Sand Gravel Research Articles

Suitability of Local Soil for Low Volume Road Construction: The Case Study of Niger Delta Region, Nigeria.

This work describes the suitability of soils located in the Niger delta region of Nigeria for road construction. The soil classification tests as well as tests to determine the moisture-density relationship and shear strength tests were carried out in accordance with British Standards. Also, additional soil data in these localities were obtained from construction and consultancy firms. A total of eighty-three (83) soil data were collected and used for analysis. The sieve analysis indicates the absence of coarse sand grains and gravels, while the plasticity chart shows that most of the soils falls within the non-plastic and low plasticity regions. The range of the angle of internal friction and cohesion obtained from the tests are 2 to 43 0 and 3 to 82 KN/m 2 respectively. These soil properties are below specified limits for base and sub base materials and will require improvement is a necessity for road construction in the region.

Effect of bio-cementation on geophysical and cone penetration measurements in sands

Microbially induced calcite precipitation (MICP) is a potentially environmentally conscious ground improvement method that can improve the engineering properties of granular soils through the precipitation of calcite. In this study, an experiment involving two 1.7 m diameter tank specimens was completed to investigate the effect of bio-cementation on cone penetrometer and geophysical measurements in sands. Following nonuniform bio-cementation treatments, specimens achieved calcite contents ranging from 0.5% to 5.3% by mass, shear wave velocity (Vs) values between 131 and 967 m/s, and mid-depth cone penetration resistances (qc) ranging between 3.6 and 32.1 MPa. At calcite contents exceeding 5.0%, qcand Vsimprovements were as high as 527% and 686%, respectively. Although cone penetration resistance, sleeve friction, and friction ratio measurements exhibited limited sensitivity to bio-cementation at calcite contents of less than 3.0%, Vsmeasurements successfully detected bio-cementation at calcite contents near 1.0%. When qcand Vsmeasurements were compared at similar locations, increases in an empirical parameter (KG) enabled improved detection of bio-cementation at calcite contents near 0.5%. Large increases in normalized tip resistances (Qtn) and small decreases in normalized friction ratios (Fr) with increasing bio-cementation resulted in cemented materials plotting near and within the gravelly sand and sand-like dilative soil behavioral type regions using two soil behavior type (SBT) charts.

Application of high-frequency impedancemetry approach in measuring the deposition velocities of biomass and sand slurry flows in pipelines

Since the lower limit to operating velocities in slurry transport systems is influenced by deposition conditions, measuring the “deposition velocity” is an essential step in slurry pipelines’ design and operation. This study proposes a new experimental technique in measuring deposition velocities in slurry pipeline transport called the high-frequency impedancemetry approach. This non-invasive technique of measuring electrical properties of substances, based on their frequency-dependent behavior, was applied using a 16-electrode impedancemetry device on a 25m long closed-circuit pipeline to measure the deposition velocities of sand- and biomass–water mixture flows. Slurries of play and gravel sands, as well as wheat straw and wood chips biomass feedstock, were prepared over a range of concentrations (1.5–20wt% dry-matter), and deposition velocities were measured over a wide range of operating velocities (0.04–4.5m/s). Experimental measurements for sand–water mixtures were found to be in good agreement with empirical correlations derived previously through various analytical and mathematical techniques. In addition, for the first time, the deposition velocities for biomass–water mixtures were measured and found to be in the range of 0.21–0.8 m/s; surprisingly well below the common range of commercial pipelines’ operating velocities, i.e., 1.4–3.0m/s.

