• Title/Summary/Keyword: Undrained shear strength

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A Study on Characteristics of Undrained Shear Strength of Remolded Marine Clays at Incheon and Busan (인천 및 부산 재성형 해성점토의 비배수 전단강도 특성에 대한 연구)

  • Yoo, Nam-Jae;Lee, Han-Sol;Jun, Sang-Hyun
    • Journal of Industrial Technology
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    • v.30 no.A
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    • pp.103-109
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    • 2010
  • This research is to determine characteristics of undrained shear strength of remolded marine clay at Incheon and Busan, representing typical marine clays in Korea. Laboratory vane tests with remolded marine clays sampled from coasts at Incheon and Busan were performed to investigate the undrained shear strength of them. Test results were compared with the predicted values of undrained shear strength proposed by many researchers. It was found that measured results about undrained shear strength with water content was in good agreements with values proposed by Terzaghi empirical formula.

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A Study on Characteristics of Undrained Shear Strength of Remolded Marine Clays at Incheon (인천 재성형 해성점토의 비배수 전단강도 특성에 대한 연구)

  • Yoo, Nam-Jae;Lee, Han-Sol;Jun, Sang-Hyun
    • Journal of Industrial Technology
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    • v.29 no.B
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    • pp.81-88
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    • 2009
  • The main purpose of this work is to determine characteristics of undrained shear strength of remolded marine clay at Incheon. Laboratory vane tests with remolded marine clay sampled from west coast at Incheon were performed to investigate the undrained shear strength of them being dumped for reclamation after dredging from the sea bottom. Test results were compared with the predicted values of undrained shear strength proposed by many researchers. It was found that measured results about undrained shear strength with water content was in good agreements with values proposed by Mikasa and Modified Mikasa's empirical formula.

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Influence of coarse particles on the physical properties and quick undrained shear strength of fine-grained soils

  • Park, Tae-Woong;Kim, Hyeong-Joo;Tanvir, Mohammad Taimur;Lee, Jang-Baek;Moon, Sung-Gil
    • Geomechanics and Engineering
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    • v.14 no.1
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    • pp.99-105
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    • 2018
  • Soils are generally classified as fine-grained or coarse-grained depending on the percentage content of the primary constituents. In reality, soils are actually made up of mixed and composite constituents. Soils primarily classified as fine-grained, still consists of a range of coarse particles as secondary constituents in between 0% to 50%. A laboratory scale model test was conducted to investigate the influence of coarse particles on the physical (e.g., density, water content, and void ratio) and mechanical (e.g., quick undrained shear strength) properties of primarily classified fine-grained cohesive soils. Pure kaolinite clay and sand-mixed kaolinite soil (e.g., sand content: 10%, 20%, and 30%) having various water contents (60%, 65%, and 70%) were preconsolidated at different stress levels (0, 13, 17.5, 22 kPa). The quick undrained shear strength properties were determined using the conventional Static Cone Penetration Test (SCPT) method and the new Fall Cone Test (FCT) method. The corresponding void ratios and densities with respect to the quick undrained shear strength were also observed. Correlations of the physical properties and quick undrained shear strengths derived from the SCPT and FCT were also established. Comparison of results showed a significant relationship between the two methods. From the results of FCT and SCPT, there is a decreasing trend of quick undrained shear strength, strength increase ratio ($S_u/P_o$), and void ratio (e) as the sand content is increased. The quick undrained shear strength generally decreases with increased water content. For the same water content, increasing the sand content resulted to a decrease in quick undrained shear strength due to reduced adhesion, and also, resulted to an increase in density. Similarly, it is observed that the change in density is distinctively noticeable at sand content greater than 20%. However, for sand content lower than 10%, there is minimal change in density with respect to water content. In general, the results showed a decrease in quick undrained shear strength for soils with higher amounts of sand content. Therefore, as the soil adhesion is reduced, the cone penetration resistances of the FCT and SCPT reflects internal friction and density of sand in the total shear strength.

