Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers
[Objective] During EPB (earth pressure balance) shield tunneling through the water-rich silty fine sand layers, the ground is characterized by high friction, poor flow plasticity, and strong permeability. These features necessitate slurry improvement to enhance construction safety. [Method] Taking t...
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| Format: | Article |
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Urban Mass Transit Magazine Press
2025-06-01
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| Series: | Chengshi guidao jiaotong yanjiu |
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| Online Access: | https://umt1998.tongji.edu.cn/journal/paper/doi/10.16037/j.1007-869x.20230555.html |
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| author | GUO Shiqing CHEN Han JIANG Peifeng GUO Pengfei SUN Yi XU Pingbao DI Honggui |
| author_facet | GUO Shiqing CHEN Han JIANG Peifeng GUO Pengfei SUN Yi XU Pingbao DI Honggui |
| author_sort | GUO Shiqing |
| collection | DOAJ |
| description | [Objective] During EPB (earth pressure balance) shield tunneling through the water-rich silty fine sand layers, the ground is characterized by high friction, poor flow plasticity, and strong permeability. These features necessitate slurry improvement to enhance construction safety. [Method] Taking the section between Qinghe Road Station and Green Expo Park Station of Nanjing Metro Line 9 (hereinafter referred to as ′Line 9′) as case study, improvement agents including foam, bentonite, and clay are used to conduct slurry modification experiments. Thus, the optimal mass ratios between each agent and water are determined. On this basis, laboratory tests—including mixing, slump, and permeability tests—are conducted using both individual and combined improvement agents to define applicable range of slurry improvement in silty fine sand layers. A slurry improvement plan for water-rich silty fine sand is proposed, with a target slump of 125-175 mm and a permeability coefficient exceeding 1×10-3 cm/s as control indicators. [Result & Conclusion] In the optimization tests of individual improvement agents, the recommended BASF foam content is 3% by mass, the bentonite-to-water mass ratio should be 1∶9, and the clay-to-water ratio be 1∶5. Individual agents significantly improve the slump performance, and slurry modified with clay show better flow plasticity. Mixed agents exhibited lower mixing current and permeability coefficient compared to single agents, indicating their superior improvement in reducing slurry friction and permeability. Among the combinations tested, a foam-to-bentonite ratio of 2∶1 yielded better performance. The recommended slurry improvement schemes for water-rich silty fine sand layers are as follows: foam-only improvement plan with foam injection rate of 20%-30%; bentonite-only improvement plan with bentonite injection rate of 15%-20%; clay-only improvement plan with clay injection rate of 40%-45%; foam-bentonite 1∶1 agent improvement plan with agent injection rate of 20%; foaming-bentonite 2∶1 agent improvement plan with agent injection rate of 20%; and foaming-clay 1∶2 agent improvement plan with agent injection rate of 20%-40%. |
| format | Article |
| id | doaj-art-699a9a01d7fe4bd4878d3ba8090f1784 |
| institution | Kabale University |
| issn | 1007-869X |
| language | zho |
| publishDate | 2025-06-01 |
| publisher | Urban Mass Transit Magazine Press |
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| series | Chengshi guidao jiaotong yanjiu |
| spelling | doaj-art-699a9a01d7fe4bd4878d3ba8090f17842025-08-20T03:29:08ZzhoUrban Mass Transit Magazine PressChengshi guidao jiaotong yanjiu1007-869X2025-06-01286818610.16037/j.1007-869x.20230555Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand LayersGUO Shiqing0CHEN Han1JIANG Peifeng2GUO Pengfei3SUN Yi4XU Pingbao5DI Honggui6Nanjing Metro Line 9 Phase I Construction Contract, China Railway Construction Corporation Limited, 210019, Nanjing, ChinaNanjing Metro Group Co., Ltd., 210008, Nanjing, ChinaNanjing Metro Line 9 Phase I Construction Contract, China Railway Construction Corporation Limited, 210019, Nanjing, ChinaChina Railway 15th Bureau Group Co., Ltd., 200070, Shanghai, ChinaChina Railway 15th Bureau Group Co., Ltd., 200070, Shanghai, ChinaCollege of Transportation, Tongji University, 201804, Shanghai, ChinaCollege of Transportation, Tongji University, 201804, Shanghai, China[Objective] During EPB (earth pressure balance) shield tunneling through the water-rich silty fine sand layers, the ground is characterized by high friction, poor flow plasticity, and strong permeability. These features necessitate slurry improvement to enhance construction safety. [Method] Taking the section between Qinghe Road Station and Green Expo Park Station of Nanjing Metro Line 9 (hereinafter referred to as ′Line 9′) as case study, improvement agents including foam, bentonite, and clay are used to conduct slurry modification experiments. Thus, the optimal mass ratios between each agent and water are determined. On this basis, laboratory tests—including mixing, slump, and permeability tests—are conducted using both individual and combined improvement agents to define applicable range of slurry improvement in silty fine sand layers. A slurry improvement plan for water-rich silty fine sand is proposed, with a target slump of 125-175 mm and a permeability coefficient exceeding 1×10-3 cm/s as control indicators. [Result & Conclusion] In the optimization tests of individual improvement agents, the recommended BASF foam content is 3% by mass, the bentonite-to-water mass ratio should be 1∶9, and the clay-to-water ratio be 1∶5. Individual agents significantly improve the slump performance, and slurry modified with clay show better flow plasticity. Mixed agents exhibited lower mixing current and permeability coefficient compared to single agents, indicating their superior improvement in reducing slurry friction and permeability. Among the combinations tested, a foam-to-bentonite ratio of 2∶1 yielded better performance. The recommended slurry improvement schemes for water-rich silty fine sand layers are as follows: foam-only improvement plan with foam injection rate of 20%-30%; bentonite-only improvement plan with bentonite injection rate of 15%-20%; clay-only improvement plan with clay injection rate of 40%-45%; foam-bentonite 1∶1 agent improvement plan with agent injection rate of 20%; foaming-bentonite 2∶1 agent improvement plan with agent injection rate of 20%; and foaming-clay 1∶2 agent improvement plan with agent injection rate of 20%-40%.https://umt1998.tongji.edu.cn/journal/paper/doi/10.16037/j.1007-869x.20230555.htmlurban rail transitshieldslurry improvement experimentgushing control testwater-rich silty fine sand layer |
| spellingShingle | GUO Shiqing CHEN Han JIANG Peifeng GUO Pengfei SUN Yi XU Pingbao DI Honggui Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers Chengshi guidao jiaotong yanjiu urban rail transit shield slurry improvement experiment gushing control test water-rich silty fine sand layer |
| title | Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers |
| title_full | Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers |
| title_fullStr | Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers |
| title_full_unstemmed | Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers |
| title_short | Experimental Study on Slurry Improvement and Gushing Control in Water-rich Silty Fine Sand Layers |
| title_sort | experimental study on slurry improvement and gushing control in water rich silty fine sand layers |
| topic | urban rail transit shield slurry improvement experiment gushing control test water-rich silty fine sand layer |
| url | https://umt1998.tongji.edu.cn/journal/paper/doi/10.16037/j.1007-869x.20230555.html |
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