Search

Subsoiling practice is an essential tillage practice in modern agriculture. Tillage forces and energy consumption during subsoiling are extremely high, which reduces the economic benefits of subsoiling technology. In this paper, a cicada-inspired biomimetic subsoiling tool (CIST) was designed to reduce the draught force during subsoiling. A soil–tool interaction model was developed using EDEM and validated using lab soil bin tests with sandy loam soil. The validated model was used to optimize the CIST and evaluate its performance by comparing it with a conventional chisel subsoiling tool (CCST) at various working depths (250–350 mm) and speeds (0.5–2.5 ms−1). Results showed that both simulated draught force and soil disturbance behaviors agreed well with those from lab soil bin tests, as indicated by relative errors of <6.1%. Compared with the CCST, the draught forces of the CIST can be reduced by 17.7% at various working depths and speeds; the design of the CIST obviously outperforms some previous biomimetic designs with largest draught force reduction of 7.29–12.8%. Soil surface flatness after subsoiling using the CIST was smoother at various depths than using the CCST. Soil loosening efficiencies of the CIST can be raised by 17.37% at various working speeds. Results from this study implied that the developed cicada-inspired subsoiling tool outperforms the conventional chisel subsoiling tool on aspects of soil disturbance behaviors, draught forces, and soil loosening efficiencies. This study can have implications for designing high-performance subsoiling tools with reduced draught forces and energy requirements, especially for the subsoiling tools working under sandy loam soil. [ABSTRACT FROM AUTHOR]

This paper puts forward an interpretation of three decisive dreams that shook Descartes taking as a starting point what Heidegger called another beginning of philosophy in horror (das Erschrecken). On the one hand, it will be shown how Descartes's nightmares opened the possibility of an initial way of thinking. On the other hand, it will be discussed how Descartes recoils from this possibility. By linking the hidden dimension of being to the demonic realm, Descartes seeked refuge in a calculating thought based on a truthful God who guarantees the availability of being. The analysis of dreams proposed here seeks to draw attention to a background that will help explain what Descartes is seeking refuge from when he builds his scientific structure and what avenues remain open in the subsoil of his thought. [ABSTRACT FROM AUTHOR]

In this paper, the authors present an extension of the scope of the previously conducted research to the full three-dimensional computer simulation (using the finite element method), which takes into account the interaction between: heavy caterpillar tracks system - working platform - weak subsoil. The article presents a computer model considering two caterpillars, resting on elastic-plastic sub-soil, with standard Mohr-Coulomb yield conditions, allowing for computer simulation of the behavior of the system up to achievement of ultimate limit state. The results of the above model are treated as the reference for a simplified Analytical Models of estimating the limit state, which might be used in design procedures. In turn, these Analytical Models are enhancements of previously presented one. The most important results concluding form the Analytical Model are simple interaction formulas, in the space of moments acting on the machine-subsoil system, limiting a domain of safety in given soil conditions. [ABSTRACT FROM AUTHOR]

Significant subsoil deformation and additional loads from the new denitrification unit caused a major problem with the load-bearing capacity of the coal power plant. It was necessary to perform an advanced assessment of the technical condition of the structure. Laser scanning (LiDAR) were used to obtain detailed data upon structure. Based on the analysis of the point cloud, the location of the column axes was determined, which allowed to determine the global and local displacements of the structure. Spatial models of the structure were created. Non-linear analyses of the structure were carried out using two types of models: 1) global beam-shell 3D models of the boiler room used to calculate the magnitude of internal forces and deformations of the structure; 2) local beam-shell detailed models of selected structural elements. Based on the results of the calculations, necessary reinforcement of the structure was designed and successfully implemented. Advanced analysis of the structure using laser scanning, subsoil monitoring and complex numerical models made it possible to perform only local reinforcements of the entire complex structure. [ABSTRACT FROM AUTHOR]

Drilled displacement columns, constructed in the form of unreinforced or reinforced concrete elements, are currently a very commonly used method of improving soft subsoil, creating an alternative to more expensive pile foundations. A frequently used solution for improving soft soils of road or railway embankments is to design a regular pattern of columns of relatively small diameter. Columns along the perimeter of the improved area are reinforced with rigid steel profiles, while the internal ones are made as concrete elements. Column heads are usually covered with a load transfer platform (layer of compacted granular fill) which is additionally reinforced with geosynthetics. The application of soil improvement with displacement columns is not always successful. It is due to the errors and shortcomings occurring at the design stage, including simplifications in modelling, to construction faults, which may include insufficient experience of contractors and/or improper supervision. Referring to the real object that failed, the article provides the results of numerical parametric analyses taking into account the influence of the key design parameters such as: the stiffness of the load transfer layers, the amount and stiffness of the geosynthetic reinforcement as well as the column spacing. The article presents comparisons of numerical results obtained with the finite element analyses for various approaches to geometry modelling (axisymmetric, 2D and 3D). The simulations indicate that the use of the axisymmetric model of a single column in routine design may lead to the deformations exceeding the serviceability limit states. [ABSTRACT FROM AUTHOR]

Soils store large quantities of carbon in the subsoil (below 0.2 m depth) that is generally old and believed to be stabilized over centuries to millennia, which suggests that subsoil carbon sequestration (CS) can be used as a strategy for climate change mitigation. In this article, we review the main biophysical processes that contribute to carbon storage in subsoil and the main mathematical models used to represent these processes. Our guiding objective is to review whether a process understanding of soil carbon movement in the vertical profile can help us to assess carbon storage and persistence at timescales relevant for climate change mitigation. Bioturbation, liquid phase transport, belowground carbon inputs, mineral association, and microbial activity are the main processes contributing to the formation of soil carbon profiles, and these processes are represented in models using the diffusion–advection–reaction paradigm. Based on simulation examples and measurements from carbon and radiocarbon profiles across biomes, we found that advective and diffusive transport may only play a secondary role in the formation of soil carbon profiles. The difference between vertical root inputs and decomposition seems to play a primary role in determining the shape of carbon change with depth. Using the transit time of carbon to assess the timescales of carbon storage of new inputs, we show that only small quantities of new carbon inputs travel through the profile and can be stabilized for time horizons longer than 50 years, implying that activities that promote CS in the subsoil must take into consideration the very small quantities that can be stabilized in the long term. [ABSTRACT FROM AUTHOR]

