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In this study, three typical limestones, including Tavel limestone, Indiana limestone, and Lixhe chalk, were selected from a large number of porous limestones. These limestones with different porosities have been largely studied in previous experimental investigations because of the complexity of mechanical behavior. According to previous experimental studies, porous limestones present two basic plastic mechanisms: plastic shear as a response at low confining pressures and plastic pore collapse at high confining pressures. In related to the plastic mechanisms, two types of plastic volumetric deformation are revealed: plastic compaction induced by pore collapse, and plastic dilatancy by plastic shearing. In this paper, a micromechanics-based plastic model is extended to describe the elastoplastic behavior of porous limestones. The plastic criterion of porous rock is explicitly dependent on the porosity in addition to being directly based on the relevant mechanical properties of solid matrix at the microscopic scale. An additional plastic hardening law for the solid matrix is proposed, in which two plastic deformation mechanisms are considered in hardening law of the solid matrix, including hardening effect caused by the local equivalent plastic deformation and weakening effect caused by the increase in porosity. Three typical porous limestones with different porosity are selected to validate the proposed model on both hydrostatic and triaxial compression tests. By comparing numerical predictions and experimental data, it is shown that the presented model can correctly describe the mechanical behavior of porous rocks. Highlights: Limestones with different porosities have been largely studied in previous experimental investigations because of the complexity of mechanical behavior. In related to the plastic mechanisms, two types of plastic volumetric deformation are revealed: plastic compaction induced by pore collapse, and plastic dilatancy by plastic shearing. A micromechanics-based plastic model is extended to describe the elastoplastic behavior of porous limestones. The plastic criterion of porous rock is explicitly dependent on the porosity in addition to being directly based on the relevant mechanical properties of solid matrix at the microscopic scale. [ABSTRACT FROM AUTHOR]

Climate change models consistently project future precipitation reduction and temperature increase during the crop growing season in the US Midwest, which may exacerbate surface water scarcity issues confronting regional agriculture. To maintain consistent crop yields under the risk of increased droughts, farmers may shift from rain-fed agriculture to irrigation agriculture, particularly during drought periods. There is an urgent need to understand whether surface water in the Midwest is suitable for irrigation. In this study, irrigation water quality was comprehensively analyzed for commonly used parameters regarding salt content including sodium adsorption ratio (SAR), adjusted sodium adsorption ratio (SAR adj ), soluble sodium percentage (SSP), electrical conductivity (EC), total dissolved solids (TDS), residual sodium bicarbonate (RSBC), magnesium adsorption ratio (MAR), permeability index (PI), Kelley's ratio (KR), synthetic harmful coefficient (SHC), and salinity. Results indicate that water in the White River at Muncie was rated mostly in excellent to good condition with regard to irrigation quality. However, the irrigation suitability level exhibited two distinct patterns between May-July and August-October. Specifically, an average of 7.8% of the samples from May to July were unsuitable for irrigation, and an average of 24.5% of samples from August to October were unsuitable for irrigation considering all parameters. Flow rate change over time and the release of pollutants from wastewater treatment plants and combine sewage outflows to the White River impacted on the irrigation water quality variations of the river. This study showed that there are higher risks during the fall season for farmers to use surface water as an irrigation source, and this risk might be greater if extended or more frequent drought events occur in the future. To our best knowledge, this is the first peer-reviewed study on irrigation water quality assessment in the Midwest and provides useful information for farmers and decision makers to consider while formulating applications for irrigation., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)