OHS Code

Published Date: July 01, 2009
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Part 32 Excavating and Tunnelling

Section 442 Classification of soil type

(1) For the purpose of this Part, soil is classified as “hard and compact” if it closely exhibits most of the following characteristics:

(a) it is hard in consistency and can be penetrated only with difficulty by a small, sharp object;

(b) it is very dense;

(c) it appears to be dry;

(d) it has no signs of water seepage;

(e) it is extremely difficult to excavate with hand tools;

(f) if has not been excavated before.

(2) For the purpose of this Part, soil is classified as “likely to crack or crumble” if

(a) it has been excavated before but does not exhibit any of the characteristics of “soft, sandy, or loose” soil, or

(b) it closely exhibits most of the following characteristics:

(i) it is stiff in consistency and compacted;

(ii) it can be penetrated with moderate difficulty with a small, sharp object;

(iii) it is moderately difficult to excavate with hand tools;

(iv) it has a low to medium natural moisture content and a damp appearance after it is excavated;

(v) it exhibits signs of surface cracking;

(vi) it exhibits signs of localized water seepage.

(3) For the purposes of this Part, soil is classified as “soft, sandy, or loose” if it closely exhibits most of the following characteristics:

(a) it is firm to very soft in consistency, loose to very loose;

(b) it is easy to excavate with hand tools;

(c) it is solid in appearance but flows or becomes unstable when disturbed;

(d) it runs easily into a well-defined conical pile when dry;

(e) it appears to be wet;

(f) it is granular below the water table, unless water has been removed from it;

(g) it exerts substantial hydraulic pressure when a support system is used.

(4) If an excavation contains soil of more than one soil type, for the purposes of this Part an employer must operate as if all of it is the soil type with the least stability.