Drainage Conditions Research Articles

Multimodal Carbonates: Distribution of Oil Saturation in the Microporous Regions of Arab Formations

Perhaps as much as 50% of the oil-in-place in carbonate formations around the world is locked away in the easy to bypass microporosity. If some of this oil is unlocked by the improved recovery processes focused on tight carbonate formations, the world may gain a major source of lower-rate power over several decades. Here, we overview the Arab D formation in the largest oil field on earth, the Ghawar. We investigate the occurrence of microporosity of different origins and sizes using scanning electron microscopy (SEM) and pore casting techniques. Then, we present a robust calculation of the probability of invasion and oil saturation distribution in the nested micropores using mercury injection capillary pressure data available in the literature. We show that large portions of the micropores in Arab D formation would have been bypassed during primary drainage unless the invading crude oil ganglia were sufficiently long. We also show that, under prevailing conditions of primary drainage of the strongly water-wet Arab formations in the Ghawar, the microporosity there was invaded and the porosity-weighted initial oil saturations of 60–85% are expected. Considering the asphaltenic nature of crude oil in the Ghawar, we expect the invaded portions of the pores to turn mixed-wet, thus becoming inaccessible to waterflooding until further measures are taken to modify the system’s surface chemistry and/or create substantial local pore pressure gradients.

Influence of modifications (from AoB2015 to v0.5) in the Vegetation Optimality Model

Abstract. The Vegetation Optimality Model (VOM, Schymanski et al., 2009, 2015) is an optimality-based, coupled water–vegetation model that predicts vegetation properties and behaviour based on optimality theory rather than calibrating vegetation properties or prescribing them based on observations, as most conventional models do. Several updates to previous applications of the VOM have been made for the study in the accompanying paper of Nijzink et al. (2022), where we assess whether optimality theory can alleviate common shortcomings of conventional models, as identified in a previous model inter-comparison study along the North Australian Tropical Transect (NATT, Whitley et al., 2016). Therefore, we assess in this technical paper how the updates to the model and input data would have affected the original results of Schymanski et al. (2015), and we implemented these changes one at a time. The model updates included extended input data, the use of variable atmospheric CO2 levels, modified soil properties, implementation of free drainage conditions, and the addition of grass rooting depths to the optimized vegetation properties. A systematic assessment of these changes was carried out by adding each individual modification to the original version of the VOM at the flux tower site of Howard Springs, Australia. The analysis revealed that the implemented changes affected the simulation of mean annual evapotranspiration (ET) and gross primary productivity (GPP) by no more than 20 %, with the largest effects caused by the newly imposed free drainage conditions and modified soil texture. Free drainage conditions led to an underestimation of ET and GPP in comparison with the results of Schymanski et al. (2015), whereas more fine-grained soil textures increased the water storage in the soil and resulted in increased GPP. Although part of the effect of free drainage was compensated for by the updated soil texture, when combining all changes, the resulting effect on the simulated fluxes was still dominated by the effect of implementing free drainage conditions. Eventually, the relative error for the mean annual ET, in comparison with flux tower observations, changed from an 8.4 % overestimation to an 10.2 % underestimation, whereas the relative errors for the mean annual GPP remained similar, with an overestimation that slightly reduced from 17.8 % to 14.7 %. The sensitivity to free drainage conditions suggests that a realistic representation of groundwater dynamics is very important for predicting ET and GPP at a tropical open-forest savanna site as investigated here. The modest changes in model outputs highlighted the robustness of the optimization approach that is central to the VOM architecture.

MPM Modeling of Cone Penetrometer Testing for Multiple Thin-Layer Effects in Complex Soil Stratigraphy

Cone penetrometer testing (CPT) is a frequently used soil characterization technique for liquefaction assessment; however, this technique has shortcomings in accurately characterizing very thin soil layers having thicknesses less than two to three times the diameter of the cone. In this study, the material point method (MPM) is used to generate numerical “measured” (or “blurred”) CPT tip resistance (qm) in complex soil profiles. Results show that MPM is capable of accurately simulating qm in soil profiles with layers as thin as 20 mm, even when using basic constitutive models and simplified drainage conditions. It is further shown that MPM simulations are able to replicate the tendency of the CPT to smear the boundaries between very thin, interbedded soil layers in a way that obscures their true thickness and stiffness (typically referred to as thin-layer, transition-zone, or multiple thin-layer effects). While previous numerical studies of CPT have been performed in profiles composed of two or three layers, this study considers highly interlayered profiles with upwards of 27 soil layers. Difficulties of developing and implementing multiple thin-layer corrections are presented. It is shown that a numerical framework like MPM can generate a larger set of data for the development and validation of multiple thin-layer correction procedures with the aim of improving liquefaction severity predictions in complex soil profiles.

