Site-specific Correlations Research Articles

Exploring indirect effects of a classic trophic cascade between urchins and kelp on zooplankton and whales

Kelp forest trophic cascades have been extensively researched, yet indirect effects to the zooplankton prey base and gray whales have not been explored. We investigate the correlative patterns of a trophic cascade between bull kelp and purple sea urchins on gray whales and zooplankton in Oregon, USA. Using generalized additive models (GAMs), we assess (1) temporal dynamics of the four species across 8 years, and (2) possible trophic paths from urchins to kelp, kelp as habitat to zooplankton, and kelp and zooplankton to gray whales. Temporal GAMs revealed an increase in urchin coverage, with simultaneous decline in kelp condition, zooplankton abundance and gray whale foraging time. Trophic path GAMs, which tested for correlations between species, demonstrated that urchins and kelp were negatively correlated, while kelp and zooplankton were positively correlated. Gray whales showed nuanced and site-specific correlations with zooplankton in one site, and positive correlations with kelp condition in both sites. The negative correlation between the kelp-urchin trophic cascade and zooplankton resulted in a reduced prey base for gray whales. This research provides a new perspective on the vital role kelp forests may play across multiple trophic levels and interspecies linkages.

Constrained modulus of fine-grained soils from in situ-based correlations and comparison with laboratory tests

The Constrained Modulus of soil is an important parameter to quantify compressibility of soils and calculate consolidation settlements, especially for clays. It is often expressed in terms of 1D constrained modulus, M or its inverse coefficient of volume change, mv. One method that has been suggested to assess M is from Cone Penetration Testing (CPTU) measurements through various correlations. Although, this is sometimes difficult, because of uncertainties regarding the appropriate stress, σ’v0, which are highly affected by the groundwater and bulk density γ, of soils. The usual method to measure M (or mv) is from oedometer tests in laboratory. Correlating in situ tests with laboratory tests results is crucial to increase the quality of soils strengths and stiffness information for design. However, most of the times it is a challenging process, which involves many uncertainties from different soils’ tests. This paper will look at comparison of CPTU derived M to oedometer tests taking into consideration various types of soils mostly from well-documented testbed sites where high quality in situ (CPTU for all sites and SDMT where available) and oedometer tests are carried out. The importance of CPTU measurements and site-specific correlations with laboratory tests to establish unique soil type coefficients for use in equations to derive CPTU-based M will be highlighted.

Multivariate probability distributions for index and mechanical clay parameters in Shenzhen

Probabilistic site characterization is the cornerstone of data-centric geotechnics, which underpins the digitalization in geotechnical engineering. The essential aspect of probabilistic site characterization is to reasonably infer the probability density distributions of geotechnical parameters, based on field and laboratory data. In this paper, a clay property database, SZ-CLAY/11/5130, was established by collecting geotechnical investigation reports from 52 engineering projects in Shenzhen city. This SZ-CLAY/11/5130 database was first compared with the global clay database CLAY/10/7490 and the Shanghai clay database SH-CLAY/11/4051, in terms of their sample ranges, correlations, and scatter plots. Then, the multivariate probability distribution of eight clay parameters was established using the training records selected from SZ-CLAY/11/5130, to characterize the generic correlations between multiple clay parameters. Based on Bayesian theory, the posterior distributions of clay mechanical parameters from a construction site in Shenzhen city were updated using both the site-specific correlations and the generic correlations given by SZ-CLAY/11/5130. The constructed multivariate probability density distribution is necessary for this updating step.

Characterizing bacterial and fungal communities along the longitudinal axis of the intestine in cynomolgus monkeys

