In the LPT, the sample is in a saturated condition and the water in the saturated sample is drained. The liquefaction potential of the sample is judged by using the degree of saturation after the drainage as an index. Because the Proctor/Fagerberg test procedure is not applicable to coal or other porous materials, the LPT is not applicable to coal.
12 Strictly speaking, characteristics of liquefaction cannot be discussed only with the degree of saturation of the sample after drainage. On the other hand, the LPT is just a complementary test procedure for the implementation of the requirements for liquefaction materials and the comprehensive procedure for evaluating liquefaction potential of solid bulk materials is proposed just as a guideline. Taking the scope and the status of the LPT into consideration, it is not important to discuss the characteristics on liquefaction of solid bulk materials in detail. It was recognized, through the discussion on introduction of the Proctor/Fagerberg test procedure into the BC Code (to BC 32), that the criterion for the moisture content, i.e. the TML, can be determined by using the degree of saturation as an index. The LPT and the Proctor/Fagerberg test procedure are based on the same principle. The LPT is for evaluating whether the material can contain high moisture which leads to liquefaction, by using the degree of saturation after the drainage as an index.
Case studies
13 In the research for developing the LPT, experiments using two materials other than coal, i.e. granulated nickel slag and granulated copper slag were conducted. It was judged empirically that these materials, as received (without controlling grain size distribution), were not liable to liquefy, because they had been carried for many years and liquefaction had not been reported. The results of the LPT for these materials, as received, agreed with the empirical judgement. Furthermore, the results of the LPT for the materials of which the grain size distributions were controlled indicated that even such materials may liquefy when the grain size distribution becomes finer. Poland also conducted the LPT for sedimentary galena and the results agreed with the empirical judgement. These experiences on the LPT can be regarded as case studies. To improve the LPT, we would like to invite the Member countries to conduct case studies.
Action requested of the Sub-Committee
14 The Sub-Committee is invited to recognize the problem of the scope of the application of the requirement for materials which may liquefy and take action as it deems appropriate based on this document.