Molecular insight into the diffusion/flow potential properties initiated by methane adsorption in coal matrix: taking the factor of moisture contents into account.

Coal seam permeability is one of the key parameters affecting coalbed methane (CBM), and plays an important role in resource evaluation and regional selection. To fully explore the diffusion/flow potential properties initiated by methane adsorption beneath diverse moisture contents (1-5%) in coal molecules. The pore size distribution and methane adsorption capacities were discussed based on Monte Carlo (MC) and molecular dynamics (MD) methods. The potential properties of diffusion/flow induced by methane adsorption were investigated using the maximum absolute adsorption capacities as benchmark. The variation patterns of the pore structure were analyzed using SEM scanning experiment to verify the results of simulation analysis. It is found that the free pores facilitate methane molecular adsorption and increase adsorption spaces; the skeleton pores restrict the flow and transport of water molecules. Reduction values in surface free energies increase at different temperatures, and released heat diffusion coefficients and permeabilities for methane molecules drop as moisture contents increase. Interestingly, however, enhancements in temperatures increase the methane molecular diffusion coefficients. The lower the activation energies, the easier they are to diffuse. Sufficiently, the optimum conditions for gas drainage of coal seam are at temperature of 293K and moisture content of 5%, indicating greater contributions to gas pressure relief for coal seam. By comparing the results of molecular simulation and SEM scanning, trend of change is basically the same. Moreover, it is explored that hydraulic measure was the most significant to the CBM stimulation technology through field engineering application. This research is expected to provide guidance for facilitating the effectiveness of gas extraction for coal seam.

Effects of principal stress rotation on deformation behaviour of clay under partially drained and undrained conditions

Subgrade clay in regions with busy roads is more likely to exhibit partially drained than undrained cyclic behaviour considering the long duration of traffic loads. To study the deformation response of soft clay under the two drainage conditions, cyclic tests were conducted on a dynamic hollow cylinder apparatus with and without principal stress rotation. The concept of transitional cyclic stress ratio (CSR) was proposed. When the CSR is lower than the transitional CSR, the partially drained condition causes permanent axial strain enlargement when compared with the undrained conditions; Once the CSR exceeds the transitional CSR, the partially drained condition markedly restricts the development of the permanent axial strain. Moreover, both critical and allowable CSR in the partially drained tests are higher than in the undrained ones, and the allowable CSR under different drainage conditions is smaller than the transitional CSR. Therefore, the influence of the partially drained condition on the cyclic deformation of clay must be considered in practice. Two empirical models were proposed to predict the permanent volumetric strain and permanent axial strain under the partially drained condition.

Assessing surface drainage conditions at the street and neighborhood scale: A computer vision and flow direction method applied to lidar data

Surface drainage at the neighborhood and street scales plays an important role in conveying stormwater and mitigating urban flooding. Surface drainage at the local scale is often ignored due to the lack of up-to-date fine-scale topographical information. This paper addresses this issue by providing a novel method for evaluating surface drainage at the neighborhood and street scales based on mobile lidar (light detection and ranging) measurements. The developed method derives topographical properties and runoff accumulation by applying a semantic segmentation (SS) model (a computer vision technique) and a flow direction model (a hydrology technique) to lidar data. Fifty lidar images representing 50 street blocks were used to train, validate, and test the SS model. Based on the test dataset, the SS model has 80.3% IoU and 88.5% accuracy. The results suggest that the proposed method can effectively evaluate surface drainage conditions at both the neighborhood and street scales and identify problematic low points that could be susceptible to water ponding. Municipalities and property owners can use this information to take targeted corrective maintenance actions.

