Permeability Of Clay Research Articles

Evaluation of the influence of geological and technological factors on oil recovery during oil displacement with water in low permeability clay reservoirs

Evaluation of the influence of geological and technological factors on oil recovery during oil displacement with water in low permeability clay reservoirs

Shear Strength of Soft Soil Reinforced with Singular Bottom Ash Column

Structures construct on soft clays are often affected by stability and settlement problems due to high compressibility, low shear strength and low permeability of soft clay which will lead to bearing capacity failure and excessive settlement. The soft clay samples had the dimensions of 50 mm diameter and 100 mm in height. The bottom ash column had two (2) different area replacement ratios which were 4% and 9% (10 mm and 15 mm diameters respectively) with the bottom ash column penetration ratio of 0.3, 0.7 and 1.0. The results of the unconfined compression test show that there is an improvement in shear strength of soft kaolin clay when reinforced with bottom ash column. For samples with area replacement ratio 4%, the results show the increment of 25%, 37.5% and 50% at height penetrating ratio of 0.3, 0.7 and 1.0, respectively in shear strength. Meanwhile, for samples of 9% area replacement ratio, the shear strength of the soft kaolin clay increased about 14.29, 28.57 and 57.14%, respectively. It can be concluded that by reinforcing the soft clay using singular bottom ash column, the shear strength of the soils increases and become more significant as the area replacement ratios and the column penetration ratios increase.

The short DMTA dissipation test

The CPT is used either in a continuous advance mode or in a rheological testing mode. Both periods are present in the short local side friction and in the short cone resistance dissipation tests made in the technical breaks of continuous penetration of the old CPT S832 equipment. The pause is a few second long. A statistical study previously made revealed that the local side resistance increased in sand and decreased in NC plastic soils with time in the first seconds after the stop of the steady penetration, the decrease was sometimes larger than 50%. The rate of stress variation was depending on the permeability and thus on the soil type. In this research, a similar, new test is considered. Before taking the standard Areading in a DMT, a short dissipation can be measured in a generally 15 s long time period, with the Medusa DAS, being able to sample an A-reading in every 20 millisecond. A series of them made at the Araquari test sites are statistically analysed here. The results are similar to the ones related to the short local side friction dissipation tests which is explained by the different residual stress state in sands and in NC clays, and by the different permeability of sands and NC clays.

Dry shrinkage cracking and permeability of biopolymer-modified clay under dry–wet cycles

Biopolymers efficiently improve the anti-seepage function of compacted clay layers, but research concerning the permeability stability of biopolymer-modified clay during cyclic wetting and drying is scarce. In this paper, the macro–microstructures and the permeability coefficients of biopolymer-modified clay and conventional bentonite-modified clay under dry–wet cycles are comparatively studied. The bentonite modifier is found to increase macro–microscopic cracks under dry–wet cycles, while the xanthan modifier decreases the macro–microscopic fracture rate of the clay. The physical properties of 2% by dry weight xanthan-modified clay are similar to those of 10% by dry weight bentonite-modified clay, but the permeability coefficient of the former is lower by approximately one order of magnitude. After the dry–wet cycles, xanthan-modified clay performed better in leakage prevention than bentonite-modified clay. For low-liquid-limit clay, the recommended mass percentage of xanthan gum was 1.5% considering the seepage resistance safety during dry–wet cycles.

Electrochemical remediation of phenol contaminated kaolin under low-strength electric fields

Soil degradation is a global concern. Electrochemical remediation (ER) technology is considered an appealing strategy for soil remediation because it is a low-cost, adaptable, and effective noninvasive in situ technology. Currently, the remediation of soil characterized by fine grains, low-hydraulic permeability, heterogeneous conditions, and mixtures of contaminants is still challenging since other conventional technologies are poorly effective. ER of soil is based on the application of low potentials between a couple of electrodes which induces an electric field (E) in the contaminated field. In this work, very low values of electric field (E≤ 0.25 V cm−1) were used for the ER of contaminated kaolin. Phenol was selected as model hazardous organic compound and kaolin as model, reproducible and low buffering and low permeability clay. The effect of several factors, including the nature of the electrodes, treatment time, kind of current, the strength of the E and the nature of supporting electrolyte, on the performance of the process was investigated in detail and discussed in terms of the normalized phenol concentration and its total removal from the kaolin. Overall, the main finding is that the use of very low value of E (0.15 V cm−1) can allow to simultaneously desorb, mobilize and also in-situ degrade phenol. The highest removals of phenol up to approximately 80% and 90% from the kaolin under both direct and sinusoidal E, respectively, were reached using compact graphite as electrodes in presence of Na2SO4 into the kaolin.