River Morphodynamic Evolution Under Dam-Induced Backwater: An Example from the Po River (Italy)

Research Article| October 16, 2018 River Morphodynamic Evolution Under Dam-Induced Backwater: An Example from the Po River (Italy) Vittorio Maselli; Vittorio Maselli 1University of Aberdeen, School of Geosciences, Aberdeen, U.K. 2Institute of Marine Sciences, ISMAR-CNR, Bologna, Italy Search for other works by this author on: GSW Google Scholar Claudio Pellegrini; Claudio Pellegrini 2Institute of Marine Sciences, ISMAR-CNR, Bologna, Italy Search for other works by this author on: GSW Google Scholar Fabrizio Del Bianco; Fabrizio Del Bianco 3Consorzio ProAmbiente, Bologna, Italy Search for other works by this author on: GSW Google Scholar Alessandra Mercorella; Alessandra Mercorella 2Institute of Marine Sciences, ISMAR-CNR, Bologna, Italy Search for other works by this author on: GSW Google Scholar Michael Nones; Michael Nones 4Research Centre for Constructions, Fluid Dynamics Unit, University of Bologna, Bologna, Italy Search for other works by this author on: GSW Google Scholar Luca Crose; Luca Crose 5Agenzia Interregionale per il Fiume Po, AIPO, Settore Navigazione Interna, Parma, Italy Search for other works by this author on: GSW Google Scholar Massimo Guerrero; Massimo Guerrero 6Department of Civil, Chemical, Environmental and Material Engineering, University of Bologna, Bologna, Italy Search for other works by this author on: GSW Google Scholar Jeffrey A. Nittrouer Jeffrey A. Nittrouer 7Rice University, Department of Earth, Environmental, and Planetary Sciences, MS-126, Houston, Texas 77005, U.S.A. Search for other works by this author on: GSW Google Scholar Journal of Sedimentary Research (2018) 88 (10): 1190–1204. https://doi.org/10.2110/jsr.2018.61 Article history first online: 16 Oct 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation Vittorio Maselli, Claudio Pellegrini, Fabrizio Del Bianco, Alessandra Mercorella, Michael Nones, Luca Crose, Massimo Guerrero, Jeffrey A. Nittrouer; River Morphodynamic Evolution Under Dam-Induced Backwater: An Example from the Po River (Italy). Journal of Sedimentary Research 2018;; 88 (10): 1190–1204. doi: https://doi.org/10.2110/jsr.2018.61 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyJournal of Sedimentary Research Search Advanced Search Abstract River systems evolve in response to the construction of dams and artificial reservoirs, offering the possibility to investigate the short-term effects of base level oscillations on fluvial architecture. A major effort has been dedicated to the understanding of river response downstream of large dams, where deep channel incisions occur in response to the removal of sediment that is sequestered in the upstream reservoir. Integrating field observations and numerical-modeling results, this work quantifies the sedimentary and morphological changes of the Po River (Italy) upstream of the Isola Serafini dam to investigate the impact of dam-induced backwater on river morphodynamics. The construction of a reservoir generates a new base level that forces an upstream shift of alluvial lithofacies and a change in the planform geometry of the river. The lateral migration rate of the channel is up to 45 m/yr upstream of the influence of backwater flow and ca. 10 m/yr at the transition from normal to backwater flow conditions (30 km from the dam). Within this reach, a reduction of the bed shear stress promotes deposition of coarse-grained sediment and the emergence of the gravel–sand transition of the river. The lateral migration of the channel continuously decreases over time, and rates < 5 m/yr can be observed in the reservoir backwater zone. This trend is accompanied by the drowning of channel bars, the reduction of river competence, and an increase in bedform spacing. Oscillatory backwater and drawdown surface water profiles can be observed closer to the dam, which are associated with varying low-discharge and high-discharge events, respectively. While low-flow conditions, persisting for much of the year, allow the deposition of fine-grained sediment, high-discharge events promote not only the resuspension and transport of fine material but also the progressive erosion of channel bars and the overall deepening of the thalweg. This study provides a clear picture of the river evolution in response to the construction of a hydropower dam that may be of help in predicting how other fluvial systems will respond to future human interventions. Moreover, the result of how changes in base level and oscillations in water surface profile (backwater and drawdown) control river hydro-morphodynamics and sediment transport may provide new insights when reconstructing ancient fluvial and deltaic sequences. You do not currently have access to this article.

