Earth Fill Research Articles

Estimating of the Dry Unit Weight of Compacted Soils Using General Linear Model and Multi-layer Perceptron Neural Networks

Compaction of earth fill is a very important stage of construction projects. Degree of compaction is defined by relative compaction. The relative compaction of a compacted earth fill is calculated by dividing the dry unit weight obtained from in situ tests by-into the maximum dry unit weight obtained from laboratory compaction tests. This rate represents compaction quality in the field. Numerous test methods such as sand cone, rubber balloon, nuclear measurements, etc., are available to determine the maximum dry unit weight of soils in the field. It is well known that these methods have disadvantages as well as advantages. This study focused on estimation of dry unit weight of soils depending on water contents and P-wave velocities of compacted soils. The multi-layer perceptron (MLP) neural networks and general linear model (GLM) were used in this study to estimate the dry unit weight of different types of soils. Results of the MLP neural networks were compared with the GLM results. Based on the comparisons, it is found that the MLP generally gives better dry unit weight estimates than the GLM technique. The laboratory experiments and modeling studies showed that a new method for compaction control can be developed depending on P-wave velocity to estimate of the dry unit weight of compacted soils.

Karstification Effect on the Stability of Mosul Dam and Its Assessment, North Iraq

Mosul Dam is located on the Tigris river, 50 Km NW of Mosul; it is 113 m in height, 3.4 Km in length, 10 m wide in its crest and has a storage capacity of 11.1 billion cubic meters. It is an earth fill dam, constructed on bedrocks of Fat’ha Formation, which consists of gypsum beds alternated with marl and limestone, in cyclic nature. The thickness of gypsum beds attains 18 m; they are intensely karstified even in foundation rocks. Therefore, continuous grouting Programme was planned during construction, which was completed in June 1984, with planned operation age of 80 years. Due to insufficient grouting in the foundation, during last years of the last century, the Karstification was enlarged in size and quantity, causing serious problems to the stability of the dam. Since late eighties of the last century, the status of the dam and its probable collapse has caused a panic to the people of Mosul city and near surroundings. Therefore, many attempts were carried out for assessment of the dam; all of them concluded that the Karstification is the main problem and recommended continuous grouting, using modern techniques. In addition, the authorities started to build another “Badush Dam” south of Mosul Dam so that it can stop the first wave if Mosul Dam if collapsed. All geophysical and geological work executed on the dam site; it concluded that the existence of many weaknesses zones, faults and large karstified areas, in different parts of the dam site.

Characterization and dewatering of flotation technological tailings

The treatment of flotation tailings is today a subject of interest in mineral processing because of the potential of wasted materials as an actual mineral resource and because of environmental reasons. Decantation ponds are found at almost every mine in the world. They are large earth fill dams containing the residue of the milling process to extract metals from mined ores. Traditional wet tailings disposal has been problematic due to the risk of ground water contamination and the difficulty in rehabilitating storage sites. Tailings dams are at risk of failure due to leakage, instability, liquefaction, and poor design. In the last few years the use of paste technology in the disposal of mine tailings is increasingly studied as an option to conventional tailings dams. The Lucky Invest Concentrator is located in the Eastern Rhodopes Mountain of Bulgaria. Since 1959 lead-zinc ores are dressed. Finally, during the flotation cycle lead and zinc concentrates are produced. The final technological processing waste precipitates in tailing pond. Research and development program has started to established opportunities to obtain dry deposit of the ore processing residue and analyses the feature of new tailing disposal method. The tailings particle size distributions and chemical compositions were determined. The data from laboratory and pilot scale tests clearly illustrate that there are the possibilities to obtaine lead-zinc dewatered tailings. The experimental results show that new cyclone modifications have a potential in dewatering technology of flotation tailings. It appears that dewatering cyclones can be an approach on new tailings pond elimination technology.