Seepage Simulation of the Proposed Makhool Dam in North Iraq

This study aims to simulate water seepage and identify areas of weakness in the foundations through the right and left sides of the proposed Makhool dam in northern Iraq, using the finite element method by advanced computer software (SEEP/ W, 2012). The earth fill dam is 3670 m long on the Tigris River. Many attempts were made to ascertain the program results on the supposed earth dam and compare the results with those of other analytical methods to verify the program. The results are comparable, showing that the program is suitable for use in the seepage analysis at the proposed Makhool dam. According to the seepage analysis, the quantity of seepage through the left side of Makhool is acceptable within permissible limits; however, the right side has a lot more than the left side because of the presence of cracks, fractures, and cavitations in the stratigraphic sequence of Fatha formation at great depths in the gypsum beds under the diaphragm. The results indicate the need to lower the diaphragm about 6 m extra in the foundation's zone to a level of 49 m.a.s.l until reaching the low permeability clay bed within the foundations' zone. This action will reduce the amount of seepage and flow velocity and avoid using more grouting during the dam life. The design limits of the piezometric head (total head) were also determined, which are supposed to be read by the monitoring devices when operating the dam at the maximum level of the reservoir and the normal operating levels.

Effects of 3D Printing on Clay Permeability and Strength

Effects of 3D Printing on Clay Permeability and Strength

ACCOUNTING FOR FLUID FLOW IN DETERMINING THE PRESSURE DROP IN FORMATIONS SEPARATED BY A CLAY INTERLAYER

The article deals with the problem of determining the pressure drop in two parallel formations operated by horizontal wells. At the same time, the layers are separated by a low permeable clay partition. The problem is solved analytically by the method of Laplace and Fourier transformations. For convenient practical use, the solutions obtained are transformed into a dimensionless form. In this paper, graphs of the dependences of pressure drops in both layers on time are constructed and the analysis of the solutions obtained is carried out depending on the ratios of the permeability of the layers and the bridge. The solutions obtained can be used to estimate the pressure drop during the development of layers alternating with clay interlayer.

Effect of low-permeability layers on vadose well recharge rates

Recharge in unconfined aquifers during Managed Aquifer Recharge (MAR) is influenced by the lithologic characteristics of the vadose zone. The capacity of vadose wells to achieve recharge rates above those possible with recharge basins is studied in heterogeneous unsaturated porous media. Although near-surface low permeability layers can be bypassed with vadose wells, subsequent low permeability layers below or adjacent to the well screen influence recharge rates by forming perched conditions. The numerical model VS2DTI was used to evaluate the effect of heterogeneous lithology on vadose well recharge. A sand aquifer was modeled using hydrogeologic characteristics from the Hueco-Bolson aquifer in Texas. Modeled recharge was studied for a 33 m deep vadose well with a 10 m high water column evaluated under conditions of both a homogenous aquifer and an aquifer with heterogeneity formed by a thin, low permeability clay layer. These low permeability layers were modeled at various depths alongside and below the well to study the impact of heterogeneity on MAR processes. Results contrast vadose wells a) without clay layers to recharge 200.6 m3/d, considered the well's maximum (100%) efficiency, and b) inclusion of clay layers creating perched conditions which are shown to reduce recharge. Specifically, recharge rates greater than 180 m3/d (90% efficiency) occur if the clay layer was aligned at or above the upper half of the well screen. Simulating the low permeability clay layer along the bottom half of the well caused recharge rates reduction to a minimum of 30 m3/d (15% efficiency). Rates above 100 m3/d (50% efficiency) occurred when the clay layer was 10 m below the base of the well. These results characterize the impact of low permeability layer distance adjacent to and below a vadose well. A low permeability horizon at a fixed depth relative to vadose wells at variable depths was also studied to demonstrate that recharge rate increases corresponding to deeper vadose wells due to additional screen length and greater pressure head. Results quantify the impact of vadose well placement relative to low permeability layer depth, and promote understanding to achieve design recharge rates using the fewest and shallowest wells possible.

