Geo-environmental Investigation · MCU25/0020

Table 5: Estimated Settlements Under Raft Slab

                       Description                                4 Storey Building + Basement

            Approximate Elastic Settlement                              15 mm to 20 mm
        Approximate Consolidation Settlement                            10 mm to 15 mm
               (in addition to above)
         Approximate Secondary Settlement                                5 mm to 10 mm
            Approximate Total Settlement                                30 mm to 45 mm

The elastic (immediate) settlements should mostly occur during the construction and initial loading
phase; however, ongoing consolidation and secondary settlement will occur over the design life of the
building, which should be considered in the design. Further analysis should be carried out once
structural design details and building loads are finalised to confirm the above estimates remain valid.
Settlement parameters were based on published and empirical correlations with in-situ test results from
the boreholes. An output from the Settle 3D modelling is presented in Text Figure 8.
It should be noted that concentrated wall/column loads or peak perimeter pressures exceeding 40 kPa
(soil contact pressure) could substantially increase settlement and thus, piled footings would likely be
required in these areas.




                              Text Figure 8: Settle 3D output of Total Settlement

6.4.2        Footing Options
For the anticipated approximate gross distributed building foundation pressure of up to 40 kPa under
the building, the adoption of strip and pad footings is not recommended as the settlement of foundation
soils would be excessive. Therefore, footing options that may be considered for the proposed building
include a well stiffened raft slab or piles. Discussion on raft slab and piled footing systems is given in
Sections 6.4.3 and 6.4.4 respectively.




Geo-environmental Investigation Proposed Residence
11 March 2025 | 25040-001-Rev0                                                                             15