• Title/Summary/Keyword: Unconfined Compressive strength

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Shear Load characteristics of drilled shafts considering socket-roughness in Constant Normal Stiffness(CNS) Test (일정수직강성시험을 통한 암반근입 현장타설말뚝의 주면마찰력특성분석)

  • Jeong, Sang-Seom;Jung, Woo-Hyun;Seol, Hoon-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.489-498
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    • 2005
  • In this study, the shaft resistance of drilled shafts socketed into weathered-and soft-rocks was examined by the constant normal stiffness(CNS) test. Large scale model tests were performed for different unconfined compressive strength, socket roughness, initial normal stress, and normal stiffness for identifying shear load transfer characteristics. Through comparisons with previous studies, it is found that the results by the present approach is good agreement with the general trend observed by existing empirical and analytical results.

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A Basic Study for Scaled Model Test (축소모형실험을 위한 기초 연구)

  • Yang, Hyung-Sik;Ha, Tae-Wook;Kim, Won-Beom;Kim, Jong-Gwan;Ryu, Chang-Ha;Choi, Byung-Hee
    • Explosives and Blasting
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    • v.25 no.1
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    • pp.79-84
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    • 2007
  • This study was conducted to investigate suitable material properties for scaled model test. Unconfined compressive strength of each material was obtained through former studies. UCS calculated from scale factor and former studies results were compared. Two results had a similar tendency, cement mortar is better than plaster for scaled model test.

Development of Amended Clay Liner for Waste Containment System (매립장의 인공점토차수재 개발에 관한 연구)

  • 신은철;김성환;오영인
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 1997.05a
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    • pp.70-73
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    • 1997
  • Recycling of$\boxUl$ useful industrial waste is highly recommended by the government. Some geotechnical properties such as specific gravity, dry density, unconfined compressive strength, pH. compressibility, permeability were determined to evaluate the feasibility of waste lime use in the landfill as an admixture clay liner. Various types of environmental tests on waste lime were conducted to compare the results with the EPA requirements. Laboratory test results indicate that admixture soil(waste lime/decomposed granite soil) is a promising material its an admixture clay liner in the sanitary landfill.

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Fundamental Study on the Solidification of Sewage Sludge by Paraffin Binder (파라핀 고화제를 이용한 하수 슬러지 고화처리를 위한 기본 연구)

  • 정하익;조진우;임재상;김상길
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.443-446
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    • 2000
  • The feasibility study on paraffin binder as a solidifying agent of digested sewage sludge cake was peformed. The availability of paraffin binder as a solidifying agent was investigated by several tests. Based on the tests, it is ascertained that paraffin binder with a small amount of quicklime and fly ash enhances the solidification of digested sewage sludge cake. Paraffin binder shortened the drying time of digested sewage sludge cake and solidified sludge with paraffin was not dissolved in water again. Also, the unconfined compressive strength of solidified sludge with paraffin increases.

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A Study on Turbidity Calibration of Borehole Roughness Measurement System (BKS-LRPS) (굴착공 벽면거칠기 측정시스템(BKS-LRPS)의 혼탁도 보정에 관한 연구)

  • Park, Bong-Geun;Choi, Yong-Kyu;Kim, Myung-Hak;Kwon, Oh-Kyun;Nam, Moon-S.
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1-10
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    • 2009
  • Based on recent studies, the side resistance of rock socketed drilled shafts was affected by unconfined compressive strength of rock, socket roughness, rock types and joints, and initial normal stress. Especially, the socket roughness was affected by rock types and joints, drilling methods, and diameters of pile. In this study, a new roughness measurement system (BKS-LRPS, Backyoung-KyungSung Laser Roughness Profiling System) usable in water was developed. Based on the laboratory model tests, an EMD (Effective Measurement Distances) according to various turbidity was proposed as EMD=$1149.2{\times}T^{-0.64}_b$.

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Evaluation of Composite Ground Improvement at Structural Foundation Ground by Super Injection Grouing (SIG공법에 의한 구조물기초지반에서의 복합지반개량 평가)

  • 김종국;손형호;이호관;성기광
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.347-354
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    • 2002
  • In this paper, when structures are constructed in the soft ground with poor bearing capacity at Incheon International Airport(railroad area), as for the grouting columns built In soft ground by high pressure jet grouting with Triple tube rod(super injection grouting), the effects on reinforcement and bearing capacity of ground are investigated. A unconfined compressive strength tests has been performed on the specimens sampled from the grouting columns and a mass plate bearing test has been performed on a grouting column. The test results show that super injection grouting has a sufficient effect on composite ground improved of foundation ground and reatraint of settlement of structure.