Integrated Geophysical and Geotechnical Approaches for Evaluating Dam Seepage in Lesser Himalayan Region of Pakistan

Dam leakage is a major problem in earth-filled reservoir dams. The present research is aimed at detecting the seepage zones in an earth-filled reservoir dam in the vicinity of Sarobi village, North Waziristan, Pakistan. The objective was achieved by integrating geological, geotechnical, and geophysical datasets. Geological survey was carried out in the area to identify the surface exposures. Geotechnical data involved was used to estimation of permeability and Lugeon values to identify network of joints/fractures whereas electrical resistivity tomography (ERT) technique (utilizing Wenner-Schlumberger configuration) was applied for the identification of the leakage zones. Geological data revealed highly deformed alluvium towards the right abutment underlain by compressed shale and highly fractured limestone beds. Geotechnical data indicated high permeability, Lugeon values, and concentration of sand and gravel towards the right abutment whereas low permeability, Lugeon values, and higher concentration of silt and clay were observed towards the left abutment. ERT data identified a conductive zone embedded between impermeable lithologies having resistivity between 10 and 60 Ω·m. This conductive zone was observed in parallel profiles acquired in upstream, dam crest, and downstream parts of the dam. The integration of all the datasets revealed a network of joints that are interconnected and provide a path for water at the upstream side to pass through right abutment of dam and leak towards the downstream.

Investigation on strong vertical permeability and micro-pore characteristics of Jinan red clay using X-ray micro-tomography

Due to the peculiarity of the spring domain strata in Jinan, the phenomenon of serious water seepage appears in the process of excavation. The macro permeability of soil is closely correlated with its microstructure. In this study, using the X-ray micro-tomography (micro-CT) system and a self-designed soil seepage device, the internal pore structure of Jinan red clay and the water flow inside the sample under different seepage stages were observed. The microstructure of water phase and air phase in the sample was segmented by the watershed algorithm. Calculation and comparison of pore and throat size distributions and coordination number (CN) at different seepage stages were conducted by establishing pore network model (PNM). Meanwhile, the seepage experiment simulations were conducted based on the 3D pore structure of red clay. The results show that the preferentially flow of Jinan red clay is obvious due to the existence of the vertically developed macropore channel. The fine particles (mainly silt particles) are washed away during seepage, thereby expanding the pore channels. The maximum pore radius and pore connectivity have important influence on seepage characteristics of Jinan red clay, but the correlation between porosity is small.

Utilization of Kenaf Core Fiber – Marine Clay Mixture as a Landfill Liner Material

Nowadays, leachate production is a big concern and causes a serious hazard to the soil and groundwater which causes the subsurface soil to be polluted as a result of the loss of soil quality and environmental pollution. This study aims to study the potential of using kenaf core fiber and marine clay mixtures as improved landfill liner material. Relevant laboratory tests such as atterberg limit test, specific gravity test, and particle size distribution were performed to examine basic geotechnical properties of marine clay soil collected from Batu Kawan, Penang. Besides that, compaction test and hydraulic conductivity test were carried out for soil mixed with kenaf core fiber to determine the strength and permeability characteristics. The results found that the marine clay has significantly adequate physical properties to be used as a landfill liner. The permeability test for marine clay soil inclusion of kenaf core fibre indicated that the hydraulic conductivity of the samples admixture for 0%, 4%, 8%, and 12% ranged between 6.68 × 10-9 and 1.57 × 10-8 m/s. Compaction of marine clay mix kenaf core fibre samples resulted in maximum dry density, ρdmax that ranged between 0.936 and 1.595 g/cm3 and optimum moisture content, wopt that ranged between 19.8% and 24%. Hence the inclusion of kenaf core fiber in marine clay soil improves the maximum dry density value, decrease permeability of marine clay and could be potentially used for landfill liner material.

