A Modified CLSM Trench Backfilling Method to Provide Immediate Bearing Capacity
Publication: Journal of Transportation Engineering, Part B: Pavements
Volume 148, Issue 3
Abstract
The use of controlled low-strength material (CLSM) to backfill the cut-and-cover pipelines trench under busy streets is getting popular nowadays. Due to the slow hydration rate of cement in CLSM, extra waiting hours are usually needed before it can develop sufficient strength to sustain traffic. To shorten the waiting time, this paper presents a method that can provide a good immediate bearing capacity for the CLSM backfilled trench right after completing narrow trench work. This modified method adds extra gravel to the top of the fresh CLSM, which is already in the trench. The gravel is then pushed down and mixed with CLSM and forms a strong upper layer for the CLSM trench. It can provide a good immediate bearing capacity to endure traffic weight. To verify the suitability of this modified CLSM trench filling method, a numerical analysis method [discrete-element method (DEM)] was adopted in this study, along with the laboratory model and field tests. The DEM results showed that high-friction material (gravel) on the upper portion of the trench could form a strong layer that sustains a large share of the surcharge load. So, it could result in a significant pressure reduction for the lower portion of the trench and around the buried pipes, even though the CLSM had not hardened yet. Such a result was confirmed by the laboratory model test and the full-scale field test, in which it showed an increase in the initial load-bearing capacity and a much smaller settlement on the surface of the CLSM backfilled trench.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
The authors wish to thank Ci-Ci Wu, the Ministry of Science and Technology, Taiwan Government (MOST 109-2221-E-011-020), and the Taipei City Government for providing financial support for this research; the Taipei Water Department for providing the field test site to verify the effectiveness and suitability of this modified CLSM backfill method.
References
ACI (American Concrete Institute). 2005. Controlled low strength material. Farmington Hill, MI: ACI.
Altair EDEM. 2020. EDEM documentation. Sterling Heights, MI: DEM Solutions.
ASTM. 2016. Standard test method for California bearing ratio (CBR) of laboratory-compacted soils. ASTM C1883. West Conshohocken, PA: ASTM.
ASTM. 2017. Standard test method for flow consistency of controlled low strength material (CLSM). ASTM D6103/D6103M. West Conshohocken, PA: ASTM.
Boschert, J., and J. Butler. 2013. “CLSM as a pipe bedding: Computing predicted load using the modified Marston equation.” In Proc., Pipelines 2013 Conf.: Pipelines 2013: Pipelines and Trenchless Construction and Renewals—A Global Perspective, 1201–1212. Elkhorn, WS: National Clay Pipe Institute.
Bowles, J. 1996. Foundation analysis and design. Singapore: McGraw-Hill International Book Company.
Calvetti, F., C. di Prisco, and R. Nova. 2004. “Experimental and numerical analysis of soil-pipe interaction.” J. Geotech. Geoenviron. Eng. 130 (12): 1292–1299. https://doi.org/10.1061/(ASCE)1090-0241(2004)130:12(1292).
Das, B. M., and N. Sivakugan. 2017. Principles of foundation engineering. Boston, MA: Cengage Learning.
Dilrukshi, S., and D. Wijewickreme. 2020. “Study of trench backfill particle size effects on lateral soil restraints on buried pipelines using discrete element modeling.” J. Pipeline Syst. Eng. Pract. 11 (1): 04019047. https://doi.org/10.1061/(ASCE)PS.1949-1204.0000423.
Hasan, A., A. Karrech, and B. Chareyre. 2017. “Evaluating force distributions within virtual uncemented mine backfill using discrete element method.” Int. J. Geomech. 17 (7): 06016042. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000850.
Li, S., I.-H. Ho, L. Ma, Y. Yao, and C. Wang. 2019. “Load reduction on high-filled cut-and-cover tunnel using discrete element method.” Comput. Geotech. 114 (Oct): 103149. https://doi.org/10.1016/j.compgeo.2019.103149.
Ling, T.-C., S. K. Kaliyavaradhan, and C. S. Poon. 2018. “Global perspective on application of controlled low-strength material (CLSM) for trench backfilling—An overview.” Constr. Build. Mater. 158 (Jan): 535–548. https://doi.org/10.1016/j.conbuildmat.2017.10.050.
Meidani, M., M. A. Meguid, and L. E. Chouinard. 2017. “Evaluation of soil-pipe interaction under relative axial ground movement.” J. Pipeline Syst. Eng. Pract. 8 (4): 04017009. https://doi.org/10.1061/(ASCE)PS.1949-1204.0000269.
Peng, J. S., Z. F. Lin, L. Y. Huang, H. M. Chen, Y. J. Q. Ou, J. M. Huang, G. Y. Wu, H. F. Lin, S. Y. Wu. 2020. “A modified CLSM trench backfill method and its application in Taipei city.” [In Chinese.] Prof. Eng. J. 89: 53–60.
Radjai, F., and V. Richefeu. 2009. “Contact dynamics as a nonsmooth discrete element method.” Mech. Mater. 41 (6): 715–728. https://doi.org/10.1016/j.mechmat.2009.01.028.
Rui, R., F. van Tol, X.-L. Xia, S. van Eekelen, G. Hu, and Y.-Y. Xia. 2016. “Evolution of soil arching; 2D D E M simulations.” Comput. Geotech. 73 (Mar): 199–209. https://doi.org/10.1016/j.compgeo.2015.12.006.
Sladen, J., and J. Oswell. 1988. “The induced trench method: A critical review and case history.” Can. Geotech. J. 25 (3): 541–549. https://doi.org/10.1139/t88-059.
Taipei City Government Public Works Bureau. 2000. Taipei city government engineering construction specifications. [In Chinese.] Taipei City, Taiwan: Taipei City Government Public Works Bureau.
Tan, X., W. Li, M. Zhao, and V. W. Tam. 2019. “Numerical discrete-element method investigation on failure process of recycled aggregate concrete.” J. Mater. Civ. Eng. 31 (1): 04018353. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002562.
Tsai, Y. Y. 2020. “A modified CLSM trench backfill method.” M.S. thesis, Dept. of Civil and Construction Engineering, National Taiwan Univ. of Science and Technology.
Zhou, F., F. Lydon, and B. Barr. 1995. “Effect of coarse aggregate on elastic modulus and compressive strength of high performance concrete.” Cem. Concr. Res. 25 (1): 177–186. https://doi.org/10.1016/0008-8846(94)00125-I.
Information & Authors
Information
Published In
Journal of Transportation Engineering, Part B: Pavements
Volume 148 • Issue 3 • September 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Jun 10, 2021
Accepted: Feb 16, 2022
Published online: May 11, 2022
Published in print: Sep 1, 2022
Discussion open until: Oct 11, 2022
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
Cited by
- Liang Zhang, Qiuhui Hu, Qiang Luo, David P. Connolly, Tengfei Wang, Assessing Workability of Ready-Mixed Soils Derived from Excess Spoil, Journal of Materials in Civil Engineering, 10.1061/JMCEE7.MTENG-17381, 36, 10, (2024).