The geotechnical subsoil conditions of the former Lake Texcoco represent a complex sequence of highly compressible lacustrine clays interbedded with layers and seams of harder and more permeable materials. Although the mechanical properties of these deposits have been extensively studied in the past, the information about their hydraulic properties is scarce. Currently, a comprehensive characterization of the hydraulic conductivity of this site has become necessary because of the construction of the New Mexico International Airport (NAIM). The present study describes a systematic evaluation of the hydraulic conductivity in the former Lake Texcoco through three different in-situ methods (well permeameter, LEFRANC and piezocone dissipation test). The measurements, taken from 155 locations, show a high spatial variability, with ranges spanning more than two orders of magnitude. The results also reveal that the estimated permeabilities vary significantly among methods. These discrepancies reflect the scale dependency of the hydraulic conductivity in the area caused by soil heterogeneities. A comparison of the presented results with previous studies demonstrates that piezocone tests provide representative results for the clayey formations, while LEFRANC tests better estimate the hydraulic conductivity of the permeable strata. Besides, CPTu tests yield more consistent values of hydraulic conductivity, with smaller dispersion than well permeameter and LEFRANC tests.
The thermal conductivity of soils is a fundamental parameter for the design of ground-source heat pump systems (GSHPs) and energy geostructures. This paper presents a comprehensive evaluation of the physical, mineralogical, and thermal characteristics of typical coastal soils from Tabasco, Mexico. Twenty-five soil samples from four different strata were studied using the thermal needle probe method, X-ray diffractometry, scanning electron microscopy, and standard geotechnical soil classification tests. The results showed a significant correlation between the dry density and porosity with the thermal conductivity of the studied samples, which ranged between 1.17 and 2.32 W m−1 K−1. The performed statistical analyses indicated that coarse-grained soils had larger thermal conductivities and higher variability than fine-grained soils. Additionally, the performance of six models to estimate the thermal conductivity of soils was validated against the experimental data. All models provided accurate estimations for fine-grained soils, but only the effective medium theory (EMT) showed an adequate fit for coarse-grained soils. The results represent one of the first datasets for the thermal properties of Mexican soils. They will contribute to the implementation of GSHPs and energy geostructures in the country and locations with similar subsoil conditions, especially where time and resources are not available for their experimental determination.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.