Influence of freezing directionality on the permeability of silty clay

During artificial ground freezing, freezing may undergo in directions either parallel or normal to the flow of water, which may result in different permeability for the water to flow. Therefore, it is of significant importance to observe the influence of freezing directionality on the permeability of soils. A set of laboratory permeation tests were performed in this study on specimens subjected to three freeze-thaw modes. Considerable change in hydraulic conductivity subsequent to freeze-thaw event was found even under condition where volume change was not allowed. Vertical freeze-thaw resulted in the lowest level of hydraulic conductivity as compared with the other two cases, irrespective of dry density and moisture content. The permeability of specimen subsequent to radial freezing was approximately 34 times in maximum greater than that subsequent to vertical freezing. The occurrence of vertical cracks was responsible for the dramatical increase in hydraulic conductivity of specimens after radial freeze-thaw. Vertical freeze-thaw, however, resulted in an apparent reduction in hydraulic conductivity because of the local consolidation of soil structure during the growth of horizontal ice lenses. Processes that larger pores became larger but smaller pores became smaller contributed to the increase in hydraulic conductivity of thawed specimens even though the total void ratio was unchanged.

An experimental investigation on the effect of soluble sugar degradation on the of domestic-source-contaminated soil sites formation and evolution

The percolation-degradation process of soluble domestic pollution is very important for the evolution of soil properties and the formation of contaminated sites. The main objective of this study is to investigate the influence of glucose seepage-degradation on the permeability of clay through an indoor percolation test in combination with thermogravimetric measurement with glucose as a representative domestic contaminant soluble sugar. We can conclude that the permeability of clay was significantly impacted by the seepage-degradation of soluble sugar. With a focus on the role of soluble sugars in domestic source pollutants on clay, the formation and evolution of the domestic source contaminated soil site went through three main stages: “generation of domestic source contaminated liquid & formation of S–C zone”, “contraction of S–C zone & formation of E-C zone and C zone”, and “disappearance of S–C zone & contraction of E-C zone and C zone”. The clay permeability decreased, the migration range shrinked, and the pollution level of the clay near the source of the contaminants increased with increasing soluble sugar solution concentration.

Permeability Prediction Model Modified on Kozeny-Carman for Building Foundation of Clay Soil

Clay soil is a common building foundation material, and its permeability is very important for the safety of foundation pits and the later settlement of buildings. However, the traditional Kozeny-Carman (K-C) equation shows serious discrepancies when predicting the permeability of clay in building foundation treatment. Therefore, solving the application of K-C equation in clay is a problem faced by the engineers and scholars. In this paper, the influence of clay mineralogy on pore structure and permeability is analyzed, and then the effective e (eeff) and effective SSA (Seff) are proposed. Based on the eeff and Seff, the permeability prediction model modified on Kozeny-Carman is built. Then, seepage experiments are conducted on two types of clay samples to test this prediction model; at the same time, the MIP combining freeze-drying methods are used to obtain the Seff and eeff. Through the discussion of the test results, three main conclusions are obtained: (1) there are invalid pores in clay due to the influence of clay mineral, this is the reason for which K-C equation is unsuitable for clay; (2) the eeff and Seff can reflect the structural state of clay during seepage; (3) the results of the permeability prediction model in this paper agree well with the test results, which indicates that this prediction model is applicable to clay. The research results of this paper are significant to solve the academic problem that K-C equation is not applicable to clay and significant to ensure the safety of building foundation pits in clay areas.

