• Title/Summary/Keyword: 평균 CBR

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Estimation of the Mean CBR for the Subgrade Layer Including the Anti-Frost Layer (동상방지층을 포함한 노상층의 평균 CBR 산정에 관한 연구)

  • Min, Gyeong-Ho;Lee, Cheo-Keun;Heo, Yol
    • Journal of the Korean GEO-environmental Society
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    • v.3 no.1
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    • pp.57-66
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    • 2002
  • Generally, the California Bearing Ratio(CBR) for the material of subgrade is estimated without considering the anti-frost layer into the subgrade layer when pavements are designed. A pavement structure is determined according to the CBR. However, recently the design method taking the anti-frost layer into the subgrade layer is getting prevail. It makes the top of the subgrade layer strengthen and the thickness of the road pavement structure decreased. By the way, some confusion may be caused because theoretically the general equation for the mean CBR to combine the material of the subgrade layer and anti-frost layer have not been developed well. In this paper, laboratory and field CBR tests were performed to estimate of the mean CBR for the subgrade layer including the anti-frost layer. From the basis of the test results, modified equation which is calculating the mean CBR of the subgrade layer has been proposed. Finally, economical efficiency was considered by comparing the pavement thickness with the road pavement design using CBR of the subgrade layer alone and the road pavement design using the mean CBR including the anti-frost layer.

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A Study on CBR Characteristics of National Highway in Yeongnam Region (영남지역 국도에 사용된 흙의 CBR 특성에 관한 연구)

  • Park, Yeong-Mog;Lee, Go-Hyeun;Kim, Nak-Seok;Cho, Gyu-Tae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.3
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    • pp.535-543
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    • 2016
  • This study has been carried out to evaluate the CBR characteristics and the correlations among every soil properties of National road in Yeongnam region. Total of 480 soil samples were collected from 41 administrative districts for more than 30 years. Their physical and mechanical properties such as natural water content, the Atterberg limit, No. 200 sieve passing, the compaction test and the CBR test results were involved. The soils in Yeongnam region, SM, SC, SP and CL by USCS have predominated approximately 79%. The test results show that average CBR values of gravel and sand range from 12.7% to 20.3% and those of silt and clay range from 4.8% to 7.1%. It means that average CBR values of fine grained soils are less than a half of coarse grained one. Natural water content, No. 200 sieve passing, optimum moisture content and maximum dry density of soils are well correlated with CBR values. Especially, it presents that No. 200 sieve passing is the best correlation factor with CBR value. If consider the partition off this region into 6 zones of classified by mother rock, the correlation between CBR value and every soil properties tends to increase. It is suggested that tables, figures and the regressions described in this paper may be available for designers and engineers to understand the characteristics of an embankment materials in Yeongnam region.

A Study on the Experimental Relationship between KS CBR and Elastic Modulus from Consolidated Undrained Triaxial Tests (CBR과 압밀 비배수 시험에 의한 탄성계수와의 상관관계에 대한 실험적 연구)

  • Kim, Su-Il;Lee, Gwang-Ho;Gwon, Mu-Seong
    • Geotechnical Engineering
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    • v.7 no.4
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    • pp.25-34
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    • 1991
  • In this study, relationships between CBR values tested by Korean Standards (KS CBR) and the elastic moduli from CU compression tests are developed for the subgrade soils. Triaxial compression and KS CBR tests are carried out on five types of samples from 15 points in Korean ezpressways. Triaxial compression tests are performed under 3 types of coifining pressures to generalize the CBR -elastic modulus relationship as functions of confining pressured and mean principal stresses. From the regression analyses of experimental results, equations for relationships between the KS CBR and elastic moduli of roadbed Boils are proposed. An equation for the relation- ship between the KS CBR and the maximum dry density of roadbed soil is also proposed.

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A Study on the Control of Multi-class Traffics in ATM Networks (ATM 망에서 멀티클래스 트래픽 제어에 관한 연구)

  • 이기학;김점구
    • The Journal of Information Technology
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    • v.1 no.2
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    • pp.65-79
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    • 1998
  • In this thesis, a buffer alloction and management algorithm is proposed in order to satisfy the QoS of CBR/VBR traffics incomming to ATM networks. Proposed traffic menagement algorithm is based on the route seperation mechanism that allocates buffers acoording to traffic characterics, and sets threshold to allocated buffers. We developed a cell scheduling algorithm and evaluated cell delay and loss probability characteristics according to incomming traffic classes. The cell scheduling algorithm uses buffer size thresholds to control overload traffic flow.

