Sand Gravel Research Articles

Variation characteristics of water and sediment of managed aquifer recharge with the Yellow River water in the piedmont sand gravel channel in the North China Plain

Abstract A two-dimensional sand tank model was designed to investigate the water distribution and sediment clogging of the Yellow River water during the seepage recharge process of the piedmont sand gravel channel in the North China Plain. Due to the high permeability of the sand gravel medium, only infiltration deep runoff (IDR) and surface runoff (SR) occurred in the sand tank experiment. The increase in water released did not improve the effective recharge. The IDR accounted for 65–85% of the water released. After clogging appeared, the value decreased to 15–30%. More than 96% of suspended solids were deposited in the surface and upper areas of the sand tank, among which the sand gravel surface covered by the thin clay layer formed by suspended particles was the main cause of the change in the distribution of IDR and SR. A rubber dam can promote the conversion of high velocity SR to low velocity lateral shallow runoff (LSR) by 25–30% while increasing the deposition mass of suspended particles in the sand tank. The rationality of the sand tank model was verified by the numerical model, and the fitting degree between the simulated and the measured results was greater than 0.9.

Unsteady-State Conjugate Heat Transfer Model of Freeze-Sealing Pipe Roof Method and Sensitivity Analysis of Influencing Factors of Freezing Effect

The freeze-sealing pipe roof (FSPR) method has been applied to the Gongbei tunnel of the Hongkong–Zhuhai–Macau Bridge, which is the first application of this method in the world. The purpose of the ground-freezing method is soil waterproofing. Temperature is an important indicator for measuring the freezing effect; however, the FSPR method involves unsteady-state conjugate heat transfer between frozen soil, steel pipes, concrete, air, and other media. This paper proposes an unsteady-state conjugate heat transfer model and establishes a global solution algorithm of a strong coupling governing equation based on the virtual density method. Then, a calculation based on COMSOL software is realized and validated. The sensitivity of different factors such as initial formation temperature, different soil layers, and brine temperature on the freezing effect was studied by simulating the FSPR model. It is concluded that the brine temperature had a greater impact on the freezing effect, followed by the soil layer, whereas the formation temperature had the least impact. For muddy silty clay, if the brine temperature is −20 °C, it takes 44 days to meet the design requirements of 2 m. If the brine temperature is −30 °C, 27 days is enough. When the formation temperature is 20 °C, it takes 20 days for medium gravel sand to reach the thickness of the freezing curtain, and 32 days for muddy silty clay. Compared to other soil layers, the freezing effect of the medium gravel sand is relatively better. This research has a certain impetus to similar multimedia freezing heat transfer issues.

Elastoplastic Constitutive Model of Sand–Gravel Composites Considering the Whole Shearing Process

Elastoplastic Constitutive Model of Sand–Gravel Composites Considering the Whole Shearing Process

Experimental Study on Shield Tunneling Control in Full Section Water-Rich Sand Layer of Collapsible Loess

Taking China’s first application of domestic shield tunneling in a water-rich sand layer for crossing a high-speed railway as research background, the influence of changes in the shield tunneling parameters on ground settlement is analyzed based on field tests, and a construction control method suitable for shield tunneling under a risk source in a water-rich sand layer is proposed. The test results show that the use of 10% sodium bentonite as the soil modifier for soil pressure balance shield tunneling into the water-rich sand layer has advantages, while adding 50% loess into the bentonite slurry in the gravel sand layer can greatly improve the impermeability of the soil; the settlement of soil can be effectively reduced by using the special segment with grouting holes for deep grouting and applying the adaptive transformation of the shield cutter. Based on the statistical analysis results, a reasonable range for the cutter head torque, cutter head speed, chamber pressure, bentonite injection volume, and advanced speed in the water-rich sand layer can provide a construction control basis for similar projects and provide data support for the compilation of relevant specifications.