ABSTRACT The gut microbiota develops specialized local communities along the gastrointestinal (GI) tract of the host. Among these microbes, intestinal bacteria and fungi interact closely with the host and play vital roles in their health. However, the gut biogeography of bacteria and fungi has rarely been studied simultaneously, and their correlations have not been reported. In this study, we collected the intestinal luminal contents from different gastrointestinal regions (the ileum, caecum, and colon) of wild-type female cynomolgus monkeys and performed 16S and 18S rRNA gene sequencing to determine the gut biogeography of bacterial and fungal communities. The richness and diversity of bacteria and fungi increased gradually from the small to the large intestine. The bacterial and fungal composition of ileum differed significantly from that of the colon. Specifically, Bacteroidia and Spirochaetia were abundant in the caecum and colon, while Actinobacteria and Cyanobacteria were enriched in the ileum. As for fungal taxa, the genera Aspergillus , Wallemia , and Cryptococcus_f_Tremellaceae were enriched in the colon, while the genus Fusarium was abundant in the caecum. Consequently, the bacterial and fungal functions of the ileum differed from those of the caecum and colon. Notably, we characterized the correlations between intestinal bacteria and fungi at different gastrointestinal regions of cynomolgus monkeys using Spearman correlation analysis. In summary, our results contribute to a more comprehensive understanding of the composition and function of intestinal bacteria and fungi in non-human primates (NHPs) and reveal their correlations along the longitudinal axis of the intestine. IMPORTANCE Gut microbiota varies along the gastrointestinal (GI) tract and exerts profound influences on the host’s physiology, immunity, and nutrition. Given that gut microbes interact with the host closely and the gastrointestinal function differed from the small to the large intestine, it is essential to characterize the gut biogeography of the microbial community. Here, we focused on intestinal bacteria and fungi in cynomolgus monkeys and determined their spatial distribution along the GI tract by performing 16S and 18S rRNA gene sequencing. The composition and function of bacterial and fungal communities differed significantly at different biogeographic sites of the intestine, and the site-specific correlations between intestinal bacteria and fungi were revealed. Thus, our studies characterized the gut biogeography of bacteria and fungi in NHPs and revealed their site-specific correlations along the GI tract.

Development of Energy-Based Site-Specific Correlations to Evaluate Liquefaction Potential

Development of Energy-Based Site-Specific Correlations to Evaluate Liquefaction Potential

Catchment scale spatial distribution of soil enzyme activities in a mountainous German coniferous forest

Topography features within catchments influence soil properties, nutrient status, microbial dynamics and ultimately enzyme activities. Extracellular soil enzymes are essential for the decomposition of organic substrates and play a central role in global biogeochemical cycles. How topography and soil properties drive the spatial expression of enzyme activities at the catchment scale is still underexplored, especially in coniferous forest ecosystems. This study investigated the activity of four extracellular soil enzymes: β-glucosidase (β-glu), β-cellobiosidase (β-cello), acid phosphatase (pho) and leucine-aminopeptidase (l-leu) in Oh and Ah horizons of a (27 ha) mountainous coniferous forest catchment (Wüstebach, Eifel National Park, Germany). Spatial patterns and "hot spots" of activities of these four enzymes (involved in C-,N-, and P- cycling) were examined in connection to catchment units differing in slope, exposure and soil type (Cambisol vs. Gleysol), and multiple soil parameters (i.e., moisture content, pH, C, N, P, K, Fe, Mn content, C:N, C:P and N:P ratio). Catchment enzyme activities were overall, except for β-cello, significantly higher in the Oh than Ah horizon. Lower β-glu, and l-leu activities were found where more anaerobic soil conditions did occur, e.g., the river valleys (RV). Neither enhanced Oh horizon erosion on steeper Eastern (ES) and Northeastern (NES) slopes nor larger spatial soil nutrients heterogeneity on Northern (NS) and Western (WS) slopes, did significantly affect enzyme activity. Landscape topography did lead to a spatial variation of the activity of the four enzymes examined. The site-specific variation in C-cycling enzymes (β-glu and β-cello) was most marked at drier East, Northeast and Northern slopes, for P-cycling (pho) within the central wetter river valley but was for N-cycling (l-leu) enzyme activity more homogeneously distributed over the whole catchment. Overall, enzyme activities were strongly correlated to soil properties (especially soil moisture and organic carbon), but locations NS (Wüstebach source area) and RV (Wüstebach river flow path) showed less site-specific correlations. Further refinement of site-specific soil and external factors driving spatial distribution of enzyme activities at catchment scales and beyond will help to further tool up this research at larger spatial scales.

