| 膨胀土地区地下结构抗浮失效机理及主动抗浮措施应用 |
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| 引用本文： | 罗益斌,陈继彬,王媛媛,沈攀.膨胀土地区地下结构抗浮失效机理及主动抗浮措施应用[J].水文地质工程地质,2022,49(6):64-73. |
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| 作者姓名： | 罗益斌 陈继彬 王媛媛 沈攀 |
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| 作者单位： | 中国建筑西南勘察设计研究院有限公司, 四川 成都 610052 |
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| 基金项目： | 中国建筑股份科技研发课题青年基金项目（CSCEC-2021-Q-64） |
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| 摘 要： | 膨胀土地层透水性弱、渗透性低，一般被视为相对隔水层或隔水层，其抗浮设防水位需综合考虑场地渗流特性、肥槽填料特性、水-结构相互作用而确定，建筑工程抗浮设计问题素来棘手难解。本文依托成都膨胀土地区某商住楼地下室局部抗浮失效案例，通过地下室渗漏水水源调查、基底地下水流量监测、排水系统排泄能力评价等方法，认为地下室上浮属肥槽施工控制不当使高压水渗入抗水板底部进而导致水力学条件失衡造成的。基于此，结合FLAC3D有限差分法，详细探讨了地下水浮力及膨胀土膨胀力作用下地下结构的力学行为特征。结合工程实际，提出一种以“卸压”为主的地下室抗浮方法，其理念是在底板开设卸压孔使地下水流动，通过主动式泄排适量地下水来减小或消除水浮力，并辅以观测及自动控制措施，实现抗浮目的。工程监测结果表明，流量及水头可控，运行效果良好，成本低廉。
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| 关 键 词： | 膨胀土 地下结构 抗浮失效 主动抗浮措施 |
| 收稿时间： | 2022-03-03 |
Anti-floating failure mechanism of underground structures in expansive soil area and application of active anti-floating measures |
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| Affiliation: | China Southwest Geotechnical Investigation & Design Institute Co. Ltd., Chengdu, Sichuan 610052, China |
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| Abstract: | Expansive soil is a weakly permeable stratum with low permeability. It is generally regarded as a relative aquiclude or water resisting layer. Its anti-floating water level is needed to comprehensively consider the site seepage characteristics, fertilizer tank filler characteristics and water-structure interaction, which makes the anti-floating problem very prominent and difficult to deal with. Based on a building failure treatment case in the expansive soil area of Chengdu, through the investigation of the water leakage source of the basement, the monitoring of groundwater flow and the evaluation of the discharge capacity of the drainage system, it is considered that the basement floating is caused by the improper construction control of the fertilizer tank, which makes the high-pressure water penetrate into the bottom of the water resistant plate, resulting in the imbalance of hydraulic conditions. Combined with the FLAC3D finite difference method, the mechanical behavior characteristics of underground structures under the action of groundwater buoyancy and expansive force are discussed in detail. Combined with the engineering practice, an anti-floating method based on "pressure relief" is proposed. The idea is to open a pressure relief hole in the bottom plate to make the groundwater flow and convert the hydrostatic pressure into kinetic energy without changing the groundwater level, and supplement observation and automatic control measures is carried out to achieve the purpose of anti-floating. The monitoring results of the project show that the flow and head are controllable and the operation cost is low. |
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