A constitutive model for geosynthetic interfaces considering nonlinear softening behavior

Geosynthetic interfaces within composite liner systems usually play an important role in failure events of landfills and should be well considered in stability assessment. A constitutive model based on the disturbed state concept is proposed to describe the shear behavior of geosynthetic interfaces under both static and dynamic conditions. The interface behavior is assumed to be governed by two states, i.e. the intact state and the fully disturbed state. The intact state is described with a bounding surface model with vanishing elastic range which has the advantages of a concise mapping rule and fewer parameters, and the fully disturbed state is characterized by a nonlinear strength envelope. The two states share the same normal stress, but the macro shear stress of the geosynthetic interface is the coupling result of the two states through a disturbance function related to accumulative plastic shear displacement. The model performs well in describing the monotonic shear behavior of typical geosynthetic interfaces for different drainage conditions and stress paths. Furthermore, a series of cyclic shear tests and shaking table tests on typical geosynthetic interfaces are also modeled, and the results indicate that the dynamic response and softening behavior can be well described with this model.

Relationship among paleosol types, depositional settings, and paleoclimates in Tetori group (Lower Cretaceous, central Japan)

AbstractOne of the key areas and periods for dinosaur evolution is considered to be Early Cretaceous East Asia, of which paleoclimate, that affected dinosaur diversity, needs to be accurately estimated. This study reconstructed paleoenvironmental information from two paleosol sections of the Lower Cretaceous Tetori Group in Hokuriku province, Japan. Elemental and isotopic compositions indicate that the two sections (Sections K5 and T1) formed under similar mean annual temperature (MAT) and mean annual precipitation (MAP) but exhibit significantly different paleosol colors (red in the Section K5, and gray in the Section T1) and mineralogy of carbonate nodules (dolomite–siderite in the Section K5, and dolomite–calcite in the Section T1). In addition, the oxygen isotopic ratio of carbonate minerals in the Section K5 was significantly low. The differences in sedimentary features and isotopic composition were considered to reflect the differences of seasonal climatic factors (e.g., monsoon) and local settings (e.g., drainage condition) despite the two sections exhibiting similar MAT and MAP. The results of this study suggest that the northeastern margin of East Asia, where the Tetori Group was deposited, had temperate and humid climate with monsoonal contrast in humidity during Aptian to Albian.

Multi-dimensional dynamic simulation of rainstorm waterlogging in urban communities

One major threat to cities at present is the increasing rainstorm waterlogging hazards due to climate change and accelerated urbanization. This paper explores the mechanism of rainstorm waterlogging and enables the fine simulation of surface water propagation over complex urban terrain. A novel community-scale waterlogging modeling scheme is presented by loosely coupling a one-dimensional sewer model with a two-dimensional overland model under an open-source framework. The coupled model was applied to Waigaoqiao Free Trade Zone located in Pudong New Area of Shanghai. To quantify the influence of rainfall intensity and drainage conditions on the waterlogging, 12 scenarios were constructed by combining four rainfall return periods (3, 5, 10, and 20 a) and three startup water depths (1.5, 2.0, and 2.5 m) of pump stations. The multi-scenario simulation results show that the waterlogging risk increases from north to south in the study area, and that risk zones with water depth above 0.3 m are mostly concentrated in the southwest and southeast corners of the site. The longer the rainfall return period, the larger the submerged area, and the spatial distribution of surface water accumulation is affected by local topography and drainage system. In addition, reducing the startup water depth of pump stations has an obvious effect on inhibiting the severity of water accumulation. The results provide insights into overland flow across an urban area with densely populated buildings and help to reduce the risk of rainstorm-induced waterlogging disasters.

Analysis of the working environment conditions in the function of water drainage into massive at the quarry Veliki Krivelj

The conditions of the open pit drainage are usually very complex and, as a rule, insufficiently researched. When it comes to the exploitation of technical stone, especially limestone, the working environment is characterized by the crack porosity, and the present system of cracks and faults, apart from being in a complex relationship with each other, is characterized by greater or lesser water permeability as a function of the size of crack openings, type of material with which they are filled and degree of filling. As a result of exploitation works, the seismic impact that occurs as a result of blasting at the open pit, change in stress conditions due to the excavation and filling of the openings of existing cracks by the formation of transport roads and working plateaus at the open pit itself and during exploitation, the working environment conditions are changed, affecting the selection and functioning of drainage system of the open pit. Due to a number of affecting factors and their changes during exploitation, the selection and achievement of high efficiency of the open pit drainage system is a complex task. When it comes to testing the possibility of applying the water drainage from the open pit into surrounding rock massif, in order to achieve the expected high efficiency and safety of the drainage system, the working environment characteristics must be well known. This paper presents an analysis of application the conditions of the Kriveljski Kamen open pit drainage system by mine water drainage into massif [1]. This type of system was analyzed as a part of development the limestone exploitation project at this open pit with the basic idea of creating a reliable and economical system for protecting the open pit from water in the conditions of extremely high rainfall.