Study the Infiltration and Stability of the Earthfill dams (Proposed Kashkan dam as a Case study)

This paper performed two steps of analysis. The first step used Soil Conservation Service (SCS) method to estimate surface water infiltration rates from the earth fill dams (proposed Kashkan dam north of Duhuk city as a case study). In the second step, a two dimensional finite element seepage analysis using (Seep/w) software was employed to determine seepage rates. The main purpose of constructing Kashkan dam is to store the rainfall water during rainy season and use it during summer season to provide the human requirements of water as well as to performed the agricultural requirements. Mean monthly rainfall data recorded for selected watersheds during the period (1986-2008) was used. The maximum infiltration rate during the depended period asymptotically tends to the value of the saturated permeability. The computed infiltration rates were used as input data for the seepage analysis by assigning the ground surface boundary condition. Finally, positive and negative pore water pressure distributions obtained

Application of geophysical methods to dam safety assessment in Korea

Electrical resistivity methods were applied to delineate leakage pathways and to investigate the condition of core material in earth fill dams. In other to evaluate the engineering geological properties of the soil deposits, two boreholes a dam were drilled to the bedrock that exceeds the height of the dam. A large set of field tests including standard penetration test(SPT) and in-situ permeability tests were carried out along the boreholes. A series of laboratory tests were also conducted on the undisturbed soil samples obtained using the split-spoon sampler and thin wall tube sampler to determine their engineering characters. The resistivity values which were estimated from the previous inversion result for each depth were compared with the N values from SPT for each borehole. It could be classified in two groups where were not showed in general trend and most of the sites had some seepage problem and decrepit facilities need to be improved. We have also measured resistivity values of undisturbed soil samples obtained from boreholes at 311 different dam sites. We confirmed low resistivity values of soil in core material were distributed at the Gyeongsang basin and some regions in Korean peninsula. As a result of these studies, it was possible to get more quantitative interpretation of seepage problem. Key words: resistivity, leakage, earth fill dam, SPT, N value

Excavation of Liu Shen’s tomb of the Western Han Dynasty on Heitou Hill in Xuzhou, Jiangsu

Abstract In June through August 2006, Xuzhou Museum excavated the M1 at the Heitou Hill in the eastern suburb of Xuzhou City. This tomb was a vertical stone shaft pit tomb of the early Western Han Dynasty; it had an earthen mound above the grave and attendant burials were found around it. In the rammed earth fill of the grave, five layers of sealing stones were found; the burial furniture was wooden coffin, in which two human remains were found, showing that this tomb was a couple joint burial. From this tomb, large amount of exquisite grave goods were unearthed, including potteries, bronzes, jades and agate objects, iron objects, bone and wooden objects, etc. The eight seals among the grave goods were the official and private seals of the tomb occupants, from the text of which we know that the name of the male occupant of the tomb is Liu Shen, and estimate him as a member of the royal family of the Chu Feudatory Kingdom of the Western Han Dynasty.

Estimation of shear wave velocity of earth dam materials using artificial blasting test

The objective of this study is to estimate the shear wave velocity of earth dam materials using the vibration generated from artificial blasting events, and to verify its applicability. In this study, near-field artificial blast testing and monitoring were carried out at the Seongdeok dam, Korea, as the first blasting tests to be carried out on an existing dam in Korea. Vibrations were induced by four different types of blasting, using various explosive charge weights and depths of blasting bore-holes. During the tests, acceleration time histories were measured at the rock outcrop adjacent to the point of the explosion, and at the crest of the dam. The fundamental frequency of the target dam was computed from the frequency analysis of measured acceleration histories. Numerical analyses were carried out, varying the shear modulus of the earth fill zone and using the acceleration histories measured at the rock outcrop as input ground motions. From a comparison between the fundamental frequencies calculated by numerical analyses and those of measured records, the shear wave velocities with depth, which are closely related to shear moduli, could be estimated. It is found that the effect of different blasting types on shear wave velocity estimation for the target dam materials is negligible, and that shear wave velocity can be consistently evaluated. Furthermore, by comparing the evaluated shear wave velocity with empirical formulae from previous research, the applicability of the method was verified. Therefore, in cases of mid-to-small earth dams, where the earthquake record is not available, the shear wave velocity of earth fill materials can be reasonably evaluated using blasting vibration records obtained at the site adjacent to the dam.