A multi-scale analysis method for the simulation of tunnel excavation in sandy cobble stratum

Sandy cobble stratum is a kind of heterogeneous geological body. A further study on the safety of wall rocks and underground structure demands developing suitable analysis method to simulate tunnel excavation in such a formation. Macro-scale simulations assume the sandy cobble soil to be homogeneous in numerical models. They get more efficient computing, but have difficulties in capturing enough information about the meso-scopic fields needed. Meso-scale simulations explicitly represent the individual components of the heterogeneous internal material structure in numerical models, e.g. the shape and the spatial distribution of rocks. They achieve high accuracy, but large computational cost would be needed. To reduce the numerical effort with the precision guaranteed, a multi-scale analysis method for simulating tunnel excavation in sandy cobble strata is proposed. In this method, the numerical model is divided into two regions, involving the meso-scale region and macro-scale region. The meso-scale region is a critical sub-domain disturbed by tunnel excavation, in it, the rocks and soil are considered as separate constituents. In the macro domain, the sand gravel soil was regarded as homogeneous materials whose effective material parameters were determined using an equivalent homogenization method. Three critical issues in the multi-scale method are explored, including: (i) the determination of meso domain and macro domain, (ii) the determination of rock maximum size that can be homogenized in the meso domain and iii) the determination of effective material parameters of soil-rock mixture during the equivalent process. By comparing with simulation results predicted by macro-scale and meso-scale simulation methods, the validation of the proposed multi-scale simulation method was carried out. The result indicates that the proposed multi-scale analysis method has a high efficiency without loosening accuracy on the simulation of tunnel excavation in sandy cobble stratum.

Modeling and simulation to predict variation of void ration and permeability influence on E-coli transport in heterogeneous sand gravel depositions

Modeling and simulation to predict variation of void ration and permeability influence on E-coli transport in heterogeneous sand gravel depositions

Hybrid Sand-Consolidation Fluid Offers Versatility in Treatment of Shallow Reservoirs

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 189548, “Tunu: From Laboratory to Field Application With a New Hybrid Inorganic/Organic Sand-Consolidation Fluid as Primary Treatment of Shallow Reservoirs,” by J. Andrieu, B. Kutzky, and B.T. Schackmann, Engineered nanoProducts Germany, and A. Mahardhini, SPE, I. Abidiy, SPE, and H.M. Poitrenaud, Total, prepared for the 2018 SPE International Conference and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 7–9 February. The paper has not been peer reviewed. The Tunu giant gas field is in the Mahakam region of the South China Sea. Because of the maturity of the field, the producing layer has moved from the deep zone of consolidated sand into the shallow zone of unconsolidated sand. Hydrocarbon production from the shallow zone is unmanageable without primary sand control downhole. In this paper, a new type of sand-consolidation low-viscous binding material, based on a combination of inorganic and organic components, is presented. Introduction Tunu produces almost 40% of total gas production in the Mahakam region. Hundreds of wells have been drilled in the field. Its primary-zone reservoirs are between 2000 and 5000 m true vertical depth (TVD) and typically consist of medium to fine sandstone with strong consolidation and high porosity. Above the primary zone, between 1500 and 2000 m TVD, is the Intra Beta section, with high porosity and sufficient consolidation. In the top layer of the field, shallow reservoirs, above 1500 m TVD, are typically poorly consolidated, with high porosity (28%) and permeability (greater than 1 darcy). Tunu’s shallow zone is an unconsolidated zone that requires sand control; types that have been used include gravel pack, standalone screen, and sand consolidation. Sand consolidation can be a challenging option because of the difficulty in finding a balance between compressive strength and regained permeability after treatment. Field Application After the first laboratory-testing phase, detailed in the complete paper, showed promising results, the decision to perform field trials on five wells was validated. Wells in Tunu are typically completed using 3.5- or 4.5-in. tubingless completion inside 7- or 9⅝-in. casing. A coiled-tubing (CT) unit was chosen for pumping into the target reservoir. First Campaign (2012–2013). The primary objective of the first campaign was to acquire experience with the composite binding material in the field without taking the risk of plugging the wells. Therefore, a large amount [6 pore volumes (PV)] of overflush was used. Several tests and subsequent adjustments were developed to tailor the product to actual field conditions. The first campaign began in October 2012 and ended in July 2013 after treatment on five wells. On the basis of laboratory test results, the treatment comprises the following steps: Activation of binding material by dissolving the initiator Injection of preflush fluid (0.75-fold binding material volume) Injection of the binding system, followed by a small pill of spacer (maximum 0.5 bbl of preflush) Post-flushing or overflushing (six-fold binding material volume for first campaign)

