• Geotechnical Engineering
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• v.14 no.6
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• pp.127-138
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• 1998

In refuse landfills, a considerable amount of settlement occurs due to the decomposition of refuse over several years. In this paper, several prediction methods are applied to the measured settlement data of fresh refuse sites. The effect of biological decomposition on the settlement characteristics is investigated in predicting the long-term settlement of refuse landfill sites in view of the predicted settlement curves and the amount of long-term settlement. Irrespective of the applied models, the long term settlement may not be correctly estimated if the model parameters do not contain the decomposition effects. Among the proposed several prediction methods, Gibson & Lo model and hyperbolic model seem to represent the long-term settlement characteristics, but the power creep law seems to considerably overestimate the long-term settlement.

• Journal of the Korean GEO-environmental Society
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• v.6 no.1
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• pp.53-62
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• 2005

This paper estimates the long-term settlement of Kimpo metropolitan landfill based on measured settlement data from 180 landfill monitors accumulated over a period of 12 years. Comparison of domestic and international settlement records indicate that the domestic compression rate is slightly lower due to greater portion of organic component. Several existing settlement models are used to compare with the observed behavior and also to estimate long-term settlement. The hyperbolic, Gibson & Lo, Bjarngard & Edgers and Power Creep Law models compare well with the measured settlement of the Kimpo metropolitan landfill. The settlement models are further used to estimate long-term settlement. Bjarngard & Edgers and Power Creep Law models result in higher estimates of the long-term settlement compared to the hyperbolic and Gibson & Lo models. Further comparisons indicate that other models, including Sowers and log models, are inapproriate for predicting the long-term settlement of the Kimpo metropolitan landfill.

• Journal of Ocean Engineering and Technology
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• v.5 no.1
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• pp.35-44
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• 1991

This study was carried out for the purpose of pre-estimating long-term settlement under condition of actual field soil's property, in case of building up industrial sites on the marine deposit silty clay located at West Coast in Korea. This study analyzed Hyperbolic Method, Square Root Time Method and Exponential Function Method with utilization of measured survey values of settlement in In-Cheon Namdong Industrial Sites. In the future, for the continuos utilization, it seemed to be needed that further the survey values of fields should be accurartely measured for the analysis of more accurate pre-estimate about long-term settlement. Among the prediction methods of settlement Hyperbolic Method seemed to be the best fitting method for measured data. The settlement equations were derived from above three methods, for long-term settlements.

• Geomechanics and Engineering
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• v.19 no.2
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• pp.115-126
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• 2019

The long-term settlement characteristics for the cast-in-place bored pile in the deep-thick soft soil are investigated by post-grouting field tests. Six cast-in-place bored engineering piles and three cast-in-place bored test piles are installed to study the long-term settlement characteristics. Three post-grouting methods (i.e., post-tip-grouting, post-side-grouting, and tip and side post-grouting) are designed and carried out by field tests. Results of the local test show that decreased settlements for the post-side-grouted pile, the post-tip-grouted pile and the tip and side post-grouted pile are 22.2%~25.8%, 30.10%~35.98% and 32.40%~35.50%, respectively, compared with non-grouted piles. The side friction resistance for non-grouted piles, post-side-grouted pile, post-tip-grouted pile and the tip and side post-grouted pile undertakes 89.6~91.3%, 94.6%, 92.4%~93.0%, 95.7% of the total loading, respectively. At last, the parameters back analysis method and numerical calculation are adopted to predict the long-term settlement characteristics of the cast-in-place bored pile in the deep-thick soft soil. Determined Bulk modulus (K) and a creep parameter (Ks) are used for the back analysis of the long-term settlement of the post-grouted pile. The settlement difference between the back analysis and the measurement data is about 1.11%-7.41%. Long-term settlement of the post-grouted piles are predicted by the back analysis method, and the predicted results show that the settlement of the post-grouted pile are less than 6 mm and will be stable in 30 days.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.993-998
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• 2009

This study was conducted to propose the model that is able to predict long-term settlement of sands containing carbonates. We can observe that in addition to the initial elastic compression, a considerable additional compression occurs with long-term period in some sands. The compressibility of sands is significantly dependent on particle characteristics. Some sands have many pores and particularly has an angular shape. To predict of long-term settlement of these sands which contain carbonates, first of all a variety of tests which are to assess chemical, physical and compression characteristics of these sands were conducted. Second, in order to know settlement with time, the time parameter was determined by analyzing the measured data obtained from $\bigcirc\bigcirc$ area. The measured settlement of this area shows that in addition to the initial elastic compression, a considerable additional compression occurring with time. It was caused by the crushing, shattering, and rearrangement of particles, which were real phenomena in sandy soils under loading condition. Based on this case study, we proposed that a simple method is able to predict settlement with time of sandy soil containing carbonates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.8-16
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• 2018

