Compacted Sand Research Articles

Effect of Sand Compaction Piles on the Swelling and Shrinkage Behavior of Expansive Soil

This study aims to investigate the effect of sand compaction piles on the swelling and shrinkage behavior of expansive clay soil. A series of experimental laboratory tests were carried out using the modified Proctor mold and a circular footing. The diameter of the sand compaction pile was selected to give a replacement area ratio equal to 57%. To model the swelling and shrinkage cycles, water was added to the sample and the heave was recorded at regular time intervals. The shrinkage was obtained by heating the outer surface of the modified Proctor mold at a temperature of 110°C ± 5°C by a development heating system designed for this purpose to accelerate the shrinkage process. The vertical movement was recorded at regular time intervals. The swelling and shrinkage cycles were carried out under an externally applied pressure equal to 120 kPa. The main results of this study showed that, for untreated expansive soil, the swelling potential reaches the highest value at the second cycle and started to decrease for the subsequent cycles. After the fourth cycle, the swelling potential decreases and reaches about half the value of the initial swelling potential and the equilibrium state occurs. For expansive soil treated with a sand compaction pile, it is found that there is a significant reduction in both swelling and shrinkage potential. Moreover, it is observed that after the first cycle both the swelling and shrinkage potential decrease significantly, and both reach a negligible value after the second cycle.

Experimental Geotechnical Characterization Campaign of the Matam Soil for Lithology: Application to the Study of Supports of the Balterdi Bridge

This paper presents a geotechnical study whose objective is to determine the lithology of the soil of Balterdi village (Matam, Senegal). A bridge-type structure with six supports is to be built on the studied site. The drilling program consisted of six core drillings (SC) each 30 m deep with sampling and six destructive drillings with pressuremeter tests (SP) every 1.5 m up to 30 m deep. A pair of core and pressuremeter tests was carried out under each support. From the results of the core drill holes and the geological model of the site, it can be seen that the lithology of the soil along the structure consists essentially of soft clay layers, becoming firm at depth over the first 18 m on average (with some incursions of sandy layers) resting on medium to compacted sand up to 30 m. Brown clayey fill is also present between piers P3 and P5. The presence of a watercourse along the structure is noted. The foundations will therefore be carried out in the water. The results of the pressuremeter tests confirm the homogeneity of the soil over the whole area. Indeed, the values obtained are almost similar for all the tests. According to the limit pressures obtained, the clayey-sandy formations encountered along the structure are respectively soft to firm and moderately compact to compact. Their limit pressures are high enough to allow good bearing capacities.

Behavior of Sand Compaction Columns Installed in Cohesionless Deposits

A critical appraisal of the reviewed literature revealed that there are very limited studies available on the strength characteristics focusing on the load-settlement behavior of sand compaction columns (SCCs) when installed in cohesionless deposits. The method, though contemporary to the reputed stone column technique, is not yet studied rigorously in the available past studies, more precisely on the load-bearing characteristics when compared to the latter. Therefore the present study focuses on studying the behavior of multiple column composite foundation supported by sand compaction columns installed in loose to medium dense sands on a lab-scale numerical model. The study is carried out using commercially available finite element (FE) code 3D PLAXIS. Spacing to diameter ratio (S/D) ranging from 1.5 to 3.5 and initial relative density (RD) from 30 to 60% was adopted to study the changes in the load-settlement behavior of the improved deposit. Extending the FE model to further parametric study, the effect of angle of internal friction of the column sand and diameter of the column on the bearing capacity and settlement characteristics were analysed with and without normalization. From the results obtained, it is found that, for the considered FE model, the improved deposit with 3D spacing between the SCCs behaves distinctly different from all other cases analyzed.