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Evaluation of Engineering Characteristics of Aggregate Base Materials and Developing the Empirical Correlation Model (입도조정기층 재료의 공학적 특성 평가 및 경험적 상관모형 개발)

  • Kweon, Gi-Chul;Lee, Seung-Jun;Lee, Ung-Se
    • International Journal of Highway Engineering
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    • v.12 no.2
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    • pp.115-121
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    • 2010
  • To evaluate the engineering characteristics of aggregate base materials, cyclic triaxial, CBR and permeability tests were performed for 15 samples. The CBR values of aggregate base materials have wide range from 32 to 110(average 81) and the amount of swelling in submerged conditions has below 0.04mm. The Modulus of aggregate base materials were significantly affected by volumetric stress, linear volumetric model was best for fitting. The modulus of aggregate base materials were determined within range of 100MPa~600MPa, 80~270 and 0.1~0.6 for model coefficient $k_1$ and $k_2$ respectively. The empirical correlation model was suggested that prediction the modulus from the basic properties obtained from particle size distribution test and compaction test. The coefficient of determination of the proposed correlation model was 0.423 for model coefficient $k_1$, 0.920 for model coefficient $k_2$ and 0.872 for modulus with stress level.

Development of an Approximate Cost Estimating Model for Bridge Construction Project using CBR Method (사례기반추론 기법을 이용한 교량 공사비 추론 모형 구축)

  • Kim, Min-Ji;Moon, Hyoun-Seok;Kang, Leen-Seok
    • Korean Journal of Construction Engineering and Management
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    • v.14 no.3
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    • pp.42-52
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    • 2013
  • The aim of this study is to present a prediction model of construction cost for a bridge that has a high reliability using historical data from the planning phase based on a CBR (Case-Based Reasoning) method in order to overcome limitations of existing construction cost prediction methods, which is linearly estimated. To do this, a reasoning model of bridge construction cost by a spreadsheet template was suggested using complexly both CBR and GA (Genetic Algorithm). Besides, this study performed a case study to verify the suggested cost reasoning model for bridge construction projects. Measuring efficiency for a result of the case study was 8.69% on average. Since accuracy of the suggested prediction cost is relatively high compared to the other analysis methods for a prediction of construction cost, reliability of the suggested model was secured. In the case that information for detailed specifications of each bridge type in an initial design phase is difficult to be collected, the suggested model is able to predict the bridge construction cost within the minimized measuring efficiency with only the representative specifications for bridges as an improved correction method. Therefore, it is expected that the model will be used to estimate a reasonable construction cost for a bridge project.

WRR Cell Scheduling Algorithm Based on BSW (BSW 기반의 WRR 셀 스케쥴링 알고리즘)

  • 조해성;정경택;전병실
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.11A
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    • pp.1717-1723
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    • 2000
  • WRR 셀 멀티프렉싱 알고리즘은 CBR, VBR 트래픽 뿐만 아니라 ABR, UBR 트래픽을 서비스하도록 설계되었다. WRR의구현에 있어 버퍼 관리를 효율적으로 하기 위한 BSW 기법의 알고리즘이제안되었다. 그러나, BSW 방식은 VC 에 실제로 할당된 가중치보다 더 큰 가중치를 할당하고 어느 한 VC의 큐가 비어있게 되면 셀 서비스를 수행하지 못하므로 각 VC의 가중치와 스케줄러의 처리율에 심각한 성능저하를 유발한다. 본 논문에서는 위에서 언급한 BSW 기법의 문제를 해결하기 위해서 셀 지연과 버퍼 이용을 개선한 BSW 구조의 WRR 스케줄링 알고리즘을 제안하였다. 제안된 알고리즘은 기존은 BSW 스케쥴링 알고리즘의 문제점들을 해결하기 위해서 각 VC에 실제로 할당된 가중치를 유지할 수 있도록 하였고, 각 VC의 큐가 비어 있을 경우 다른 VC 셀을 서비스하게 함으로서 평균 셀 지연과 평균 버퍼의 길이를 감소시키고 전체적으로 셀 서비스 율을 높일 수 있다.