A Study on the Generation Mechanism and Development Process of Piping Based on the Theory of Muddy Water Seepage

In the process of piping development, the sediment carried by seepage causes the change of porosity and then causes the change of permeability coefficient. Therefore, piping belongs to muddy water seepage (i.e., unstable seepage). Based on the theory of muddy water seepage, the new control equation of piping model is established. The generation mechanism and development process of piping for white fine sand and sand gravel are explored. The advantages for the new control equation of piping model are discussed. The results show that the new control equation of piping model is not only simpler in form but also easier to solve and can better describe the characteristics of piping generation, development, and stability. Compared with white fine sand (the initial relative density and porosity are smaller, and the initial permeability coefficient and critical gradient are larger), the porosity, permeability coefficient, seepage flow, and sediment volume of sandy gravel increase faster with time. When the porosity is the same, the permeability coefficient, seepage flow, and sediment volume of sand gravel are larger. The smaller the area affected by piping, the faster the increase of porosity, permeability coefficient, seepage flow, and sediment volume. When the porosity and permeability coefficient are the same, the seepage flow and sediment volume are smaller. The smaller the initial porosity and permeability coefficient, the later the generation, and development of piping. It can provide a reference for piping danger forecast and emergency response.

Experimental Study on the Permeability Damage Mechanism of Gravel Pack Sand Control Medium in Mud Hydrate Reservoirs

Yu, L.; Han, Z.; He, J., and Li, G., 2022. Experimental study on the permeability damage mechanism of gravel pack sand control medium in mud hydrate reservoirs. Journal of Coastal Research, 38(6), 1104–1115. Coconut Creek (Florida), ISSN 0749-0208. The high argillaceous gas hydrate reservoir contains high silt and fine sand content. During the mining process, the fine silt sand will cause blockage of the gravel sand control medium, resulting in reduced medium permeability, that is, penetration damage. Penetration damage will reduce productivity and affect the long-term effectiveness of gravel. For the penetration damage problem of gravel sand control medium, the sand blocking simulation experiment of different reservoir water content, experimental pressure, and gravel specifications were carried out by self-developed sand blocking experiment system. A laser particle size analyzer and electron microscope were used to measure and observe the deposition of sand particles in the upper, middle, and lower layers of gravel layer after the sand retention experiment. The law of permeation damage and the mechanism of media permeation damage were summarized. The research results show that the blockage of sand control media can be divided into four stages: the beginning of blockage, the intensification of blockage, the dredging of blockage, and the balance of blockage. Reservoir water content, experimental pressure, and gravel size all influence permeability damage of gravel. The primary and secondary relationship of the influence of these factors on permeability damage is gravel size, experimental pressure, and reservoir water content. The pressure mainly affects the invasion depth of reservoir sand. The reservoir water content mainly affects the degree of permeability damage. The optimum particle size median ratio D50/d50 is about 25, and the medium has strong antipermeability damage ability and good sand retaining effect.

Effect of the covariance matrix type on the CPT based soil stratification utilizing the Gaussian mixture model

Abstract The identification and stratification of soils represent an essential step in designing various geotechnical structures. The cone penetration test (CPT) measurements are used widely to classify the soil; however, the soil classification charts such as the Robertson chart undergo uncertainty from different sources that make overlapping of soil types. This article aims to develop a probabilistic approach employing clustering with Gaussian mixture model, which can deal with the uncertainty and classify the soil based on CPT. The spatial parameters were obtained assuming the different types of covariance matrices. The data utilized in this study represent the results of CPT in four locations in Nasiriyah, Iraq. Both spatial and feature patterns were produced and used to classify the soil. This research revealed that the soils deduced from the Robertson chart were clay, silt, and sand. No gravelly sand appeared on the chart. The soil at shallow depth was clay soils, and it changed to be sandy silt at fairly great depth. They were close to the boundary curve between the stiff clay and sand zones and relatively existed at great depth. The probabilistic approach can detect the soil layers fast without experience-based decisions. Moreover, the type of assumed covariance matrix may affect the soil profile.

One-Dimensional Experimental Investigation of Polyethylene Microplastic Transport in a Homogeneous Saturated Medium

Plastics are widely used in every part of life. Microplastics (MPs) are classified as emerging contaminants in nature. Yet, microplastic transportation parameters in groundwater are not characterized well. In this study, microplastic transport in saturated homogeneous media was investigated. For this purpose, one-dimensional column tests were performed using the fluorescent and microplastic tracers to figure out the hydrodynamic conditions for the microplastic transport. Large silica, small silica, sand, and coarse gravel were the tested media. The hydrodynamic transport parameters were calculated by inverse solution methodology using the experimental and the analytical solution results. Only the coarse gravel medium with a minimum 1 mm and maximum 20 mm (5 mm of median) pore sizes and kinematic porosity 40.2% were found to be suitable for the transport of the used polyethylene (PE) whose particle size was between 200 and 500 µm. It is not possible to transport PE particles of selected size from fine-grained media. Transportation occurred in coarse-grained media such as coarse gravel. The calculated dispersivity values for the coarse gravel were 2.58 and 3.02 cm by using fluorescent and PE tracers, respectively. The experiments showed that the used PE particles cannot be transported if the mean flow velocity is lower than 2.02 cm/min in the coarse gravel medium. The microplastic accumulation might be an issue for an actual aquifer rather than the transportation of it considering the actual groundwater flow velocity is generally much lower.