Does normalization of SARS-CoV-2 concentrations by Pepper Mild Mottle Virus improve correlations and lead time between wastewater surveillance and clinical data in Alberta (Canada): comparing twelve SARS-CoV-2 normalization approaches

Wastewater-based surveillance (WBS) data normalization is an analyte measurement correction that addresses variations resulting from dilution of fecal discharge by non-sanitary sewage, stormwater or groundwater infiltration. No consensus exists on what WBS normalization parameters result in the strongest correlations and lead time between SARS-CoV-2 WBS data and COVID-19 cases. This study compared flow, population size and biomarker normalization impacts on the correlations and lead times for ten communities in twelve sewersheds in Alberta (Canada) between September 2020 and October 2021 (n = 1024) to determine if normalization by Pepper Mild Mottle Virus (PMMoV) provides any advantages compared to other normalization parameters (e.g., flow, reported and dynamic population sizes, BOD, TSS, NH3, TP). PMMoV concentrations (GC/mL) corresponded with plant influent flows and were highest in the urban centres. SARS-CoV-2 target genes E, N1 and N2 were all negatively associated with wastewater influent pH, while PMMoV was positively associated with temperature. Pooled data analysis showed that normalization increased ρ-values by almost 0.1 and was highest for ammonia, TKN and TP followed by PMMoV. Normalization by other parameters weakened associations. None of the differences were statistically significant. Site-specific correlations showed that normalization of SARS-CoV-2 data by PMMoV only improved correlations significantly in two of the twelve systems; neither were large sewersheds or combined sewer systems. In five systems, normalization by traditional wastewater strength parameters and dynamic population estimates improved correlations. Lead time ranged between 1 and 4 days in both pooled and site-specific comparisons. We recommend that WBS researchers and health departments: a) Investigate WWTP influent properties (e.g., pH) in the WBS planning phase and use at least two parallel approaches for normalization only if shown to provide value; b) Explore normalization by wastewater strength parameters and dynamic population size estimates further; and c) Evaluate purchasing an influent flow meter in small communities to support long-term WBS efforts and WWTP management.

Development of empirical CPTu-Vs correlations for post-glacial sediments in Southern Quebec, Canada, in consideration of soil type and geological setting

The correlation of shear wave velocity (Vs) with piezocone penetration test (CPTu) parameters is investigated in post-glacial sediments along the St. Lawrence and Saguenay rivers, Southern Quebec, Canada. The compiled database includes 991 CPTu-Vs measurements at 40 sites. The objectives are to examine the applicability of existing CPTu-Vs correlations, identify the main CPTu parameters and develop specific CPTu-Vs correlations that account for the effects of soil type (sandy or clayey) and geological setting (Champlain or Laflamme sea sediments). Results reveal that the application of existing correlations is biased in varying degrees, denoting a need for site-specific correlations for the study area. Multivariate regression analyses confirm the importance of cone tip resistance and depth as Vs predictors assisted by normalised pore pressure and soil behaviour type index. Consideration of soil type and geological setting helps reduce uncertainties in CPTu-Vs correlations for fine-grained soils.

The response of sediment microbial communities to temporal and site-specific variations of pollution in interconnected aquaculture pond and ditch systems

Sediment microbial communities play critical roles in the health of fish and the biogeochemical cycling of elements in aquaculture ecosystems. However, the response of microbial communities to temporal and spatial variations in interconnected aquaculture pond and ditch systems remains unclear. In this study, 61 sediment bacterial samples were collected over one year from 11 sites (including five ponds and six ditches) in a 30-year-old fish aquaculture farm. The 16S rRNA approach was used to determine the relative abundances of microbial communities in the sediment samples. The relationships among nutrients, heavy metals, and abundant microorganisms were analyzed. Our results showed that Proteobacteria, Bacteroides and Chloroflexi were the predominant phyla in the sediments of aquaculture pond, with average abundances of 36.33%, 18.60%, and 14.58%, respectively. The microbial diversity in aquaculture sediments was negatively correlated (P < 0.05) with the concentrations of total nitrogen and total phosphorus in sediments, indicating that the microbial diversity is highly associated with the remediation of nutrients in sediments. The sediment samples with high similarities were discovered by the t-distributed stochastic neighbor embedding (t-SNE) method. The site-specific correlations between specific microorganisms and heavy metals were explored. The network analysis revealed that the microbial diversities in aquaculture ponds were more stable than that in aquaculture ditches. The network analysis also illustrated that the microbial genera with low relative abundances may become key groups of microbial communities in sediment ecosystems. Our work deepens the understanding of the relationships between microbial communities and the spatiotemporal characteristics of surface water and sediments in aquaculture farms.

