 mm of ground level overcomes this consideration.
Fig. 9.5 Concrete trench ﬁll.
Fig. 9.6 Concrete trench ﬁll.