Landslide Susceptibility Mapping for Poulrood Earth Fill Dam Reservoir (The Comparison of Two Methods) Iran, Guilan Province

The purpose of this study is to produce the Landslide susceptibility zonation map for Poulrood earth fill dam reservoir with using fuzzy muti criteria decision analysis and fuzzy logic methods. To obtain the Fuzzy relations for producing the susceptibility map, a landslide inventory database is obtained by both field surveys and desk studies. To produce susceptibility map with User define and Gaussian functions then landslide related parameters such as lithology, distance from faults, distance from drainage, slope angle, slope aspect, slope curvature, distance from road, NDVI, earth quick horizontal acceleration and Precipitation were used in the landslide susceptibility analysis. The results obtained in this study showed that the frequency ratio can be used as a simple tool in assessment of landslide susceptibility when a sufficient number of data were obtained. The prediction performance of the susceptibility map is checked by considering quality sum amount ( ). According to landslide susceptibility index for different parameters, it was found that the aspect, lithology and drainage system are the most effective parameters in the study area. With investigation get values of quality sum index( ), landslide density for two types of function in two methods(fuzzy logic and Fuzzy multi criteria decision analysis) and attention to good work of operator Gamma in landslide susceptibility mapping, produced map with Gaussian function and Gamma0.7 operator (fuzzy logic method) has topmost quality.

Geotechnical Mitigation Strategies for Earthquake Surface Fault Rupture

AbstractSurface fault rupture can be damaging to structures built on or near active faults if the hazard is not addressed properly. Fault-induced angular distortion and lateral ground strain can cause beams to yield and eventually lead to structural collapse. When avoidance is not possible, geotechnical mitigation strategies can be used. These strategies include spreading fault displacement over a large area, causing the structure to respond with rigid-body movement, and diverting the fault rupture around the structure. The effectiveness of these strategies can vary from protecting life safety to preventing significant damage and can be effective for a range of dip-slip fault displacements. Earth fills should be sufficiently thick and ductile to prevent the underlying fault dislocation from developing at the ground surface. Thick RC mat foundations proved to be especially effective in shielding the superstructure from the damaging effects of the underlying ground movements. Although more challenging to im...

인공발파진동실험을 이용한 흙댐 축조재료의 전단파속도 산정

본 연구의 목적은 인공 발파진동실험을 이용하여 흙댐 축조재료의 전단파속도를 추정하고 산정 방법의 실효성을 확인하는 것이다. 이를 위하여 운영 중인 성덕댐에 대하여 국내 최초로 실대규모 근접 발파진동 실험을 수행하였다. 장약량과 발파 시추공심도를 4가지 유형으로 달리한 발파진동을 유발시키고, 각 유형별 발파 시에 폭원에 인접한 기반암노두와 댐 정상부에서 가속도를 각각 계측하였다. 발파진동실험으로부터 댐 정상부에서 얻어진 계측기록을 주파수 분석하여 대상댐의 고유진동수를 산정하고, 계측된 가속도기록으로 산정한 고유진동수와 기반암에서 계측한 발파파 가속도를 입력하중으로 한 반복적인 동적수치해석을 수행하여 계산한 고유진동수를 일치시키는 방법으로, 흙댐 성토재료의 심도별 전단파속도를 추정하였다. 산정된 대상댐 성토재료의 전단파속도는 발파유형에 영향을 받지 않고 일관성 있는 결과를 산정함을 확인하였고, 기존의 경험적 연구결과와 비교하여 그 실효성도 확인하였다. 이로부터 지진계가 설치되지 않아 실지진 계측기록을 이용할 수 없는 중소규모 댐의 경우, 인접발파에 따른 발파진동계측기록에 대한 분석으로도 댐 축조재료의 전단파속도를 실효성 있게 추정할 수 있음을 확인하였다. The objective of this study is to estimate shear wave velocity of earth dam materials using artificially generated vibration from blasting events and to verify its applicability. In this study, the artificial blasting and vibration monitoring were carried out at the site adjacent to Seongdeok dam, which is the first blasting test for an existing dam in Korea. The vibrations were induced by 4 different types of blasting with various depths of blasting boreholes and explosive charge weights. During the tests, the acceleration time histories were recorded at the bedrock adjacent to the explosion and the crest of the dam. From frequency analyses of acceleration histories measured at the crest, the fundamental frequency of the target dam could be evaluated. Numerical analyses varying shear moduli of earth fill zone were carried out using the acceleration histories measured at the bedrock as input ground motions. From the comparison between the fundamental frequencies calculated by numerical analyses and measured records, the shear wave velocities with depth, which are closely related to shear moduli, could be determined. It is found that the effect of different blasting types on shear wave velocity estimation for the target dam materials is negligible and the shear wave velocity can be consistently evaluated. Furthermore, comparing the shear wave velocity with the previous researchers' empirical relationships, the applicability of suggested method is verified. Therefore, in case that the earthquake record is not available, the shear wave velocity of earth dam materials can be reasonably evaluated if blasting vibration test is allowed at the site adjacent to the dam.

