Hydraulic Fill Research Articles

Soft soil foundation treatment of hydraulic fill site based on vibration boosting drainage consolidation method

Reclamation from the sea is a method of expanding urban area, but it also faces the problem of difficult treatment of soft soil foundation by hydraulic reclamation. Therefore, a soft soil consolidation method that combines vibration pressure boosting drainage and piled-load static pressure stacking is now proposed. To verify the effectiveness of this method, a consolidation test based on soft soil samples was designed and conducted in the study. The test results showed that when the sampling height was 240mm, the overall moisture content of the consolidated soil sample was the highest, 44.3%, and the consolidation effect was the worst. When the sampling height was 140mm, the overall moisture content obtained from the test was the lowest, 43.1%, and the consolidation effect was the best. The displacement of corner 2 and center point at the intersection of the preceding and following periods was greater, with values of 37.1 mm and 39.2 mm, respectively. At this point, the displacement of corner 1 was significantly smaller, at 30.9 mm. In the later loading stage, the slope of the vertical displacement curve significantly increased. When the experimental time reached 7000 min, the mixed method designed in this study had a drainage rate of 0.53 ml/min, which was significantly higher than other traditional methods. The experiment outcomes indicated that the method designed in this study had certain application potential for improving the consolidation effect of soft soil foundation in hydraulic fill sites.

Measurements of Shear Wave Velocity for Collapsible Soil

This paper examines the effects of collapsible soil structure on shear wave velocity. The study attempts to simulate hydraulic fill sand deposits, which represent a natural soil deposition process that can result in a collapsible soil structure. A series of resonant column tests and bender element tests on Ottawa sand was conducted on sand specimens and prepared by dry pluviation and simulated hydraulic fill methods subjected to various confining pressures. Shear wave velocities measured from both methods of deposition are compared and discussed. Results from this study show that for soil specimens with the same void ratio, samples prepared by simulated hydraulic fill have a lower shear modulus and shear wave velocity than the specimens prepared by dry pluviation, and the differences are more pronounced at higher confining pressures. The resonant column test results performed in this study were consistent with results from the discrete element analysis, full-scale testing, and centrifuge testing. The discrete element analysis suggests that soil fabric and number of particle contacts are the key factors affecting the shear wave velocity. These factors are dependent on the methods of deposition. Results from this study examining hydraulic fill collapsible structure shear wave velocity provide a step forward toward a better correlation between soil dynamic properties measured in field and laboratory tests.

Settlement prediction of shallow foundations for quality controls of sandy hydraulic fills

This paper describes a procedure for settlement prediction of shallow foundations on carbonate sands, but it is fully applicable and valid for siliceous sands. For practical purposes, the design of shallow foundations resting on medium dense and dense granular soils is typically governed by limiting settlement to tolerable values. Predicting foundation settlement is therefore important, but in standard practice it is necessarily based on indirect (and therefore often conservative) determinations of soil compressibility (or modulus), due to the intrinsic difficulties in obtaining direct measurements.While numerical analyses incorporating non-linear soil behaviour may be a preferred method for computing expected total and differential settlement of shallow foundations of given geometry and stiffness on sand under static loading, the method described in this paper consists of a simplified and expeditious method based on equivalent linear elasticity. The method uses: i) the elastic soil stiffness profile at small strain, E0(z) obtained from the shear wave velocity as the primary measurement of deformability and ii) the reduction in modulus as a function of strain magnitude, E(ε) to account for stiffness non-linearity. The beneficial effect on the soil initial stiffness of the applied footing load is also considered. The method was developed as an on-site tool for checking the compaction of hydraulic fills made of carbonate sand to form artificial islands, but its application can be extended to other natural and anthropogenic coarse-grained materials.

