Estimating the spatial distribution of hydromechanical properties in the investigated subsoil by defining an Engineering Geological Model (EGM) is crucial in urban planning, geotechnical designing and mining activities. The EGM is always affected by (i) the spatial variability of the measured properties of soils and rocks, (ii) the uncertainties related to measurement and spatial estimation, as well as (iii) the propagated uncertainty related to the analytical formulation of the transformation equation. The latter is highly impactful on the overall uncertainty when design/target variables cannot be measured directly (e.g., in the case of piezocone Cone Penetration Test-CPTu measurements). This paper focuses on assessing the Propagated Uncertainty (PU) when defining 3D EGMs of three CPTu-derived design/target variables: the undrained shear resistance (su), the friction angle ((p'), and the hydraulic conductivity (k). We applied the Sequential Gaussian Co-Simulation method (SGCS) to the measured profiles of tip (qc) and shaft resistance (fs), and the pore pressure (u2), measured through CPTus in a portion of Bologna district (Italy). First, we calculated 1000 realizations of the measured variables using SGCS; then, we used the available transformation equations to obtain the same number of realizations of su, (p', and k. The results showed that PU is larger when the transformation equation used to obtain the design/target variable is very complex and dependent on more than one input variable, such as in the case of k. Instead, linear (i.e., for su) or logarithmic (i.e., for (p') transformation functions do not contribute to the overall uncertainty of results considerably.

Agricultural soils are often affected by compaction due to machinery loads, which alters pore-size distribution and thus hydraulic properties. Up to date most studies on traffic and its impact on soil functions lack a detailed analysis of the effect on pore-size distribution (PSD). Our study aimed to understand how different machinery types, load levels, and moisture conditions impact the water retention curve (WRC) and PSD at various soil depths and field areas (headland or inner field). Eight field campaigns were conducted between 2016 and 2019 on a variety of sub-fields within one agricultural farm site with a clayey-silty soil. Undisturbed soil samples were collected before and after the harvest of winter wheat, silage maize, and sugar beet, and before and after digestate application. The van Genuchten model was fitted to the laboratory data, and parameters were interpreted to deduce WRC features. Additionally, the pore water pressure head at the pore-size density maximum (PSDmax) was determined and interpreted. The parameter alpha responded to all types of field traffic and decreased with increased load, indicating a shift from coarser to finer pores. The parameter n generally increased due to field traffic, suggesting a narrowed pore-size distribution. The theta s parameter, associated with porosity, decreased in all trials, with the tendency of lowest values occurring after wheeling under moist conditions. Load-induced shifts in the PSDmax towards finer pores were obvious down to 50 cm depth, even with relatively low loads. Our findings indicate that the majority of vehicles utilized in conventional agricultural operations can lead to severe soil compaction.

Strongly alkaline dispersive soils pose a significant global challenge to both engineering applications and agricultural production, particularly in arid and semi-arid regions. Conventional soil modifiers used to address this issue not only present environmental and economic concerns but also fail to effectively improve soil alkalinity. This study investigates the potential application of acidic desulfurization gypsum (DG) as a soil modifier for dispersive soils, aiming to achieve high-value utilization of industrial solid waste. The dispersibility of soil under hydrostatic and dynamic conditions are studied using the mud ball test and pinhole test. The engineering properties and modification mechanism of DG consolidated soils were revealed by combining the unconfined compressive strength (UCS), Brazilian split tensile strength (BTS), microstructure, and mineral evolution. Results show that 3% DG significantly reduces soil dispersibility and improves disintegration and erosion resistance, with UCS and BTS increases of 210% and 94%, respectively. The mechanism involves DG releasing hydrogen ions to reduce soil alkalinity, which in turn activates cation activity of DG, replacing sodium ions on the soil surface and forming a binding hydrate within 7 days. Tests on natural dispersive soil from check dams confirmed effectiveness of DG. Advanced machine learning techniques quantitatively analyzed the impact of DG on soil dispersibility, highlighting the relationship between soil dispersibility and chemical/mechanical properties. This study establishes a novel link between hydraulic erosion parameters, mechanical parameters, and soil stressstrain relationships, providing valuable insights for future soil stabilization. The results show potential of waste acidic DG in practical engineering applications and contribute to the sustainable advancement of dispersive soil stabilization technology. Alkaline dispersive soils also aid in regulating the acidity and alkalinity of DG and controlling toxic emissions.

