| 软土狭长深基坑抗隆起破坏模式试验研究 |
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| 引用本文： | 张 飞,李镜培,孙长安,沈广军,李 飞.软土狭长深基坑抗隆起破坏模式试验研究[J].岩土力学,2016,37(10):2825-2832. |
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| 作者姓名： | 张 飞 李镜培 孙长安 沈广军 李 飞 |
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| 作者单位： | 1. 盐城工学院 土木工程学院，江苏 盐城 224051；2. 同济大学 地下建筑与工程系，上海 200092； 3. 同济大学 岩土及地下工程教育部重点实验室，上海 200092 |
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| 基金项目： | 国家自然科学基金青年基金项目(No. 41402270)；江苏省科技计划前瞻性联合研究项目(No. BY2014108-26)。 |
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| 摘 要： | 针对软土地区基坑底土层为饱和软黏土的情况，设计了狭长深基坑的抗隆起离心模型试验，分析不同开挖深度和水位条件下的基坑围护墙弯矩、土压力分布、水平位移以及基坑隆起稳定破坏机制。基于离心模型试验的基本参数和工况，建立了有限元数值模型，分析试验工况基坑的抗隆起稳定性与破坏状态，并进行对比验证。试验结果表明：随着开挖深度和坑外水位的增加，坑底软土层产生向上的隆起变形，当隆起变形较大时，围护墙由于坑内土体侧向约束的减弱，底部产生较大的向坑内的水平位移，同时导致支撑轴力增大，基坑最终表现出围护墙绕某道支撑点向坑内的转动踢脚破坏。数值计算结果表明：随着坑外水位的升高，基坑抗隆起稳定性安全系数逐渐减小，当发生抗隆起稳定破坏时，基坑底产生较大的隆起位移，破坏机制与离心模型试验结果相同。
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| 关 键 词： | 基坑 抗隆起破坏 离心模型试验 地下水位 强度折减法 安全系数 |
| 收稿时间： | 2016-06-06 |
Experimental study of basal heave failure mode of narrow-deep foundation pit in soft clay |
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| ZHANG Fei,LI Jing-pei,SUN Chang-an,SHEN Guang-jun,LI Fei.Experimental study of basal heave failure mode of narrow-deep foundation pit in soft clay[J].Rock and Soil Mechanics,2016,37(10):2825-2832. |
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| Authors: | ZHANG Fei LI Jing-pei SUN Chang-an SHEN Guang-jun LI Fei |
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| Institution: | 1. School of Civil Engineering, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, China; 2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; 3. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China |
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| Abstract: | Centrifugal model test is designed to simulate basal heave failure of narrow-deep foundation pit in soft clay. The bending moment and horizontal displacement of retaining wall, the earth pressure distribution as well as basal failure mechanism of excavation at different groundwater levels are analyzed. Based on fundamental parameters and excavation procedures of the centrifugal model test, a finite element model is established to analyze the basal heave stability factors and failure modes of foundation pit, comparing with the centrifugal test results. The results of centrifugal model test show that, with the excavation depth increases and groundwater level rises, the bottom uplift and deformation increase. Horizontal displacement towards pit occurs at the bottom of retaining wall, because of the lateral restraint reduction and greater uplift, at the same time, the axis force of internal struts increases. Eventually, retaining wall rotates around a braced point of its own, resulting in a skirting failure. The results of numerical simulation show that, with the increase of groundwater level outside the pit, the safety factor of basal heave stability gradually reduces. When foundation pit collapses due to basal heave failure, the uplift displacement at bottom is greater. The basal failure mechanisms revealed by centrifugal model test and numerical simulation are similar. |
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| Keywords: | foundation pit basal heave failure centrifugal model test groundwater level strength reduction method factor of safety |
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