Optimal Backfilling Materials with High Compressive Strength Based on Multiple Linear Regression

Backfilling material such as tailing (mine wastes) mixing with cement or gypsum has grown throughout the world’s underground mines. However, despite their growing popularity, the typical hydraulic and mechanical fill types utilized in many mines still exist. Deep underground mining has increased due to the lack of commercial minerals nearby. Mine wastes were considered the main part of backfilling to prevent environmental pollution, ground subsidence after mine abandonment, and mine collapse during deeper extraction phases. The cemented backfill technique is the principal technique used in underground mines, which include cement with fly ash and/or filter dust, cement with tailing material and fly ash, gypsum with fly ash, and synthetic anhydrite with fly ash and have been reviewed. It has concluded that a backfilling material must be selected based on further goals, available material near the mine site, and economic factors. This paper analyzes different backfill material mixtures to create a technique that will increase safety in underground mining conditions and foresees an appropriate formula that gives high uniaxial compressive strength. The multiple linear regression (MLR) on the collected data from the experimental works to construct the relationship between the uniaxial compressive strength (UCS) of the mixture and the components of the backfilling and the prediction formula for expected compressive strength was obtained. The results revealed that the predicted regression equation was robust and reliable to predict the (UCS) for the new components of the filling (cement (CE), filter dust (FD), water content (WC), and time (T)).

Experiences of Underground Mine Backfilling Using Mine Tailings Developed in the Andean Region of Peru: A Green Mining Solution to Reduce Socio-Environmental Impacts

In Peru, socio-environmental conflicts related to the development of mining-metallurgical processes and the responsible disposal of mine tailings have become central issues for accepting mining projects, especially regarding building relationships of trust with the communities. This condition has prompted the Peruvian mining industry to advance in managing alternatives to the conventional surface disposal of mine tailings. A promising and increasingly popular management strategy for mine tailings in Peru is their disposal inside underground mines. This article presents: site-specific conditions, advantages/disadvantages, and lessons learned from practical experiences of mine tailings disposal in underground mines in Peru. In addition, some techniques are highlighted, such as (i) hydraulic fill, (ii) cemented hydraulic fill, and (iii) cemented paste backfill. Finally, this article concludes that the responsible disposal of mine tailings in underground mines is a green mining solution that reduces negative socio-environmental impacts, limiting the generation of acid rock drainage (ARD) and the leaching of metals due to the decrease in contact with oxygen and rainfall, thus mitigating the contamination of surface and underground waters, reducing the footprint of affectation in the territory, and eliminating the emission of particulate matter in the environment.

Mechanical behavior analysis and bearing capacity calculation of CFG pile composite foundation on coral sand site

Coral sand foundation formed by hydraulic fill often faces the problem of poor bearing capacity. This paper proposed for the first time to apply CFG pile composite foundation to coral sand sites to verify the feasibility of this scheme and understand its mechanical characteristics. Firstly, taking on-site coral sand as the research object, a pile sand interface shear test was conducted to clarify the mechanism of pile side friction. At the same time, the ultimate bearing capacity of CFG pile and its composite foundation was measured through in-situ static load tests. Then, based on the strength parameters of the pile sand interface revealed by indoor tests, numerical simulations were conducted to analyze the bearing characteristics of CFG piles and their composite foundations. Finally, a method for calculating the vertical bearing capacity of rigid piles in composite foundation considering interface parameters was proposed. The results showed that the bearing capacity characteristic values of single pile and composite foundation meet the design requirements; The interface friction angle and cohesion together increased the ultimate side friction by 64.41%; The load is mainly borne by the pile tip resistance, and the increase of the interface friction angle will make the proportion of the side friction load first increase and then decrease more obviously; The pile soil stress ratio first increased and then tended to stabilize as the interface strength increased. Compared with the field static load test results, the rationality of the calculation method for composite foundation rigid piles was verified. This study may have reference significance for the design and construction of coral sand foundation treatment in offshore island and reef projects.