Crash Wall Design to Protect Mechanically Stabilized Earth Retaining Walls

Mechanically stabilized earth (MSE) retaining walls are used to provide roadway elevation for bridge approaches, underpass frontage roads, and other roadway elevation applications. Vehicular traffic may exist on the high (fill) side of the MSE retaining wall, the low side, or both sides. For traffic on the high side, a conventional traffic barrier might be placed on or near the top of the wall and mounted on a moment slab or a bridge deck. For traffic on the low side, a conventional traffic barrier might be installed adjacent to the wall or the wall itself may serve as the traffic barrier. Typical MSE wall panels are not designed to resist vehicle impacts. Therefore, structural damage to the wall panels and the earth fill would require complicated and expensive repairs. A simple reinforced-concrete crash wall constructed in front of the MSE wall panels could significantly reduce damage to the panels. It might prove practical to implement such a design to reduce costly repairs to the MSE wall structure. In this paper, LS-DYNA finite element analysis code was used to model and analyze a sacrificial crash wall design to determine its effectiveness in protecting an MSE retaining wall. Based on the LS-DYNA simulations, a crash wall that is 8 in. (0.2 m) thick is considered to be an adequate design to reduce damage to the MSE wall.

Building damage associated with geotechnical problems in the 2011 Tohoku Pacific Earthquake

An overview of the geotechnical aspects of the building damage due to the 2011 Tohoku Pacific Earthquake is presented, based on field reconnaissance made after the earthquake. It is shown that (1) Extensive soil liquefaction occurred along the coast of Tokyo Bay and around the floodplain of the Tonegawa River. Liquefaction was primarily found within the relatively newly reclaimed area, with numerous sand boils and large ground settlements up to 60cm, accompanied by the settlement/tilting of wooden and reinforced concrete buildings supported by spread foundations. The extent and the distribution of the damage were significantly affected by the local soil conditions, including the thickness and the age of the reclaimed fills, the depth to the bedrock or the natural site period, and whether remedial measures had been taken against soil liquefaction, as well as the effects of structure–soil–structure interaction. (2) Numerous houses in Sendai's hilly residential areas constructed with the cut-and fill method were badly damaged not only by the simple collapse of retaining walls, but also by slope failures in the fills. It was found that most of the slope failures occurred on earth fills. (3) Several pile-supported buildings tilted and settled not only in the Tohoku region, but also on the Kanto plain, implying damage to pile foundations. Ground subsidence with sand boils around those buildings suggests that soil liquefaction might have played a significant role in intensifying the damage. (4) Within Onagawa and Rikuzen-Takata, several steel and reinforced concrete structures were knocked over by tsunami surges, probably after having suffered damage to their pile foundations. Much of the pile damage was concentrated (a) at the joints between pile caps and the piles themselves and (b) near the pile heads. The buildings suffering such damage were old; apparently their pile foundations were not designed to withstand earthquakes.