Empirical correlations of soil parameters based on piezocone penetration tests (CPTU) for Hong Kong-Zhuhai-Macau Bridge (HZMB) project

The site investigation is a key part of the foundation analysis and design in the Hong Kong-Zhuhai-Macao Bridge (HZMB) mega project, as it provides accurate geotechnical parameters. This paper discusses about the collection of undisturbed soil samples, laboratory tests, and extensive piezocone penetration tests (CPTU) performed at the Pearl River Delta sites. First, soils were classified based on CPTU data and statistical analyses were conducted to determine the correlation between the physical parameters and CPTU data. Current interpretation methods were used to evaluate the physical, state, strength, and deformation characteristics of soil and develop new site-specific correlations. The analysis of a large amount of available data not only illustrated the significant potential of CPTU for obtaining soil stratification details and in-situ soil properties, but also revealed some limitations of widely used empirical correlations for characterizing the physical, state, strength, and deformation properties of soil. In this study, region-specific correlations between piezocone penetration resistance and soil properties, with special reference to physical, strength, and deformation characteristics, are established and verified with the existing recommendations.

Variations in surface area of six ice aprons in the Mont-Blanc massif since the Little Ice Age

AbstractDeglaciation of high mountain rockwalls alters slope stability as rockwalls become more sensitive to modifications in environmental factors (e.g. seasonal temperature variations). In the past decades, increasing efforts focused on studying deglaciated Alpine rockwalls. Yet, currently deglaciating rockfaces remain unstudied. Here, we quantify surface area variations of massive ice bodies lying on high mountain rockwalls (ice aprons) in the French sector of the Mont Blanc massif between the end of the Little Ice Age (LIA) and 2018. Surface area estimates are computed from terrestrial and aerial oblique photographs via photogrammetry. This technique allows using photographs taken without scientific intent, and to tap into diverse historical or recent photographic catalogs. We derive an ice apron surface area model from precipitation records and the positive degree-days. The studied ice aprons shrank from 1854 to the 1950s, before expanding until the end of the 1990s. The beginning of the 21st century shows a decrease in surface area, leading to the complete melt of one of the studied ice aprons in 2017. Observed variations correlate with modeled surface area, suggesting strong sensitivity of ice aprons to changes in climatic variables. By studying site-specific correlations, we explore the importance of local drivers over the balance of ice aprons.

Inverse analysis of Hypoplastic Clay model for computing deformations caused by excavations

For effective applications of the adaptive management approach, inverse analysis procedures are used to update model parameters based on observations made during early stages of construction projects. These updated parameters are then used to compute the responses at later stages. This paper describes the inverse analysis of lateral wall deformations from a deep supported excavation in Chicago using the Hypoplastic Clay model. Initial parameters for the soil model are based on inverse analyses of laboratory test results and site-specific correlations with in situ data of Chicago clays. Field observations made during construction are used to conduct sensitivity and correlation analyses, and the most effective parameters to optimize are selected. These parameters are optimized at three depths during excavation where plane strain conditions were applicable. Changes in the optimized parameters at the excavation levels are analyzed to assess how and if the parameters are optimized satisfactorily. Computed responses using the optimized parameters are compared to field measurements, and recommendations regarding the parameters to optimize are provided.

Shear Wave Velocity in the East Nile Delta Clay: Correlations with Static CPT Measurements

The East Port Said region, one of the most vibrant areas in the East Nile Delta, is a strategic economic zone that is receiving growing local and global investments. The near surface formations, however, typically comprise very soft clays deposited during the Holocene epoch. Collecting undisturbed samples and conducting laboratory evaluation of these sensitive soils could be cumbersome, inaccurate, and uneconomical. Therefore, the use of in-situ cone penetration test (CPT) provides a viable and convenient characterization alternative. This study attempts to establish site-specific correlations between the measurements of the static CPT and shear wave velocities (Vs) furnished by seismic piezocone soundings. The mathematical regressions were developed utilizing a number of measurements and factors, namely, tip resistance, sleeve friction, effective stress, depth, voids ratio, and soil behavior type index. The proposed correlations demonstrate different levels of predictability, with a few warranting confidence in employing static CPT for estimation of Vs profile in this region. Two correlations, one utilizing void ratio and tip resistance and the other employing sleeve friction solely, have shown to provide the most reliable Vs predictions for the soft clay in the East Nile Delta.