A NEW CPT-BASED METHOD FOR UNDRAINED SHEAR STRENGTH ESTIMATION OF CLAYS

  • Lee, Jun-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09c
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    • pp.18-23
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    • 2010
  • The estimation of the undrained shear strength $s_u$ for clays using CPT results has been mainly based on the cone factor $N_k$. In this study, a new CPT-based method for the estimation of the undrained shear strength $s_u$ is presented. This aims at reducing uncertainties for the estimation of $s_u$ and enhancing the application of CPT results in more effective manner. For this purpose, a site located at a marine clay deposit is selected and test results from extensive experimental testing program are adopted. The new method defines a direct correlation between the undrained shear strength $s_u$ and the cone resistance $q_t$, excluding the procedure of the overburden pressure correction and therefore undisturbed soil sampling process. In order to verify the new CPT-based method, additional test sites and example sites from literature, which consist of a variety of soil conditions, are selected and examined. It is observed that values of su obtained from the proposed method are in good agreements with measured values of $s_u$ for all the selected verification cases.

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Assessment on Design Applicability of Analysis of the Undrained Shear Strength in Korea Coastal Marine Clay (국내 해성점토의 비배수 전단강도 분석을 통한 설계 적용성 평가)

  • Kim, Myeong Hwan;Song, Chang Seob
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.1
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    • pp.61-71
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    • 2016
  • This study performed the physical and mechanical experiment on the samples of costal marine clays individually collected in western and southern regions to identify the characteristics of western and southern costal marine clay. Based on the experiment result, the characteristics of costal marine clay is identified undrained shear strength. Based on the experiment result on the physical and mechanical characteristics of costal marine clays, the regression is presented that can analyze the mechanical characteristics of undrained shear strength in costal marine clay of Korea, region of Korea and western-southern region. The correlation of uniaxial compressive strength and undrained shear strength was suitable for use of western-southern region correlation equation. The test result of Jeonnam Yeosu area compares with prediction results of previous researchers formula and western-southern region formula. Prediction results appear highest reliability on the 0.827 of coefficient of determination in the prediction results of the western-southern region formula.

Characteristics of Behavior of Pressurized light-weight steel Anchor according to undrained shear strength (비배수 전단강도에 따른 압입식 경량강재앵커블록의 거동 특성)

  • Heo, Yol;Ahn, Kwang-Kuk;Park, Kyoung-Soo;Lee, Yong-Jun;Kang, Hong-Sig
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.219-224
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    • 2009
  • In this study, the characteristics of pullout behavior of Pressurized light-weight steel Anchor was investigated through centrifuge model tests considering pull-out angle $0^{\circ}$ with changing undrained shearstrength(0~1, 2~4, 5~7kPa) of clay. According to the results of tests, the yield pullout load of clay ground was gradually increased up to 30% as undrained shear strength was increased. Therefore, it was known that the yield pullout load was affected by increasing the undrained shear strength, in addition, the pattern of behavior was not changed.

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Determination of Undrained Shear Strength using Miniature Cone and T-bar Penetrometers for Kaolin Clay (소형콘과 T-bar 관입기를 이용한 카올린 점토의 비배수전단강도 산정에 관한 연구)

  • Sespene, Shemelyn;Choo, Yun Wook
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.38 no.3
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    • pp.429-438
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    • 2018
  • Cone and T-bar penetrometers have been frequently used to estimate the undrained shear strength of clay. For small-size model tests, miniature penetrometers should be used but their correlation factors have not been well published. In this study, a testing setup was developed to derive empirical factors of the miniature cone and T-bar penetrometers. A 350mm-diameter chamber and kaolin clay were utilized to prepare soil specimens consolidated under four different pre-consolidation pressures controlling undrained shear strength. Two miniature cones with two diameters of 10-mm and 16-mm and a T-bar penetrometer with 10-mm diameter were used to investigate boundary effect, penetration rate effect, and diameter and shape effect. Unconsolidated-undrained triaxial tests were carried out with samples taken from the specimens to measure undrained shear strength. Finally, empirical factors for the penetrometers were constructed to correlate tip resistance to undrained shear strength.