Displacement based coupled model for unconfined seepage problems applied to the Gasset Dam (Ciudad Real, Spain)

The present work shows the application of a new methodology, to find out the free surface inside earth fill dams under steady flow conditions, to a real field case: the Gasset Dam, in Ciudad Real, Spain. An accurate and fast computation of the free surface is of paramount importance, since it is a previous and necessary step for evaluating the safety of an earth dam in terms of its stress–strain behavior. This new methodology is based on a coupled numerical model formulated in terms of displacements (so called u–w formulation) instead of a more usual approach of water heads. The developed general code has been previously validated using several theoretical seepage problems through porous media. The selected field case is an earth dam built a century ago, which has been subjected to several rehabilitation works since then. Hence, it is a very irregular and nonhomogeneous dam. The comparison of computations and real field measurements, in terms of the free surface location and the total discharge through the dam under steady conditions, is presented in this paper, demonstrating the accuracy and applicability of this formulation to this kind of problems.

Dynamic response law about gravity retaining wall to seismic characteristics and earth fill properties

In order to find the dynamic response laws of retaining walls affected by certain earthquake loads, the influence of the seismic wave characteristics and sub-grade fill parameters (including the foundation surface slope) were focused on, and a series of tests were performed. The results show that the maximum stress of the retaining wall decreases as internal friction angle, foundation slope, filled soil cohesion and the biggest dynamic elastic modulus increase, while it increases with the seismic frequency and seismic input peak dropping. The addition value of dynamics earth pressure increases when seismic frequency and seismic input peak are reduced, while it decreases when the filled soil cohesion and internal friction angle rise. Meanwhile, dynamic elastic modulus and foundation slope have no obvious influences on addition value of dynamics earth pressure. The slope will be instable if the seismic input peak exceeds 0.5g and be disruptive if seismic frequency is larger than 2.5 Hz. The mid-lower parts of retaining walls are in most heavy and obvious response to these factors, which reveals the mechanism of “belly burst” in retaining wall that appears commonly in practical projects.

Spanish technical regulation for road construction

Abstract The new Technical Regulation for Road Construction (PG3) has applied in Spain since 2002 and governs execution of all the highways, expressways and motorways run by State Administration. The most important aspects introduced in this regulation in terms of the construction of fills are (1) extending the characteristics of the fill material to use as large a quantity as possible of the excavated ground in situ and to keep the amount sent to dump sites to a minimum; (2) to set up standards to regulate finished fills; and (3) to define a new type of random or quarry-run fill consisting of materials with a grading between earth and rock fill that were not in the earlier PG3 regulation. The new PG3 regulation refers to the construction of earth, rock and random fills, and pays particular attention to the placement, installation and the relevant control of the methods involved. In the case of earth fills, the control method involves fixing some preliminary characteristics for the soils to be used in fills, determined by laboratory tests, whereas for random and rock fills, the control consists of first creating test fills through which the previously established compaction procedure is accepted or modified. For random and rock fills, the control of the finished fill requires dividing the layers into set-sized sections and running tests on predetermined strips. The regulation also defines the criterion for acceptance or rejection of the zone being tested.

Penalty Function Element Free Method to Solve Complex Seepage Field of Earth Fill Dam

Element Free Method only needs to solve node information in domain and calculate domain boundary condition without need of any element information and it is easy to handle, with high computing efficiency. Dynamic radius of influence selection scheme is adopted and nodes are arranged flexibly, which can effectively reduce leveling effect. Penalty Function Element-free Method is used in this paper to study the steady seepage field in main dam that is with protective concrete slab and structure of hydrofracture grouting cutoff wall, of Dashi Bu reservoir located in Donghai County, when it is normal water level for the reservoir, and compare the errors between measured value and computed value from piezometer tube. The analysis shows that computed value is fully in line with measured value; distribution of seepage and free surface conforms to universal law, so Element Free Method can solve seepage issue of fill dam under complex condition.