This article proposes an analytical layer element methodology for transversely isotropic (TI) laminated water-saturated subsoils to a harmonically moving load over the media surface. Biot's elastodynamic equation is decoupled by the double Fourier transform combined with the Heaviside step function of the load source. Exact 3D dynamical stiffness matrices of the soil layer element and the TI saturated half-space are established based on the derived displacement and stress components in the transform domain. Assembling the stiffness matrices of the discrete layer elements and underlying half-space yields the total 3D dynamical stiffness matrices. Considering the element boundary conditions, the analytical layer-element solutions in the wavenumber domain are obtained. The space domain result is retrieved by the inverse Fourier transformation. The results have a good consistency with the current solutions. The effects of the soft soil layer thickness, the material anisotropy, stratification characteristics, the load frequency, and the load moving velocity are analyzed.

A major full-scale experiment called the Tunnelling and Limitation of Impacts on Piles (TULIP) project was conducted in 2020 on Line 16 of the Grand Paris Express project to analyze the tunnel boring machine-soil-pile interactions during tunnel excavation near deep structures. This paper presents the greenfield ground response observed when the tunnel boring machine (TBM) crossed the TULIP site: surface displacements, subsurface displacements, and pore water pressures are presented. The originality of the paper lies in the fact that details are provided not only on the site geological and geotechnical characteristics, but also on the TBM operation: a detailed analysis of the variations in pressure inside the cutting chamber of the earth-pressure balanced machine (EPBM) is proposed. This paper reports factual data without bias induced by a preconceived numerical model, but highlights open questions that challenge the advanced numerical models, that will be required to analyze completely the tunnel-soil-pile interactions.

Phosphate fertilizers are applied to the soil surface, especially in vineyards in production in subtropical regions. Nowadays, phosphorus (P) is not incorporated into the soil to avoid mechanical damage to the root system in orchards. However, over the years, successive surface P applications can increase the P content only in the topsoil, maintaining low P levels in the subsurface, which can reduce its use by grapevines. For this reason, there is a need to propose strategies to increase the P content in the soil profile of established orchards. The study aimed to evaluate the effect of management strategies to (i) increase the P content in the soil profile; (ii) enhance the grape production; and (iii) maintain the grape must composition. An experiment on the 'Pinot Noir' grape in full production was carried out over three crop seasons. The treatments were without P application (C), P on the soil surface without incorporation (SP), P incorporated at 20 cm (IP20), P incorporated at 40 cm (IP40), and twice the P dose incorporated at 40 cm (2IP40). The P concentration in leaves at flowering and veraison, P content in the soil, grape production and its components, and chemical parameters of the grape must (total soluble solids, total polyphenols, total titratable acidity, total anthocyanins, and pH) were evaluated. The P concentration in leaves did not differ among the P application modes. The application of P associated with soil mobilization, especially at 20 cm depth, increased grape production. The P application modes did not affect the values of the chemical parameters of the grape must except for the total anthocyanins, which had the highest values when the vines were subjected to 2IP40. Finally, the P application and incorporation into the soil profile was an efficient strategy for increasing the grape production in full production vineyards.