Thermal effects of the hydraulic conductivity and threshold gradient of sand–clay liners in municipal solid waste landfills

High leachate heads and dry cracking of clay barriers are common problems in landfills. The use of sand-clay barriers with a non-darcy percolation patterns can not only prevent leakage of large amounts of leachate but can also potentially reduce the development of dry fractures due to loss of water. Thus, it has been suggested that sand-clay materials could be used as barriers at the bottoms of landfills or as a vertical barriers. However, biochemical degradation of waste in a landfill generates much heat, and the temperature can reach 60 °C. A high-temperature field can inevitably affect the permeability of sand-clay barriers. The change in sand-clay barrier permeability under the influence of temperature has received increasing attention. Therefore, in this study, a temperature-controlled permeameter with flexible walls was used to conduct experiments on permeability of sand-clay mixtures at four temperatures. The results indicated that the hydraulic conductivity gradually increased and the threshold gradient gradually decreased with increasing temperature. The hydraulic conductivity and threshold gradient exhibited exponential relationship with the temperature, respectively. Experiments were designed to measure changes in the permeate viscosity at different temperatures. The previously established hydraulic conductivity equation (that considered only the influence of temperature on the permeate viscosity) greatly differed from the measured values. In contrast, the newly established hydraulic conductivity equation (that considered the influence of temperature on both the permeate viscosity and intrinsic permeability) agreed well with the measured values. Statistics based on a large amount of data (collected previously) showed that the intrinsic clay permeability exhibited a power law relationship, with increasing temperature to a threshold gradient at 25 °C (Eq. (9)). Above the threshold, the intrinsic permeability experimental data increasingly deviated from Eq. (9). To consider the effect of the temperature on both the intrinsic permeability and permeate viscosity, an equation for calculation of the threshold gradient was proposed, and it could be found that the calculated values suitably agreed with the measured values. The results of this study provide an important theoretical basis and data to support the development of high-performance barriers with long service life for landfills.

Sawdust Recycling in the Development of Permeable Clay Paving Bricks: Optimizing Mixing Ratio and Particle Size

The permeable pavement system (PPS) has effectively contributed to stormwater management as a low-impact development (LID) technology. The suitability of clay bricks, consolidated with waste materials, for sustainable PPS applications in urban infrastructure needs further attention. In this study, several series of permeable clay paving bricks samples were prepared by mixing different ratios and particle sizes of sawdust (SD) with clay soil and firing at 900 °C. The raw soil and SD samples were characterized through sieve analysis, X-ray Fluorescence (XRF), X-ray diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FTIR). The bricks were tested for their compressive strength, bulk density, apparent porosity, water adsorption, permeability coefficient, and stormwater treatment efficiency. The clay soil comprised 17.5% clay/silt with appropriate amounts of SiO2 (50.47%), Al2O3 (19.14%), and fluxing agents (15.34%) and was suitable for brick manufacturing. XRD and FTIR analysis revealed that the soil predominantly comprises quartz, dolomite calcite, feldspar, kaolinite, illite, and chlorites. The SD samples were enriched with amorphous and crystalline cellulose. The compressive strength of the bricks decreased, while the permeability of the bricks increased with an increasing percentage of SD. An optimal percentage of 10% SD achieved a 21.2 MPa compressive strength and a 0.0556 m/s permeability coefficient, meeting the ASTM specifications for PPS. The optimal size of SD, between 0.5 and 1.0 mm, achieved the desired compressive strength of the bricks. The permeable bricks effectively removed the total suspended solids (TSS), turbidity, and BOD5 from the stormwater, which complies with the guidelines for wastewater reuse applications.

Finite Element Modelling Of An Embankment Seated On Pervious Concrete-Stone Composite Column

Embankments rested on soft soils reinforced with stone columns cannot provide enough support. In such soils, to increase their bearing capacity, pervious concrete can be applied to upper portion of the stone column forms a composite column to restrain bulging collapse. Pervious concrete is a type of concrete made without adding fine aggregate and having permeability comparable with stone column materials. The current research work carried out to study the behaviour of embankment rested on composite column through a parametric study using finite element analysis. The parameters; soft clay elastic modulus, embankment fill elastic modulus, stone column material elastic modulus, pervious concrete column elastic modulus, spacing of column, length of pervious concrete column in composite column, permeability of soft clay, and construction rate are considered for the parametric study. The influence of these parameters are compared and rated in terms of the degree of importance.

