AS 1839:2021 Swimming pools – Premoulded fibre- reinforced plastics 一Installation.
Section 8 Installation of pools in reactive clay soils
8.1 General
The reactivity of clay soils and the depth of that reactivity varies around Australia. AS 2870 specifies a general definition of both parameters for any area, however, variation for individual sites does still occur. An investigation of any clay site shall be undertaken, see Clause 3.3.
NOTE 1 See Appendix A for further information on reactive clay soil.
NOTE 2 Refer to AS 1838 for further information on the design of pools for installation in reactive clay soils.
8.2 Seasonal movement
Clay soils are subject to seasonal movement, which may affect the long-term shape and level of the pool as well as the relationship of the pool with any surrounding structures and drainage.
NOTE 1 See Clauses 6.1.1 and 6 notes.
Seasonal movement resulting in deflection in the pooi walls and bond beam may occur in highly to
extremely reactive clay soils, see Appendix A.
8.3 Differential movement
Differential movement between the deep end and shallow end of the pool may occur in highly to extremely reactive clay soils. Where deemed necessary by a competent person, over excavation of the shallow end of the pool to match the deep end of the pool and backfilling with non-reactive material, shall be undertaken to control differential movement of the pool, see Figure 8.3(A). Where the excavation exceeds 150 mm under the pooi, the additional base fill shall be stabilized or compacted prior to installation of the pool.
NOTE 1 Over excavation of the shallow end of the pool to match the deep end may not be required in slightly reactive and moderately reactive clay soils. Standard excavation, drainage and bedding practices may be applied in these soils, see Figure 8.3(B).
NOTE 2 For additional information on reactive clay soil classifications, see Appendix A.
8.4 Other installation requirements in reactive clay soils
The floor of the pool shell shall be installed with a concave profile and hydrostatic relief valve in accordance with this document.
NOTE 1 To ensure that the installed pool shell has the required structural integrity, changes to the excavation profile and to the backfill may be required, see Clause 5.2.
Installation methods shall be undertaken to control ground water and surface water to minimize moisture change in clay soils.
A gravity flow to existing drainage, including any drainage installed at the base of the excavation, shall be created.
NOTE 2 If connecting to existing stormwater drainage it may be necessary to prevent back surcharge in the event of a storm or blockage. When this is not possible, a pump and sump system approved by a competent person may be considered.
AS 1839 pdf download.