Given the importance of soil for the global carbon cycle, it is essential to understand not only how much carbon soil stores but also how long this carbon persists. Previous studies have shown that the amount and age of soil carbon are strongly affected by the interaction of climate, vegetation, and mineralogy. However, these findings are primarily based on studies from temperate regions and from fine‐scale studies, leaving large knowledge gaps for soils from understudied regions such as sub‐Saharan Africa. In addition, there is a lack of data to validate modeled soil C dynamics at broad scales. Here, we present insights into organic carbon cycling, based on a new broad‐scale radiocarbon and mineral dataset for sub‐Saharan Africa. We found that in moderately weathered soils in seasonal climate zones with poorly crystalline and reactive clay minerals, organic carbon persists longer on average (topsoil: 201 ± 130 years; subsoil: 645 ± 385 years) than in highly weathered soils in humid regions (topsoil: 140 ± 46 years; subsoil: 454 ± 247 years) with less reactive minerals. Soils in arid climate zones (topsoil: 396 ± 339 years; subsoil: 963 ± 669 years) store organic carbon for periods more similar to those in seasonal climate zones, likely reflecting climatic constraints on weathering, carbon inputs and microbial decomposition. These insights into the timescales of organic carbon persistence in soils of sub‐Saharan Africa suggest that a process‐oriented grouping of soils based on pedo‐climatic conditions may be useful to improve predictions of soil responses to climate change at broader scales. [ABSTRACT FROM AUTHOR]

This article presents an analytical method which takes into account the beneficial effects of the sheet piling located around the foundation in the calculations of ULS and SLS of shallow foundations. The analytical method proposed by the author was described in detail on the example of a “theoretical bridge” with the assumed geometry and loads as well as with the assumed subsoil and water conditions under the bridge. The stresses in the subsoil under the foundation and the settlement were determined. The author’s method was also used to calculate the foundation settlement of an “existing bridge” located in Gdańsk (Poland). In both cases, the results were compared with the results obtained using PLAXIS 3D Advanced 2023.1 and additionally with geodetic measurements for “existing bridge”. The author’s proposal was based on the EN 1997-1: Eurocode 7 standard applicable in the European Union. It has original elements that are not included in the cited standard. The proposed method is not the only one that could be used to assess the limit states of shallow foundations with sheet piling cover. However, it is based on the applicable regulations, gives similar results to the results obtained with FEM and geodetic measurements. [ABSTRACT FROM AUTHOR]

This study explored the impact of organic soil stabilizing agent on the engineering behaviors of subsoil commonly used for engineering applications in Nigeria. The soil obtained from a borrow pit and air-dried under laboratory conditions (30±5° C and 81±7% relative humidity). The dried soil sample was stabilized with rice husk ash (RHA) at the rate of 2, 4, 6, 8 and 10% (by mass of the soil) and cured for 14 days under natural conditions. A J-band microwave at a frequency of 7.0 GHz was used to measure the dielectric properties, while the standard proctor compaction test was used to determine the maximum dry density “MDD” and optimal moisture content “OMC” of the soil samples. Results obtained from the study depicted that the RHA had a significant effect on both the electrical properties of the soil. It was noted from the findings that, as the quantity of RHA used in stabilizing the soil increased from 0 to 10%, MDD values declined non-linearly from 1.61-1.42 g/cm³, while the OMC values inclined in a non-linear pattern from 14.8 - 17.1%. Similarly, the study results indicated that the soil dielectric constant and loss increased from 3.41 to 5.13 and 0.91 to 1.44 respectively, as the RHA incorporated into the soil raised by 10%. Present findings offer valuable insights into the fields of civil and electrical engineering, especially in the context of soil treatment for engineering applications. [ABSTRACT FROM AUTHOR]

The application of straw and nutrients to agricultural subsoils is of significant interest to enhance carbon (C) sequestration and soil fertility. However, little research has explored the effect straw application on microbial stoichiometry, soil organic carbon (SOC) mineralization and accumulation and their relationships, in subsoil. In order to address these knowledge gaps, we examined the soil characteristics (organic carbon mineralization, available nutrient contents and microbial stoichiometric ratio) under straw addition (maize leaf and stem) with and without nitrogen (N) supplementation (no addition, 30 mg N kg-1 dry soil-1, 60 mg N kg-1 dry soil-1) during an 80-day incubation experiment. The microbial stoichiometric ratio imbalance (C:N and C:Phosphorus (P)) and extracellular enzyme stoichiometry were measured as indicators of the systematic relationship between soil resource availability and the mineralization of organic carbon. Our study demonstrated that the addition of straw significantly enhanced CO2 emissions and led to an increase in the C:N imbalance, while simultaneously decreasing microbial carbon use efficiency (CUE). In addition, stem addition showed 5.6% lower CUE, but 8.2% higher SOC compared with leaf addition. We also found that nitrogen addition to subsoil alleviated microbial nitrogen limitation. 60 mg N kg-1 dry soil rates of nitrogen application had a positive effect on reducing C:N imbalance and promoting the accumulation of SOC. Extracellular enzyme activity and microbial stoichiometric ratio were the most important controlling factors of SOC mineralization and microbial CUE, respectively. In conclusion, the application of straw alongside N to balance stoichiometric ratios can significantly increase SOC content, indicating the potential for carbon sequestration in agricultural subsoils. [ABSTRACT FROM AUTHOR]

Rice cultivation has been found to be an effective and feasible approach for improving saline soils and increasing food production. Most studies on the improvement of rice cultivation on saline soil have focused on the several individual soil properties in the topsoil, and we know little about the importance of rice cultivation for improving multifunctionality in coastal saline soils. We investigated basic soil properties (soil physical sand content, soil physical clay content, pH, EC, soil organic carbon, total nitrogen, alkaline hydrolysis nitrogen, available potassium, available phosphorus), enzyme activities (urease, catalase, protease) and soil multifunctionality (SMF) in 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm soil layers with rice cultivated for 0 (tidal flat; CK), 20 (R20), 44 (R44) and 70 years (R70). We found that soil EC was alleviated markedly in the first 20 years after rice cultivation. Soil physical sand content, pH, EC and available potassium (AK) decreased while total nitrogen (TN), alkaline hydrolysis nitrogen (AN), urease (URE), catalase (CAT) activities and SMF increased with the increase in rice cultivation years. The highest soil total organic carbon (SOC) was shown in R44. Soil pH, EC, AK and physical sand content increased while SOC, TN, AN, enzyme activities decreased with the increase in soil depth. Redundancy (RDA) analysis showed soil physicochemical properties explained 97.53% of the variation in soil enzyme activities. Soil CAT, URE and protease (PRO) had a positive correlation with soil physical clay content, SOC, TN, AN and AP while negatively correlated with pH and AK. The increased SOC and clay content by rice cultivation might be the main reasons stimulating soil enzyme activities. In summary, long-term rice cultivation could alleviate soil salinity, increased SMF down to 1 m, implying that rice cultivation effectively improved coastal saline soil, and the improvement could last for 70 years. [ABSTRACT FROM AUTHOR]

