| Duties of qualified person appointed to prepare the plans of geotechnical aspects of geotechnical building works |
[S 591/2012 wef 01/12/2012] 1. In the preparation of plans relating to the geotechnical aspects of any excavation or other building works to construct a tunnel with a diameter, width or height of more than 2 metres, the qualified person shall —| (a) | determine the site investigation, namely type, extent (which shall include quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the tunnel; | | (b) | analyse the site investigation results and determine the geotechnical parameters for the design, taking into consideration onerous water conditions, seepage pressures, and surcharge, earth, water, construction and accidental loadings; | | (c) | determine and adopt appropriate method or model for the analysis and design including the consideration of drained, undrained and consolidation analyses, and appropriate drainage conditions; | | (d) | determine suitability of tunnelling method, sequence of construction, and tunnel support system including face pressures and ground support system; | | (e) | determine allowable limits of ground deformation and changes in groundwater and piezometric levels, and measures to control groundwater where required; | | (f) | analyse the stability of excavation and determine the ground stabilisation or improvement works as appropriate; | | (g) | design soil or rock reinforcement, where applicable, including the consideration of the structural and geotechnical capacity; | | (h) | determine the instrumentation and monitoring of geotechnical engineering parameters such as tunnel face pressures, pore pressures, water table level, ground deformation and stresses including the consideration of location, type and number of instruments, and frequency of monitoring and reporting; and | | (i) | assess monitoring results and site conditions to ensure that the geotechnical aspects during construction are within design assumptions and parameters at every critical stage of construction, and review or modify the design so as to ensure its adequacy as appropriate. |
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2. In the preparation of plans relating to the geotechnical aspects of any excavation or any building works for constructing, altering or repairing any earth retaining structure (including slope) in or for a caisson, cofferdam, trench, ditch, shaft or well for supporting earth which has a depth or height of more than 6 metres, or of any earthworks or other building works for constructing or stabilising a slope with a height of more than 6 metres, the qualified person shall —| (a) | determine the site investigation, namely type, extent (which shall include quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the earth retaining structure including earth slope; | | (b) | analyse the site investigation results and determine the geotechnical parameters for the design of the earth retaining structure including consideration of onerous water conditions, seepage pressures, and surcharge, earth, water, construction and accidental loadings; | | (c) | determine and adopt appropriate method or model for the analysis and design including the consideration of drained, undrained and consolidation analyses, and appropriate drainage conditions; | | (d) | determine suitability of earth retaining structure types and scheme, and the method and sequence of construction; | | (e) | analyse the stability of the excavation work, taking into consideration groundwater, drainage and seepage conditions, basal heave, hydraulic uplift and piping, and determine the ground stabilisation or improvement works as appropriate; | | (f) | determine allowable limits of ground deformation and changes in groundwater and piezometric levels, and measures to control groundwater where required; | | (g) | design tie-backs, soil or rock reinforcement, where applicable, including the consideration of the structural and geotechnical capacity; | | (h) | ensure that drawings of the earth retaining structure, including earth slopes, are consistent with the calculations relating to the geotechnical aspects; | | (i) | determine the instrumentation and monitoring of geotechnical engineering parameters such as pore pressures, water table levels, ground deformation and stresses including the consideration of location, type and number of instruments, and frequency of monitoring and reporting; and | | (j) | assess monitoring results and site conditions to ensure that the geotechnical aspects during construction are within design assumptions and parameters at every critical stage of construction, and review or modify the design so as to ensure its adequacy as appropriate. [S 591/2012 wef 01/12/2012] |
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3. In the preparation of plans relating to the geotechnical aspects of such type of foundation works for buildings of 30 or more storeys, the qualified person shall —| (a) | where a caisson, raft or piled-raft foundation is adopted —| (i) | determine the site investigation, namely type, extent (which shall include quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the caisson, raft or piled-raft foundation; | | (ii) | analyse the site investigation results and determine the geotechnical parameters, such as soil strength and deformation characteristics, pile shaft friction, downdrag, pile base resistance or bearing pressures and pile lateral geotechnical capacity, for the design of the foundation taking into consideration the onerous water conditions, seepage pressures, and loads from surcharge, earth, water and construction; | | (iii) | determine and adopt appropriate method or model for the analysis and design including the consideration of drained, undrained and consolidation analyses, and appropriate drainage conditions; | | (iv) | determine suitability of the foundation type and the method of construction; | | (v) | where applicable, determine and analyse the negative shaft friction; | | (vi) | ensure that the drawings of the foundation are consistent with the calculations relating to the geotechnical aspects; | | (vii) | analyse the stability of excavation for the caisson or raft during construction taking into consideration groundwater, drainage and seepage conditions, basal heave, hydraulic uplift and piping, and determine the ground stabilisation or improvement works as appropriate; | | (viii) | analyse the forces and deformation of the raft or pile-raft foundation and stability of the foundation including the consideration of short-term and long-term conditions; | | (ix) | determine the number, location and types of load tests, analyse the results of load tests; or |
| | (b) | where jacked-in piles or driven piles or bored cast in-place piles or barrettes are adopted —| (i) | determine the site investigation including the extent (which shall include the quantity, layout and depth), method of sampling, coring and laboratory tests results for the design and construction of the piled foundation; | | (ii) | analyse the site investigation results and determine the geotechnical parameters such as soil strength and deformation characteristics, negative skin friction or downdrag, pile shaft friction, founding depth, pile base resistance, pile group effects, settlement, bearing capacity, and where applicable, lateral geotechnical capacity; and | | (iii) | determine the load tests and analyse results of load tests to ensure that the pile shaft friction, founding depth, base resistance, pile movement, and other appropriate geotechnical parameters are within the design, and as appropriate, review or modify the design so as to ensure its adequacy. [S 643/2008 wef 18/12/2008] |
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