OPW052025 Report - Part 2

Contents
1.     Introduction ............................................................................................................................................................ 1
2.     Proposed Development ....................................................................................................................................... 1
3.     Aims & Method of Investigation .......................................................................................................................2
       3.1 Fieldwork ...................................................................................................................................................................... 2
       3.2 Laboratory Testing ................................................................................................................................................... 3
4.     Site Description ......................................................................................................................................................3
       4.1 Topography................................................................................................................................................................. 4
       4.2 Geology ........................................................................................................................................................................ 7
             4.2.1    Regional Geology.................................................................................................................................... 7
             4.2.2    Subsurface Conditions .......................................................................................................................... 9
             4.2.3    Groundwater ........................................................................................................................................... 10
       4.3 Laboratory Test Results ........................................................................................................................................ 10
       4.4 Surface Drainage ..................................................................................................................................................... 11
       4.5 Vegetation ................................................................................................................................................................. 11
       4.6 Buildings & Other Structures ............................................................................................................................. 11
5.     Slope Stability Assessment ............................................................................................................................... 13
       5.1 Existing Conditions................................................................................................................................................. 13
       5.2 Slope Stability Assessment.................................................................................................................................. 14
            5.2.1     Qualitative Assessment ....................................................................................................................... 14
            5.2.2     Numerical Modelling ........................................................................................................................... 16
6.     Geotechnical Recommendations ..................................................................................................................... 18
       6.1 Site Layout and Geotechnical Constraints..................................................................................................... 18
       6.2 Earthworks ................................................................................................................................................................. 19
            6.2.1   Site Preparation and Trafficability................................................................................................... 19
            6.2.2   Filling ......................................................................................................................................................... 19
            6.2.3   Excavations & Batter Slopes ............................................................................................................. 20
       6.3 Building Foundations ............................................................................................................................................ 20
            6.3.1   Indicative Site Classification .............................................................................................................. 20
            6.3.2   Footings .................................................................................................................................................... 21
       6.4 Retaining Structures .............................................................................................................................................. 22
       6.5 Pavement Design .................................................................................................................................................... 23
       6.6 Drainage ..................................................................................................................................................................... 24
       6.7 On-Site Effluent Disposal ..................................................................................................................................... 24
7.     Limitations ............................................................................................................................................................ 24




Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0                                                                                                                                                            iii