A Review Study on Sand Compaction Piles in Cohesive Soils and as a Liquefaction Resistance Technique

The paper presents a detailed review of the state-of-the-art ground improvement technique namely sand compaction piles. The technique being originated in Japan has flourished around the globe for its efficient characteristics to act as a reinforcing member when it is installed in clays and is recognized as one of the best methods to prevent liquefaction. Known for its larger bandwidth of advantages, articles summarising the literature contribution on the technique are found to be very limited. Therefore, an attempt has been made to review the noteworthy literature that provides valuable information on the subject. An overview of the literature present on sand compaction piles installed in cohesive soils targeted to meet various demands like increasing bearing capacity, settlement, etc., and the technique’s efficiency in mitigating liquefaction associated problems are discussed.

Research on settlement test and numerical calculation of west artificial island foundation of Hong Kong-Zhuhai-Macao Bridge

ABSTRACT The artificial island project of the Hong Kong-Zhuhai-Macao Bridge includes the island construction project, the island part at the junction of the island and the tunnel, and the transition section between the island and the tunnel. The bearing capacity and deformation characteristics of the compacted sand pile composite foundation are studied through the load test of underwater compacted sand pile composite foundation, and given the parameters such as pile-soil stress ratio of composite foundation. In addition, the numerical simulation analysis of the three-dimensional foundation model of the West artificial Island was carried out. The parameters were adjusted through back analysis of the calculated results and the measured data, and the adjusted parameters were used to calculate the post-construction settlement of the West artificial Island, which met the design requirements of no more than 50 cm.

Different Soft Soil Improvement Techniques of Dhaka Mass Rapid Transit Project

The objective of this research is to the analysis of the different soil improvement techniques and the comparable model of these soil improvement techniques. In Bangladesh, different soil improvement techniques were used by different construction firms to improve the soil bearing capacity, but many of them could not verify the techniques after improvement. The verification of the soil improvement techniques is more important than the implementation of the soil improvement techniques. A comparison has been made between results obtained from three soft soil improvement techniques. Analysis of the effectiveness of soft soil improvement technique before and after improvement technique. From analyses, it has been revealed that for Tongi to Uttara along the Project package CP01 soft clay layer is effective for Sand Compaction Pile (SCP) and the sand layer, which is susceptible to liquefaction is effective for Dynamic Compaction (DC) method. After the improvement standard penetration test (SPT) value increases dramatically; this is a significant finding of this research.
 Journal of Engineering Science 11(2), 2020, 37-44

Impact of biochar produced from hardwood of mesquite on the hydraulic and physical properties of compacted soils for potential application in engineered structures

Biochar is a carbon-rich porous material obtained after pyrolysis of labile biomass in oxygen deficit condition. The production of biochar from invasive weed mesquite biomass could be beneficial of managing waste and preventing the emission of CO2 gas by open combustion, and amending them in soil could sequester carbon in soil and improve soil properties. The effect of biochar on soil hydraulic properties was studied for loose soils suitable for agriculture. However, soils in engineered/bioengineered structures often compacted for achieving structural stability. Moreover, biochar of different feedstock poses variable effect on soil hydro-physical properties and a combined study of hydro-physical properties of soil amended with mesquite biochar lacks in the existing literature. In the present study, the effect of mesquite biochar on the hydro-physical properties, such as Atterberg limits, compaction characteristics, infiltration rate (I) and saturated hydraulic conductivity (Ksat) of compacted silty sand and pure sand is investigated for potential application in bioengineered structures. The results show that the amendment of 5%, 10% and 15% biochar increased the atterberg limits and water absorption capacity while decreased the plasticity index, specific gravity, dry density and I of the soils. Moreover, the Ksat is found to be increased in silty sand whereas decreased in pure sand due to biochar amended. These changes in soil properties are attributed to the altered physical properties, mainly porosity (inter-pores) of the soil by the biochar amendment and the presence of chemical compound in biochar surface. The reduced I and Ksat in the present study suggest application of biochar amended soil in bioengineered structures; however, further field-scale studies are needed before implication.