MODELLING OF LAND SUBSIDENCE ALONG TANAH MAS -PELABUHAN SECTION SEMARANG CITY USING FINITE ELEMENT METHOD

Land subsidence has been an apparent problem in the northern part of Semarang city, Central Java, which has caused enormous physical and economical impacts. This area is underlain by alluvium sediments of clay, silt, sand and gravel. The nature of the alluvium soil is soft and highly compressible which induces natural consolidation to occur. The lowering of groundwater table due to exploitation and loads of building and earth fill accelerate the rate of consolidation settlement. A study of land subsidence modeling was carried out in the northern part of Semarang city. Collection and analysis of data on the geology, hydrology, soil properties and monitored settlements were conducted. Modeling of land subsidence involved stress deformation analysis using finite element method. The settlements computed for selected section of the city of Semarang were compared with measurements of settlement in the city area. The simulation results appear to be in reasonably good agreement with the measurement results. Simulation results at selected section indicated that the contribution of lowering groundwater table factor accounts for less than 50% of total monitored subsidence. Meanwhile simulation results using application of external loading and lowering of groundwater table showed better agreement with the monitored subsidence. Information of magnitude and factors causing land subsidence is important particularly for city planning purposes.

English

The aim of this study is to prepare a mix that can be used in impermeable fill as an alternative to clay which can sometimes be difficult to find. In the study, bentonite and cement were chosen as admixtures and sand was chosen as the main material. The main reason for choosing bentonite and cement as admixtures is that they are impermeable and easy to find. Sand was chosen as the main material in the experiments to make use of the available sand pits at Yenicekent in Denizli, and to provide a pre-investigation for a possible future impermeable fill construction in the said region. Another reason for choosing sand as a main material was its low price. According to the result of the three mixtures tested, the mixture including 10% bentonite + 90% sand is the most economical solution that satisfies the limits values needed for clay core of earth fill dams and clay liners of solid waste storage areas. Key words: Bentonite, cement, earthfill, sand, unpermeable layer.

Elasto-viscoplastic modeling of the consolidation of Sri Lankan peaty clay

The consolidation behavior of Sri Lankan peaty clay is analyzed using an elasto-viscoplastic model. The model can describe the secondary compression behavior as a continuous process and it can also account for the effect of structural degradation on the consolidation analysis. The analysis takes into account all the main features involved in the process of peat consolidation, namely, finite strain, variable permeability, and the secondary compression. The material parameters required for the analysis and the procedures to evaluate them, using both standard laboratory and field tests, are explained. Initially, the model performance is assessed by comparing the predicted and the observed peat consolidation behavior under laboratory conditions. The results indicate that the model is capable of predicting the observed creep settlements and the effect of layer thickness on the settlement analysis of peaty clay. Then, the model is applied to predict the consolidation behavior of peaty clay under different field conditions. In this context, firstly, the one-dimensional field consolidation of peaty clay, brought about by the construction of compacted earth fill, is predicted. Then, the two-dimensional peat foundation response upon embankment loading is simulated. A good agreement is seen in the comparison of the predicted results with the field observations.

Study on Seismic Permanent Deformation of Earth Rock Fill Dam

For the flaw of safety evaluation system using safety factor as control index, seismic permanent deformation is used to evaluate the safety of earth rock fill dam. In this study, the seismic deformation of Zipingpu dam after Wenchuan earthquake is measured and analysis. The deformation in the middle of the riverbed on the crest is the largest. The deformation in the left dam abutment is smaller than that in the right. The seismic permanent deformation on the crest grows rapidly in the first three days, and then develops slowly. The results show that deformation grows along the height of dam with the relation of exponential or power function.