Defective vacuum well in a deep excavation, prevention of a serious incident

AbstractIn the course of the new construction of the Wehrhahn Line in Düsseldorf, works included the top‐down building of the station at Schadowstraße with back‐anchored diaphragm walls embedded up to 12 m into the Tertiary fine sand. The formation of the excavation was planned to lie above this in the Quaternary sand gravel. During the construction period, it was noticed that the Tertiary groundwater aquitard in the east part of the excavation is up to 2.5 m higher than forecast. This made necessary the installation of partially inclined suction wells in the Tertiary, in the protection of which the Tertiary groundwater was to be replaced by a surface filter. Altogether 41 suction wells were sunk.Shortly before reaching the excavation bottom level, an increased sand freight and an unplanned higher inside water level were recorded in places. Immediately introduced investigations showed that a defective foot cap had led to the intake of fine sand. In consequence, an erosion channel had formed at the underside of the lance, running through under the diaphragm wall. After a first stabilisation, a remedial concept was worked out collaboratively with all parties. Accordingly the filter section was closed by nitrogen freezing and the action point of the heave was moved downward. An adapted excavation concept was also decided from heave calculations. The extent of the frozen body was checked with an extensive monitoring programme. Through meticulous preparation and the frictionless collaboration of all parties, a major incident could be prevented.

Evaluation of groundwater potential in Kabirwala area, Pakistan: A case study by using geophysical, geochemical and pump data

ABSTRACTKnowledge of hydraulic parameters (hydraulic conductivity and transmissivity) is essential for the delineation of groundwater potential zones. Conventionally, these parameters are measured using pumping tests carried out on boreholes. However, pumping tests are costly, labour intensive and require a considerable amount of equipment. The integration of geophysical methods with pumping tests provides efficient and cost‐effective alternative to calculate hydraulic parameters. Fifty electrical resistivity soundings were carried out in the study area using Schlumberger inter‐electrode configuration to obtain hydraulic characteristics that are estimated through the pumping tests. To apply this approach successfully, sufficient number of boreholes are used. Part of the boreholes, in which pumping tests were carried out, is used for both to constrain resistivity inversions and to establish the empirical relationship between the interpreted geophysical and hydraulic parameters. The rest of the boreholes without pumping tests are still used for constraining the inversions. Initially, aquifer parameters were measured using pumping tests at 12 water wells. Afterwards, transmissivity (T) and hydraulic conductivity (K) were correlated with transverse resistance (Tr) and the bulk resistivity (ρo) of the aquifer at other sites where pumping tests had not been conducted. In this way, the entire study area was covered to assess the groundwater reserves. The hydraulic properties obtained by the geophysical method fit pretty well to both the pumping and physicochemical data of the investigated area. The integrated study reveals five layers (i.e. topsoil, clay, clay sand, sand and gravel sand) and three potential zones (i.e. high, medium and low potential aquifer zones) with specific ranges of T, K, Tr and ρo. The results suggest that, in case of sparse well data, the aquifer parameters can be estimated using the relations depending on the specifications of the area.