Structurally based joint inversion of electromagnetic, seismic and potential field data for improved classification and characterization: Field examples from the vadose zone

A key strategy to characterize subsurface materials is the integrative analysis of tomograms of several physical properties provided by different geophysical data. Among the recent strategies to produce these tomograms is the joint inversion. Unfortunately, most joint inversion techniques are based on hypothetical property relationships that hinder the site-specific property correlations that characterize individual materials. Differently, a recently developed cross-gradient joint inversion technique is underpinned by the hypothesis of structural resemblance and permits the coexistence of natural property correlations that provide the key to unravel the signatures of subsurface materials. In the present work, electromagnetic, seismic and potential field data are jointly inverted for several field sites with near surface targets. The results show not only a clearer disposition of the mapped units in structural terms, but also a sound evidence of their actual fluid-mineral characteristics. In general, the results demonstrate the power of analyzing multiple-property images when they are structurally consistent.

Assessing compressibility characteristics of silty soils from CPTU: lessons learnt from the Treporti Test Site, Venetian Lagoon (Italy)

This paper explores the capability of cone penetration testing as an effective tool to estimate the compressibility characteristics of silts, silt mixtures and sand mixtures. The study uses part of the large amount of piezocone (CPTU) data and subsoil deformation measurements assembled over approximately 6 years at the Treporti Test Site (Venice, Italy), within an extensive research project aimed at thoroughly analyzing the stress-strain-time response of the complex assortment of sandy and silty sediments forming the Venetian lagoon subsoil. The combined analysis of piezocone data and subsoil deformations measured beneath a full-scale test embankment primarily showed that the existing interpretation approaches developed for 'standard' sands or clays - and thus based on the idealized assumption of fully drained or fully undrained testing conditions - generally result in invalid estimates of soil compressibility parameters. Therefore, site-specific correlations have been developed in order to correctly predict the compressibility of Venetian sediments, both primary and secondary, and consequently obtain the best fit of the measured settlements. By taking this very well documented case study as a base, the proposed paper aims at discussing some key issues on the use of piezocone tests for the geotechnical characterization of silts and other sedimentary soils with very scattered grain size distributions, thus falling in the so-called intermediate permeability range. The idea is basically to provide a critical appraisal of the CPTU-based approaches currently available for the mechanical characterization of natural soils, and explore potential advances in the interpretation methods, which might take account of possible partial drainage phenomena around the advancing cone during the test.

An assessment of correlations between chlorinated VOC concentrations in tree tissue and groundwater for phytoscreening applications

The majority of prior phytoscreening applications have employed the method as a tool to qualitatively determine the presence of contamination in the subsurface. Although qualitative data is quite useful, this study explores the potential for using phytoscreening quantitatively. The existence of site-specific and non-site-specific (master) correlations between VOC concentrations in tree tissue and groundwater is investigated using data collected from several phytoscreening studies. The aggregated data comprise 100 measurements collected from 12 sites that span a wide range of site conditions. Significant site-specific correlations are observed between tetrachloroethene (PCE) and trichloroethene (TCE) concentrations measured for tree tissue and those measured in groundwater for three sites. A moderately significant correlation (r2=0.56) exists for the entire aggregate data set. Parsing the data by groundwater depth produced a highly significant correlation (r2=0.88) for sites with shallow (<4m) groundwater. Such a significant correlation for data collected by different investigators from multiple sites with a wide range of tree species and subsurface conditions indicates that groundwater concentration is the predominant factor mediating tree-tissue concentrations for these sites. This may be a result of trees likely directly tapping groundwater for these shallow groundwater conditions. This master correlation may provide reasonable order-of-magnitude estimates of VOC concentrations in groundwater for such sites, thereby allowing the use of phytoscreening in a more quantitative mode.

Site characterisation for the Ballina field testing facility

A soft soil field testing facility has been recently established near Ballina, New South Wales, on the east coast of Australia, which is aimed at improving design and construction methods for transport infrastructure. Several sampling, laboratory and in situ testing campaigns have been performed to characterise the material properties of the soil. High-quality laboratory testing has been performed at one location through the soil profile and a range of geophysics, cone penetrometer, seismic dilatometer, shear vane and permeability tests have been carried out at other locations. The in situ tests have demonstrated that the stratigraphy and test data are reasonably uniform across the site. Seasonal groundwater variations cause the in situ stress state to vary with time. In situ test data have been compared with laboratory tests in order to estimate soil material properties at the locations of the in situ tests. The accuracy of published correlations was variable and site-specific correlations were found to provide a better outcome. The coefficient of consolidation and the water permeability obtained from small-scale laboratory tests shows good agreement with in situ estimations based on piezocone penetration test (CPTu) dissipation tests and BAT tests, respectively. The correlation between laboratory and in situ data is used to develop a robust geotechnical model for the Ballina site.