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Stress-strain behavior of geopolymer under uniaxial compression

  • Yadollahi, Mehrzad Mohabbi;Benli, Ahmet
    • Computers and Concrete
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    • v.20 no.4
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    • pp.381-389
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    • 2017
  • The various types of structural materials that are available in the construction industry nowadays make it necessary to predict their stress-strain behavior. Geopolymer are alternatives for ordinary Portland cement concrete that are made from pozzolans activation. Due to relatively new material, many mechanical specifications of geopolymer are still not yet discovered. In this study, stress-strain behavior has been provided from experiments for unconfined geopolymers. Modulus of Elasticity and stress-strain behavior are critical requirements at analysis process and knowing complete stress-strain curve facilitates structural behavior assessment at nonlinear analysis for structures that have built with geopolymers. This study intends to investigate stress-strain behavior and modulus of elasticity from experimental data that belongs for geopolymers varying in fineness and mix design and curing method. For the sake of behavior determination, 54 types of geopolymer are used. Similar mix proportions are used for samples productions that have different fineness and curing approach. The results indicated that the compressive strength ranges between 7.7 MPa and 43.9 MPa at the age of 28 days curing.

Basic Physicochemical and Mechanical Properties of Domestic Bentonite for Use as a Buffer Material in a High-level Radioactive Waste Repository

  • Cho, W.J.;Lee, J.O.;Chun, K.S.;Hahn, D.S.
    • Nuclear Engineering and Technology
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    • v.31 no.6
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    • pp.39-50
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    • 1999
  • The physicochemical, mineralogical, hydraulic, swelling and mechanical properties of a domestic bentonite for use as the buffer material in a high-level waste repository have been measured. The bentonite is identified to be a Ca-bentonite, and the hydraulic conductivity of the compacted bentonite with the dry density higher than 1.4 Mg/㎥ is lower than 10$^{-11}$ m/s When the dry densities are 1.4 to 1.8 Mg/㎥, the swelling pressures are in the range of 6.6 to 143.5 kg/$\textrm{cm}^2$. The unconfined compressive strength is about 94 kg/$\textrm{cm}^2$, and the coefficient of volume change and the coefficient of consolidation are in the range of 0.O0249 to 0.02142 $m^2$/MN and 0.018 to 0.115$m^2$/year, respectively.

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Behavior and Capacity of Compression Lap Splice in Unconfined Concrete with Compressive Strength of 40 and 60 MPa (횡보강근이 없는 40, 60 MPa 콘크리트에서 철근 압축이음의 거동과 강도)

  • Chun, Sung-Chul;Lee, Sung-Ho;Oh, Bo-Hwan
    • Journal of the Korea Concrete Institute
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    • v.21 no.3
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    • pp.291-302
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    • 2009
  • A compression lap splice can be calculated longer than a tension lap splice in high strength concrete according to current design codes. New criteria for the compression lap splice including the effects of concrete strength are required for practical purpose of ultra-high strength concrete. Characteristics of compression lap splice have been extensively investigated and main parameters are derived. In addition, an experimental study has been conducted with column specimens in concrete strength of 40 and 60 MPa. The strength of the compression lap splice consists of bond and end bearing and two contributors are combined. Therefore, combined action of bond and end bearing should be assessed. Compared with tension splices, concrete strength significantly affects the strength of compression splices due to short splice length and existence of end bearing. Test results show that the splice strength can be evaluated to be proportional to square root of compressive strength of concrete. The stress states of concrete surrounding spliced bars govern the strengths of bond and end bearing. Because the axial stress of the concrete is relatively high, the splice strength is not dependent on clear spacing. End bearing strength is not affected by splice length and clear spacing and is expressed with a function of the square root of concrete strength. The failure mode of specimens is similar to side-face blowout of pullout test of anchors and the strength of end bearing can be evaluated using the equation of side-face blowout strength. Because the stresses developed by bond in compression splices are nearly identical to those in tension splices, strength increment of compression splices is attributed to end bearing only.

A Study on Strength Characteristics of Sand-gravel Mixtures (모래-자갈 혼합토의 강도 특성에 관한 연구)

  • Park, Sung-Sik
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.5
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    • pp.13-19
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    • 2011
  • The strength of granular mixtures can be controlled by the majority of the mixture, fine grains. However, in some cases, the small amount of gravel in the mixture may influence the strength of the mixture. In this study, the effect of some dispersed gravels on strength of sand is evaluated. Gravels are embedded in the middle of each cemented sand layer. The size and number of embedded gravels varies. After two days curing, a series of unconfined compression tests is performed on the cemented sand with dispersed gravels. In addition to that, a series of direct shear tests is also carried out on clean sand with gravels to evaluate its friction angle. For the specimens with the same ratio of gravel weight of 7% in which gravel size and number are different, an unconfined compressive strength(UCS) of a specimen with gravels decreases up to 15% compared to a specimen without gravel and then increases with increasing gravel number. For specimens embedded with the same size of gravel, UCS decreases and then increases as a number of gravel increases. As a number of gravel increases, a friction angle of clean sand with gravels decreases up to $5^{\circ}$ and then recovers up to that of a specimen without gravel.