PROCEDURE FOR EVALUATING LIQUEFACTION POTENTIAL OF SOLID BULK MATERIALS
l Scope
This procedure is applicable to granular materials not listed in Appendix A of the Code of Safe Practice for Solid Bulk Cargoes (BC Code) such as slags. If a shipper or master of a ship have doubts that the cargo may liquefy at a certain moisture content, the procedure presented in this annex is recommended to be applied to the material.
The basic principle of the procedure for evaluating liquefaction potential is that when a material, under ordinary drained condition, cannot contain a moisture at which the liquefaction may take place, the material is regarded as not liable to liquefy. If a material which is evaluated as not liable to liquefy by this procedure was carried without. pumping of bilge water and a water bed was formed at the bottom of the hold, liquefaction might take place. It should, therefore, be emphasized that the procedure is based on the premise that the bilge water in the hold is to be pumped out during carriage of solid bulk materials.
2. Comprehensive procedure for evaluating liquefaction potential
The comprehensive procedure for evaluating liquefaction potential of solid bulk material is shown in Figure I . The material can be evaluated as not liable to liquefy by satisfying one of the following conditions presented in the figure.
(1)The material does not contain a certain proportion of fine particles.
(2)Under the ordinary drained condition, the material can not contain high moisture.
Each condition, i.e., the branching element in the figure, is judged in accordance with the following criteria.
(1)Does the material contain a certain proportion of fine particles?
(A)For coals or materials having small solid density, i.e., solid density is smaller than 2.000 kg/m3, the answer is "No" in case that the effective size D10 of the material is not less than 2.0 mm.
(B)For materials having bigger solid density than 2.000 kg/m3, the answer is "No" in case that D10 of the material is not less than 1.0 mm.
Here, D10 is the grain size at which thc grain size accumulation curve of the material denotes 10 %. D10 should be measured under the condition that the maximum grain size is not bigger than 19.0 mm and 9.5 mm for materials (A) and for materials (B), respectively.
(2)Can the material contain high moisture?
To judge whether this condition is satisfied or not, the liquefaction potential test introduced in the next paragraph should be carried out. Based on the results of the liquefaction potential test, the material is judged as not liable to liquefy in case that the degree of saturation of the sample after drainage is less than 70 %. This test is not applicable for coals or other materials having lower solid density than 2,000 kg/m3.
3. Liquefaction potential test
3.1 Outline of the test procedure
The principle of the test is based on the Proctor/Fagerberg method presented in D.1.3 of the BC Code, by which the TML is determined by assuming that the material having moisture lower than that corresponding to 70 % degree of saturation is not liable to liquefy. Based on the same principle, it can be said that the material is not liable to liquefy when it can not keep moisture corresponding to 70 %, degree of saturation. Thus, the material is made be saturated