Copyright of Escritos is the property of Escritos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article discusses the issue of reinforced concrete industrial floors being affected by subsoil swelling, which can lead to cracks and shifting. The main cause of this problem is the presence of swelling soil in the subsoil. The article provides regression relationships for predicting swelling pressure and deformation of these floors based on indirect measurements. It also offers a risk classification system for assessing the likelihood of surface damage due to subsoil swelling. The text emphasizes the importance of considering swelling during the design and construction of these floors. Additionally, the document explores methods for predicting soil swelling potential and presents prediction relationships for quantifying swelling pressures and deformations of reinforced concrete floors. Finally, it introduces a risk classification system for wire reinforced concrete surfaces based on variables influencing swelling. The text highlights the issue of industrial floors being susceptible to failure due to swelling soils and provides valuable information for predicting and assessing the risk of damage. [Extracted from the article]

The topic of the article is the design of reinforcement layers for the railway track bed on the basis of theory and practice. It focuses on presenting issues related to technical requirements for the track bed, requirements for track reinforcing layers, making strength calculations for the track structure, designing the thickness of the reinforcing layer and deciding on the right system. The article concludes with information on an innovative ground reinforcement material: the TriAxial geo-grids. [ABSTRACT FROM AUTHOR]

Long-term excessive application of mineral fertilizer leads to phosphorus (P) accumulation, increasing the risk of P migration and loss from the soil profile. The colloids in the soil profile are important carriers for P migration due to their high P adsorption and transport capacity. It is not clearly understood how colloidal P (CP) is distributed in subsoils (<1.2 m) of a Vertisol, contributing to subsurface P loss. Understanding the depth sequence distribution and speciation of colloidal P in the soil profile is critical for a comprehensive assessment of P loss. In this study, water-extractable colloids (WECs) with the size of 0.35–2 µ m were obtained from a 0–120 cm soil profile by a sedimentation and centrifugation scheme. The dissolved reactive P (DRP) and dissolved total P (DTP) in soil supernatant with particle sizes <0.35 µ m were measured by molybdate blue colorimetry. Solution 31 P nuclear magnetic resonance (NMR) and P K-edge XANES (X-ray absorption near-edge structure) were used to characterize the species and distribution of CP in the soil profile of fertilized farmland. Total and available P in bulk soil and colloids decreased with soil depth. The organic P (OP) contained 97–344 mg kg -1 per bulk soil and 110–630 mg kg -1 per WEC. The OP in soil profile consists of orthophosphate mono-esters and diesters primarily according to NMR results. It suggested that OP in WECs from subsoils might be affected by the translocation of CP from surface soils, probably due to soil acidification and preferential flow caused by swelling–shrinkage clays, including montmorillonite and nontronite detected by X-ray powder diffractometer (XRD) results. Additionally, the more negative zeta potential of surface soil colloids suggests the high mobility of colloidal P towards the subsoils. The CP concentration for <2 µ m was about 38–93 mg P kg -1 per bulk soil, which is 6–37 times that of DRP, suggesting that CP plays a dominant role in P transport within the soil profile. The relatively small fraction of orthophosphate diesters suggests limited P assimilation by microorganisms for the accumulation of WECs containing organically bound P in subsoils. The P K-edge XANES results indicated that the proportions of Al-P, Fe-P, and inositol hexakisphosphate (IHP) of WECs decreased, but hydroxyapatite (HAP) increased with soil depth. This study showed that inorganic and organic P migrated from the surface to deeper layers along the soil profile, with soil colloids having a significant effect on P migration from both surface and subsurface layers. The findings have an important significance for soil P migration evaluation and agricultural non-point source pollution control in Vertisols. [ABSTRACT FROM AUTHOR]

Predicting the quantity of soil organic carbon (SOC) requires understanding how different factors control the amount of SOC. Land use has a major influence on the function of the soil as a carbon sink, as shown by substantial organic carbon (OC) losses from the soil upon deforestation. However, predicting the degree to which land use change affects the OC content in soils and the depth down to which this occurs requires context-specific information related to, for example, climate, geochemistry, and land use history. In this study, 266 samples from forests and agricultural fields were collected from 94 soil profiles down to 300 cm depth in a subtropical region (Arvorezinha, southern Brazil) to study the impact of land use on the amount of stabilized OC along the soil profile. We found that the stabilized OC content was not affected by land use below a depth of 90 cm. Along the soil profile, the amount of stabilized OC was predominantly controlled by land use and depth in addition to the silt and clay content and aluminium ion concentrations. Below 100 cm , none of the soil profiles reached a concentration of stabilized OC above 50 % of the stabilized OC saturation point (i.e. the maximum OC concentration that can physically be stabilized in these soils). Based on these results, we argue that it is unlikely that deeper soil layers can serve as an OC sink over a timescale relevant to global climate change due to the limited OC input in these deeper layers. Furthermore, we found that the soil weathering degree was not a relevant control on the amount of stabilized OC in our profiles because of the high weathering degree of the studied soils. It is therefore suggested that, while the soil weathering degree might be an effective controlling factor of OC stabilization over a large spatial scale, it is not an informative measure for this process at regional and local scales (with similar climate, bedrock, and weathering history) in highly weathered soils. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Royal Asiatic Society Hong Kong is the property of Royal Asiatic Society Hong Kong and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on PLAXIS 3D finite element software, a 34-floor multi-story building piling group foundation under vertical loads and large moments is examined. It comprises seven different strata with different properties, with groundwater located 19.6 m below ground level. In drained situations, the soil is modeled as hardening soil, while piles are modeled as embedded beams. The study involved extensive parametric analysis. It includes pile spacing-diameter ratios, number of piles, pile slenderness ratios, square or triangular pile layout patterns with equal or variable pile length, raft, pile, and subsoil load sharing, pile modeling as an embedded or volume pile, gap effects between rafts and subsoils, and type of pile connections to evaluate their effects on rectangular unpiled and pile raft foundations in planning under large moments and vertical loads. Analysis results show volume piles yield less raft settlement and pile moment than embedded piles. Further, moment load effects increased raft bending moments by 2.2, 5.4, and 6.1 and absorbed loads by 1.4, 1.7, and 2.2 ratios for 24, 40, and 60 pile groups, respectively. In square and triangle pile configurations, at specified pile spacing, raft bending moments decrease with pile length. In contrast, it increases as pile spacing decreases. Thus, s/dpile = 4 gives the highest bending moment, with its variation along pile lengths depending on the pile head's hinge or fixation. A 0.2-m gap between raft and subsoil allows piles to absorb 71% of the load and rafts 29%, compared to 65% for piles, 29% for rafts, and 6% for subsoil without a gap. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate how changes in substrate availability (stimulating root exudate input) affect the temperature response (Q10) of soil organic carbon (SOC) mineralization across different soil profiles to increase our ability to predict the response of soil organic matter dynamics to climate change. Materials and methods: We sampled the topsoil and subsoil of two typical mineral soil profiles and one buried soil profile. Soils were incubated at 10–25 °C at 0.75 °C intervals, SOC mineralization rates were continuously measured with and without glucose addition, and Q10 was calculated. Results and discussion: Our results showed that Q10 decreased with increasing depth in typical mineral soils, but decreased before increasing with depth in buried soil. As expected, substrate addition significantly increased Q10 across soil depths; however, the magnitude of this increase (ΔQ10) differed with soil depth and type. Unexpectedly, in typical mineral soils, ΔQ10 was higher in topsoil than in subsoils, and vice versa for buried soil. ΔQ10 was negatively correlated with initial soil substrate availability (CAI) and positively correlated with soil inorganic N. Conclusions: Overall, our results suggested that increased substrate availability under climate change scenarios (i.e., increased root exudates with elevated CO2 concentrations) could further strengthen the temperature response of SOC mineralization, especially in soils with high inorganic N content or regions with high N deposition rates. [ABSTRACT FROM AUTHOR]