Elastoplastic Model of Sand Under Complex Loading

The unified hardening model for overconsolidated clay is extended to the cyclic model considering the stress–strain relationship for sands by adopting the rotational hardening rule. The equations for the normal consolidated line and critical state line are revised in the e – ln p space to describe the breakage behavior of gravel sands under high pressures. The power function is used to define the above equations. The model features the following characteristics: (1) equations for the above lines are redefined in the e – ln p space; (2) potential strength is revised by the Hvorslev line containing the power parameter; (3) cyclic behavior of sands is described by the evolutionary rule of current yield surface and rotational hardening rule; (4) generalized cyclic model is realized using the transformed stress method based on the spatially mobilized plane criterion. Simulation results show that the breakage and cyclic loading behavior of gravel sands are adequately described.

Incipient Motion for Gravel Particles in Cohesionless Sediment Mixtures

This paper deals with the incipient motion for gravel particles in cohesionless sediment mixtures having silt and sand. The mixtures comprised of gravel–silt and gravel–sand–silt were used in the present experimental study. The critical shear stress for gravel particles was noted to be lower in the presence of silt particles. A formulation has been developed for the determination of critical shear stress of gravel particles. The governing factor includes the mean size of gravel particles, arithmetic mean of mixture, and the probability of hidden–exposure factor. The regression analysis as well as goodness-of-fit test was conducted for the proposed relationship which was found to be in good agreement with the data of present study as well as for other authors. The proposed formulation for the critical shear stress converges to Brownlie’s (1981) equation in case of uniform sediment.

Physico-Mechanical Properties and Microstructure of Polymer Concrete with Recycled Glass Aggregate.

The paper presents an analysis of the possibility of using glass waste from worn out lighting materials as an aggregate for a polymer concrete. Glass waste was obtained from the company utilizing glass lighting elements, which was then subjected to crushing. The aggregate obtained was subjected to the tests of basic features, which were compared with aggregates that are traditionally applied to concretes. The next stage of the research program was the production of a polymer concrete that contained glass aggregate. Several types of mixtures were prepared in which glass waste was combined in various proportions with traditional sand–gravel aggregate. As a part of the research, the basic physical and mechanical characteristics of polymer concretes were determined. The microstructure of composites was also analyzed using a scanning electron microscope. The results of the research have shown that the aggregate obtained from glass waste can be successfully used for the production of a polymer concrete. The most beneficial physico-mechanical properties were obtained for a composite in which glass waste was used as a 50% substitute for traditional aggregate.

Numerical Simulation for Shallow Strata Stability of Coral Reef in the Southwest of Yongshu Reef (South China Sea)

In recent years, infrastructure construction on coral reefs has been increasingly developed. Therefore, the shallow strata stability of coral reefs in the South China Sea should be evaluated. This study aims to investigate the profiles for the shallow strata of coral reefs in the southwest of the Yongshu Reef, particularly in the hydrodynamic marine environment, and to establish a geological model for numerical simulation using Geo-Studio. The shallow strata of the coral reefs include mass gravel, sand gravel, mid-coarse sand, silty sand, fine sand, and reef limestone. The shallow reef slope near the lagoon is similar to a ‘layer cake’, in which the side close to the sea is analogous to a ‘block cake’. The simulation results showed that coral reef stability depends on wave loads and earthquake strength and on the physical properties of coral reefs. The factor of safety for the outer reef is greater than 10.0 under static, wave, and seismic conditions; this indicated that the outer reefs were less affected by waves and earthquakes. However, the factor of safety next to the lagoon varied from 0.1 to 5.3. The variation was primarily caused by the thick strata of coral reefs close to the sea (reef limestone, typically with the thickness > 10 m and equivalent to a block). The soil and rock layers in the coral reef strata with thicknesses < 10 m showed weak engineering geological characteristics. Our findings can provide useful information to future construction projects on coral reefs.

