Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process
Predicting the inner displacements of deep vertical shafts during the excavation process has been a difficult task considering the geological, structural, and constructional influences. In fact, the two-dimensional (2D) analytical solution based on the retaining wall model remains insufficient for u...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co., Ltd.
2022-10-01
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| Series: | Underground Space |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2467967422000265 |
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| author | Tanawat Tangjarusritaratorn Yuusuke Miyazaki Yasuo Sawamura Kiyoshi Kishida Makoto Kimura |
| author_facet | Tanawat Tangjarusritaratorn Yuusuke Miyazaki Yasuo Sawamura Kiyoshi Kishida Makoto Kimura |
| author_sort | Tanawat Tangjarusritaratorn |
| collection | DOAJ |
| description | Predicting the inner displacements of deep vertical shafts during the excavation process has been a difficult task considering the geological, structural, and constructional influences. In fact, the two-dimensional (2D) analytical solution based on the retaining wall model remains insufficient for understanding the actual behavior during an excavation. This is because the deformation of vertical shafts becomes complicated due to the unexpected arching effect brought about by the three-dimensional (3D) flexible displacements occurring in the excavation process. Previous analytical solutions only considered the limit equilibrium. Therefore, the present study deals with a 3D soil-structure simulation by considering the displacements of a cylindrical shaft and the mechanical behavior of the surrounding soil as well as the geometry of the cylindrical structure. Moreover, this mechanical behaviors of the surrounding soil and shaft are controlled by the shaft stiffness; hence, the relationships among the shaft stiffness, mechanical behavior of the surrounding soil (in terms of earth pressure coefficient), and shaft displacement were investigated. A cylindrical model, 120 m in depth and 20 m in diameter, was positioned at the center of a sand domain, and each excavation step was performed at an interval depth of 20 m. A 3D finite difference method analysis was applied using the modified Cam-Clay (MCC) model to represent the soil behavior. As a result, the present study provides a new normalized lateral earth pressure theory for excavated shafts by considering the 3D arching effect obtained from parametric studies using various levels of shaft stiffness. From a comparison with the analytical solutions of previous studies (Terzaghi, 1943a; Prater, 1977; Cheng & Hu, 2005), it is found that the previous studies underestimated the earth pressure acting on the cylindrical shaft because they did not consider the accurate arching effect. |
| first_indexed | 2024-03-12T18:02:36Z |
| format | Article |
| id | doaj.art-8517e2aeb50449d491e0e180a9270fa8 |
| institution | Directory Open Access Journal |
| issn | 2467-9674 |
| language | English |
| last_indexed | 2024-03-12T18:02:36Z |
| publishDate | 2022-10-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Underground Space |
| spelling | doaj.art-8517e2aeb50449d491e0e180a9270fa82023-08-02T09:34:37ZengKeAi Communications Co., Ltd.Underground Space2467-96742022-10-0175944965Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation processTanawat Tangjarusritaratorn0Yuusuke Miyazaki1Yasuo Sawamura2Kiyoshi Kishida3Makoto Kimura4Dept. of Urban Management, Kyoto Univ., Katsura Campus, Kyoto 615-8540, Japan; Corresponding author.Dept. of Urban Management, Kyoto Univ., Katsura Campus, Kyoto 615-8540, JapanDept. of Urban Management, Kyoto Univ., Katsura Campus, Kyoto 615-8540, JapanDept. of Urban Management, Kyoto Univ., Katsura Campus, Kyoto 615-8540, JapanDept. of Civil and Earth Resources Engineering, Kyoto Univ., Katsura Campus, Kyoto 615-8540, JapanPredicting the inner displacements of deep vertical shafts during the excavation process has been a difficult task considering the geological, structural, and constructional influences. In fact, the two-dimensional (2D) analytical solution based on the retaining wall model remains insufficient for understanding the actual behavior during an excavation. This is because the deformation of vertical shafts becomes complicated due to the unexpected arching effect brought about by the three-dimensional (3D) flexible displacements occurring in the excavation process. Previous analytical solutions only considered the limit equilibrium. Therefore, the present study deals with a 3D soil-structure simulation by considering the displacements of a cylindrical shaft and the mechanical behavior of the surrounding soil as well as the geometry of the cylindrical structure. Moreover, this mechanical behaviors of the surrounding soil and shaft are controlled by the shaft stiffness; hence, the relationships among the shaft stiffness, mechanical behavior of the surrounding soil (in terms of earth pressure coefficient), and shaft displacement were investigated. A cylindrical model, 120 m in depth and 20 m in diameter, was positioned at the center of a sand domain, and each excavation step was performed at an interval depth of 20 m. A 3D finite difference method analysis was applied using the modified Cam-Clay (MCC) model to represent the soil behavior. As a result, the present study provides a new normalized lateral earth pressure theory for excavated shafts by considering the 3D arching effect obtained from parametric studies using various levels of shaft stiffness. From a comparison with the analytical solutions of previous studies (Terzaghi, 1943a; Prater, 1977; Cheng & Hu, 2005), it is found that the previous studies underestimated the earth pressure acting on the cylindrical shaft because they did not consider the accurate arching effect.http://www.sciencedirect.com/science/article/pii/S2467967422000265Deep cylindrical shaftExcavation analysisSoil mixing wall methodArching effectFinite different methodThree-dimensional analysis |
| spellingShingle | Tanawat Tangjarusritaratorn Yuusuke Miyazaki Yasuo Sawamura Kiyoshi Kishida Makoto Kimura Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process Underground Space Deep cylindrical shaft Excavation analysis Soil mixing wall method Arching effect Finite different method Three-dimensional analysis |
| title | Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process |
| title_full | Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process |
| title_fullStr | Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process |
| title_full_unstemmed | Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process |
| title_short | Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process |
| title_sort | numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process |
| topic | Deep cylindrical shaft Excavation analysis Soil mixing wall method Arching effect Finite different method Three-dimensional analysis |
| url | http://www.sciencedirect.com/science/article/pii/S2467967422000265 |
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