Stormwater Pollutant Process Analysis with Long-Term Online Monitoring Data at Micro-Scale Sites

Stormwater runoff quality was measured with online turbidity sensors at four common types of small urban subcatchments: (i) a flat roof; (ii) a parking lot; (iii) a residential catchment; and (iv) a high-traffic street. Samples were taken to estimate site-specific correlations between total suspended solids (TSS) and turbidity. Continuous TSS time series were derived from online turbidity measurements and were used to estimate event loads and event mean concentrations. Rainfall runoff event characteristics were subjected to correlation analysis to TSS loads. Significant correlations were found for rainfall intensities at sites with high imperviousness and decrease with increasing catchment size. Antecedent dry weather periods are only correlated at the parking lot site. Intra-event TSS load distributions were studied with M (V)-curves. M (V)-curves are grouped at runoff quantiles and statistically described with boxplots. All sites show, in general, a more pronounced first-flush effect. While wash-off of the flat roof tends to be source-limited, the parking lot and high-traffic street sites show a more transport-limited behavior. Wash-off process of the residential catchment appears to be influenced by a composition of different subcatchments.

Quantitative Assessment of Shear Wave Velocity Correlations in the Shallow Bedrock Sites

In this study shear wave velocity (V s ) and standard penetration test (SPT) N values up to the bedrock have been measured by multichannel analysis of surface wave and drilling of boreholes at 51 locations in shallow bedrock sites of South India, as part of the intraplate seismic region of India. Testing covers the major cities as Bangalore, Chennai, Coimbatore, and Vizag in South India. Drilling of boreholes in the above locations shows that the top surface consists of soft to very dense soil followed by very hard Granitic rock. N values are measured up to 100 and values beyond 100 were reported as rebound. Soil thickness of these locations varies from 1 m to about 20 m. The measured N and V s values are used to generate correlations between N and V s values for each city and also for the combined data by excluding and including SPT N of 100 for rebound layer. Further the applicability of the V s and N correlations developed for a particular site to other sites in the same region has been studied and it has been found that the site specific correlations are more accurate. The correlations developed for other cities display high percentages of error, even though the sites are similar in geology and soil type. Additionally, the developed empirical correlations have been compared with the existing worldwide correlations using logarithmic Euclidian distance (logED). The logED value has been estimated between the measured and calculated lower logED respectively for different cities and arrived the best suitable predictive equations for the four cities. Lower logED value between the measured and calculated V s corresponds to better empirical relationship.

Drilled Shaft Design and Load Testing in Florida Intermediate Geomaterial and Weak Limestone

This case study summarizes the design, construction, load testing, and integrity testing of nonredundant drilled shafts for a bridge project in northwest Florida. The subsurface profile consisted mainly of calcareous sandy and silty clay (marl and marlstone) interfingered with limestone and cemented sand layers. The results of unconfined compression tests revealed significant variability in strength, with strata within the depth of interest holding strength properties that fall within the generally accepted range of cohesive intermediate geomaterial. This paper discusses local geology, geotechnical investigation, design, construction, load testing, and site-specific correlations. Important aspects of the project, including the use of the shaft inspection device to examine the cleanliness of the bottom of the shafts, Osterberg cell load testing, and the site-specific correlations developed from the results, as well as integrity testing with cross-hole sonic logging and a thermal integrity profiler, are presented. The inability of the standard penetration test (SPT) to delineate boundaries adequately between strong and (relatively) weaker layers is presented, as well as nonlinear site-specific relationships between anticipated skin friction resistance and SPT blow count. The nonlinear SPT-based relationships attempt to address the strain incompatibility between strong and weak seams that may exist within a given stratum. Proposed correlations for skin friction and end bearing that are based on laboratory strength testing are presented in terms of revised unconfined compressive strength to address variability in strength characteristics across the site.