ЧИННИКИ КАТАСТРОФІЧНОЇ АКТИВІЗАЦІЇ ЛІНІЙНОЇ ЕРОЗІЇ ТА ІНЖЕНЕРНО-ГЕОЛОГІЧНІ ПРОБЛЕМИ ЕКСПЛУАТАЦІЇ СОНЯЧНИХ ЕЛЕКТРОСТАНЦІЙ, ПОБУДОВАНИХ НА СХИЛАХ І ЗОНАХ ВПЛИВУ ГІРНИЧО-ХІМІЧНИХ ПІДПРИЄМСТВ

The results of monitoring studies on the state of solar power plants in the zones of influence of mining and chemical enterprises are presented. The experience of construction and operation of these facilities has shown that, in comparison with other locations, specific “umbrella” effects can be manifested in areas with unstable soils, concentration of heavy rainfall, activation of erosion processes and changes in the engineering and geological conditions of soils at operation of solar power plants built in the zones of influence of mining and chemical enterprises. The described effects may be characteristic, not only for the described territories of disturbed lands, but also for any erosionally unstable landscapes, in which solar panels will act as rainwater concentrators that actively contribute to the development of near-surface linear erosion processes, especially in conditions of unregulated drainage and non-compliance with anti-erosion protection norms

О техногенных преобразованиях речной сети на Азово-Кубанской равнине (реки Челбас, Албаши)

The article analyzes changes in steppe agricultural landscapes in the central part of the Azov-Kuban Plain over the period 2000–2020 using satellite imagery and DEM ASTER GDEM data. in terms of changing the structure of land use and hydrographic characteristics. Most of the agricultural land of the Krasnodar territory, occupying 61.4 % of the region’s territory, is located on the Azov-Kuban plain in the steppe river basins. The territory under consideration with an area of 6268 km², covering the basins of the Chelbas and Albashi rivers, according to its geographical characteristics, is typical from the standpoint of the modern dynamics of agrolandscapes and transformations of the river network. The transformation of agrolandscapes is accompanied by redevelopment and plowing of the territory, mass construction of dams on rivers, violation of the conditions of natural drainage, which leads to the restructuring of water exchange processes in river basins. 19 private river basins have been identified with the definition of land use types on the surface of the basins. In each of the private basins, a land use structure has been established that affects hydrographic indicators, a decrease in the length of watercourses and the density of the river network has been revealed. For 2000–2020 in private basins, the total length of watercourses, due to plowing and redevelopment of the surface, decreased by 1.51–33.14 %, and in general, in the analyzed section of the Azov-Kuban Plain, by 437 km or by 16.5 %. A widespread “die-off” of the upper sections of the river and ravine network was recorded, most noticeable in the peripheral watersheds.

Prevention and Control of Spontaneous Combustion of Residual Coals in Acid‐Soaked Goaf in Gas Drainage Condition

With the increase of mine mining intensity, the scope of goaf continues to expand, a large amount of coal remains in goaf, and the spontaneous combustion fire of coal is particularly serious. In addition, the spontaneous combustion of coal under the condition of gas mining is not clear. At once, spontaneous combustion can induce gas explosion, resulting in the waste of manpower and material resources, bringing hidden dangers to the mine safety production. In order to prevent and control the fire caused by spontaneous combustion of left coal under the condition of gas mining, in this paper by means of laboratory test, field measurement, and numerical simulation, the law of spontaneous combustion of residual coal under gas mining is studied. The index gas of coal spontaneous combustion was determined by temperature‐programmed experimental device. Secondly, the distribution of the stope working face, goaf, and O2 is discussed. It is of great significance to study the spontaneous combustion rule of three belts in goaf under acid leaching condition and then to discuss the best position of injection idling opening and put forward targeted precontrol measures, which is of great significance to guarantee the safety of mine production. The results show that CO begins to appear when the temperature rises to 40 °C, and its concentration increases exponentially with the increase of coal temperature, which can reflect the degree of coal oxidation in goaf. Therefore, CO should be selected as the indicator gas in the working face. Under the influence of negative drainage pressure, the dangerous area will be enlarged. The optimal drainage volume of high drainage roadway is 90 m3/min, and the optimal air intake volume of working face is 1400 m3/min. The area 0–34 m away from the working face is scattered zone, 34–135 m away is spontaneous combustion zone, and 135 m away is asphyxiation zone. When the position of the idler is 50 m behind the working face, the reduction of the oxidation zone is the largest.