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Fundamental Study on Establishing the Subgrade Compaction Control Criteria of DCPT with Laboratory Test and In-situ Tests (실내 및 현장실험를 통한 DCPT의 노상토 다짐관리기준 정립에 관한 기초연구)

  • Choi, Jun-Seong
    • International Journal of Highway Engineering
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    • v.10 no.4
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    • pp.103-116
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    • 2008
  • In this study, in-situ testing method, Dynamic Cone Penetration Test(DCPT) was presented to establish a new compaction control criteria with using mechanical property like elastic modulus instead of unit weight for field compaction control. Soil chamber tests and in-situ tests were carried out to confirm DCPT tests can predict the designed elastic modulus after field compaction, and correlation analysis among the DCPT, CBR and resilient modulus of sub grade were performed. Also, DCPT test spacing criteria in the construction site was proposed from the literature review. In the result of laboratory tests, Livneh's equation was the best in correlation between PR of DCPT and CBR, George and Pradesh's equation was the best in the predicted resilient modulus. In the resilient modulus using FWD, Gudishala's equation estimates little larger than predicted resilient modulus and Chen's equation estimates little smaller. And KICT's equation estimates the modulus smaller than predicted resilient modulus. But using the results of laboratory resilient modulus tests considering the deviatoric and confining stress from the moving vehicle, the KICT's equation was the best. In the results of In-situ DCPT tests, the variation of PR can occur according to size distribution of penetrate points. So DCPT test spacing was proposed to reduce the difference of PR. Also it was shows that average PR was different according to subgrade materials although the subgrade was satisfied the degree of compaction. Especially large sized materials show smaller PR, and it is also found that field water contents have influence a lot of degree of compaction but a little on the average PR of the DCPT tests.

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Development of Approximate Cost Estimation System Based on CBRT echnique; Applicability Study for Landfarming Soil Remedation Technology (사례기반추론을 이용한 개략비용 예측시스템 개발 - 토양경작법 정화비용사례를 중심으로 적용가능성 검토 -)

  • Kim, Sang-Tae;Shim, Jin-Ah;Kim, Heung-Rae
    • Korean Journal of Construction Engineering and Management
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    • v.17 no.1
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    • pp.3-9
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    • 2016
  • This study proposes a approximate cost estimation system based on Excel with VBA using weighted CBR(Case Based Reasoning). One characteristic of this system is that it generates the sheet automatically as many as the number of similar case and new estimation when it performs a case learning and a new estimate and cell formula is automatically entered into each sheet. User can be free to compose a combination of attribute factors because they can select up to ten attribute factors. This paper presents an applicability of estimation model for estimating the soil remediation cost when it use a landfarming method. When compared to a estimation model by using average unit cost and optimum multiple regression, this model shows a better result. This study was aimed at landfarming method, but it is expected that a cost estimation model using CBR will be more likely to apply in soil remediation technologies which various remediation technologies and pollutant species exist.

An Integrated Power Management Framework for WiFi-based Mobile Embedded Systems (WiFi기반 모바일 임베디드 시스템을 위한 통합 전력 제어 기법)

  • Min Jung-Hi;Cha Ho-Jung
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.9
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    • pp.658-665
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    • 2006
  • In these days, the demand of users to extend available period of mobile systems is increased according as the functions of mobile systems have been varied and the use of multimedia application has been increased. This paper proposes an integrated power management framework that considers executed workload types for effective energy management. The conventional methods use DVFS technique for CPU and DPM technique for WNIC separately or simply combine them based on the assumption that they are orthogonal one another. However, the proposed mechanism determines the kind of workload under analysis of the characteristics of workloads incoming through a WNIC. The proposed method can reduce energy consumption of system level effectively by controlling CPU and WNIC to proper power mode based on analyzed characteristics of workload. The experimental result shows the proposed method reduces energy consumption by 9% for BE (Best Effort) workload, CBR (Constant Bit Rate) workload, and Interactive workload on average and by 16% to maximum when compared with the conventional methods which simply combine DVFS technique for CPU and DPM technique for WNIC.