Geotechnical Visualization and Three-Dimensional Geostatistics Modeling of Highly Variable Soils of a Hydraulic Fill Dam

Geotechnical Visualization and Three-Dimensional Geostatistics Modeling of Highly Variable Soils of a Hydraulic Fill Dam

Dynamic Response Analysis of Pile Group Foundation of Super-Giant Sewage Treatment Structure on Hydraulic Fill Foundation

In this study, a 3D numerical model, considering the dynamic interaction between soil, pile foundation, and super structure, and the parameter analysis of internal force response of pile group foundation under differences seismic intensity, was established based on the Bangladesh sewage treatment plant project to investigate the dynamic response of pile group foundation of liquid-containing structures. The results show that the internal force of pile gradually increases with time, and the horizontal dynamic displacement peak value appears earlier under different seismic wave responses and seismic intensity. With the increase of seismic time history, the variation degree of dynamic impedance with frequency and impedance peak will increase. The pile group effect and single pile bearing capacity of foundation in hydraulic fill fine sand and silty clay were verified. By comparing numerical simulation and theoretical calculation, the results show that the pile group foundation exerts the soil squeezing effect after pile construction is completed, and the dynamic elastic modulus of the soil layer can be increased. Simultaneously, the soil layer will have a better integral stiffness. The pile group effect coefficient obtained by the solid perimeter method is most consistent with the numerical simulation method.

Increase of CPT Cone Resistance in Sand Due to Installation of Press-in Piles

A pile testing programme in Tuas Racetrack, South-west Singapore, involved installing 600-mm diameter 30 m long, closed-toe, spun piles by jacking (press-in system) through about 10 m thick loose hydraulic sand fill and 20 m of marine clay, sandy silt, and into weathered mudstone. Static cone penetrometers soundings, CPTU, were pushed both before and after the pile installation at each pile location and two distances away from the test pile. The post-test CPTU soundings showed that the press-in installation resulted in significant increase of cone resistance in the sand fill even at several pile diameters away from the piles. No similar effect occurred in the natural soils.

Influence of fines on the monotonic and cyclic shear behaviour of volcanic soil “Shirasu”

Drained and undrained monotonic and undrained cyclic triaxial tests have been carried out on reconstituted samples of Shirasu originally deposited from pyroclastic flows in the Kagoshima area, Japan. This material contains 20%–30% fines derived from the same minerals as the coarse grains. Well-graded fines can form a weakly interlocked structure in loose Shirasu separating the coarse grains and resulting in a weak liquefiable soil. In order to clarify the mechanical characteristics of Shirasu, a series of triaxial tests were carried out on the original Shirasu and a material whose fines had been washed out. The “fines” Shirasu was weak with its properties highly dependent on the confining stress while the “no-fines” Shirasu had a high strength which decreased with increasing confining stress due to breakage of asperities. The presence of fines between coarse grains altered the location of critical state line of Shirasu. Under undrained cyclic loading and low confining pressures, the weakly interlocked structure of medium-dense “fines” Shirasu collapsed resulting in contractive behaviour and liquefaction. As the confining pressure was increased, this weak fine structure was compressed and the soil structure became stiffer under cyclic loading. In practical terms, this means that Shirasu which is placed as a loose hydraulic fill will be prone to liquefaction. The undrained cyclic response of medium-dense “no-fines” Shirasu was similar to that of dense “fines” Shirasu. Thus, the removal of fines was equivalent to compacting the material to a relatively high density.