This study examined the long-term behavior of a roadbed using high-speed railway concrete track and roadbed measurement data and evaluated the long-term performance of the track and roadbed. Recently, high-speed railway track type has been adopted as a concrete slab. On the other hand, the concrete track is vulnerable to roadbed settlement. In the case of gravel tracks, it is easy to restore the original state by maintenance even if the roadbed settles. On the other hand, in the case of the concrete track, if excessive settlement of the roadbed occurs, cracks are generated continuously on the slabs and sleepers, resulting in greatly reduced usability. For this reason, it is difficult to restore the original state only by partial maintenance. In this paper, a long-term performance evaluation was carried out on a concrete track during operation by monitoring the measurement data of sensors buried from the beginning of construction for approximately 3 years after the high-speed railway opened. Performance evaluation methods include a performance evaluation of track/roadbed when the train passes, long-term track and roadbed performance evaluation, analysis of the track/roadbed effect on long-term settlement and analysis of the factors influencing long-term settlement. The trail response of KTX-Sancheon was greatest in the track/roadbed performance evaluation by train. The results of the long-term track and roadbed performance evaluation were measured within the standard values. The track and roadbed performance impact assessment with long-term settlement was strongly related to TCL settlement. The influences of the water content and groundwater level were verified by analyzing the external factors of long-term settlement. Through such a method, the stability of a track/roadbed can be secured.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.605-610
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• 2002

Waste body settlement is an important aspect of management of landfill sites both during the operational and the post-closure phases. Settlement in landfill waste is caused by combination of load, creep and biodegradation induced effects. In this paper, settlement characteristics of closed waste landfill were studied by analyzing in situ measured data and computer simulation technique. Techniques for the analysis of load-induced and creep settlement, and for their implementation, can be adapted for landfill waste. The estimate of settlements from models shows a increase according to time.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1219-1226
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• 2005

In this study, crest settlement characteristics of CFRD (Concrete Faced Rockfill Dam) and ECRD (Earth Cored Rockfill Dam) were analysed through the instrumentation data from representative 7 large dams in Korea. Also, We have studied the effect of valley shape and uniaxial compressive strength of intact rock to better understand the impact of the parent rock strength and the valley shape on the long term crest settlement of CFRDs. From the results, we found that the valley shape and strength of intact rock on crest settlement of dams are an important parameters. As a result, we obtained that the maximum crest settlement of CFRD is larger than that of ECRD and long term crest settlement rate per dam height of rockfill dams is less than 0.60% during service period.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.106-116
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• 1989

This study aims at scrutinizing the long4errn consolidation characteristics of peats sampled at three different regions of Chonbuk province. The standard consolidation test and the single load consolidation test were performed about these samples and especially in case of the latter the loading period was 350 days. The main condusions analyzed are as follows. 1. Void ratio showed much greater values than that of the general clay and was decresed greatly according to the increase of the load. 2. In case of the relationship between the sefflement and the long-term settlement time the rate of settlement increment became great according to the increase of the load step and the long4erm settlement became linely proportional to the logarithm of time alter 10 minutes. 3. The linear correlation was showed between the long4erm settlement time and the void ratio and therefore equations by regression analysis were derived in order to estimate the long-term settlement The slope of straight lines increased according th the increase of the load step and secondary consolidation coefficients ranged from 0.04-0.27. 4. The secondary consolidation coeffcient became linealy proportional to the compression index and the ratio of Ca to CC was 0.072. 5. The period required in ending the primary consolidation was about 10 minutes and alter that the secondary consolidation coefficient appeared to have constant value. Therefore the secondary consolidation coefficient was judged to be used as a significant factor in estimating the long4erm settlement. 6. In case of the single load consolidation test the secondary consolidation coefficient showed the tendancy increasing according to the increase of the consolidation pressure.

• Journal of the Society of Disaster Information
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• v.4 no.2
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• pp.52-66
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• 2008

It has been a growing concern about reusing Sudokwon landfill 2nd site and other sanitary landfills located around the metropolitan areas. In this paper, settlement characteristics of Sudokwon landfill 2nd site were studied by analyzing the data collected over the period of six years. Three equations are combined in order to modeling the long-term settlement behavior of refuse landfill caused by mechanical secondary composition and secondary composition caused by the decomposition of biodegradable refuse. It is suggested that mechanical secondary composition is linear with respect to the logarithm of time. The models proposed by hyperbolic method and Gibson & Lo model, power creep law are considered to be suitable for the long-term prediction value of Sudokwon landfill 2nd site. The fifteen-year-period prediction value of hyperbolic method and Gibson & Lo model is considerably different from that of power creep law model. The average settlement for Block I in Sudokwon 2nd site is approximately 3.9m with 4 steps of final landfill stages.