Uniaxial compaction of sand using 4D X-ray tomography: The effect of mineralogy on grain-scale compaction mechanisms

The mechanical behaviour of sand aggregates is often studied as a proxy for poorly consolidated sands and highly porous sandstones. Only recently research aimed at understanding sand deformation has started to use techniques that allow for direct observation of the in-situ grain-scale processes. Using state-of-the-art, time-lapse micro X-ray computed tomography (micro-XCT) imaging, the influence of mineralogy on the compaction of sand aggregates has been investigated by performing uniaxial compaction experiments on four different mineral assemblies (quartz, K-feldspar, quartz + K-feldspar and quartz + K-feldspar + clay) at room temperature and dry conditions. For the experiments, a bespoke uniaxial compaction device (sample diameter 2 mm) was constructed and coupled with micro-XCT imaging. This enabled in-situ observation of the strain-accommodating processes during deformation. To verify that the microstructural evolution observed in the small-scale experiments is representative for larger aggregate behaviour, conventional, centimetre-sized, control experiments were performed. The observed inelastic deformation was mainly accommodated by processes such as intragranular cracking and intergranular sliding. At low axial stresses (10 MPa), grain fracturing mainly occurred in K-feldspar grains, if present, along cleavage planes. Only at higher axial stresses, fracturing of quartz grains, if present, was also observed. Presence of clays, in pores and grain contacts, delayed the onset of quartz grain breakage and enhanced porosity reduction as clay in grain contacts facilitated grain sliding and rearrangement.

Effect of racetrack surface on glycolytic activity of trained endurance horses

ABSTRACT No study has analysed the effects of wet and dry racetrack surface on the glycolytic activity of Arabian horses. The aim of the present study was to investigate the effects of wet and dry racetrack surfaces during a riding test in an Arabian endurance horse. Using a counterbalanced design, nine healthy and trained mixed-bred Arabian horses performed a single-step riding test on a wet (compacted sand) or dry (uncompacted sand) racetrack surface. The wet racetrack received a daily wetting and was compacted using a tractor, while the dry racetrack was upturned by a tractor daily. Both racetracks were elliptical with straight lines of 600 m and total length around 900 metres. Blood samples were drawn from the jugular vein, immediately after the end of the test, and used for the analysis of blood lactate concentration. Mean blood lactate concentration was significantly higher after the riding test on the dry racetrack (2.6 ± 1.6 mmol/L) compared with wet racetrack (0.9 ± 0.3 mmol/L) surface (p = 0.007; d = 1.48, [large]; 95%CI = 0.37–2.44). In conclusion, dry racetrack surface increases lactic anaerobic contribution in trained Arabian horses during a single-step riding test in the field.

Optical non linear characteristics of particles from natural resources

In these work some nano and micro particles such as granite, zeolite, diopside ferrous and sand glass which considered as waste or byproduct from mining industries. The micro and nano particles from natural resources were prepared by sieving and mixing with acidic solution at certain concentration, the particles are soaked and immerged in the acidic solution for long time to achieve reasonable hemogenity, sterring is done directly before measurements. The non linear characteristics of the prepared solution were measured by z-scan open aperture technique. The results explained in terms of the composition and structure of the micro and nano particles. Granite particles does not introduce any emission due to compact structure, while zeolite, diopside ferrous and sand glass have significant non linear spectrum related to their structure. The research introduces new applications of the ceramics materials micro and nano particles in non linear optical devices. The research ends with conclusions and recommendation for future work in this new field of applications. The new techniques and the new materials selected in the current study have good non linear optical characteristics; these are promising for practical application. It can be used for various optical applications such as optical modulators, sensors and other optical protection applications.

