• Coupled systems mechanics
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• v.3 no.1
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• pp.27-52
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• 2014

For landfill monitoring and aftercare, long-term prognoses of emission and deformation behaviour are required. Landfills may be considered as heterogeneous porous soil-like structures, in which flow and transport processes of gases and liquids interact with local material degradation and mechanical deformation of the solid skeleton. Therefore, in the framework of continuous porous media mechanics a model is developed that permits the investigation of coupled mechanical, hydraulical and biochemical processes in municipal solid waste landfills.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.528-541
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• 2007

To get the possible for management and maintenance, it was analyzed the deformation characteristics, such as crest of embankment and concrete face slab, and leakage of concrete faced rockfill dams (CFRD). There are trends that embankment deformation depends on intact strength used rockfills rather than dam height, deformation normal to concrete face slab during the first reservoir filling is occurred more than 80% of the total deformation in general, and the magnitude and trend of concrete face slab deformation is similar to post-construction crest settlement. The results showed that the range of post-construction crest settlement suggested by Sherard and Cooke (1987), and Clements (1984) had a good agreement in the cases using rockfill with very high intact strength, but it had a trend which underestimated crest settlement in the cases using rockfill with medium to high intact strength. The maximum leakage rate in general was observed during the first reservoir filling and long-term leakage rate was rapidly increased when the dam height exceeds approximately 120m.

• Structural Engineering and Mechanics
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• v.69 no.5
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• pp.557-566
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• 2019

The reservoir basin bedrock produced significant impact on the long-term service safety of super-high arch dams. It was important for accurately identifying geomechanical parameters and its evolution process of reservoir basin bedrock. The deformation modulus mechanism research methods of reservoir basin bedrock deformation modulus for super-high arch dams was carried out by finite element numerical calculation of the reservoir basin bedrock deformation and in-situ monitoring data analysis. The deformation modulus inversion principle of reservoir basin bedrock in a wide range was studied. The convergence criteria for determining the calculation range of reservoir basin of super-high arch dams was put forward. The implementation method was proposed for different layers and zones of reservoir basin bedrock. A practical engineering of a super-high arch dam was taken as the example.

• Structural Engineering and Mechanics
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• v.84 no.5
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• pp.699-706
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• 2022

Settlement control techniques are critical for the safety of shield tunnel constructions, especially for facing complex situations. In this study, the shield tunnel structure from Huaita east road station to Heping Road station in Xuzhou metro No.3 line (China) is taken as engineering background, which has various complex problems of the upper-soft and lower-hard composite stratum conditions, twin curve shield tunnels, and underpass the foundation of the piled raft. The deformation characteristics of shield tunnelling passing through buildings are explored. Subsequently, comprehensive research methods of numerical simulation and field measurement are adopted to analyzing the effectiveness of settlement control by using the top grouting technique. The results show that the settlement of the buildings has obvious spatial characteristics, and the hysteresis effect can be obviously observed in soil deformation caused by shield construction. Meanwhile, the two shield constructions can cause repeated disturbances, reducing the soil deformation's hysteresis effect. Moreover, the shield tunnel's differential settlement is too large when a single line passes through, and the shield construction of the outer curve can cause more significant disturbance in the tunnel than the inside curve. Notably, the proposed process control parameters and secondary topgrouting method can effectively control the deformation of the shield tunnel, especially for the long-term deformation.

• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.43-52
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• 2007

This study analyzes the characteristics of creep deformation behavior of weathered granite soils used in road embankments. The creep strain under the unconfined compressive state demonstrated an excellent agreement with the theoretical analysis of the burgers substance. The elastic deformation showed a termination in its characteristics after a long-term period owing to the increase in applied loads. The primary creep strain was 0.0028 and concluded that the deformation completed within $3{\sim}5$ days after applying the loads. Also, the completing time of creep deformation in the embankment soils increased in proportion to the height of embankment soils. The secondary creep strain is about 50% of the primary creep strain.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.33-46
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• 2013