Influence of Five Additives on No Loading Swelling Potential of Red Clay

In this study, cement, zeolite powder and three industrial by-products (blast furnace slag, steel slag, and fly ash) were selected as additives to study their effects on the swelling potential of red clay with different curing ages and dosages. At the same time, the mechanism of additives reducing the swelling potential of red clay was analyzed by scanning electron microscope (SEM) and X-ray fluorescence (XRF) tests. The X-ray diffraction (XRD) test was used to detect the clay mineral content of the red clay specimens before and after the modification to determine the change in the clay mineral content of the specimens. The direct shear test was used to explore the influence of additives on the strength of red clay. The results show that with 9% cement content, the no loading swelling potential of specimens can be reduced by 82.5% under 28 days of curing, and the cohesion of the specimens can be greatly increased by 82%. However, the specimens with cement have an increase in no loading swelling potential under the condition of no curing. In contrast, when steel slag is used as an additive to modify the swelling properties of red clay, the swelling potential can be reduced without curing, but the addition of steel slag will reduce the cohesive strength of specimens. XRD testing shows that the clay mineral composition in cement-modified specimens and steel slag-modified specimens experienced a relative change, the relative content of montmorillonite and illite decreased, and the relative content of kaolinite increased. Combined with SEM and XRF test results, it is concluded that cement’s reduction in the swelling potential of red clay depends on pozzolanic reaction products filling the pores in specimens and bonding clay particles, so as to reduce the permeability of red clay and increase the resistance during swelling. The addition of cement can also convert hydrophilic clay minerals into nonhydrophilic clay minerals. Compared with cement, the reduction in swelling potential caused by steel slag mainly depends on the adsorption of ions to reduce the adsorption of water molecules on the surface of clay slices.

Assessing Groundwater Dynamics and Hydrological Processes in the Sand River Deposits of the Limpopo River, Mozambique

Drought and water scarcity constrain the socioeconomic development of many (semi-)arid regions of Southern Africa. Moreover, due to the increase of water withdrawals upstream, the Limpopo River is no longer perennial in Mozambique. Fortunately, its river bed can store significant amounts of freshwater, because of the occurrence of thick and often coarse sand deposits formed through pronounced dryland weathering, erosion, and sedimentation in the river channel. Such so-called “sand rivers” exist in many parts of semi-arid Africa and have varying configurations and hydrological conditions. The current research aims to comparatively assess the Limpopo sand river aquifer in terms of recharge and discharge dynamics, storage potential, and interactions with the surface water flow, as a function of its specific hydrological conditions: its large size, location downstream of a dam releasing permanent ecological flow, and its relatively undeveloped state. For this purpose field investigations were carried out at two sites, involving groundwater level measurements, 2D geoelectrical surveying, water chemical and stable isotope analysis, and sediment classification. These investigations reveal the occurrence of medium to coarse sands with thicknesses that can reach 10–15 m, dropping to 2–5 m in the main river channel, underlain by less permeable clays and silts. Analysis of the river level shows that large parts of the sand river are flooded almost every year, providing optimal conditions for recurring and rapid recharge of the system (confirmed by infiltration tests) through two mechanisms: direct infiltration of surface runoff and lateral flow toward non-flooded areas of the river valley, also confirmed by the chemical and isotope study. During the dry season, groundwater provides base flow to the river and the average water level drop in the sand river system is about 1.8 m. The connectivity with the river margins is limited, due to the clayey nature of the river bank sediment, but local paleochannels can result in a continuation of sand layers. Hydrological processes controlling the water quality are evapoconcentration, mixing of discharging groundwater with the perennial surface water flow, and to a minor extent mineral dissolution, with the groundwater being of Ca-HCO3 type. The combination of the large size, high permeability, and frequent flooding of the sand river deposits provides optimal conditions for groundwater abstraction, requiring additional assessment of the impact on riparian vegetation and downstream users.