Shear strength characteristics of a sand clay liner

This study investigated shear strength behaviour of compacted sand–clay mixtures used as liners, with 10%, 20%, and 30% clay contents. A natural high-plasticity and highly expansive clay found in the eastern province of Saudi Arabia was used. A series of consolidated undrained triaxial tests and pore water pressure measurements of saturated samples with various clay contents and confining pressures was conducted using a computer-controlled Bishop and Wesley triaxial cell. The unit was equipped with pressure volume controllers and a pressure transducer for measuring sample volume changes and excess pore water pressure. The experimental test results indicate that clay content and confining pressure significantly affect stress strain response curves, pore water pressure generation curves, and steady-state shear strength. Sand–clay mixtures with clay content less than 10% showed a tendency toward contractive behaviour. The failure line slope increased in accordance with clay content increase. The deviator stress versus axial strain of saturated sand–clay mixtures indicated a hyperbolic trend. The stress ratio versus axial strain representation was more informative for the shear strength behaviour assessment. Clay content did not significantly affect critical-state friction angle. Scanning electron microscope images of the sand-clay mixtures with different clay contents are presented.

Centrifuge model tests and effective stress analyses of offshore wind turbine systems with a suction bucket foundation subject to seismic load

The seismic behavior of a suction bucket foundation for offshore wind turbine systems is studied using centrifuge model tests with a scaling factor of 1/100 and an effective stress analysis based on the strain space multiple mechanism model implemented in the FLIP computer code (Finite element analysis program of Liquefaction Process). The primary dimensional parameters of the prototype scale suction bucket foundations selected for this study are as follows: skirt length L = 8 m, diameter D = 19 m, L = 9 m and D = 12 m. Placed on firmly compacted saturated sand, suction bucket foundations supporting an idealized wind turbine tower 100 m in height are subject to a recorded earthquake motion with a peak acceleration of 0.25g.Results of the model tests and the analyses indicate that the constitutive model used in this study is capable of capturing the essential features of the seismic behavior of offshore wind turbine systems supported by suction bucket foundation. In particular, this model is capable of evaluating the confining effect of a suction bucket on the increase in excess pore water pressure inside the bucket in response to the vertical confining pressure applied from the tower and shaft structure of the wind turbine system. This model is also capable of evaluating the inertia effects of the tower and shaft structure above the foundation affecting the driving mudline moment and shear, which leads to the deformation of the suction bucket in terms of rotation. The residual inclination of the tower is less than 0.001 rad, which satisfies the design criteria, and has a rotation angle of 0.005 rad.The strain space multiple mechanism model is applied to a general combination of static and cyclic loads in storm conditions. The computed results are consistent with those of a proposed cyclic load response diagram based on 1 g model tests at partially drained conditions in an earlier study by Nielsen et al. (2017), suggesting the applicability of this model to general load conditions is reasonable.

Effectiveness of sand compaction piles in improving loose cohesionless soil

This paper investigates the effectiveness of Sand Compaction Pile (SCP) in improving the density characteristics of cohesionless soil. The performance of SCP for different pile spacing, pile arrangement such as triangular and square, and coarseness of bed materials on the degree of soil improvement is studied in a better-controlled laboratory environment rather than more variable field environment. A SCP miniature device and a miniature dynamic cone penetrometer (DCP) were designed and fabricated in the laboratory. Sand beds containing loose cohesionless soil were prepared in a fabricated tank by sand raining from the pre-calibrated height. The SCPs were installed using the miniature device on the sand bed by displacing soil in the lateral direction in order to densify the bed prior to pouring sand in the displacement holes. The data of DCP in terms of penetration index and field density were measured at various depths to obtain correlation parameters between DCP and relative density of soil. This correlation was used to determine the relative density of improved soil beds due to the installation of SCPs. The improved soil condition was measured in terms of a decrease in penetration index or an increase in the relative density of bed materials. Some of the major findings include: the rate of increase of relative density due to installment of SCP is similar irrespective of the coarseness of bed materials; smaller pile spacing compared to an optimum spacing causes insignificant soil improvement; the triangular pattern shows better soil improvement compared to the square pattern for a given pile spacing.