Nsukka is a rapidly developing City with considerable number of commercial activities, such as increasing number of vehicles, automobile shops and vehicular movement. Emissions from these vehicles, wastes from automobile shops and petrochemical retail shops pose a serious environmental concern. The aim of this study is centred on the assessment of heavy metal pollution in dust and top soil along major roads within in Nsukka metropolis using multivariate statistical analyses to unravel the relationships between the analysed parameters, and how they predict each other. A total of 21 samples of soil and dust were collected along the major and minor roads in Nsukka town at zero metre (0 m) and 0.5 m depth for dust and soil, respectively. Three control samples were collected at 400 m distance from the road for comparative reasons. For the two depths, two trends of relationships were established from the correlation, cluster and factor analyses. The first trend could be attributed to geogenic contamination due to its direct relationship with iron which happens to be the dominant heavy metal associated with Nsukka Formation. The second trend of analysis could be attributed to anthropogenic impacts due the presence of automobile and petrochemical wastes indicator parameters. There was no significant spatial variation (@p > 0.05) in the values of parameters such as arsenic and manganese for 0 m depth while in 0.5 m depth, there was no significant spatial variation (@p > 0.05) in the values of parameters such as arsenic, manganese and nickel. [ABSTRACT FROM AUTHOR]

This study presents a novel methodology for determining the apparent thermal diffusivity of subsoil in situ, employing two heat transfer models within the subsurface: one method is based on heat conduction caused by air temperature oscillations, while the other considers heat transmission via both conduction and convection due to groundwater flow. Differential equations were solved, and non-linear regression analysis was employed. This method has direct applications in various engineering and environmental domains, such as underground transmission lines, oil and gas pipelines, radioactive waste management, and geothermal systems, especially in the context of implementing horizontal geothermal collectors (HGC). The apparent thermal diffusivity value of 1.514 × 10−6 m2 s−1, within a 95% confidence interval spanning 1.512 × 10−6 m2 s−1 and 1.516 × 10−6 m2 s−1, was obtained from the section between 1.67 and 3.86 m depth in a research borehole located in Asturias, Northern Spain, using twenty-one temperature sensors. The method allowed for the calculation of the subsoil's apparent thermal diffusivity up to a depth of 14.55 m. [ABSTRACT FROM AUTHOR]

The frequency and intensity of droughts worldwide are challenging the conservation of soil organic carbon (SOC) pool. Microbial necromass is a key component of SOC, but how it responds to drought at specific soil depths remains largely unknown. Here, we conducted a 3‐year field experiment in a forest plantation to investigate the impacts of drought intensities under three treatments (ambient control [CK], moderate drought [30% throughfall removal], and intensive drought [50% throughfall removal]) on soil microbial necromass pools (i.e., bacterial necromass carbon, fungal necromass carbon, and total microbial necromass carbon). We showed that the effects of drought on microbial necromass depended on microbial groups, soil depth, and drought intensity. While moderate drought increased total (+9.1% ± 3.3%) and fungal (+13.5% ± 4.9%) necromass carbon in the topsoil layer (0–15 cm), intensive drought reduced total (−31.6% ± 3.7%) and fungal (−43.6% ± 4.0%) necromass in the subsoil layer (15–30 cm). In contrast, both drought treatments significantly increased the BNC in the topsoil and subsoil. Our results suggested that the effects of drought on the microbial necromass of the subsoil were more pronounced than those of the topsoil. This study highlights the complex responses of microbial necromass to drought events depending on microbial community structure, drought intensity and soil depth with global implications when forecasting carbon cycling under climate change. [ABSTRACT FROM AUTHOR]

In railway construction practice, we are increasingly faced with the problem of having to pass our new lines through areas with unfavorable subsoil conditions or with the need to reinforce the substructure of our existing lines due to increasing traffic demands (speed, axle load). The low strength, high compressibility, and low permeability of unfavorable subsoil will result in stability problems and prolonged consolidation with extremely high settlements, respectively. One of the effective technologies to counter the geotechnical problems is the deep mixing. The technology requires the addition of a binder (cement, lime) to the local soils. These materials have a high installed CO2 emission, thus significantly increasing the ecological footprint of infrastructure development. Due to the increasing demands on reducing CO2 emissions, secondary raw materials, e.g., fly ash or slag, have been increasingly prioritized. The study reports the methodology for calculating the ecological footprint of deep-mixing as an embankment foundation. Based on a simple case, the effect of different cement content (5 and 8%), and the application of slag and fly ash as a secondary raw material is analyzed, and the ecological footprint is calculated separately. The results show that the ecological footprint of deep mixing can be drastically reduced; under the conditions of the study, the reduction compared to clean cement is 40% for slag stabilization and 50% for fly ash. [ABSTRACT FROM AUTHOR]

This document presents a study of thermal inertia in the subsoil adjacent to the Civil Engineering laboratory of the Technological Institute of Sonora (ITSON) in the south of Sonora, Mexico, in service of the development of a solution proposal of a ground-coupled air heat exchanger for the cooling months. The research was divided into three phases: first, the monitoring of temperature in 10 layers of the ground; second, the analysis of thermal ground properties; and last, the design and simulation of a ground-coupled air heat exchanger. The objectives were to determine the variation in the thermal inertia of the soil with depth and over time and to determine the optimum depth for a ground-coupled heat exchanger system. The second objective was to develop a design proposal for a ground-coupled heat exchanger for the university laboratory. We found that the optimum depth is 3.0 m in a soil with high-compressibility clay with 21% humidity and 0.152 W/mK of thermal conductivity. However, the proposed design identified the best depth for the cooling system as 3 m considering a ground-coupled heat exchanger for a volume of 222.2 m3, corresponding to the volume of the classrooms of the building. With this design, the approach was to reduce the temperature by at least 10 °C on the hottest day (41 °C) of the year studied. We concluded that with this kind of system, the climate of the building studied could reduce the thermal load of active AC systems and reduce the energy load by 59%. [ABSTRACT FROM AUTHOR]

