# Diatomaceous Soils and Advances in Geotechnical Engineering--Part I
## 3 Review of Progress in Geotechnical Lines
### Consistency and Plasticity in Diatomaceous Soils
However, they clarify that, for mixtures of these two inputs, such as 20% diatomaceous and 80% kaolin, classification as silt below the \"A-line\" is inappropriate. These same authors [14] disagree with some values of high plasticity indexes reported for artificial mixtures (diatomite-kaolin) with diatomaceous earth contents higher than 60% due to the more meaningful presence of frustules. However, this leads to a greater water storage capacity, which does not necessarily imply an increase in plasticity. The increases in LL and PL are almost the same; therefore, there should be no variation in PI. Figure 8: Variation in the liquid limit of fine soils as a function of diatom content. Ref. [25] ([PERSON] et al., 2021), Ref. [40] ([PERSON] et al., 2002), Ref. [56] ([PERSON], 2009), Ref. [20] ([PERSON] et al., 2011), Ref. [12] ([PERSON] et al., 2019), Ref. [87] ([PERSON], 2001), Ref. [44] ([PERSON] et al., 2017), Ref. [14] ([PERSON] et al., 2022), Ref. [32] ([PERSON], 2011), Ref. [79] ([PERSON] & [PERSON], 2013), Ref. [33] ([PERSON] & [PERSON], 1999). Figure 9: Variation in the plastic limit of fine soils as a function of diatom content. Ref. [25] ([PERSON] et al., 2021), Ref. [40] ([PERSON] et al., 2002), Ref. [56] ([PERSON], 2009), Ref. [20] ([PERSON] et al., 2011), Ref. [12] ([PERSON] et al., 2019), Ref. [87] ([PERSON], 2001), Ref. [44] ([PERSON] et al., 2017), Ref. [14] ([PERSON] et al., 2022), Ref. [32] ([PERSON], 2011), Ref. [79] ([PERSON] & [PERSON], 2013), Ref. [33] ([PERSON] & [PERSON], 1999). Figure 11 presents the LL vs. PI ratio in DS of multiple origins. The values show the classification below the graphical limits of A-line, which classifies them mostly as high plasticity salts (MH). This representation is given for soils with diatom contents equal to or greater than 50%. From Figure 12 and for the PL vs. PI ratio, no pattern of variability is identified. However, PL values ranging between 30% and 100% are mainly associated with PI records lower than 80%. The water-holding capacity of diatoms considerably influences the index properties, which are calculated from the total amount of water in the soil. However, Ref. [33] states that the water resting inside the intraskeletal pores has little influence on the index properties--i.e., any relationship based on water proportion or void content for soils that contain microfossils should be redefined in order to avoid calculation and classification errors. Water held within skeletal and intraskeletal pores is retained by suction. With increasing levels of stress, microfossils will fracture, and thus the number of intraskeletal pores will be drastically reduced. At this point, the overall effects of the index properties will have vanished [33]. If small changes in diatom geometry are evident at a given geostatic stress, the amount of water retained in the frustules will be nearly constant. Representative variation will be evident with depth [8]. Determining the liquid and plastic limits in DS through the traditional Casagrande methods presents certain complications, given the non-plasticity of this type of deposit. This parameter has been calculated indirectly through the relationship between the cone fall method and the flow rate [12; 14]. Figure 10: Classification of diatomaceous soils of multiple origin according to the plasticity chart. Ref. [25] ([PERSON] et al., 2021), Ref. [40] ([PERSON] et al., 2002), Ref. [56] ([PERSON], 2009), Ref. [20] ([PERSON] et al., 2011), Ref. [12] ([PERSON] et al., 2019), Ref. [87] ([PERSON], 2001), Ref. [44] ([PERSON] et al., 2017), Ref. [14] ([PERSON] et al., 2022). Figure 11: Relationship between LL and plasticity in DSs of different origin—concentrations higher than 50%. Ref. [25] ([PERSON] et al., 2021), Ref. [40] ([PERSON] et al., 2002), Ref. [56] ([PERSON], 2009), Ref. [20] ([PERSON] et al., 2011), Ref. [12] ([PERSON] et al., 2019), Ref. [87] ([PERSON], 2001), Ref. [44] ([PERSON] et al., 2017), Ref. [14] ([PERSON] et al., 2022), Ref. [32] ([PERSON], 2011), Ref. [79] ([PERSON] & [PERSON], 2013), Ref.