Morphostratigraphy of an active mixed sand–gravel barrier spit (Baie de Somme, northern France)

ABSTRACTThis study focuses on the architectural characterization of a mixed sand‐and‐gravel spit in relation to its multi‐decadal evolution. The spit, located in the Somme estuary in northern France, is a 5 km long sedimentary body made of several amalgamated ridges with a hooked terminus. Flint pebbles originating from the erosion of Cretaceous chalk cliffs and sands reworked from the tidal flat constitute the spit. Aerial photographs demonstrate that the spit formation started in the 1940s and document its growth through time. The architecture of the spit has been characterized by ground‐penetrating radar (GPR) investigation using 400 MHz and 900 MHz antennas. The GPR data are used to distinguish progradational, aggradational and transgressive geometries that are related to cross‐shore and longshore construction, respectively. Three main morpho‐stratigraphic domains characterize the spit from the root to the terminus: (i) a beach‐ridge domain mainly made of progradational structures; (ii) an intermediate domain formed by beach‐drift structures topped by deposits with cross‐shore geometries; and (iii) a spit‐terminus domain mainly composed of beach drift structures which incorporate sand deposits. At the scale of an individual ridge, high‐frequency GPR data indicates five types of sedimentary architectures associated with the evolution from a hook stage to the subsequent elongation stage. The overall development of the barrier spit is the result of complex interactions between wave and storm dynamics, potentially modulated by the variability of submersion time related to the 18.6 year tidal cycle, and anthropogenic activities including groyne construction and gravel reloading.

Mapping riverbed sediment size from Sentinel‐2 satellite data

AbstractA comprehensive understanding of river dynamics requires the grain size distribution of bed sediments and its variation across different temporal and spatial scales. Several techniques are already available for grain size assessment based on field and remotely sensed data. However, the existing methods are only applicable on small spatial scales and on short time scales. Thus, the operational measurement of grain size distribution of riverbed sediments at the catchment scale remains an open problem. A solution could be the use of satellite images as the main imaging platform. However, this would entail retrieving information at sub‐pixel scales.In this study, we propose a new approach to retrieve sub‐pixel scale grain size class information from Copernicus Sentinel‐2 imagery building upon a new image‐based grain size mapping procedure. Three Italian gravel‐bed rivers featuring different morphologies were selected for unmanned aerial vehicle (UAV) acquisitions, field surveys and laboratory analysis meant to serve as ground truth grain size data, ranging from medium sand to coarse gravel. Grain size maps on the river bars were generated in each study site by exploiting image texture measurements, upscaled and co‐registered with Sentinel‐2 data resolution.Relationships between the grain sizes measured and the reflectance values in Sentinel‐2 imagery were analysed using a machine learning framework. Results show statistically significant predictive models (MAE of ±8.34 mm and R2 = 0.92). The trained model was applied on 300 km of the Po River in Italy and allowed us to identify the gravel–sand transition occurring along this river length.Therefore, the approach presented here—based on freely available satellite data calibrated by low‐cost drone‐derived imagery—represents a promising step towards an automated surface mean grain size mapping over long river length, easily repeated through time for monitoring purposes.

The Possibility of Separation of Heavy Minerals as Byproduct of the Danube River Gravel Sand Extraction

The history of exploitation of gold from the Danube River’s sandy gravels is centuries long. The extraction of valuable heavy minerals (VHM) concentrate was never intended. Our aim is to find out an effective separation process to produce monomineral concentrates of the following minerals: garnet, ilmenite, zircon, monazite, magnetite, rutile, gold. The essential condition is to use no chemistry (no flotation, leaching, activating). The experimental concentrates were prepared by sluicing on active river channel. Next, the separation results were achieved using gravity and electromagnetic methods with different magnetic intensities. The prepared rutile contained from 63.3% TiO2 to 87% TiO2. The ilmenite concentrate contained 20.5% TiO2 and 39.2% ilmenite. The garnet concentrate contained 94% garnet. The monazite concentrate contained 86.6% monazite, and the sum of REE oxides was 50.1%. The zircon concentrate containing 63.7% ZrO2 means that the prepared concentrate contained 96.1% zircon.