In the paper, there are examples of complex geotechnical problems in both 2D and 3D that are modelled using PLAXIS software on the specialist workstation provided by the Czech Geotechnical Society to their members. [ABSTRACT FROM AUTHOR]

Using a demolition hammer among the power tools is one of the most challenging job tasks for the operators of these tools, which exposes users to high levels of hand-transmitted vibrations. The focus of this study was for finding the vibration levels transmitted to the handles, the frequency content transmitted by the tool, and the effect of using insert bits with different tip shapes and lengths using conventional demolition hammers under controlled operating conditions on typical concrete slabs in the field. Three demolition hammers (weighing between 14 and 27 kg) with two handles installed were subjected to simultaneous measurements based on ISO 5349 as the field measurement technique. The findings demonstrated that even while the vertical axis dominated, several samples also produced equivalent x -axis results. The impact energy of the tools employed and the transmitted vibration to the tool handles are not significantly correlated with each other. All mean values were higher in the slabs with a thickness of 15 than those with 10 cm. The mean values of the total results for the two forms of flat and point tip inserted bits were 16.85 and 15.86 m/s2, respectively, and in the samples with the same operating factors, this difference was more than 3 m/s2 (p <.03). The a wrms (frequency-weighted root mean square acceleration) produced at tools using 60 cm bits were more than those with a length of 40 cm, both for the average of the total results and the average of the results of each hammer. The difference between the average bit length groups over samples with the same factors reached 4.65 m/s2 (p =.02). Frequency analysis for the flat and point insert bits with 60 cm length in the concrete slabs with a thickness of 15 cm showed that the dominant frequencies detected at lower frequencies for point bits. This difference is almost two frequency parts of 1/3 octave band. [ABSTRACT FROM AUTHOR]

Reducing CO2 emissions from agricultural soils is a key component of the overall carbon reduction strategy. The closed chamber method was used to continuously monitor CO2 concentration in soil profiles of winter wheat-summer maize rotation fields in the North China Plain (NCP) during 2015–2017. Additionally, we evaluated the contribution of different tillage methods (Rotary tillage (RT), Subsoiling (SS), No- tillage (ZT), and conventional tillage (CT) in combination with Straw return (s) and straw removal (0)) to reducing soil CO2 emission. The results showed that the concentration of CO2 increased with the soil depth and peaked at the 150 cm layer. The trend of CO2 concentration in soil profiles under different tillage treatments was CTS > RTS > ZTS > SSS, and the average concentration in maize season was higher than that in wheat season. In addition, soil moisture and temperature in the 0–10 cm soil layer were significantly correlated with soil CO2 concentrations. Thus, our results highlight that the SSs plays a critical role in moderating soil CO2 emissions. This process merits further study to effectively regulate soil CO2 release and achieve carbon neutrality with less carbon emissions in farmland ecosystems. [ABSTRACT FROM AUTHOR]

Mud volcanoes are geological structures observed throughout the world that arise from the upwelling of deep fluids along discontinuities in the subsoil. The detection of mud fluid migration pathways can be challenging, even when using Electrical Resistivity Tomography (ERT) as detectability issues may arise from complex geological settings. This paper presents new results from 2D and 3D ERT synthetic modelling for the investigation of the shallow, internal structure of terrestrial mud volcanoes. This study revealed the internal structure of the 'Cenerone-Pineto' mud volcano (Central Italy) and provided further clues as to its internal structure. The main results of the study are: the presence of a mud chamber, which represents the last phase of mud accumulation before final emission, not located beneath the crater but laterally offset, as well as the presence of a narrow, shallow feeder channel; these findings represent evidence of a much more complex structure than one would expect. This means that the mud volcano is not supplied with mud fluids directly from below as would be the case with an uprising of deep fluid along a near-vertical open fracture and that the shallow mud fluid reservoir is not correlated to the distribution of any mud volcano observed on the surface. Findings from this study are consistent with the observed structural features already noted in ERT and seismic field data collected at the 'Cenerone-Pineto' mud volcano and may be helpful in explaining the mechanisms and processes involved in mud volcanism in similar geological settings. [ABSTRACT FROM AUTHOR]

Stress history acquired by any cohesive soil influences, to a large extent, three groups of fundamental properties indispensable in geotechnical design i.e. state of soil, shear strength, and stiffness characteristics. The basic stress history parameter (from which other parameters are derived) determined directly from laboratory tests is a preconsolidation stress σ′p. Since the first method proposed by Casagrande in 1936, value σ′p is determined in the oedometer test as a border between overconsolidated (OC) and normally consolidated (NC) zones. Approach based on division between predominantly elastic, (recoverable) strain, and plastic (irrecoverable) strain is a main principle of several methods of σ′p determination, which have been proposed over the past eighty-six years. Accumulated experiences have revealed that any laboratory procedure based on the oedometer test does not provide realistic value of preconsolidation stress, especially in heavy preconsolidated soils. The major reason for that results from the fact that the mechanism responsible for natural overconsolidation is more complicated than mechanical preloading. Therefore, there is a necessity to reevaluate effectiveness of standard methods and look for another solution of evaluation yield stress σ′Y in natural soils. This article presents the comparison between σ′Y determined for various soils with use of standard methods based on conventional oedometer test and yield stress determined on the basis of alternative procedures. The latter are represented by various approaches as e.g. based on SHANSEP procedure or initial shear modulus and others. The most promising among these alternative methods is a new concept based on dilatancy phenomenon that takes place during shearing of a dense soil. The parameter reflecting stress history is derived from pore pressure response and is based on characteristic values of Skempton's parameter A record. Consistency of data concerning stress history parameters profile obtained for deep subsoil on the basis of various methods is shown for comparison. [ABSTRACT FROM AUTHOR]