Effects of plant growth and spacing on soil hydrological changes: a field study

Effects of plant growth on soil hydrological changes need to be considered for long-term vegetation management of geotechnical infrastructure. Most existing studies focused on one particular plant age. This study quantifies the effects of plant growth on the evolution of soil hydraulic properties and matric suction over time, through field monitoring and numerical soil–plant–atmosphere interaction modelling. A full-scale flat landfill cover in China was monitored for more than a year. Four 6 m × 6 m grass plots made of compacted silty sand were formed, three of which were vegetated with shrubs having different plant spacing (0·5, 0·8 and 1·1 m), while the fourth one was left grassed. In addition to monitoring matric suction changes, multiple soil cores were sampled to determine the root length density (RLD) and saturated hydraulic conductivity (ks) after 2, 4, 7 and 13 months of transplantation. Regardless of plant spacing, ks always reduced during the first 2–3 months of growth. When a threshold RLD of 2 cm/cm3 was reached, ks increased substantially. This was especially the case for closely spaced shrubs, whose roots were decayed. Suction preserved upon rainfall depended on the plant growth-induced changes in ks. Although closely spaced (0·5 m) shrubs preserved the most suction during the first 6 months of growth, the beneficial hydrological effects vanished after growing for 9 months because of the shrub growth-induced increase in ks. Instead, the widely spaced (1·1 m) shrubs, which showed the least increase in ks, preserved the most suction in later stages. Nonetheless, the spacing of shrubs did not affect the annual cumulative percolation of the landfill cover very significantly, which narrowly ranged between 3·1 and 4·7% of the annual precipitation during the monitoring period.

Effect of biochar type on infiltration, water retention and desiccation crack potential of a silty sand

Biochar is a carbon-rich material obtained after thermochemical conversion of biomass under no oxygen environment. The effect of biochar amendment on soil properties, such as water retention, infiltration and desiccation crack potential was studied in the recent years. However, the effect of biochar or feedstock type on these properties is not explicit. This study investigates the effect of two different (in terms of feedstock) types of biochar on the water retention, infiltration and desiccation cracking behavior of compacted silty sand. Water retention characteristics, infiltration rate and the progression of desiccation cracks were measured after compacting soil amended with 5–10% (w/w) biochar produced from water hyacinth (WHB) and mesquite. Measurements were also taken for an unpyrolyzed material coir pith (CP, sourced from coconut husk)-amended soil for comparing the results of biochar-amended soil. The results show that the amendment of 5% to 10% biochar increased the maximum water holding capacity (θs), air entry value (AEV) and water content at 1500 kPa (θ1500) of the soil, whereas decreased the infiltration rate and peak crack intensity factor (CIF) of the soil. Moreover, the application of CP increased the infiltration rate. The amendment of WHB showed the highest increment in AEV and θ1500 and the highest decrement in infiltration rate and CIF compared to the other amendments. Based on the results, it is advisable to use the WHB-amended soil in bioengineered structures that could promote the growth of vegetation by higher water retention and could reduce the potential of leachate formation by decreasing water infiltration and desiccation crack potential.

Effects of the inclusion of industrial and agricultural wastes on the compaction and compression properties of untreated and lime-treated clayey sand

The reuse of industrial and agricultural wastes is an alternative method to provide low-cost building materials for the construction industry and reduce the environmental pollutions. This study evaluates the feasibility of using a couple of waste materials including palm fiber, palm fiber ash and fiber bundles both individually and in combination with lime to improve strength characteristics of clayey sand. A series of laboratory tests were performed on samples cured for 7, 14, 28 and 56 days to investigate the compaction properties, unconfined compressive strength (UCS) and failure characteristics of the untreated and lime-treated clayey sand. The results demonstrate that the application of all the additives resulted in a noticeable increase in strength, and both treated and untreated specimens exhibited more ductile behavior. It was also revealed that the mixture of lime and fiber performed more impressively compared to that of lime and fiber individually and the UCS of the improved specimens depends on fiber length and curing period. Inclusion of the various proportions of palm fiber, palm fiber ash and lime increased the optimum moisture content (OMC) and decreased the maximum dry density (MDD), while the addition of fiber bundles decreased the value of MDD and OMC. Palm fiber ash was more effective in increasing the UCS of specimens, and fiber bundles had the most significant impact on the variations of compaction properties.

