1 / 19

Ph D. candidate Kwak , Tae-young

2015 Wednesday Seminar. Investigation on Mechanism of Ground Cave-ins and Subsidence induced by Damaged Sewer Pipelines. Geotechnical and Geoenvironmental Engineering Laboratory. 2015.03.18(Wed). Ph D. candidate Kwak , Tae-young. CONTENTS. Introduction. 1. Literature Review.

myrat
Télécharger la présentation

Ph D. candidate Kwak , Tae-young

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 2015 Wednesday Seminar Investigation on Mechanism of Ground Cave-ins and Subsidence induced by Damaged Sewer Pipelines Geotechnical and Geoenvironmental Engineering Laboratory 2015.03.18(Wed) Ph D. candidate Kwak, Tae-young

  2. CONTENTS Introduction 1 Literature Review 2 Research Plan 3 Summary 4

  3. Introduction

  4. Introduction Background Seoul, 2014 - Length8m - Width2.5m - Depth5m Guatemala, 2010 - Diameter 20m - Depth30m

  5. Introduction Background (September, 2014, ‘Sink HoleAssessment and Countermeasures‘, Policy forum) 854 689 573 435 - Annual occurrences of ground cave-ins have increased. - Research for ground cave-ins needed.

  6. Introduction Ground Cave-ins and Subsidence (Sink Hole) : Depression or hole in the ground caused by some form of collapse of the surface layer

  7. Introduction Types of Ground cave-ins and subsidence 1. Inherent ground cave-ins : Development of cavities by dissolution of limestone by groundwater 2. Artificial ground cave-ins : Development of cavities by 1) Ground excavation , 2) Damaged pipelines (September, 2014, ‘Sink HoleAssessment and Countermeasures‘, Policy forum) Ground cave-ins and subsidence are induced by groundwater seepage and soil leaking through damaged sewer pipelines

  8. Literature Review

  9. Literature Review Ground Cave-ins and Subsidence by Excavation • Nakai et al. (1997) • : Comparison between model tests and numerical analyses by evaluating • the surface settlement • Type of soils (Dry toyoura sand & Kaolin clay) • Height of tunnel (D/B)

  10. Literature Review Ground Cave-ins and Subsidence by Excavation • Lee et al. (2006) • : Comparison between centrifuge tests and numerical analyses by • evaluating the surface settlement • Number of tunnels (Single-tunnel / Parallel-tunnel) • Center to center distance (d) • Cover to diameter ratio (C/D)

  11. Literature Review Ground Cave-ins and Subsidence by Excavation • Coudron et al. (2006) • : Comparison between model tests and numerical analyses by evaluating • the surface settlement • Width of cavity • Height of cavity • Structure above soils

  12. Literature Review Ground Cave-ins and Subsidence by Damaged Sewer Pipelines Water Research Center (England) : Explanation on development of underground cavities by poor connections of sewer pipelines • Limitations of WRC • Explanation limited to the phenomena • of cavity development • No explanation given on mechanism of • ground cave-ins and subsidence • induced by damaged sewer pipelines

  13. Literature Review Ground Cave-ins and Subsidence by Damaged Sewer Pipeline Higashi et al. (2003), Kuwano et al.(2009), Mukunoki et al.(2009) : Simulation of ground cave-ins and subsidence by damaged sewer pipelines (By naked eye or X-ray Computed Tomography (CT))

  14. Literature Review Ground Cave-ins and Subsidence by Damaged Sewer Pipeline Higashi et al. (2003), Kuwano et al.(2009), Mukunoki et al.(2009) : Some limitations existing in researches performed in Japan (1) No consideration on the soils at site - Used typical soils (ex. Toyoura sands) (2) No consideration on the seepage pressure at site - Used arbitrary differential heads (3) No investigation on the mechanism of ground cave-ins and subsidence - Evaluated only the cavities and loosening sections of soils - Evaluated cavities and loosening sections of soils only at specific times

  15. Research Plan

  16. Research Plan Steps of Research

  17. Summary

  18. Summary • Annual occurrences of ground cave-ins (Sink holes) have been increasing recently. Consequently, research of ground cave-ins is needed. • Most of artificial ground cave-ins are induced by groundwater seepage and soil leaking through damaged sewer pipelines. • Many researches have performed the evaluation of ground cave-ins and subsidence by model tests and numerical analyses. However, they do not properly investigate the overall mechanism of the development of ground cave-ins and subsidence. • Evaluation of external deformation by model tests and internal deformation by DIA will be performed. ⇒ The mechanism of ground cave-ins will be investigated, and the prevention methods will be established and verified.

  19. 2015 Wednesday Seminar THANK YOU Geotechnical and Geoenvironmental Engineering Laboratory Any question?

More Related