Building information modeling (BIM) in the planning and construction of infrastructure projects, such as roads, tunnels, and excavations, requires the generation of comprehensive 3D subsoil models that encompass relevant geological and geotechnical information. Presently, this process relies on the deterministic interpolation of discrete data points obtained from exploratory boreholes and soundings, resulting in a single deterministic prediction. Commonly employed interpolation methods for this purpose include radial basis function and kriging. This contribution introduces probabilistic methods for quantifying prediction uncertainty. The proposed modeling approach is illustrated using simple examples, demonstrating how to use sequential Gaussian and Indicator Simulation techniques to model sedimentary processes such as erosion and lenticular bedding. Subsequently, a site in Munich serves as a case study. The widely used industry foundation classes (IFC) schema allows the integration of the model into the BIM environment. A mapping procedure allows transferring voxel models to the IFC schema. This article discusses the significance of incorporating uncertainty quantification into subsoil modeling and shows its integration into the BIM framework. The proposed approach and its efficient integration with evolving BIM standards and methodologies provides valuable insights for the planning and construction of infrastructure projects. [ABSTRACT FROM AUTHOR]

A broad understanding of the subsoil characteristics is required to deal with uncertainty in the infrastructure planning phase or even in the diagnosis of infrastructure damage. In this work, electrical resistivity and seismic methods have been employed for lithological characterization and geomechanical parameters assessment. The study area is characterized by high variability in geotechnical characteristics due to complex lithology. For lithological discrimination, we have used a soft clustering method to combine the independently electrical‐ and seismic‐derived models. The outputs of this integration process are zonal models that help to decrease interpretation uncertainties. From single seismic profiles, both Vp and Vs information are extracted allowing geomechanical parameters to be estimated. All this information is critical for assessing the variance and inhomogeneity of the subsoil characteristics. The methodology shown in this work can be used in the infrastructure planning phase as well as to ascertain the causes of detected damage on built infrastructure. [ABSTRACT FROM AUTHOR]

Between September and December 2021, the first subaerial volcanic eruption in the Canary Islands in 50 years took place on the island of La Palma. Since November 2021, we have been conducting a long-period magnetotelluric (MT) monitoring experiment at a site located 2.4 km east of the volcanic cone. Having continuously recorded data since then, the obtained dataset shows significant changes in resistivity over the fourteen months following the eruption: more than ± 20% in apparent resistivity and ± 2 degrees in phase. These temporal variations in electrical resistivity, recorded continuously using long-period MT during both the syn- and post-eruptive stages, have not been reported to date, making this dataset unique. Four estimated impedances have been selected as representatives of the major temporal changes observed and inverted to generate new 3-D resistivity models. The results provide novel key information on the spatiotemporal evolution of the subsoil's electrical resistivity, enabling the characterization of a set of structures acting as preferred magmatic fluid pathways. Therefore, our study highlights the strong potential of MT as a volcanic monitoring tool and provides new insights about the evolution of the fluid pathways during the post-eruptive stage. These findings enhance our understanding of the magmatic system and may contribute to volcanic hazard mitigation in the future. [ABSTRACT FROM AUTHOR]

Determining soil and water conditions is essential for designing the optimal foundation and safely transferring loads, including the self-weight of structures, to the ground. Excessive or uneven settlement of the subsoil may ultimately lead to the formation of structural cracks in buildings or the loss of slope stability. In extreme cases, the damage results in structural failure. This paper presents the application of simple solutions from plasticity theory—an evaluation of the upper and lower bounds of the exact solution—to estimate the slope safety factor. It is demonstrated that simple kinematically admissible mechanisms for the non-associated flow rule provide solutions are close to those obtained from the traditional Fellenius method. [ABSTRACT FROM AUTHOR]

Plant‐ and microbially derived carbon (C) are the two major sources of soil organic matter (SOM), and their ratio impacts SOM composition, accumulation, stability, and turnover. The contributions of and the key factors defining the plant and microbial C in SOM along the soil profile are not well known. By leveraging nuclear magnetic resonance spectroscopy and biomarker analysis, we analyzed the plant and microbial C in three soil types using regional‐scale sampling and combined these results with a meta‐analysis. Topsoil (0–40 cm) was rich in carbohydrates and lignin (38%–50%), whereas subsoil (40–100 cm) contained more proteins and lipids (26%–60%). The proportion of plant C increases, while microbial C decreases with SOM content. The decrease rate of the ratio of the microbially derived C to plant‐derived C (CM:P) with SOM content was 23%–30% faster in the topsoil than in the subsoil in the regional study and meta‐analysis. The topsoil had high potential to stabilize plant‐derived C through intensive microbial transformations and microbial necromass formation. Plant C input and mean annual soil temperature were the main factors defining CM:P in topsoil, whereas the fungi‐to‐bacteria ratio and clay content were the main factors influencing subsoil CM:P. Combining a regional study and meta‐analysis, we highlighted the contribution of plant litter to microbial necromass to organic matter up to 1‐m soil depth and elucidated the main factors regulating their long‐term preservation. [ABSTRACT FROM AUTHOR]

Sandy soils can benefit greatly from the addition of biochar, but the benefits depend on the properties of both the soil and the biochar. This study investigated the role of biochar particle size in controlling pore size distribution, hydraulic conductivity and water retention after careful mixing with coarse sandy subsoil. Intact commercial pellets of straw biochar (SB; approx. 8 × 5 mm) and ground pellets separated into 6 size fractions (median diameter 15, 33, 44, 81, 135 and 205 μm) were investigated at two concentrations (1.50 and 3.00 wt%). The results were compared with effects obtained with another feedstock (wood; WB) and another soil. Light microscopy and water retention measurements showed that smaller biochar particles settled into large existing soil pores, creating smaller interstitial pores to a much greater extent than larger particles. Accordingly, small particles (≤44 μm) had large enhancing effects on water retention and hydraulic conductivity in the medium suction range (pF1.7‐pF3.0), which were not found to a similar extent after the addition of larger particles (>81 μm). It was not possible to systematically distinguish the effects obtained with the three smallest particle fractions (SB15, WB18 and SB33). All effects measured were greatest at the highest biochar concentration level. In one soil, amendment with 3.00 wt% of SB15 decreased the fractional volume of drainable pores with an equivalent diameter of ≥60 μm from 31.3 vol% in the control to 19.1 vol%, while increasing the volume of pores in the 0.2–60 μm range that could potentially retain plant‐available water from 8.7 vol% to 20.1 vol%. Hydraulic conductivity at pF1.7 was increased by a factor of 10 (from 2.3 to 22.5 cm/day) and at pF3.0 by a factor of 14 (from 0.1*10−3 to 1.4*10−3 cm/day). Similar effects were observed in the other soil but at slightly different levels. The PDI version of the bimodal van Genuchten model was successfully fitted to measured water retention and log‐transformed hydraulic conductivity data (RMSE values in the interval 0.0011–0.0029 and 0.024–0.215, respectively). Dynamic simulation under variable field conditions including the hydraulic properties of biochar‐amended soil layers could be a useful method to investigate the effects on crop water supply, water and fertilizer utilization and yields. [ABSTRACT FROM AUTHOR]

