Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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Strength Characteristics of Improved Dredged Clay for Urgent Recovery of Ground Subsidence

함몰지반 긴급복구를 위한 개량준설점토의 강도 특성

  • Oh, Sewook (Department of Construction & Disaster Prevention Engineering, Kyungpook National University) ;
  • Baek, Seungju (Department of Disaster Prevention & Environmental Engineering, Kyungpook National University) ;
  • Bang, Seongtaek (Department of Construction & Disaster Prevention Engineering, Kyungpook National University)
  • Received : 2019.03.15
  • Accepted : 2019.04.10
  • Published : 2019.05.01
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Abstract

Recently, there has been an increasing number of ground subsidence (sink-hole) in the downtown areas, and in such a case, it is important to minimize accidents and passages through prompt recovery. With respect to the present recovery method for ground subsidence, the methods of applying the back filling after excavating the ground subsidence or using the grouting injected materials to restore the ground are mostly used, but there has been few studies on materials used for recovering the ground subsidence. Therefore, in order to clarify the characteristics of back filling materials used in the ground subsidence, this study uses the environment-friendly hardening agent to improve the dredged clay, and then, the mixture ratio of hardening agent and mixture ratio of decomposed granite soil is changed to cure for 3, 7, 14 and 28 days to analyze the intensity characteristics of the unconfined compression, and it was compared with the unconfined compression intensity for the previously used cement, a hardening agent. In order to evaluate the characteristics of intensity on the back filling materials, the C.B.R test was carried out, and for the review on whether the back filling materials influence on corrosion of water and sewer pipes and others, the soil non-resistance test was carried out. As a result of the test, for the case of the recovery work of the ground subsidence that requires urgency, it is considered as prudent if the hardening agents of 12% are integrated to cure for 3 days or longer, and for not having the influence on the corrosion of the gas tube or water pipes, it is proposed to mix for 30% or more of the decomposed granite soil. Door model test were conducted To confirm the bearing capacity characteristics of the solidified layer.

최근 도심지에서 지반함몰의 발생이 증가하고 있으며, 이러한 경우 신속한 복구를 통해 안전사고 및 통행에 대한 불편을 최소화하는 것이 중요하다. 현재의 지반함몰 복구 방법으로는 함몰지반을 개착한 후에 되메우기를 하거나 그라우팅 주입재를 사용하여 지반을 복구하는 방법이 주로 적용되고 있으나. 지반 함몰복구 시 사용되는 재료에 대한 연구는 미비한 실정이다. 따라서 본 연구에서는 함몰지반에 사용되는 되메움재료의 특성을 규명하기 위하여 준설점토를 친환경 고화재를 이용하여 개량한 후 고화재의 혼합비율 및 화강풍화토의 혼합비율을 변화시켜 3, 7, 14, 28일 양생시킨 후 일축압축 강도특성을 분석하였으며, 기존에 사용되던 고화재인 시멘트의 일축압축강도와 비교하였다. 되메움재료의 강도특성을 평가하기 C.B.R 시험을 수행하였고, 되메움 재료가 상하수도관 등의 부식에 영향을 주는지에 대한 검토를 위하여 토양비저항시험을 수행하였다. 시험결과 긴급을 요하는 함몰지반 복구공사의 경우 12%의 고화재를 혼합하여 3일 이상 양생하는 것이 좋다고 판단되며, 가스관이나 상하수도관의 부식에 영향을 미치지 않도록 하기 위하여 화강풍화토를 30% 이상 혼합할 것을 제안한다.

Keywords

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Fig. 1. Unconfined compressive strength according to the curing period (w.s 0%)

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Fig. 2. Unconfined compressive strength according to the curing period (w.s 30%)

HJHGC7_2019_v20n5_31_f0003.png 이미지

Fig. 3. Unconfined compressive strength according to the weathered soil content

HJHGC7_2019_v20n5_31_f0004.png 이미지

Fig. 4. Unconfined compressive strength according to the curing period (w.s 0%)

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Fig. 5. Unconfined compressive strength according to the curing period (w.s 30%)

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Fig. 6. Comparison of unconfined compressive strength with stabilizer and cement

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Fig. 7. Comparison of unconfined compressive strength with stabilizer and cement

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Fig. 8. Comparison of unconfined compressive strength with stabilizer and cement

HJHGC7_2019_v20n5_31_f0009.png 이미지

Fig. 9. Comparison of strength ratio with stabilizer and cement

Table 1. Physical properties of improved dredged clay

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Table 2. Elution test result of stabilizer and cement

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Table 3. Experimental condition

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Table 4. Result of soil resistivity

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