Tillage, as a key agricultural operation, has an important influence on soil properties and crop productivity. However, tillage at the same depth is not always the best choice as differences in soil texture, compacted topsoil, or plow pan at different depths, crop rotation, and root penetration potential signal that the depth of tillage should take greater account of the factors involved. Variable depth tillage (VDT) is an important precision farming operation, linking soil, plants, tillage machinery, smart sensors, measuring devices, computer programs, algorithms, and variability maps. This topic is important from an agronomic, energy, and environmental perspective. However, the application of VDTs in practice is currently still very limited. The aim of this study was to carry out a detailed review of scientific work on variable depth tillage, highlighting the importance of soil compaction and VDT; the measurement methods and equipment used; and the impact on soil, crops, the environment, and the economy. Based on the reviewed studies, there is a lack of studies that use fully automated depth control of tillage systems based on input data obtained with on-the-go (also known as online) proximal soil sensing. In precision agriculture, rapidly developing Internet of Things technologies allow the adaptation of various farming operations-including tillage depth-to site-specific and temporal conditions. In this context, the use of proximal soil sensing technologies coupled with electromagnetic induction, gamma rays, and multi-sensor data fusion to provide input for recommended tillage depth would be beneficial in the future. The application of VTD in specific areas is promising as it helps to reduce the negative effects of soil compaction and avoid unnecessary use of this expensive and environmentally damaging technological operation.

Freeze-thaw cycles and compactness are two critical factors that significantly affect the engineering properties and safety of building foundations, especially in seasonally frozen regions. This paper investigated the effects of freeze-thaw cycles on the shear strength of naturally strongly chlorine saline soil with the compactness of 85%, 90% and 95%. Three soil samples with different compactness were made. Size and mass changes were measured and recorded during freeze-thaw cycles. Shear strength under different vertical pressures was determined by direct shear tests, and the cohesion and friction angle were measured and discussed. Microstructure characteristic changes of saline soil samples were observed using scanning electron microscopy under different freeze-thaw cycles. Furthermore, numerical software was used to calculate the subsoil-bearing capacity and settlement of the electric tower foundation in the Qarhan Salt Lake region under different freeze-thaw cycles. Results show that the low-density soil shows thaw settlement deformation, but the high-density soil shows frost-heaving deformation with the increase in freeze-thaw cycles. The shear strength of the soil samples first increases and then decreases with the increase in freeze-thaw cycles. After 30 freeze-thaw cycles, the friction angle of soil samples is 28.3%, 29.2% and 29.6% lower than the soil samples without freeze-thaw cycle, the cohesion of soil samples is 71.4%, 60.1% and 54.4% lower than the samples without freeze-thaw cycle, and the cohesion and friction angle of soil samples with different compactness are close to each other. Microstructural changes indicate that the freeze-thaw cycle leads to the breakage of coarse particles and the aggregation of fine particles. Correspondingly, the structure type of soil changes from a granular stacked structure to a cemented-aggregated system. Besides, the quality loss of soil samples is at about 2% during the freeze-thaw cycles. Results suggest that there may be an optimal compactness between 90 and 95%, on the premise of meeting the design requirements and economic benefits. This study can provide theoretical guidance for foundation engineering constructions in seasonally frozen regions.

Determining the deformation trend of silt subsoil under long-term aircraft loading by conventional numerical methods based on finite elements is challenging and poses several limitations. In this study, a boundary surface model for remolded saturated silt considering the influence of the soil dry density was developed, and an explicit integral algorithm with error control was used to incorporate the model into a user-defined material subroutine that the finite element software (ABAQUS 6.14) could call. In this way, the consolidated undrained dynamic triaxial test of a soil unit was established for simulation and model validation, which corroborated that the model could describe the dynamic properties of the saturated silt. Then, a numerical model of the runway with layered compaction and different compaction degrees was also developed to numerically analyze the deformation of the subsoil under cyclic aircraft loading. The results showed that the subsoil deformation increased continuously with the increase of cycle number. However, the deformation rate decreased gradually, and the silt subsoil deformation remained stable after 50 loading cycles. After the same number of loading cycles, the cumulative plastic deformation of the subsoil model with the overall compaction degree of 94% was smaller than that of the model with layered compaction. It was also shown that different aircraft speeds have minimal effect on the cumulative plastic deformation of the subsoil. Nevertheless, the ultimate cumulative plastic deformation is larger, as the loading duration is longer at low aircraft speeds. It indicates that strictly controlling of the compaction degree within a certain range of load influence is imperative in practical engineering, as it reduces the associated costs.