Study on the quantitative relationship between soil in situ strength and drilling parameters

The rational use of drilling parameters is a hot issue in the field of geotechnical engineering and geological engineering. A new method, for evaluating the bearing capacity of soils using drilling parameters was proposed. First, through the mechanical analysis of the drill bit, the preconditions and theoretical formulas for calculating the bearing capacity of soils using the bit’s torque are clearly defined. Next, drilling tests and dynamic cone penetration tests were performed on miscellaneous fill, silty clay, sandy clay, medium coarse sand and gravel sand, and the empirical formula for calculating the bearing capacity of these soils were given. Then, using the new method and the empirical formula, the bearing capacity of the soil under the roadbed was examined. The test results show that the bit’s torque is a good parameter for the evaluation of the bearing capacity of the soil. Finally, the application scope of the new method and the empirical formula is discussed, and the subsequent research directions are pointed out.

Palaeolithic occupation of the Anatolian High Plateau during a cold period: An MIS 6 aged artifact from the Avlamış Valley, Eskişehir, NW Turkey

AbstractIn the Avlamış Valley, 10 km north of Eskişehir (NW Anatolia), an undamaged triangular Levallois flake was encountered in a paleosol, 430 cm beneath the ground surface. The artifact has a minimal dorsal retouch on the right margin, and there is a light beige partial patina on the ventral surface. Based on the technological investigations, this artifact was made using the centripetal recurrent Levallois technique. An observation of the trench walls revealed the triple nature of the stratigraphy: an upper gravelly sand (Unit‐1), an underlying reddish‐brown pebbly paleosol (Unit‐2), and a lowermost dominantly pink, finer‐grained deposit (Unit‐3) where the artifact was retrieved. Optically stimulated luminescence ages indicate a strong influence of global marine isotopic stages (MIS) on the trench stratigraphy, with the deposit hosting the artifact dating to 148 ± 20 ka (MIS 6 cold period). The available pollen data from the same stratigraphic level verified an open steppe landscape with some arboreal plant cover during deposition. This is the first stratigraphically dated Middle Palaeolithic artifact from NW Anatolia, and one of the few in the whole country, thus igniting further discussion about the ways Pleistocene hominins adapted to cold and arid environmental conditions.

Sedimentary dynamics and benthic macrofauna distribution: Insights from the shoreface in southern Portugal

This study examined temporal distributions of macrobenthic communities in relation to bottom depth and specifically addressed whether variation in sedimentary dynamics affects species composition and functional structure. Sampling was carried in 2014 (February, May and September) off Tavira Island (southern Portugal). In each sampling period, three replicates of sediment samples were collected at 7, 12, 17 and 22 m deep for both macrobenthic and sediment characterisation. Distributional patterns of macrofauna communities were a function of the interaction between depth and temporal variability, influenced by a gradient in hydrodynamics and species recruitment. The duration of sediment remobilisation and the organic matter content in sediments were the main features of the shoreface sedimentary dynamics responsible for differences in macrobenthic species composition and feeding habits. At low depths (7 m), under intense hydrodynamic conditions and longer period of sediment remobilisation, sediments were characterised by slightly gravelly sand with low contents of organic matter and calcium carbonate. Macrobenthic communities inhabiting shallow depths displayed low abundance and species richness, being dominated by grazers and suspension feeders. In contrast, at the highest studied depth (22 m), subject to low sediment remobilisation, sediments were composed by gravelly sand with high contents of organic matter and calcium carbonate. This depth (22 m) was characterised by high abundances and species richness, reflecting a more stable macrobenthic community composed mainly by surface deposit feeders. According to the benthic communities, the seaward limit of significant wave effects on the seabed is around 7 m in low-energy periods and over 17 m in high hydrodynamic energy periods.

