• Geomechanics and Engineering
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• v.8 no.4
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• pp.511-521
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• 2015

It is a common failure type that high-filled embankment slope sideslips. The deformation mechanism and factors influencing the sideslip of embankment slope is the key to reduce the probability of this kind of engineering disaster. Taking Liujiawan high-filled embankment slope as an example, the deformation and failure characteristics of embankment slope and sheet-pile wall are studied, and the factors influencing instability are analyzed, then the correlation of deformation rate of the anti-slide plies and each factor is calculated with multivariate linear regression analysis. The result shows that: (1) The length of anchoring segment is not long enough, and displacement direction of embankment and retaining structure are perpendicular to the trend of the highway; (2) The length of the cantilever segment is so large that the active earth pressures behind the piles are very large. Additionally, the surface drainage is not smooth, which leads to form a potential sliding zone between bottom of the backfill and the primary surface; (3) The thickness of the backfill and the length of the anti-slide pile cantilever segment have positive correlation with the deformation whereas the thickness of anti-slide pile through mudstone has a negative correlation with the deformation. On the other hand the surface water is a little disadvantage on the embankment stability.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.41-47
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• 2009

In this paper, the long-term performance of highway embankment using tire shred-sandy soil mixture as a lightweight fill material was evaluated through the field monitoring and field test programs. A tire shred-sandy soil embankment was constructed to support a four-lane highway in Indiana, which was built with a 50 : 50 volumetric ratio of tire shreds (maximum particle dimension of 76 mm) and sandy soil (SP, USCS). After opening of the road for traffic, no noticeable differential settlement and lateral deformation were observed, and no adverse environmental impact on temperature was detected as a result of the construction of the tire shred-sandy soil embankment. Moreover, FWD test results showed that tire shred-sandy soil mixture provides bearing capacity comparable to that of conventional fill and meets the criterion for a design life of 20 years.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.381-388
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• 2002

A series of centrifuge model tests were performed to investigate the behavior of piled bridge abutment subjected to lateral soil movements induced by the construction of approach embankment. In these tests, both the depth of soft clay and the rate of embankment construction are chosen as key parameters to examine the effects on lateral soil movements. The depth of soft clay layer varies from 5.2 m to 11.6 m, and the rate of embankment construction has two types of staged construction(1m/30days, 1m/15days) and instant construction. It is shown that, the distribution of lateral flow induced by stage embankment construction has a trapezoidal distribution. And practical guidelines to check the possibility of some lateral movement of piled abutment were investigated. The validity of the proposed guidelines by centrifuge test was compared with the observed performance by lateral movement index, F(Japan Highway Public Corporation) and modified I index(Korea Highway Corporation). Based on the results obtained, the critical values of F and modified I, as a practical guidelines, are proposed to 0.03 and 2.0, respectively.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.523-532
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• 2021

The treatment of acid rock drainage was reviewed and evaluated for the case of pyrite rocks distributed in a highway embankment. During the highway's construction, neutralization using alkaline water repellent was applied to the embankment section to prevent acid rock drainage. However, it still occurred long after the construction was completed owing to rain infiltration, and the acid rock drainage polluted the surrounding soils and streams. To solve this problem, treatment facilities such as SAPS (Successive Alkalinity Producing Systems) or ecological wetlands and sand filtration were installed. After the installation of the treatment facilities, the effluent and soils contaminated by acid rock drainage nearby the outlet of the facilities were analyzed and evaluated for a period of years. Measurements of the pH of the effluent and analysis of the heavy metal contamination of the soils confirmed that the neutralization treatment for acid rock drainage is being performed properly and that contamination of heavy metals in the acid rock drainage is also being stably controlled by the treatment facilities.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.507-534
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• 2015

The present work investigates the behavior of the embankment models resting on soft soil reinforced with ordinary and stone columns encased with geogrid. Model tests were performed with different spacing distances between stone columns and two lengths to diameter ratios (L/d) of the stone columns, in addition to different embankment heights. A total number of 42 model tests were carried out on a soil with undrianed shear strength $${\sim_\sim}10kPa$$. The models consist of stone columns embankment at s/d equal to 2.5, 3 and 4 with L/d ratio equal 5 and 8. Three embankment heights; 200 mm, 250 mm and 300 mm were tested for both tests of ordinary (OSC) and geogrid encased stone columns (ESC). Three earth pressure cells were used to measure directly the vertical effective stress on column at the top of the middle stone column under the center line of embankment and on the edge stone column for all models while the third cell was placed at the base of embankment between two columns to measure the vertical effective stress in soft soil directly. The performance of stone columns embankments relies upon the ability of the granular embankment material to arch over the 'gaps' between the stone columns spacing. The results showed that the ratio of the embankment height to the clear spacing between columns (h/s-d) is a key parameter. It is found that (h/s-d)<1.2 and 1.4 for OSC and ESC, respectively; (h is the embankment height, s is the spacing between columns and d is the diameter of stone columns), no effect of arching is pronounced, the settlement at the surface of the embankment is very large, and the stress acting on the subsoil is virtually unmodified from the nominal overburden stress. When $(h/s-d){\geq}2.2$ for OSC and ESC respectively, full arching will occur and minimum stress on subsoil between stone columns will act, so the range of critical embankment height will be 1.2 (h/sd) to 2.2 (h/s-d) for both OSC and ESC models.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.337-348
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• 1998