Reservoir Interpretation of Intrusive Rock Buried-Hill with Mud-Logging Data while Drilling—Taking the Y Area in the Qiongdongnan Basin of the South China Sea as an Example

The intrusive rock buried-hill reservoir is one of the main targets for oil and gas exploration in the offshore sedimentary basins of China. In order to discover the reservoir as early as possible for decision-making to save costs, reservoir interpretation with mud-logging data needs to be studied. Previous studies have showed that the homogeneity rocks reservoir can be well interpreted with mud-logging data u the Kb (mechanical specific energy ratio) method and the WL (tangential power)-WH (vertical power) intersection method. However, reservoir interpretation with mud-logging data for intrusive rock buried-hill has not been reported. The key steps or parameters of these two kinds of methods used for reservoir interpretation need to be modified for the vertical variation of intrusive rock buried-hill. Furthermore, confirming the interpretation of these two kinds of methods has not been reported. Taking the Y area in the Qiongdongnan Basin of the South China Sea as an example, the intrusive rock buried-hill can be divided into four zones based on its characteristics and genesis in descending order: the sand–gravel weathering zone, the weathering fracture zone, the inner fracture zone, and the base rock zone. The reservoir can be well interpreted when taking the MSE (mechanical specific energy) geometrical mean of the base rock zone as a basic value to calculate Kb. The reservoir will also be well interpreted when WH ranges from 0 to 4.5 MPa and WL ranges from 0 to 99 MPa in the column while intersecting. The layers of the reservoir can be interpreted as Kb < 1 in the sand–gravel weathering zone and the weathering fracture zone. The Kb < 1 and effective intersection of WL-WH layers at the same time could be interpreted as a reservoir in the inner fracture zone and the base rock zone. After combining the Kb method with the WL-WH intersection method, the reservoir of intrusive rock buried-hill can be well interpreted. The total thickness of the uninterpretable reservoir ratio is less than 20% compared to reservoir interpretation with well-logging for each well.

Research on profile design criteria of 100 m CSG dams

Cemented sand gravel (CSG) dams, as a newly-developing dam type, has attracted great attention in dam construction industry around the world due to its environmental friendliness and economic efficiency. However, there has been no uniform design specification for its construction yet due to insufficient application research. Based on the design theories of concrete dam and earth-rock dam, this paper quantified the impact and control factors of the foundation with reference to the sluice design theory, proposed the structural failure mode and optimal profile of four 100 m CSG dams with different cementing material content under different foundation conditions, and analyzed the profile design criteria of 100 m CSG dams. Results showed that: (1) the failure modes of CSG dams may include overall instable failure along the dam foundation plane, instable failure of dam slope and local stress failure of dam or dam foundation, etc.; (2) if CSG materials were used in rock foundation, the dam body stress should be used as the control criterion; while on extremely soft rock foundation, the control criterion should be based on the amount of CSG materials; (3) if CSG materials were used on rock-soil foundation, bearing capacity and anti-sliding stability of the foundation should be used as the control criterion; while on gravelly soil foundation, the control criterion should be based on the amount of CSG materials. These results may be used as a reference for designers, laying a foundation for the extension and application of CSG dams.

A Synthetic Chart for Internal Stability Assessment of Soils Based on Soil PSD Curves

Awareness of granulated soils’ internal instability is an important parameter when designing granulated filters, and the ability of a granulated soil’s internal stability can be verified using the soil PSD (Particle Size Distribution) curves’ secant slopes. The current work presents a new method to calculate the soil PSD curves’ secant slopes automatically, and a synthetic diagram is presented for the potential examination of the granulated soils’ internal stability. To verify the feasibility and accuracy of this synthetic diagram, 80 specimens of soil were investigated in this work and categorized into two groups: 50 sand–gravel soils and 30 (clay)–silt–sand–gravel soils. The obtained conclusions indicate that the internal stability and instability potentials of sand–gravel soils can be distinguished successfully with a synthetic chart and the Kenney and Lau criterion but cannot be assessed with the Kezdi and Sherard criteria. None of the criteria studied here can be used for the internal stability assessment of silt–sand–gravel and clay–silt–sand–gravel soils.