Assessing the role of SuDS in resilience enhancement of urban drainage system: A case study of Gurugram City, India

The increasing frequency of urban floods worldwide due to rapid urbanization, frequent climatic extremes, or poor drainage conditions necessitates evaluating the performance of the urban drainage systems (UDS) and enhancing their resilience. In this study, a comprehensive assessment of the UDS of Gurugram City, India, through the concepts of sustainable drainage systems (SuDS) is presented. A stormwater management model (SWMM) was set up to model the existing UDS response to a design storm of a 5-year return period. The increase in percentage imperviousness (due to urbanization) and rainfall intensity (due to climate change) are considered the governing factors for functional failures. The results revealed climate change to be a more severe threat to UDS than urbanization, while their combinations can further worsen the repercussions. The structural failure was modelled using the single link-failure scenarios, where 3 and 12 conduits possessed low resilience and no resilience (severe), respectively. The role of SuDS in enhancing the resilience of UDS was assessed by simulating all these functional and structural failure scenarios for three SuDS-implemented conditions, i.e., only infiltration trenches (SuDSIT), only retention ponds (SuDSRP), and both of them together (SuDSIT+RP). The SuDS abated the flood magnitudes, delayed the time to peak flow, and stored an additional volume of water within the catchment, thereby justifying their efficacy to mitigate the pluvial flood and enhance the resilience of UDS. The findings of this study encourage implementing SuDS over the developing countries to bring down the frequency of urban floods.

Characteristics of soils of lower Indo-Gangetic plains of West Bengal under rice cultivation

Five typical pedons developed from alluvium on lower Indo-Gangetic plain under major land use system of rice from Murshidabad district, West Bengal were studied for their morphological, physical and chemical characteristics. Soils were very deep with varying texture and drainage classes and have some common characters during pedogenesis under impeded drainage condition. Soils were characterized by the redoximorphic features viz., mottle in the form of segregation of Fe-Mn depletion or gleying, mostly in the sub-surface to sub-soil. Soils were strongly acidic (pH 5.1) to slightly alkaline in the surface and neutral (pH 6.5 to 7.5) in the sub-surface to sub-soil, low to high in soil organic carbon (SOC) content (0.40 to 9.60 g kg−1), low to medium in cation exchange capacity (CEC) [4.0 to 42.0 cmol(p+)kg−1] with high base saturation (61 to 90%). Among the exchangeable bases, Ca2+ is the dominant cation followed by Mg2+, Na+ and K+. Low to medium CEC of soil indicates the mineralogy of the soil as kaolinite and illite (mica). However, clay CEC value indicates the presence of smectite along with hydroxyl-interlayered vermiculite. The high clay CEC value with neutral soil reaction and high content of Ca2+ indicates the dominance of smectite in the soils of pedons 2 and 3. The SOC stock suggested implementation of appropriate conservation measures to the soils of young alluvial plains to improve the quality of soil. The soils of old alluvial plains are generally more fertile in comparison to that of the young alluvial plains. The study indicates that land use has got significant effect on soil characteristics, influencing the soil fertility.