Since 1970s, though many effective construction methods have been established to solve soft ground problems which had occurred in the off shore land reclamation and on shore highway construction, lateral movement of structure on soft ground is still a big problem to engineers. In this study an applicability of criteria for determining the lateral movement of the structure in soft ground is examined and most measured data is obtained from 140 bridge abutments in highway construction sites. Characteristics and effectiveness of existing methods that used for deciding amount of lateral movements of abutment are analyzed using the obtained data. From the analysis, a proper method to prevent lateral movement is proposed. This method is confirmed on several case histories which were constructed on marine clay.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.583-598
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• 2022

The Compaction effect is important for evaluating the subgrade construction. However, there is little research exploring the compaction quality of deep soil using hydraulic compaction. According to reinforcement effect analysis, dimensional analysis is adopted in this work to analyze subgrade compactness within the effective reinforcement depth, and a prediction model is obtained. A hydraulic compactor is then employed to carry out an in-situ reinforcement test on gravel soil subgrade, and the subgrade parameters before and after reinforcement are analyzed. Results show that a reinforcement difference exists inside the subgrade, and the effective reinforcement depth is defined as increasing compactness to 90% in the depth direction. Layered compactness within the effective reinforcement depth is expressed by parameters including the drop distance of the rammer, peak acceleration, tamping times, subgrade settlement, and properties of rammer and filler. Finally, a field test is conducted to verify the results.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.157-168
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• 1999

Geosynthetics are commonly used for filtering, layer separations, drainages, cutoffs, and reinforcements. In highway constructions, geotextile mats have been used for the purposes of vehicle trafficability, separations and embankment reinforcements. Geosynthetics are utilized as prefabricated vertical drains and also used as horizontal drainage layers substituted for the sand mat. Geogrids, essential element of reinforced retaining walls, are sometimes spread under the highway pavement. Besides various usage mentioned above, many type of them are also used as drainage of backfill in culverts and bridge abutments. In this paper, problems of specifications and regulations concerning mostly used geotextiles are specifically dealt with from the practical aspects of field engineering and efforts are given upon improvement of them. Especially, relevant sections of "Standard Specifications for the Highway Construction by Korea Highway Corporation"are being revised and these are introduced in detail.

• Geomechanics and Engineering
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• v.1 no.3
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• pp.193-204
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• 2009

A 10.4-m high highway embankment retained behind mechanically stabilized earth (MSE) walls is under construction in the northeastern part of the Indian state of Bihar. The structure is constructed with compacted, micaceous, grey, silty sand, reinforced with polyester (PET) geogrids, and faced with reinforced cement concrete fascia panels. The connections between the fascia panels and the geogrids failed on several occasions during the monsoon seasons of 2007 and 2008 following episodes of heavy rainfall, when the embankment was still under construction. However, during these incidents the MSE embankment itself remained by and large stable and the collateral damages were minimal. The observational data during these incidents presented an opportunity to develop and calibrate a simple procedure for estimating rainfall induced pore water pressure development within MSE embankments constructed with backfill materials that do not allow unimpeded seepage. A simple analytical finite element model was developed for the purpose. The modeling results were found to agree with the observational and meteorological records from the site. These results also indicated that the threshold rainwater infiltration flux needed for the development of pore water pressure within an MSE embankment is a monotonically increasing function of the hydraulic conductivity of backfill. Specifically for the MSE embankment upon which this study is based, the analytical results indicated that the instabilities could have been avoided by having in place a chimney drain immediately behind the fascia panels.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.177-186
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• 1992

In this study, the proper mixing ratio of fly ash to bottom ash is evaluated and bearing capacity of this mixed ash is examined for use of highway embankment and subgrade materials in large quantities. Independently of the mixing ratio of fly ash to bottom ash or the method of compaction test, maximum dry density ${\gamma}_{dmax}$ and CBR value of anthracite mixed coal ash is greater than that of bituminous mixed coal ash. The mixed ashes to contain more fly ash than that of which the ratio of fly ash to bottom ash is 8 : 2, are slaked readily when the water contents of compaction are greater than optimum moisture content O.M.C. The proper mixing ratios of fly ash to bottom ash are about 5 : 5 to 6 : 4. Coal ashes mixed with these ratios exhibit proper physical and geotechnical properties for use of highway embankment and subgrade materials, and enable coal ashes to be used in large quantities.