Liquefaction study of soils in unified model and liquefaction potential evaluation of compacted sand

Owing to their specific sedimentary or weathering formation history, most soils confronted in civil engineering can be categorised into clayey and sandy soils. In view of the great mechanical difference, particularly the distinct liquefaction resistance, then precisely simulate the mechanical and liquefaction characteristics of different type soils become an important research issue in seismic design of civil engineering structures. Considering soil turns into overconsolidated state once experiences stress unloading, and which affects the mechanical and liquefaction characteristics in turn. Based on the classical Cam-clay model, with the introducing of subloading surface concept, the subloading surface Cam-clay model provide an unified constitutive model in the numerical simulation of different type soils. Based on the comprehensive parametric studies of state variables evolution and anti-liquefaction capability of soil conducted in this paper, we creatively unified the relationship between OCR and relative density of soil that widely adopted in the liquefaction resistance evaluation of sandy soil, and our test results shows high correlation between these two parameters. These findings provide a solid theoretic support and guidance for the dynamic compaction method that widely adopted in anti-liquefaction design.

Experimental studies of the working process of compaction of sand with a vibrating plate

The paper investigates the process of compaction of a sand layer with a manual vibroplate under various technological conditions. The moisture content of the sand layer was previously determined in accordance with the accepted methodology. Then, as a result of preliminary experiments, the authors selected the limits of variation of some technological parameters of the vibroplate. To reduce the volume of experiments and increase their accuracy, the authors used an almost rotatable three-level non-factorial plan. The obtained experimental data were processed using the Statistika.exe software. As a result, the obtained mathematical models describe the dependences of the density of the sand layer on the mass of the additional load and the speed of the vibroplate, as well as on the frequency of rotation of its unbalanced shaft. The results are presented in the form of three-dimensional graphs and equations describing the compaction process. The paper analyses the research results and conclusions. They will allow to determine some optimal technological parameters of the vibroplate during the compaction of the sand layer.

Study on fluidization process in jet flow dredging device and the effects of device structure to sand collecting performance

The device structure has important influence on the sand collecting performance of jet flow dredging device. In order to study the effects of device structure, this paper presents a research for fluidization process of compact packing sand in jet flow dredging device. The calculation method which considers the cohesive strength between particles is proposed. The effects of arrangement of jet pipe and diameter ratio between jet pipe and suction pipe on sand collecting performance are studied. By comparison, we found that the structure of jet pipe inside suction pipe has better sand collecting performance than it outside suction pipe. With the jet velocity increasing, the pipe diameter ratio corresponding to the maximum concentration of particle phase at outlet reduces.

DISPLACEMENT ANALYSIS OF SHEET PILE WITH TIE BEAM ON BREAKWATER CONSTRUCTION BY USING PLAXIS

The breakwater construction usually founded in coastal area with many public or company facilities. It is very useful to break the ocean waves so it can not reach the shore line. Furthermore, the breakwater construction is also applied as a barier for a port for ship docked. One of the type of breakwaters is tube column filled with compacted sand reinforced by sheet file and tie beam. This research will discuss about the sheet pile displacement in static and dynamic condition. Plaxis is applied as the main tool to built the 2-D model based on given data from field observation. The input parameter for this model is applied in soil stratigraphy, compacted sand column, sheet pile, tie beam, pseudostatic wave force, sea level and earthquake acceleration. The running of this model divided in three condition. There are static condition, static condition with pseudostatic wave force, and dynamic condition. The results show different displacement between the conditions. The sheet pile displacement in static condition is 3.35 cm at harbor side and 1.91 cm at open sea. The sheet pile displacement in static condition with pseudostatic wave force is 12.14 cm at harbor side and 12.08 cm at open sea. The sheet pile displacement in dynamic condition has 5 cm peak both harbor side and open sea.