Deep‐ploughing far beyond the common depth of 30 cm was used more than 50 years ago in Northern Germany with the aim to break root‐restricting layers and thereby improve access to subsoil water and nutrient resources. We hypothesized that effects of this earlier intervention on soil properties and yields prevailed after 50 years. Hence, we sampled two sandy soils and one silty soil (Cambisols and a Luvisol) of which half of the field had been deep‐ploughed 50 years ago (soils then re‐classified as Treposols). The adjacent other half was not deep‐ploughed and thus served as the control. At all the three sites, both deep‐ploughed and control parts were then conventionally managed over the last 50 years. We assessed yields during the dry year 2019 and additionally in 2020, and rooting intensity at the year of sampling (2019), as well as changes in soil structure, carbon and nutrient stocks in that year. We found that deep‐ploughing improved yields in the dry spell of 2019 at the sandy sites, which was supported by a more general pattern of higher NDVI indices in deep‐ploughed parts for the period from 2016 to 2021 across varying weather conditions. Subsoil stocks of soil organic carbon and total plant‐available phosphorus were enhanced by 21%–199% in the different sites. Root biomass in the subsoil was reduced due to deep‐ploughing at the silty site and was increased or unaffected at the sandy sites. Overall, the effects of deep‐ploughing were site‐specific, with reduced bulk density in the buried topsoil stripes in the subsoil of the sandy sites, but with elevated subsoil density in the silty site. Hence, even 50 years after deep‐ploughing, changes in soil properties are still detectable, although effect size differed among sites. [ABSTRACT FROM AUTHOR]

Subsoiling is an essential practice in conservation tillage technology. The amount of disturbed soil at various depths resulting from subsoilers with different parameters has an important effect on soil properties (e.g., bulk density and water infiltration). The information regarding the effects of subsoiling on the characteristics of soil water infiltration is essential for the design of subsoiling tools. In this study, the effects of the wing mounting height (h) (75–155 mm) of the subsoiler on soil disturbance and soil water infiltration were modelled using HYDRUS-2D and validated using field experiments. Results showed that reducing h values resulted in larger soil disturbance area ratios, soil water infiltration rates (f(t)), distances of vertical wetting front movement (DVWs), accumulative infiltrations (AINs), and soil moisture contents at depths of 10–30 cm. The relationships among characteristics of soil water infiltration, h and time (t), were developed. The stable infiltration rates (fs) varied quadratically with h and the corresponding coefficient of determination (R2) was 0.9869. The Horton model is more suitable for describing the relationship between f(t) and t under the tested soil conditions, as compared with the Kostiakov and Philip models. According to the results of soil water content at different depths from the HYDRUS simulations and field experiments, the developed soil water infiltration model had a good accuracy, as indicated by RMSEs of <0.05, R2 values of >0.95, and mean relative errors of <12%. The Above results indicated that increasing the hardpan disturbance by optimizing wing parameters of the subsoiler could improve soil water infiltration characteristics. [ABSTRACT FROM AUTHOR]

Many underground metal drainage pipes start deteriorating by developing small perforation holes throughout their invert wall sections. Once the holes open up, drainage flow can enter into them and begin eroding the subsoil layer. This can lead to a partial loss of soil support under the pipe invert. In this technical note, the approach established by Spangler in his classic analysis of buried flexible metal pipes was employed to update the modified Iowa formula for buried pipes having a partial loss of soil support in the invert region due to perforation holes in the pipe wall. The new equations provide interesting insights into aspects of the pipe-soil interaction problem that is not often reported by other researchers. Furthermore, limited 2D simulations with a computer program CANDE-2007 appear to support the theoretical work carried out. [ABSTRACT FROM AUTHOR]

Copyright of Vadose Zone Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Predicting the quantity of soil organic carbon (SOC) requires understanding about how different factors control the amount of SOC. Land use has a major influence on the function of the soil as a carbon sink, as shown by substantial organic carbon (OC) losses from the soil upon deforestation. Yet, predicting the degree to which land use change affects the SOC content, and the depth down to which this occurs, requires context-specific information related to, for example, climate, geochemistry, and land use history. In this study, soil samples collected down to 300 cm depth from forests and agricultural fields in a subtropical region (Arvorhezina, southern Brazil) were used to study the impact of land use on the amount of stabilized OC along the soil profile. We found that the stabilized SOC content was not affected by land use below a depth of 90 cm. Along the soil profile, the amount of stabilized OC was predominantly controlled by land use and depth, in addition to the silt and clay content, and aluminum ion concentrations. Below 100 cm, none of the soil profiles reached a concentration of stabilized SOC above 50 % of stabilized SOC saturation point (i.e., the maximum OC concentration that can physically be stabilized in these soils). Based on these results, we argue that it is unlikely that deeper soil layers can serve as an OC sink over a time scale relevant to global climate change, due to limited OC input in these depth layers. Furthermore, we found that soil weathering degree was not a relevant control on the amount of stabilized SOC in the profiles we investigated, because of the high weathering degree of the studied soils. It is therefore suggested that while the soil weathering degree might be an effective controlling factor of OC stabilization over large spatial scale, it is not an informative measure for this process at the scale of the soil profile in highly weathered soils. [ABSTRACT FROM AUTHOR]

The wear of cutting tools in mechanised tunnelling is closely linked to the abrasiveness of the present subsoil. Therefore, most of the models used for wear prediction take an abrasiveness index into account. The most common index used for hard rock is the Cerchar Abrasiveness Index (CAI); whereas such a standard does not yet exist for soil. Both the literature research and the results of calculation examples presented in the article show that significantly more practical models are currently available for wear prediction in hard rock. One reason for this is that far more wear‐relevant influencing factors have to be quantified for soft ground. Another reason is that the scientific studies concerning this topic only started in the course of mechanised tunnelling. Since especially the calculations carried out for low‐abrasive rocks differ widely among the different models for tool life, further research is needed also for wear prediction in hard rock [ABSTRACT FROM AUTHOR]

