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1 r , INTERPRETATION 1N COARSE-GRAINED SOILS 87 10-4 Most of the interpretation methods described in this section are based on results from large laboratory calibration 6 mm chamber tests (for instance, Schmertmann, 1975, Veisma- 10-5 ' (10CMI) ms, 1975, Bellotti et al, 1982, Parkin and Lunne 1982 `"u2 Baldi et al, 1986, Ghionna and Jamiolkowskl 1992) For O N completeness, a summary of calibration chamber testing 15* 10-6 ' techniques and results is included in Appendix C r � 5 5.1 State characteristics 10-' , The following sections detail the interpretations related to the parameters that describe soil state and stress history 10-8 schmertmann(1974) O N ' 5 5 1 1 Relative density(density index) For cohesionless soils, the density, or more commonly, the 10-g relative density or density index, is often used as an inter- 4 mediate soil parameter ;l 10-10 Table 513(a) Estimation of soil permeability (k) from CPT soil n k401 01 1 10 100 1000 10 000 behaviour charts Based on a CPT chart by Robertson et al, 1986 t ,(Min) (Figure 5 7) Figure 5 42 Proposed chart for evaluating KA from t5D for 10 cm2 Range of soil permeability �F piezocones(after Robertson et al, 1992a) Zone Soil behaviour type(SBI) k(m/s) Figure 5 42 can be used as a rough1 Sensitive fine v s guide to estimate kh grimed 3 x I4` to 3 x 10 from t5o Jamiolkowski et al (1985) presented Table 5 12 2 Organic soils I x 10_e to 1 x 10-6 which can be used to estimate k„from kh 3 Clay 1 x 10-"to 1 x 10` Soil permeability can also be estimated as a function of 4 Silt'clay to clay I x 10-9 to I x 10` soil types from the CPT classification charts as shown in 5 Clayey silt to silty clay I X to-1 to I x 10` Tables 5 13a and b 6 Sandy silt to clayey silt 1 X lo-,to, 1 x 10' a Estimation of sail permeability from CPT and dissipation 7 Silty sand to sandy silt I x 10`to I x 10-6 8 Sand data is subject to much uncertainty and should be used as a 9 Sand to silty sand 1 x 10-5 to 1 x 10-3 1 x 10-"to 1 x I O_3 guide only 10 Gravelly sand to sand I x 10-3 to I 1 l *Very stiff fine-grained soil 1 X 10-1 to 1 x to-" 5.5 INTERPRETATION IN COARSE-GRAINED 12 *Very stiff sand to clayey sand I x 10-$to 1 x 10-6 SOILS *Overconsolidated or cemented Colic penetration testing in coarse-grained soils, such as sandy soils, is generally drained Under drained conditions Table 5.13(6) Estimation of sail permeability(k) frons CPT soil there should be no excess pore pressures generated as a behaviour charts Based on normalized CPT chart by Robertson, I result of cone penetration, that is, the in situ static pore 1990(Figure 5 8) Pressure is measured An example of a CPTU in sand (McDonalds Farm,BC) is shown in Figure 5 43 Range of Boal permeability I However, sometimes equipment-related pore pressures Zone Soil behaviour type(m) k(m/s) may be generated on the cone(ui)due to high compressive 1 Sensitive fine grained 3 X 10-'to 3 X 10` II stresses(for example,Bruzzi and Battagho, 1987,Gillespie, 2 Organic soils I x 10-11 to 1 X 10-6 1990 I� In very dense fine or silty sands negative pore 3 Clay 1 x 10-10 to I X 10-1 Pressures may be recorded behind the cone (u2) due to 4 Silt mixtures 3 x 10-9 to 1 x 10-7 I� dilatancy effects(Figure 5 44) 5 Sand mixtures I x 10-'to 1 x 10-1 In the following sections,fully drained cone penetration is 6 Sands 1 x 10-5 to 1 X 10-, considered then only measured cone resistance and sleeve 7 Gravelly sand to sand 1 x 10v3 to I faction are used in the interpretation However, it is impar- 8 *Very stiff sand to clayey sand I x 10�$to 1 x 10-6 i tart to rev9 Very stiff fine-grained soil 1 x 10-1 to 1 X 10` review the recorded pore pressures to check if the assumption of fully drained conditions is valid_ *Overconsolidated or cemented