A case study on trench collapse of deep diaphragm wall

Jing-Wen Chen, Fu Cheng Chen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

This paper presents a remedy case of a large-scaled trench collapse during the construction of a deep cylindrical diaphragm wall located in the south of Taiwan. Through a well-organized field monitoring system and suitable countermeasures, the potential disaster was mitigated in time. Thirty-two panels in total were designed to form the 70 m-diametered diaphragm with 1.2 m thickness and 90 m depth. During the trench excavation, a deep and large collapse of soils, approximately 110 m3, occurred at the depth of GL.-43 m to GL.-52 m in the trench. The overlapped reinforcing bars (rebar) of previously installed panels were serious deformed and impeded the coming rebar cage insertion. A series of monitoring activities including ultrasonic sounding and piezometer measurement was performed to figure out the causes and damaged situation. Relevant remedial measures as well as the monitoring data during the post-treatment are addressed. Three main concerns are concluded: (1) a well-organized field monitoring system during construction would be helpful for judgment in case any accident occurred, (2) an improper construction activity using percussion drill inside the coming-close cylindrical diaphragm wall built up the excess pore water pressure of the confined aquifer at the collapse depth and resulted in the serious collapse, and (3) the long stand-by duration of the excavated trench would increase the possibility of collapse.

Original languageEnglish
Title of host publicationFMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics
Number of pages1
Edition175
DOIs
Publication statusPublished - 2007 Dec 1
Event7th International Symposium on Field Measurements in Geomechanics, FMGM 2007 - Boston, MA, United States
Duration: 2007 Sep 242007 Sep 27

Publication series

NameGeotechnical Special Publication
Number175
ISSN (Print)0895-0563

Other

Other7th International Symposium on Field Measurements in Geomechanics, FMGM 2007
CountryUnited States
CityBoston, MA
Period07-09-2407-09-27

Fingerprint

diaphragm wall
diaphragm
Diaphragms
trench
case studies
Monitoring
monitoring
monitoring system
piezometers
disasters
accidents
Aquifers
Excavation
Disasters
aquifers
piezometer
confined aquifer
Taiwan
ultrasonics
Accidents

All Science Journal Classification (ASJC) codes

  • Building and Construction
  • Architecture
  • Soil Science

Cite this

Chen, J-W., & Chen, F. C. (2007). A case study on trench collapse of deep diaphragm wall. In FMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics (175 ed.). (Geotechnical Special Publication; No. 175). https://doi.org/10.1061/40940(307)27
Chen, Jing-Wen ; Chen, Fu Cheng. / A case study on trench collapse of deep diaphragm wall. FMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics. 175. ed. 2007. (Geotechnical Special Publication; 175).
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abstract = "This paper presents a remedy case of a large-scaled trench collapse during the construction of a deep cylindrical diaphragm wall located in the south of Taiwan. Through a well-organized field monitoring system and suitable countermeasures, the potential disaster was mitigated in time. Thirty-two panels in total were designed to form the 70 m-diametered diaphragm with 1.2 m thickness and 90 m depth. During the trench excavation, a deep and large collapse of soils, approximately 110 m3, occurred at the depth of GL.-43 m to GL.-52 m in the trench. The overlapped reinforcing bars (rebar) of previously installed panels were serious deformed and impeded the coming rebar cage insertion. A series of monitoring activities including ultrasonic sounding and piezometer measurement was performed to figure out the causes and damaged situation. Relevant remedial measures as well as the monitoring data during the post-treatment are addressed. Three main concerns are concluded: (1) a well-organized field monitoring system during construction would be helpful for judgment in case any accident occurred, (2) an improper construction activity using percussion drill inside the coming-close cylindrical diaphragm wall built up the excess pore water pressure of the confined aquifer at the collapse depth and resulted in the serious collapse, and (3) the long stand-by duration of the excavated trench would increase the possibility of collapse.",
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Chen, J-W & Chen, FC 2007, A case study on trench collapse of deep diaphragm wall. in FMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics. 175 edn, Geotechnical Special Publication, no. 175, 7th International Symposium on Field Measurements in Geomechanics, FMGM 2007, Boston, MA, United States, 07-09-24. https://doi.org/10.1061/40940(307)27

A case study on trench collapse of deep diaphragm wall. / Chen, Jing-Wen; Chen, Fu Cheng.

FMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics. 175. ed. 2007. (Geotechnical Special Publication; No. 175).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Chen J-W, Chen FC. A case study on trench collapse of deep diaphragm wall. In FMGM 2007 - Proceedings of the 7th International Symposium on Field Measurments in Geomechanics. 175 ed. 2007. (Geotechnical Special Publication; 175). https://doi.org/10.1061/40940(307)27