- Volume 34 Issue 10
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An Experimental Study on the Elastic Modulus of Deep Mixing Ground Specimen
심층혼합 시료의 탄성계수에 관한 실험적 연구
- Park, Choon-Sik (School of Civil, Environmental and Chemical Engrg., Changwon Univ.) ;
- Park, Hwan-Ki (Province of Gyeongsangnam-do)
- Received : 2018.09.06
- Accepted : 2018.10.13
- Published : 2018.10.31
In this study, aimed at determining the elastic modulus of deep mixed samples, 320 test specimens were developed by mixing 8%, 10%, 12%, and 14% of stabilizer mixture in the granular conditions of clay, sand and gravel. Uniaxial compression tests were carried out using these specimens, and the uniaxial compression strength and strain were analyzed to determine the secant elastic modulus and tangent elastic modulus. Laboratory test results showed that the uniaxial compression strength of all deep mixed samples increased with increasing curing time and stabilizer mixing ratio, and that the secant elastic modulus and the tangen elastic modulus also increased. The increase of the elastic modulus according to the curing period turned out greater in the tangent elastic modulus than in the secant elastic modulus. In order to measure elastic modulus with changes in stabilizer mixing ratio, the correlation coefficient between the elastic modulus for stabilizer mixing ratio of 8% and that of 10%, 12% and 14% was calculated respectively by the specimen condition. The elastic modulus tended to increase as the grain size in a deep mixed specimen increased. The distribution of grain size that had the greatest effect appeared when the composition ratio of sand was high. On the other hand, the increase in the elastic modulus was larger in the sand specimens than in the clay and gravel specimens. Based on these results, it is suggested that a pertinent soil parameter of the deep mixed ground in the field may be obtained by the particle size distribution and the mixing ratio of stabilizer of the deep mixed soil.
본 연구는 심층혼합시료의 탄성계수를 파악하기 위하여 점토, 모래, 자갈의 입도 구성조건에 안정재 혼합비 8%, 10%, 12%, 14%로 혼합하여 총 320개의 공시체를 제작하였다. 이러한 공시체를 사용하여 일축압축시험을 수행하였고, 일축압축강도와 변형률을 분석하여 할선탄성계수와 접선탄성계수를 구하였다. 실내시험 결과 모든 심층혼합시료는 양생기간과 안정재 혼합비가 증가함에 따라 일축압축강도가 증가하였는데, 이에 대한 할선탄성계수와 접선탄성계수도 증가하는 경향이 뚜렷하게 나타났다. 양생기간에 따른 탄성계수 값의 증가는 할선탄성계수보다 접선탄성계수가 크게 나타났지만, 탄성계수의 증분비는 할선탄성계수가 크게 나타났다. 안정재 혼합비 8%에 대한 탄성계수와 안정재 혼합비 10%, 12%, 14%에 대한 탄성계수 값을 비교하여 안정재 혼합비에 따른 탄성계수를 추정할 수 있는 상관관계식을 공시체 조건별로 구하였다. 심층혼합시료의 입경이 굵어지면 각각의 탄성계수가 증가하는 경향이 나타났으며,가장 큰 영향을 미치는 입경의 분포는 모래질의 구성비가 높을 때 나타났다. 한편 탄성계수증가는 공시체 종류별로는 모래질 공시체가 점토질과 자갈질 공시체보다 크게 나타났다. 이러한 결과를 바탕으로 심층혼합시료의 입도 분포와 안정재 혼합비로 현장의 심층혼합지반의 적절한 지반정수를 제안할 수 있을 것으로 판단된다.
- Chun, B. S., Lim, H. S., and Jeon, J. G. (2000), "A Study on the Design-parameter of Mixed Ground by Using Cement-type Stabilizer", Journal of the Korean Geotechnical Society, Vol.16, No.2, pp.79-81 (In Korean).
- George, K. P. (1968), "Shrinkage Characteristics of Soil-Cement Mixtures", Highway Research Record, No.255, pp.42-58.
- Jeong, K. H., Shin, M. S., Han, K. T., Lee, J. H., and Kim, J. H. (2008), "Suggestion for Determination of DCM Design Parameter Based on the Statistical Method", KGS Spring Conference 2008, pp.462-471 (In Korean).
- Kim, B. I., Wee, S. H., Lee, S. H., and Kim, Y. U. (2003), "Strength Characteristics of Soil-Cement Mixed with Inorganic Solidification Liquid", Journal of the Korean Society of Civil Engineering-C, Vol.23, No.3, pp.135-141 (In Korean).
- Moh, Z. C., Chin, Y. P., and Ng, S. C. (1970), "Cement Stabilization of Lateritic Soils", Proc. of Asian Conference Soil Mechanics and Foundation Engineering, Vol.1, pp.42-46.
- Park, C. S., Kim, J. H., Kim, J. J., and Baek, J. S. (2014), "An Experimental Study on the Strength of Deep Mixing Specimen According to the Stabilizer Content", Journal of the Korean Geotechnical Society, Vol.30, No.1, pp.27-26 (In Korean). https://doi.org/10.7843/KGS.2014.30.1.27
- Park, H. K. (2013), "An Experimental Study on the Elastic Modulus of Deep Mixing Ground Specimen According to the Stabilizer Contents", Doctor of Eng. thesis, Changwon Univ., pp.55-169 (In Korean).
- Pendola, H. J., Kenndy, T. W., and Hudson, W. R. (1969), "Evaluation of Factor Affecting the Tesile Proerties of Cement Treated Material", Texas Univ. of Texas at Austin, Research Report, 98-3.
- Terashi, M. and Tanaka, H. (1981), "Ground Improved by the Deep Mixing Method", Proc. of the 10th International Conference on Soil Mechanics and Foundation Engineering, pp.777-780.
- Terashi, M. and Tanaka, H. (1983), "Settlement Analysis for the Deep Mixing Method", Proc. of the 8th European Conference on Soil Mechanics and Foundation Engineering, pp.955-960.
- Terashi, M., Tanaka, H., and Kitazume, M. (1983a), "Extrusion Failure of Ground Improved by the Deep Mixing Method", Proc. of the 7th Asian Regional conference on Soil Mechanics and Foundation Engineering, pp.313-318.
- Terashi, M., Tanaka, H., Mitsumoto, T., Honma, S., and Ohhashi, T. (1983b), "Fundamental Properties of Lime Treated Soil (3rd report)", Report of the Port and Harbour Research Institute, Vol.22, No.1, pp.69-96 (in Japanese).
- Terashi, M., Tanaka, H., Mitsumoto, T., Niidome, Y., and Honma, S. (1980), "Fundamental Properties of Lime Treated Soil (2nd report)", Report of the Port and Harbour Research institute, Vol.19, No.1, pp.33-62 (In Japanese).
- Terashi, M., Tanaka, H., Mitsumoto, T., Niidome, Y., and Honma, S. (1979), "Engineering Properties of Lime Treated Marina Soils", Proc. of the 6th Asian Regional conference on soil Mechanics and Foundation Engineering, pp.191-194.
- Yang, T. S., Jeong, G. H., Yeo, B. G., and Lee, S. S. (2000), "A Study on Design Strength and Elastic Modulus Using Deep Cement Mixing Method", KSCE Conference, Vol.2000, No.2, pp.615-618 (In Korean).