Forest stand and environmental factors influence soil organic carbon (SOC) storage, but little is known about their relative impacts in different soil layers. Moreover, how environmental factors modulate the impact of stand factors, particularly species mixing, on SOC storage, is largely unexplored. In this study, conducted in 21 forest triplets (two monocultures of different species and their mixture on the same site) distributed in Europe, we tested the hypothesis that stand factors (functional identity and diversity) have stronger effects on topsoil (FF + 0–10 cm) C storage than environmental factors (climatic water availability, clay + silt content, oxalate-extractable Al–Alox) but that the opposite occurs in the subsoil (10–40 cm). We also tested the hypothesis that functional diversity improves SOC storage under high climatic water availability, clay + silt contents, and Alox. We characterized functional identity as the basal area proportion of broadleaved species (beech and/or oak), and functional diversity as the product of broadleaved and conifer (pine) proportions. The results show that functional identity was the main driver of topsoil C storage, while climatic water availability had the largest control on subsoil C storage. Functional diversity decreased topsoil C storage under increasing climatic water availability, but the opposite was observed in the subsoil. Functional diversity effects on topsoil C increased with increasing clay + silt content, while its effects on subsoil C were negative at increasing Alox content. This suggests that functional diversity effect on SOC storage changes along gradients in environmental factors and the direction of effects depends on soil depth. [ABSTRACT FROM AUTHOR]

Background: The intricate pathogenesis of metastatic neuroblastoma (MNB) and the lack of effective diagnosis model are two main reasons for higher mortality of MNB than that of non-metastatic neuroblastoma (non-MNB). Objective: The biofunctional variation of MNB was investigated to explore pathogenesis and diagnostic models were developed to improve the early diagnosis of MNB. Methods: The differentially expressed genes (DEGs) and the biofunctional variation of MNB were studied by analyzing the transcriptome of 39 MNB and 17 non-MNB tissue samples. In addition, a diagnostic model of MNB was developed based on logistic regression analysis using three DEGs. Results: A total of 1142 mRNAs showed significantly altered, of which 814 were upregulated and 328 were downregulated. GO analysis showed that the DEGs were mainly involved in tumor microenvironment (TME). KEGG analysis showed that the DEGs played biological roles mainly by participating in neuroactive ligand-receptor interaction. An early diagnosis model was constructed based on CGA, CXCL9 and UNC5D genes, with sensitivity of 93.3%, specificity of 80% and AUC of 0.907. Conclusions: The disorder of TME and the dysfunction of neuroactive ligand-receptor interaction are imperative pathogenesis for the occurrence and development of MNB, which can lay a foundation for further research of MNB. The non-invasive plasma model based on CGA, CXCL9 and UNC5D is expected to be used in NB metastasis diagnosis. [ABSTRACT FROM AUTHOR]

The paper aimed to study the effectiveness of corn cultivation under different irrigation methods on the experimental field of the Askanian State Agricultural Research Station, which is located in the semi-arid, steppe, arid climate zone of the Southern Steppe of Ukraine, in the Kakhovsky irrigated massif. The investigation pointed out the effectiveness and provided an economic assessment of the use of different irrigation methods in corn cultivation. Two methods of irrigation (sprinkling and subsoil drip irrigation) were studied, with the maintenance of the humidity of the soil layer 0-50 cm at the level of 80% LMC and corn hybrids of different maturity groups. Under subsoil drip irrigation, the irrigation rate was lower on average by 24% than when sprinkled, on the other hand, the yield was higher on average by 40.9%, which significantly affected the cost price of the obtained corn grain. Subsoil drip irrigation yielded a net profit of 62% higher than sprinkler irrigation. and the profitability accordingly increased by 78.8%. [ABSTRACT FROM AUTHOR]

The Garisenda Tower and the Asinelli Tower, also widely known as the Two Towers, are the best preserved and famous medieval towers in the city of Bologna (Northern Italy). Standing one close to the other, right in the heart of the city centre, the Two Towers are delicate remains of the old towered city, which counted more than 75 towers in the 12th century. The foundations of historic towers and the surrounding soil often hide major hazards for the long-term preservation of these heritage structures. The initial fundamental step to this aim is indeed a deep understanding of their original conception, foundations and subsoil. However, the idea that also such elements are an integral part of the overall structure, and thus subjected to the same conservation rules, is relatively new. The present paper outlines the investigation criteria applied to the soil-foundation systems of the Two Towers of Bologna and describes the authenticity of their characteristics, through the interpretation of new experimental data and the analysis of historical documents. A geotechnical perspective on this type of monuments turns out to be crucial in order to effectively understand the soil-structure interaction mechanisms, which govern their safety conditions over time. This study also aims to better understand the reasons why the Two Towers of Bologna, despite their numerous similarities, have reached completely different structural configurations. The methodology described to investigate this case study, which required the integration of several aspects, can be usefully applied to any historic tower. [ABSTRACT FROM AUTHOR]

Objective The dense plough layer is difficult for airs and water to move into and out the root zone, hindering root penetration as a result. Deep loosening techniques, including the innovative air pressure subsoiling method, offer a solution by effectively breaking up this compacted layer. In contrast to traditional mechanical subsoiling, air-pressure subsoiling involves injecting high-pressure gas into the bottom of the plough layer. This paper studies the influence of air pressure on permeability of the loosen plough layer. Method Laboratory experiments were conducted to investigate the effect of air pressure subsoiling. We analyzed the mechanism underlying this process and assessed the impact of operating factors, including air jet pressure, bulk density of the plough layer, subsoiling position, and air jet direction, on loosening the soil. Result Among the factors we studied, subsoiling position had the most pronounced effect on soil permeability, and bulk density of the plough layer had the least impact. These factors collectively influenced the porosity of the loosened plough layer. Under the test conditions, when the bulk soil density was 1.8 g/cm3 and the subsoiling depth was 0.35 m, an air jet direction of 75° combined with a jet pressure of 2.2 MPa yielded the most effective results. Similarly, with the bulk density was 1.8 g/cm3 and subsoiling depth was 0.25 m, using a jet pressure 2.2 MPa was highly effective. Conclusion Deep loosening the plough layer by air injecting can increase the permeability of the plough layer and enhance its water storage capacity. Under the test condition, 75° is an appropriate angle to inject the air; injecting the air at the depth of 0.35 m is the most suitable for plough layer loosening. [ABSTRACT FROM AUTHOR]

The construction history of a site is partially preserved underground and can be revealed through archaeological investigations, including excavations, integrated with earth observation (EO) methods and technologies that make it possible to overcome some operational limits regarding the areal dimensions and the investigation depths along with the invasiveness of the excavations themselves. An integrated approach based on EO and archaeological records has been applied to improve the knowledge of Machu Picchu. The attention has been focused on the first construction phase of Machu Picchu, and for this reason the investigations were directed to the imaging and characterization of the subsoil of the Plaza principal, considered the core of the whole archaeological area. Archaeological records and multiscale remote sensing (including satellite, UAS, and geophysical surveys) enabled the identification and characterization of the first construction phase of the site, including the preparation phases before building Machu Picchu. The interpretative hypothesis on the constructive history of Machu Picchu started from the identification and use of the quarry, followed by the planification and set of the drainage systems and by the next steps based on diverse reshaping phases of what would be the central plaza. [ABSTRACT FROM AUTHOR]