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기초형식 및 뒤채움재 종류별 강성관용 하수관거의 안전율

Safety Factor of Rigid Sewer Pipe by Different Types of Foundation and Backfill

  • 이관호 (국립공주대학교 건설환경공학부) ;
  • 김성겸 (국립공주대학교 건설환경공학부)
  • Lee, Kwan-Ho (Department of Civil & Environmental Engineering, Kongju National University) ;
  • Kim, Seong-Kyum (Department of Civil & Environmental Engineering, Kongju National University)
  • 투고 : 2019.01.11
  • 심사 : 2019.04.05
  • 발행 : 2019.04.30

초록

도심지 도로하부에서 발생하는 지반침하 및 싱크홀의 주요 원인은 하수관로 기초 및 관로뒤채움재의 부적절한 다짐 등이다. 이로 인해 하수관거의 이음부 파손 및 접합 불량, 관의 파손 및 균열 등 많은 문제점이 발생하고 있다. 이를 해결하기 위해 하수관거 기초와 관련된 받침계수 및 굴착 깊이에 따른 안전율을 평가하였다. 강성관용 기초로는 쇄석기초, 버림 콘크리트 기초, 그리고 최근 새로 개발된 현장조립식 경량플라스틱 기초를 이용하였고, 뒤채움재는 현장발생토사(사질토 및 점성토), 현장발생토사를 재활용한 유동성뒤채움 등을 적용하였다. 굴착 깊이 및 하수관 기초별 안전율을 평가하기 위하여 하중 계수 및 받침계수 등을 고려한 설계하중을 평가하였다. 받침계수는 쇄석기초 0.377, 버림 콘크리트 기초($180^{\circ}$$120^{\circ}$) 0.243 및 0.220, 경량 플라스틱 기초와 유동성 뒤채움재는 0.231로 적용하였다. 전체적으로 쇄석기초 사용 시 안전율이 작게 나왔고, 받침각 $180^{\circ}$ 버림 콘크리트 기초 사용 시 안전율이 가장 크게 나타났다. 또한, 경량 플라스틱 기초와 유동성 뒤채움재의 조합을 이용할 경우 받침각 $120^{\circ}$ 버림 콘크리트 기초보다 안전율이 크게 나타났다. 이는 새로 개발된 재활용 경량 플라스틱 기초가 강성관의 또 다른 대안 기초로 활용이 가능함을 의미한다.

The main causes of subsidence and sinkholes in the lower part of urban roads are sewage line foundation and inadequate compaction of backfill material. This leads to many problems, such as the breakage of joints in sewer pipes, poor connection, pipe breakage, and cracks. To solve this problem, the support factor related to the sewer foundation and the safety factor according to the excavation depth were evaluated. For the foundation of rigidity tolerance, crushed stone foundation, and abandoned concrete foundation, a recently newly developed site assembly-type lightweight plastic foundation were used. Backfill materials were applied on site (sandy soil and clayey soil) and fluid backfill was recycled onsite. To evaluate the depth of excavation and the safety factor of each sewer pipe foundation, the design load considering the load factor and the support factor was evaluated. The support coefficients were 0.377 for a crushed stone foundation, 0.243 and 0.220 for an abandoned concrete foundation ($180^{\circ}$ and $120^{\circ}$), and 0.231 for a lightweight plastic foundation and fluid backfill. Overall, the safety factor was low when using the crushed stone foundation, and the safety rate was the highest when the foreclosed concrete foundation ($180^{\circ}$) was used. In addition, when the combination of lightweight plastic and fluid backfill materials was used, the safety factor was higher than that of abandoned concrete foundation ($120^{\circ}$), which means that the newly developed lightweight plastic foundation can be used as another alternative base of a steel pipe.

키워드

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Fig. 1. Subsidence and sink hole in road

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Fig. 2. Contact type of foundation

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Fig. 3. Three-edge bearing test

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Fig. 4. Cross Section

Table 1. Budget for Sewer System (unit : billion won)

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Table 2. Foundation of pipe for soil type

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Table 3. Bedding factor (k)

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Table 4. Material properties of backfill

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Table 5. Parameter of design analysis

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Table 6. Design parameter of concrete pipe (Case A)

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Table 7. Design parameter of concrete pipe (Case B)

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Table 8. Design parameter of concrete pipe (Case C)

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Table 9. Design parameter of concrete pipe (Case D)

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Table 10. Safety factor of case A

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Table 11. Safety factor of case B

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Table 12. Safety factor of case C

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Table 13. Safety factor of case D

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참고문헌

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  6. Arulrajah, A., J. Piratheepan, M.M. Disfani, M.W. Bo, "Geotechnical and geo-environmental properties of recycled construction and demolition materials in pavement sub-base applications", J. Mater. Civil Eng., pp. 1077-1088, 2013. DOI: https://doi.org/10.1061/(ASCE)MT.1943-5533.0000652
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  8. American Concrete Pipe Association, "Design Data 9 : Standard Installations and Bedding Factors for the Indirect Design Method", ACPA, pp. 13, 2013.
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