Effect of geomaterial variability on seismic response analyses of earthen dams

In a recently completed research study, two-dimensional (2D) and three-dimensional (3D) seismic response analyses were performed on a hydraulic fill earthen dam located in north Texas, USA. Analysis results obtained from both methods were compared to study and address the influence of geomaterial variability on the seismic response of heterogeneous earthen dams such as hydraulic fill dams. For evaluating the material variability within the dam, twenty-eight piezocone penetration soundings (CPTu) were conducted along the crest of the dam. These CPTu soundings, along with the available laboratory test results, were utilized to represent various scenarios that depict geomaterial variability within the dam for numerical modeling and seismic response analysis. In the first scenario, limited subsurface investigation information obtained from six CPTu soundings distributed along the dam crest was considered to develop the numerical models. In the second scenario, all the twenty-eight CPTu soundings were utilized to model the same dam using extensive site characterization test results. The first natural frequency, earthquake-induced crest accelerations, and shear stresses of the dam segments were computed from 2D and 3D numerical analyses for both scenarios of site characterization results. Results indicated that a 3D analysis might be more appropriate than a 2D analysis for studying the seismic response of a heterogeneous earthen dam, especially when extensive site characterization information is available to model the dam for numerical analyses. Overall, the findings of this study emphasize the impact of geomaterial variability on seismic response analyses of heterogeneous earthen dams and will enable engineers to assess the conditions that warrant a comprehensive 3D analysis.

EVALUATION OF BUND STABILITY USING GEOSTUDIO SOFTWARE WITH GROUND IMPROVEMENT METHOD USING SAND-KEY AT RECLAMATION WORK ON SOFT SOIL

The use of sand-key reclamation works in soft and very soft soils to increase the stability of the bund construction. Reclamation using the hydraulic fill method requires a stable embankment structure to withstand the potential for landslides from landfills, and in sea areas with very soft subgrade soils, with small undrained cohesion values causes the bund to be unstable and do not exceed the critical limit. The purpose of this study is to evaluate the improvement of soft soil in bund construction so that it is stable using GeoStudio. The Bund stability analysis results show that the value of the sand-key depth depends on the variation in the depth of the seabed. At a seabed depth of -6 m, there is a sand-key depth of 7 m, -5 m the sand-key depth of 10 m, -4 m thesand-key depth of 10 m, -3 m the sand-key depth is 5 m. The final safety number of 1.404,1.438,1,675, and 1.354 respectively.

Stabilization of sand pit wall permeability using Ranney wells

Safety of operating conditions is the paramount objective in any mine design, planning, construction and performance. In the Kursk Magnetic Anomaly, the emphasis is laid on the integrated and efficient protection of surface and underground mines from groundwater inflows. Stoilensky iron ore field hydrogeologically adjoins the northeast of Dnepr–Donets artesian basin which is contiguous to the southwest slope of Voronezh crystalline massif. The field mostly occurs in the zone of damaged groundwater dynamics under the impact of drainage facilities at opencasts of Lebedinsky and Stoilensky GOKs (Mining and Processing Plants) and at Gubkin Mine, hydraulic fills and tailings ponds of operating processing factories, and Stary Oskol water storage basin. The adversities of groundwater catchment inside sand pit wall rock mass are analyzed. The capabilities of a pit wall drainage system in stabilization of sand permeability are discussed. The experience gained in design and construction of a local drainage system based on Ranney-type well within the limits of Novaya station of an operating opencast is summarized.

Model Uncertainty for Settlement Prediction on Axially Loaded Piles in Hydraulic Fill Built in Marine Environment

Model uncertainty is present in many engineering problems but particularly in those involving geotechnical behavior of pile foundation. A wide range of soil conditions together with simplified numerical models makes it a constant necessity to review the accuracy of the predictions. In this paper, the outputs of some seventy (70) pile axially-loaded tests have been reviewed with a classic numerical model to assess pile deformation. Probabilistic approach has been used to quantify uncertainties coming from soil tests, statistic uncertainty and also from the model itself. In this way, a critical review of the prediction method and a way to quantify its uncertainty is presented. The method is intended to be used in a wide range of engineering problems.

Economic substantiation of construction of narrow profile hydraulic-fill structures

Hydraulic-fill structures with free flow of pulp have a flattened transverse profile, especially in cases of hydraulic fill of the structure into water. The flattened profile of the structure demands significant financial and labor costs for its construction, reducing the efficiency of the hydraulic-fill structure. This paper deals with the existing methods for the construction of narrow profile hydraulic-fill structures, their economic indicators; the designs of hydraulic-fill structures using geosynthetic materials developed by the authors, which make it possible to increase their efficiency in comparison with previously known methods, especially when the structures are hydraulically filled into water.

