Page 19 - Handbook GEOTEKNIK_Final_Neat

What is Site Investigation…? Boreholes Spacing

Building Works Road Works
• A process of site exploration consisting of site inspection, boring, sampling and testing so as to
obtain geotechnical information for a safe, practical and economical geotechnical evaluation or Spacing of boreholes for multistory building normally The spacing of boreholes for highway projects should
design ranges from 15m to 45m be between 60m – 600m
(depending on the uniformity of strata, geological (depending on geological formation whether the
• The main objective of site investigation is to determine the properties of soil, rock and conditions and foundation type) ground is flat, undulating, hilly terrain, peat, soft soils,
groundwater as they may affect the choice of the foundation works in terms of cost, time and swampy or limestone areas)
construction method of a project
Two boreholes for a block of low rise building on flat For road alignment passing through the same type of
land is sufficient geological formation, less number of boreholes are

required or spacing should be 500m interval or more

Site Investigation
For problematic and erratic soil formation like For road alignment passing through complex,
limestone areas, uncontrolled filled ground or boulder variable/different geological formations, more
abundant areas, or structures sensitive to settlement, boreholes at closer spacing are necessary
Desk Study & Site Boring Sampling Field Testing Lab Testing more boreholes are required
Reconnaissance For slopes on hilly terrain, recommended 3 numbers
of borehole on its vertical cross section (i.e. crest,
mid-section and toe)
Figure 1: Components of Site Investigation

Note:
i. There are no hard and fast rules in determining the numbers and spacing between boreholes
ii. However, it is good practice to follow the guidelines as stated above

2 PUBLIC WORKS DEPARTMENT MALAYSIA GEOTECHNICAL ENGINEERING HANDBOOK 3