Water saving with permanent skip furrow irrigation under Cut-soiler drainage condition

Water saving with permanent skip furrow irrigation under Cut-soiler drainage condition

Water saving with permanent skip furrow irrigation under Cut-soiler drainage condition

Water saving with permanent skip furrow irrigation under Cut-soiler drainage condition

Soil-landform relationship and pedogenesis of flood plain soils of Mahananda sub-basin, Bihar

Alluvial flood plain soils are one of the major soil groups in northern Bihar and are highly heterogeneous as a result of the hydromorphic environment in which they are formed. Hence, the present investigation was carried out to understand the soil-landform relationship in Katihar district of Bihar. Five major landforms like old alluvial plains (1.97%), young alluvial plains (35.64%), meander plains (30.85%), flood plains (25.35%) and, char land and point (4.5%) were identified after visual interpretation of Sentinel-2 data in conjunction with survey of India toposheet and digital elevation model (SRT DEM). The detailed soil survey was carried out to understand the variability in the study area and 200 soil profiles were studied in different identified landforms. The soils of active alluvial plain (flood plain, char land and point bar) showed wide range of soil morphological properties with lithological discontinuities. Low chroma and value in soils of meander plain due to poor drainage conditions and high groundwater table showed gleying characteristics. The soils of young alluvial plain and active alluvial plain showed irregular distribution of clay content, cation exchange capacity (CEC) and organic carbon (OC). This study indicates that the soil-landform relationship in alluvial floodplains of Mahananda sub-basin partially followed due to mass movement of sediments from Himalayas, periodic flooding and deposition of alluvium during different fluvial cycles of Mahananda river and its tributaries. This was further confirmed by study on pedogenic indices of different landforms. The study on pedogenic indices in two selected sites (window area) away from the Mahananda river like fine sand/total sand, very fine sand/total sand, sand/silt, silt/clay, index of weathering and CEC/clay in the study area doesn't follow the trend in the flood plain as compared to nearly stable land. This may be due to the effect of shifting of river course and their tributaries in the selected two window areas across the different landforms. To overcome the above mentioned problems in soil-landform relationship in the study area, the identified landforms were further sub-divided based on the local factors like percentage of crop cover and moisture content. In revised landforms soil types present in each landform showed soil-landform relationship. Thus, the knowledge on soils in relation to landforms vis-a-vis soil properties and their pedogenesis is useful in understanding their potentials and problems for sustainable land use planning.

A critical state based viscoplastic model for crushable granular materials

Experimental studies have confirmed that the critical state of a granular material varies with alteration in granular fabric, particle shape and grain size. On the other hand, granular materials demonstrate significant strain rate dependency in the presence of particle crushing. While the first feature is well explored, the strain rate effects on the crushability of granular material and consequent critical state alteration are less ventured. This study highlights the strain rate dependence of the critical state of crushable granular materials like sand. A rate-dependent model is proposed bridging the macro and microscopic understanding. The model follows a consistent viscoplastic formulation without using any overstress function. The proposed model considers various loading rate effects at different porosities, confinements and pore water drainage conditions. Further, it can predict the strain rate-dependent particle crushing and dilation features that affect the critical state of granular materials. The model has been validated by comparing its responses with both the experimental and discrete particle simulations for drained and undrained triaxial conditions. An implicit stress return integration scheme is devised to enable accurate numerical response from the model.  Finally, a parametric study is presented that envisages the evolution of critical state due to coupled strain rate and particle crushing effect.

Analisis Tingkat Bahaya Longsor pada Jalan Nasional untuk Prioritas Penanganan dengan Metode AHP: Studi Kasus Jalan pada Satker PJN III dan PJN IV

Landslides are a very dangerous threat to the roads. Good management is required to prevent the problems occurring from extensive possible landslides. This is because the number of potential landslide points on the National roads are numerous. Maintenance and prevention are crucial to keep these disasters from occurring. Therefore these need to be a priority. The locations in question are: The National Road in the Provence of North Sumatra, the area of Satker PJN Ill (Satuan Kerja Pelaksanaan Jalan Nasional III) and The Satker PJN IV (Satuan Kerja Pelaksanaan Jalan Nasional IV). There are 26 roads in the Satker PJN III and IV areas with 34 that have occurred. The method that is used in this study is the AHP (Analytical Hierarchy Process). Method using two stages: The first stage is to analyze the level of landslide hazard on the road. The second stage is to determine the priority level for the handling of each landslide point for each section of the road. The parameters used determining the level of landslide hazard are: Soil, slope, landcover, rainfall, subgrade and drainage conditions, at the same time as using the landslide hazard perimeters, landslide dimensions, slope engineering and every day traffic