Second law based thermodynamic analysis of crushed gravel sand and biomass evaporator assisted solar still

The thermodynamic analysis of crushed gravel sand and biomass evaporator assisted solar still (CBSS) using the second law has been explored in this study, and the results have been compared to conventional solar still (CSS) in same climatic conditions of Coimbatore city in India. The saline water and air vapour were pre-heated before entering the solar still basin using the thermal energy extracted from crushed gravel sand and biomass evaporator. The air vapour mixture and saline water temperature of CBSS were greatly improved by 23.2% and 23% than CSS, respectively. The maximal cumulative productivity and exergy efficiency of CBSS were found to be 51% and 35% greater than CSS, respectively. The diffused heat rate observed in both the solar stills were estimated using entropy analysis and the results revealed that the highest entropy observed in CBSS was 60.7% higher than CSS. In CBSS, the basin and saline water exergy destruction was about 12% and 22% higher than CSS, respectively. The results demonstrated that the CBSS can greatly lower the demand for potable water.

Analisis Jenis Mikroplastik pada Sedimen Dasar Perairan Pulau Untung Jawa, Kepulauan Seribu, DKI Jakarta

Microplastics are small plastics (<5 mm) that are difficult to decompose, thus making this material last for a long time. This causes serious problems, especially in the waters. This study aims to quantitatively analyze the sediments found at the bottom of the waters and the types of microplastics as well as the factors that influence their presence in the seabed sediments of Untung Jawa Island, Seribu Islands. The method used is descriptive and observation, wherefrom these methods are determined 4 sampling stations with a depth of 15.4 – 23 m sediment sampling. The result of this research is that the most commonly found microplastics are fragments. The total number of microplastics found was 1324 microplastic particles with characteristic sizes ranging from 15-900µm and various colors. The highest abundance that dominates the number of microplastics based on their size is in the <250 m category with a percentage of 47%. Meanwhile, in the 250 m size category, the frequency was 36% of the total number of microplastics found, then 13% for the 500 m size category, and the remaining 4% frequency for the >750 m size category was found. The results showed that the gravel sand sediment had the highest number of microplastics compared to other sediments. Based on descriptive observations of current data, it is known that there is a relationship between currents and the distribution of microplastics at the research station.

Permeation grouting diffusion mechanism of quick setting grout

Quick setting grout is used in permeation grouting projects to control the grouting diffusion range effectively and reduce the waste of grout. Owing to the double-component injection method and quick setting property of the grout, the viscosity of the quick setting grout is non-uniformly distributed in the grouted region, which has a significant influence on the grouting diffusion process. In this study, the permeation grouting process of a quick setting grout was studied. A 2-D cylindrical permeation grouting diffusion model was developed considering the non-uniform distribution of grout viscosity. A visible permeation grouting diffusion simulation test system was designed and established. A series of tests were carried out to verify the correctness of the theoretical model, in which cement–sodium silicate grout, a typical quick setting grout, with two water–cement ratios (W/C = 1, 2) and gravel sand with two different ranges of particle size (2–5 mm, 5–20 mm) were used. The results show that (1) when the size of the void space in the sand stratum exceeds a certain value, the permeation diffusion of grout is completely controlled by grout gravity, and the influence of the quick setting characteristics can be ignored. Otherwise, the quick setting characteristics have the most important effect on permeation diffusion. (2) The calculated results agree well with the test results. The calculated injection pressure result is 1.0–1.4 times the experimental result, and the calculated diffusion radius is 95.7% –98.5% of the test value with the same final injection pressure. (3) It is necessary to consider the non-uniform distribution of viscosity in the calculation of the permeation grouting process of a quick setting grout. For a quick setting grout, if the non-uniform distribution of viscosity is not considered, the injection pressure would be overestimated by more than 10 times the actual value, and the diffusion radius would be underestimated by 30%–50% of the actual value.

Shear characteristics of calcareous gravelly sand considering particle breakage

Shear characteristics of calcareous gravelly sand considering particle breakage

Experimental Study on the Dilatancy Characteristics and Equation of Saturated Sand–Gravel Composites during the Whole Shearing Process

Experimental Study on the Dilatancy Characteristics and Equation of Saturated Sand–Gravel Composites during the Whole Shearing Process

PREPARATION OF CONCRETE BASED ON GLASS WASTE

PREPARATION OF CONCRETE BASED ON GLASS WASTE