Control settlement of recharge in ultra-deep excavations under partial block effect of aquifer
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摘要: 在中国沿海城市地区,以天津为例,承压含水层厚度较大,埋深较深,若全部截断含水层,工程造价昂贵,因此多采用悬挂式止水帷幕,此时基坑周边难免受到基坑降水的影响。为保护周边建筑物安全,常采用回灌措施来控制沉降。通过监测天津地铁6号线某车站基坑工程降水与回灌过程中的水位变化与地表沉降数据进行分析。研究表明,在回灌全面开启后,基坑邻近区的水位得到控制,地表沉降发展逐渐趋于稳定。回灌区附近水位抬升较快,地表沉降有所恢复,存在一定延迟现象,可以达到预期回灌保护效果。在基坑降水过程中应持续回灌,定期监测承压含水层及地表沉降的变化,若出现异常应逐渐增加回灌量,避免水位骤升骤降引起地表沉降甚至建筑不均匀沉降。Abstract: In coastal cities in China, taking Tianjin for an example, the pressure aquifer is rather thick and buried deep. Cutting off all the aquifer will lead to high construction cost. Therefore, the suspended water-stop curtain is often adopted, in which the water level outside the excavation is inevitably influenced by dewatering. To protect building safety, the recharge is often introduced to control settlement. An analysis is given based on the drawdown and ground surface settlement data monitored during dewatering and recharging in the excavation of a station of Tianjin Rail Transit line 6. After the recharge is fully started, the water level of the neighboring area remains stable, and so is the development of ground surface settlement. The water level near the recharging area rises quickly, which is related directly to the amount of recharge. The ground surface settlement is recovered to a certain extent after starting recharging, but with certain delay. The expected recharge protection can be achieved. Recharging is kept during pit excavation and change in the pressure aquifer and ground surface settlement regularly is monitored. Upon exceptions, the amount of recharge is gradually increased to avoid change of ground surface settlement or even differential settlement of buildings caused by sudden change in the water level.
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Keywords:
- dewatering /
- ground settlement /
- suspended impervious curtain /
- diaphragm wall /
- recharge
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图 3 基坑邻近区地表沉降与承压水水位变化对比曲线
Figure 3. Contrast curves of change of surface settlement and confined water level at edge of excavation area
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图 4 回灌区地表沉降与承压水水位变化对比曲线
Figure 4. Contrast curves of change of surface settlement and confined water level in recharge area
表 1 现场试验工况
Table 1 Test conditions of site
日期 现场工况 回灌井/口 回灌量/(m3·d-1) 降水井/口 10.9—10.10 工况A — — 6 10.11—10.13 工况B 17 83 6 10.14—10.16 工况C 17 380 6 10.17—10.20 工况D 22 490 12 10.21—10.25 工况E 29 630 12 10.26—11.10 工况F 29 800 12 
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[1] 段永侯. 中国地面沉降研究现状与21世纪可持续发展[J]. 中国地质灾害与防治学报, 1998, 9(2): 3-7. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGDH802.000.htm DUAN Yong-hou. Research status on land subsidence and sustainable development in the 21st century of China[J]. The Chinese Journal of Geological Hazard and Control, 1998, 9(2): 3-7. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZGDH802.000.htm
[2] GAMBOLATI G, TEATINI P. Geomechanics of subsurface water withdrawal and injection[J]. Water Resources Research, 2015, 51(6): 3922-3955. doi: 10.1002/2014WR016841
[3] 俞建霖, 龚晓南. 基坑工程地下水回灌系统的设计与应用技术研究[J]. 建筑结构学报, 2001, 22(5): 70-74. https://www.cnki.com.cn/Article/CJFDTOTAL-JZJB200105014.htm YU Jian-lin, GONG Xiao-nan. Study on the design and the application of the groundwater recharge system in excavation[J]. Journal of Building Structures, 2001, 22(5): 70-74. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-JZJB200105014.htm
[4] 郑刚, 曾超峰, 薛秀丽. 承压含水层局部降压引起土体沉降机理及参数分析[J]. 岩土工程学报, 2014, 36(5): 802-817. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201405003.htm ZHENG Gang, ZENG Chao-feng, XUE Xiu-li. Settlement mechanism of soils induced by local pressure-relief of confined aquifer and parameter analysis[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(5): 802-817. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201405003.htm
[5] 曾超峰, 薛秀丽, 罗鹏. 基坑工程地下水回灌对土层变形的影响[J]. 工程建设, 2017, 49(11): 1-5. https://www.cnki.com.cn/Article/CJFDTOTAL-YJKS201711001.htm ZENG Chao-feng, XUE Xiu-li, LUO Peng. Influence of artificial recharge on ground deformation in excavation engineering[J]. Engineering Construction, 2017, 49(11): 1-5. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YJKS201711001.htm
[6] 金小荣, 俞建霖, 祝哨晨, 等. 基坑降水引起周围土体沉降性状分析[J]. 岩土力学, 2005, 26(10): 1575-1581. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200510009.htm JIN Xiao-rong, YU Jian-lin, ZHU Shao-chen, et al. Analysis of behaviors of settlement of pit's surrounding soils by dewatering[J]. Rock and Soil Mechanics, 2005, 26(10): 1575-1581. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200510009.htm
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