Recently, the projects which are to increase the capacity of the flood control are being actively performed because of the abnormal climate changes throughout the country. In this study, the regression analysis was performed using both Kelvin model and the real settlement measured at the crest of the existing concrete face rockfill dam(CFRD) to estimate the long-term deformation behavior characteristics such as creep which occurs without additional load. In addition, the effects on changes in physical properties (E, G, K) of the dam construction materials by deformation characteristics of the dam were evaluated, and the reasonable stability analysis method of the dam was proposed to obtain the long-term stability considering the changes in physical properties induced by the long-term deformation behavior in case of heightening the existing dams.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.75-84
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• 2010

In this study, the long-term performance tests, which have extensibility, creep deformation, installation resistance and durability characteristic, is conducted to apply geosynthetic strip in field. The strength reduction factors using the test results are evaluated in order to calculate long-term design tensile strength. First, the creep deformation was evaluated by both the stepped isothermal method(SIM) and the time-temperature superposition(TTS) method. The creep reduction factor is reasonable to apply 1.6. Second, the result of installation damage test had little damage of yarn, which affected strength of reinforcement. Therefore, it can be analyzed that the installation damage of geosynthetic strip has little effect of long-term design tensile strength. Finally, the durability reduction factor considering chemical, biological and outdoor exposure resistance is reasonable to apply 1.1, which is considered the stability and economic efficiency of reinforced earth wall using geosynthetic strip.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.123-134
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• 2007

This study was carried out for evaluating correlation of aging level and deformation resistance of asphalt mixtures conditioned by artificial aging treatment. The specimens were made of the short-term aged loose asphalt mixture which was kept in a convection oven at $154^{\circ}C$ for 2 hours, and then were artificially aged at $110^{\circ}C$ for 24, 48, 72 and 96 hours for long-term aging. Deformation strength ($S_D$) and large molecular size ratio (LMS(%)) were measured after short-term and each long-term aging treatment to evaluate aging extents of each mixture with aging time using GPC(Gel-permeation chromatograph) test. It is shown that the $S_D$ and LMS(%) were increased with aging time increment, and that LMS(%) quantity and $S_D$ have relatively good correlation each other. This study found that the aged asphalt mixture had better resistance against rutting and it was possible to estimate rutting characteristics of asphalt mixtures by using LMS(%) without a binder recovery.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.521-529
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• 2002

A restraint coefficient for creep and dry shrinkage deformation of concrete in a composite section was derived to calculate the residual stress, and an equation for the loss rate of the pre-compression force was proposed. The derived restraint coefficient was computed by using the transformed section properties for the age-adjusted effective modulus of elasticity. The long-term behavior of complicate composite sections could be analyzed easily with the restraint coefficient. The articles of the current design code was examined for PSC and steel composite sections. The dry shrinkage strains of $150 ~ 200$\times$10^{-6}$ for the computations of the statically indeterminate force and the expansion joint could be under-estimated for less restrained sections such as the reinforced concrete. The dry shrinkage strain of $180$\times$10^{-6}$ for the computation of residual stress in the steel composite section was unreasonably less value. The loss rate of 16.3% of the design code for the PSC composite section in this study was conservative for the long-term deformation of the ACI 205 but could not be used safely for that of the Eurocode 2. For pre-compressed concrete slab in the steel composite section, the loss rate of prestressed force with low strength reinforcement was much larger than that with high strength tendon. The loss rate of concrete pre-compression increased, while that of pre-tension decreased due to the restraint of the steel girder.

• Journal of the Korean Geosynthetics Society
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• v.3 no.2
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• pp.39-45
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• 2004

Geocomposite mechanically bonded with woven type geotextile and nonwoven geotextile was used to examine to the long-term creep deformation behaviors by the SIM(Stepped Isothermal Method). The temperature steps were $26^{\circ}C$, $40^{\circ}C$, $54^{\circ}C$, $68^{\circ}C$, $82^{\circ}C$ and loading levels were 40%, 50%, 60% of designed strength for stepped isothermal method. Results of creep tests are showing that their strain were lower than 10% during 10,000 hours(GRI GS 10). Also, the effect of weft injection density to the creep deformation behaviors were examined. The weft densities of 0%, 50%, 100% of the original weft density showed the creep strain within 10% and the creep strain was increased with the decrease of weft injection density.