1.1 FOUNDATION DESIGN IN SCHEDULED AREAS
1.1.1 GENERAL
In accordance with the Fifth Schedule to the Buildings Ordinance, there are five Scheduled Areas specified in Hong Kong at present. These areas are:
Area No. Scheduled Areas
- Mid-levels
- North-west New Territories
- Railway Protection Areas
- Ma On Shan
- Sewage Tunnel Protection Areas
Particular requirements for foundation design in the Scheduled Areas are given in the relevant PNAP issued by the Building Authority. When planning and designing foundations in the Scheduled Areas, reference should be made to these PNAP.
1.1.2 FOUNDATION DESIGN IN SCHEDULED AREA NOS. 2 AND 4
- 2.8.2.1 GENERAL
The geology of Scheduled Area No. 2 (North-west New Territories) and Scheduled Area No. 4 (Ma On Shan) comprises superficial deposits overlying metamorphosed sedimentary strata (meta-siltstones, meta-sandstones and marble) as well as igneous rocks. The marble usually has a karstic upper surface with solution features. Large cavities with or without infilled material may be present within the marble.
Foundation design in karst marble requires careful consideration of the karst morphology, loading intensity and layout of load bearing elements. The main problem affecting the design is the potential presence of overhangs, channels and cavities. The stability of the pile foundation will depend on the particular geometry of such karst features and the rock mass properties.
Given that karstic marble and the related complex and adverse geological features could give rise to difficulties and uncertainties in foundation design and construction, ensuring sufficient geotechnical input is of the essence.
hkbuildercodeofpractice 