Study on sedimentation characteristics of soft clay

There are large areas of soft clay distributed in coastal areas of China, which are often used as raw materials for hydraulic fill engineering in recent years, and its sedimentation characteristics have attracted more and more attention. In this paper, the influence of initial water content on the sedimentation characteristics of soft clay is studied through the experiment. The results show that: (1) the sedimentation process of soft clay can be divided into two stages: sedimentation stage and self weight consolidation stage. The sedimentation stage has a short time, and the soil property index tends to be stable quickly; the self weight consolidation stage is very slow, and the soil property index almost has no change; (2) the larger the initial water content of soft clay, the greater the sedimentation rate and the faster the sedimentation; (3) the higher the initial water content, the faster the sedimentation, the higher the water content and the void ratio, the smaller the density.

The Main Features of Hydraulic Fill Soils and River Dnieper Alluvial Deposits in the Kyiv Region

The features of the tectonic structure together with the geological and geomorphological zoning of Kyiv city are highlighted in the article. Particular attention is paid to the floodplains of the Dnieper River, which were formed by the hydraulic fill method. As a rule, such sites were created for new constructions and were quickly built up with low rise buildings, the bases of which were made using such hydraulic soils. Completed engineering-geological investigations of sites after hydraulic filling and observation of the base deformation over time allowed setting of the basic regularity and rules for construction on such territories. The ongoing development of the city has also covered these territories, where high-rise buildings, shopping malls, and other buildings are actively being built, and the loads from these must be transferred to reliable bases.

Geomaterial Characterization and Stability Assessment of Hydraulic Fill Dams

AbstractIn this research study, the stability of a hydraulic fill dam located in a newly declared seismically hazardous zone in north Texas was evaluated, incorporating the effect of geomaterial va...

Geotechnical characterization and liquefaction evaluation of gravelly reclamations and hydraulic fills (Port of Wellington, New Zealand)

In the 2016 Mw7.8 Kaikōura earthquake, widespread liquefaction occurred in the reclamations at CentrePort, Wellington (New Zealand), while less intense shaking during two earthquakes in 2013 produced only some liquefaction manifestation over isolated areas of the port. The two types of reclamations, comprised of end-dumped gravelly fills and hydraulically placed silty-sandy fills, are not well represented in current empirical simplified liquefaction procedures. Comprehensive CPT investigations are presented and used to characterize the fills, and then perform CPT-based liquefaction evaluation for the three earthquakes that affected the port in 2013 and 2016. The results of the analyses are compared to observations of liquefaction performance and are examined in relation to the soil and deposit characteristics of the fills. The CPT-based liquefaction assessment was generally consistent with observations, though clear shortcomings and limitations of these procedures were also evident. The paper scrutinizes conventional engineering procedures for liquefaction assessment when applied to non-conventional or problematic soils for such assessment, with reference to a well-documented case history.

Retraction Note to: Dynamic compaction evaluation using in situ tests in Sagunto’s Harbor, Valencia (Spain)

This paper presents an assessment on the use of dynamic compaction as a ground improvement technique in a port’s hydraulic fill in the new southern dock of Sagunto’s Harbor near Valencia (Spain). Soil behavior improvement was monitored by several in situ techniques such as boreholes with SPTs, DPSH, CPTU and CSWS geophysical tests. A total energy between 2188 and 3125 kN/m2 (depending the area) was applied to the hydraulic fill by the dynamic compaction procedure. In situ techniques led to evaluate dynamic compaction efficiency, as well as controlling ground modifications that might cause potential damages to adjacent buildings. The dynamic compaction carried out was capable of fulfilling requirements established to use the area, that is, an average deformability modulus (E′) of 30 MPa with a minimum of 20 MPa, in a depth of 10 m. Moreover, dynamic compaction increased hydraulic fill relative density by about 75%.