Feasibility of Artificial Neural Network Model Application for Evaluation of Undrained Shear Strength from Piezocone Measurements (피에조콘을 이용한 점토의 비배수전단강도 추정에의 인공신경망 이론 적용)

  • 김영상
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.287-298
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    • 2003
  • The feasibility of using neural networks to model the complex relationship between piezocone measurements and the undrained shear strength of clays has been investigated. A three layered back propagation neural network model was developed based on actual undrained shear strengths, which were obtained from the isotrpoically and anisotrpoically consolidated triaxial compression test(CIUC and CAUC), and piezocone measurements compiled from various locations around the world. It was validated by comparing model predictions with measured values about new piezocone data, which were not previously employed during development of model. Performance of the neural network model was compared with conventional empirical method, direct correlation method, and theoretical method. It was found that the neural network model is not only capable of inferring a complex relationship between piezocone measurements and the undrained shear strength of clays but also gives a more precise and reliable undrained shear strength than theoretical and empirical approaches. Furthermore, neural network model has a possibility to be a generalized relationship between piezocone measurements and undrained shear strength over the various places and countries, while the present empirical correlations present the site specific relationship.

Characteristics of Undrained Shear Strength of Yangsan Clay (양산지역 점토의 비배수 전단강도 특성)

  • 김길수;임형덕;이우진
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.02a
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    • pp.71-78
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    • 2000
  • SHANSEP method involves the consolidation to stresses in excess of the preconsolidation pressure in order to overcome sample disturbance effect. The concept of SHANSEP is based on an approach to laboratory test which attempts to reproduce the in-situ conditions more closely than is possible in routine tests and evaluates normalized strength parameters for the soil as a function of OCR. But SHANSEP method can be applied only to fairly uniform clay deposits, and is unsuitable for a random deposit. In this study, CK/sub o/U triaxial compression test and incremental loading consolidation test were performed for the application of SHANSEP method on Yangsan clay. During the K/sub o/-consolidation, triaxial specimens were consolidated to stress equal to two times the in-situ vertical effective stress. And for overconsolidated condition, the specimens were swelled to a known vertical effective stress in order to have the desired OCR. With the results of CK/sub o/U triaxial compression test using the block samples, the relationship between c/sub u//σ/sub vc/' and OCR on Yangsan clay was established. For evaluating the undrained shear strength of Yangsan clay with depth, CK/sub o/U triaxial compression test was performed using the piston samples taken from Yangsan site. And also undrained shear strength was analyzed from the in-situ test such as Cone Penetration Test(CPT), Dilatometer Test(DMT), and Field Vane Test(FVT) and was compared with that of CK/sub o/U triaxial compression test.

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Index Properties and Undrained Shear Strength of the Pusan Clays by Fall Cone Test (부산점토의 Fall Cone Test에 의한 지수 및 강도특성)

  • ;;Pham Huy Giao
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.391-398
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    • 2000
  • The index properties of cohesive soils play an important role to examine entire tendency of soil properties. Especially, the Atterberg limits have a good correlation with compression and shear strength of cohesive soils. However, these values strongly depend on their testing methods. In this study, for Pusan clays the Atterberg limits were peformed under different conditions; for example, four kinds of specimen preparation, two kinds of testing equipment, and four kinds of estimating method. And a laboratory vane test was peformed to compare the undrained shear strength with that of the fall cone test. As experimental results, the value of liquid limit performed for oven-dried sample, followed in ASTM D4318, underestimated by about 10% compared to those of another three methods, irrespective to the used equipments. But the value of plastic limit was not influenced by sample preparation methods and equipments. The liquid limits by one-point methods(Leroueil et al., 1996; Nagaraj et al., 1981) were agreed well with those of different methods. Finally, the undrained shear strength by laboratory vane test was relatively larger than that of fall cone test, and the relationship between both showed a bad trend.

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