An Experimental Study on Mechanical Behavior of a Calcite Cemented Gravelly Sand

Abstract In the study presented herein, a simple method for laboratory calcite cementation of a reconstituted gravelly sand was presented. This method was used to prepare cemented gravelly sand specimens, which have similar natural characteristics to alluvial deposit of the city of Tehran. The formation and distribution of calcite bonds, as well as the effectiveness of the presented calcite cementation method in increasing interparticle cohesion, as observed in weakly to moderately cemented soil in Tehran, were evaluated by means of chemical analysis, X-ray diffraction technique, and unconfined compressive strength tests. The cementation technique was used to prepare triaxial specimens with calcite contents ranging from 1.5 to 6 %. Then, a series of monotonic and cyclic undrained triaxial tests was performed to characterize the behavior of calcite-cemented gravelly sand with different calcite contents under different loading conditions. In comparison with the specimens with zero calcite content, the cemented specimens exhibited a distinctly different behavior in terms of static stiffness and strength, cyclic pore pressure generation, and cyclic strength. Results of the monotonic triaxial tests indicated an increased shear strength with an increase in calcite content and confining pressure in the tested soil. Because of the presence of interparticle cohesion, cemented soils behaved less compressive during cyclic loading, and accordingly, the rate of positive pore pressure generation in these specimens was lower during loading with smaller induced plastic deformations.

ANALISIS LOST CIRCULATION PEMOMPAAN GRAVEL SLURRY PADA SUMUR X BERDASARKAN WAKTU TUNGGU

Unconsolidated formations tend to have sand problem that can lead to decline of production in Oil and Gas Well. There are some methods can be used to resolve sand problem like liner completion, meshrite liner, perforated liner completion, and gravel pack completion. Rock type of Well X is unconsolidated stone and the method which used in that well to surmount sand problem that occurred is gravel pack method. However, during pumping of gravel slurry there are some problems, partial or complete loss of the gravel slurry into the formation (lost circulation), waiting on sand sattle is one method that has developed to resolve loss circulation. This method is done by stopping pumping slurry after the amount of incoming sand has reached teoritical and more than 50%. The aim of this research to determine volume of gravel slurry that is needed and total of lost gravel sand. Gravel slurry needed to overcome sand problem in Well X consists of 109 sacks of gravel sand, 259.5 bbl of water, and 1834 lb (18 sacks) of KCL. Analysis of pressure test line chart to find out lost circulation problem. There are 147 sacks gravel sand missing as a result of lost circulation problem from 256 sacks of gravel sand that is pumped.

Vertical drains to minimize duration of seasonal waterlogging in Eastern Ganges Basin flood plains: a field experiment

In the Ganges basin, 8268.6 km2 of irrigation command area is waterlogged following monsoon rains. In this study, vertical drain (VD) (L × D, 7 × 1 m) filled with drainage gravel (6.5 m) and coarse sand (0.5 m) is installed in farmer’s agricultural field to minimize the duration of seasonal waterlogging and tested in Mukundpur village, Vaishalli District, Bihar, India. At the experimental site, inundation of rainfall and runoff from surrounding areas along with the seepage from an earthen canal start in September and remain till February, every year which prevents timely planting of wheat in November-end/December. Drainage due to percolation and recharge to groundwater is constrained by 6.4-m thick clay layer, below 0.5-m root-zone, and the groundwater level, which rises to the surface level. VDs were installed to provide a path and allow inundated water to recharge the aquifer, as groundwater level recedes. Groundwater level drop, floodwater infiltration rate, groundwater discharge, and VD capability were estimated through field data. Results show that VDs connected the floodwater to groundwater and transferred the floodwater to the aquifer when groundwater level started to recede. The site was fully drained by the end of December, permitting farmers to plant wheat in January providing cool nights at germination, thus increasing yields.

Shear Modulus and Damping Ratio of Sand–Gravel Mixtures Over a Wide Strain Range

ABSTRACTA total of 153 cyclic triaxial tests were performed on 19 sand–gravel mixtures over the strain range of 10–5–10–2, which shows that the particle characteristics have significant influence on the small-strain shear-modulus G0, shear modulus reduction G/G0, and damping ratio λ. An improved Hardin’s equation for the G0 was proposed to consider the effects of particle characteristics and consolidation state. Furthermore, the KZM model correlation was improved to characterize the G/G0 curve. A four-parameter equation of λ with parent rock type, particle gradation, and consolidation condition was also introduced to characterize the λ curve.