微型桩群加固土坡稳定性分析

孙书伟; 陈冲; 丁辉; 刘英

doi:10.11779/CJGE201412020

微型桩群加固土坡稳定性分析 English Version

1. 中国矿业大学（北京）资源与安全工程学院,北京 100083; 2. 中国水利水电第七工程局有限公司,四川成都 610081

基金项目: 国家自然科学基金项目（41002090）; 中央高校基本科研业务费专项资金项目（2011QZ05）

详细信息

作者简介:
孙书伟(1980- ),男,副教授,主要从事岩土边坡工程方面的教学和科研。E-mail: ssw1216@163.com。

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出版历程
- 收稿日期: 2014-06-05
- 发布日期: 2014-12-25

Stability analysis of earth slopes reinforced with micropiles

1. Faculty of Resources and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; 2. Sinohydro Bureau 7th Co., Ltd., Chengdu 610081, China

摘要

摘要: 微型桩是一种边坡快速加固技术,多大面积成群布置。基于强度折减技术研究了微型桩群加固边坡安全系数的数值计算方法,并对微型桩群加固均质土坡和含软弱夹层土坡的稳定性进行了对比分析。结果表明,微型桩群加固均质土坡的破坏模式与其布设位置关系密切,采用传统非耦合方法假定滑动面位置不变进行微型桩群的工程设计值得商榷;对于均质土坡,微型桩群锚固深度较小时,桩身变形以刚性旋转为主,随着锚固深度的增加,微型桩群的变形由刚性倾斜转化为柔性弯曲变形,对于含软弱夹层边坡,微型桩群的变形主要是弯曲变形;微型桩群最优锚固长度约为滑面以上自由段长度的1.5~2.0倍。削剪作用能够改善微型桩群受力并降低成本;对于均质土坡,当削剪长度小于自由段长度1/4时,不会降低加固边坡的安全系数,对于含软弱夹层边坡,最大削剪长度约为自由段长度的1/2;实际工程中对于可削剪的微型桩部分,无需设计加筋体,仅将钻孔回填压实即可,能够在确保加固效果的同时降低成本。
- 微型桩群 /
- 边坡 /
- 安全系数 /
- 锚固长度 /
- 削剪效应
Abstract: Micropiles are common reinforcements often used for slope stabilization under emergency conditions. In many circumstances they are extensively installed to cover a large area. A flow chart was suggested to calculate the factor of safety for micropile-reinforced slopes according to the shear strength reduction technique. Coupled analyses are performed for micropiles in a homogeneous slope with and without a thin weak layer. It is shown that the position of the micropiles has a significant impact on the failure mode of the reinforced slope for a homogeneous slope, indicating that the conventional design method based on uncoupled analysis in which the pile response and slope stability are considered separately is inaccurate. For relatively small embedment of micropiles, the response of micropiles is dominated by rigid-body rotation without substantial flexural distortion. The critical embedment depth to achieve fixed conditions at the base of the micropiles is found to range from 1.5 to 2 times the length above the sliding plane. Truncation of micropiles likely increases the capacity of the reinforcement system, and this benefit is particularly important for the slope with a thin weak layer. The largest truncation length of micropiles for homogeneous slopes and the slope with a thin weak layer is about 1/4 and 1/2 times the length above the sliding plane, respectively. The portion of truncated micropiles can be filled with soils and compacted in the standard procedure to decrease the cost in practice engineering.
- micropile /
- slope /
- factor of safety /
- embedment length /
- truncation effect

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参考文献(18)

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