滨海软弱地层深基坑扩大头锚索受力变形特性
Stress and Deformation Characteristics of Underreamed Anchor in a Deep Excavation in Coastal Soft Soils
刘凯 1李文辉 1耿林 1张文斌 1孙伟青 1袁敬强2
作者信息
- 1. 青岛地质工程勘察院(青岛地质勘查开发局),山东青岛 266000;青岛地矿岩土工程有限公司,山东青岛 266000
- 2. 中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉 430071
- 折叠
摘要
针对滨海地区回填土及淤泥质土等软弱地层基坑支护技术难题,采用高压旋喷扩大头锚索、普通预应力锚索及钻孔灌注桩对深基坑工程进行支护.在扩大头锚索施工过程中,采用套管跟进钻孔穿越易塌孔段、钻孔与锚索安装同步施工、钻孔注浆与高压旋喷注浆一体化施工等工艺,有效解决了滨海软弱地层钻孔坍塌及锚固力不足的难题.在此基础上,开展了锚索承载能力验收试验,试验表明高压旋喷扩大头锚索在滨海软弱土层中能够提供足够的拉拔荷载.同时,对验收试验中出现的锚索伸长量值小于自由段理论伸长量值的现象进行了讨论分析,指出锚索自由段摩阻力偏大、自由段注浆体的锚固约束、锚头位置局部摩阻与嵌固作用是导致锚索拉拔伸长量值偏小的主要原因,并提出了相应的改进方法.
Abstract
To solve the technical difficulties in a deep excavation support in the coastal soft soils such as new backfill soils and silty soils,the underreamed anchor by the jet grouting or ordinary prestressed anchor and cast-in-place pile are used in a pro-ject.The problems such as borehole collapse and insufficient anchoring force of the anchor construction in coastal soft soils are effectively solved by adopting such technologies as drilling with pipe,simultaneous installation of the anchor cable and full-length grouting,thus ensuring the safety and stability of the deep excavation supporting structure.On this basis,the accept-ance test of the uplift capacity of the underreamed anchor by the jet grouting and ordinary anchor is performed.The acceptance test of the uplift capacity of anchor cable shows that the underreamed anchor by the jet grouting can provide enough uplift load in the coastal soft soils.Meanwhile,the result of the cable elongation value in the acceptance test less than the theoretical elon-gation value of the free section was discussed and analyzed,and improvement solutions were proposed.
关键词
深基坑/高压旋喷扩大头锚索/滨海软弱地层/验收试验/受力变形特性Key words
Deep Excavation/Underreamed Anchor by Get grouting/Coastal Soft Stratum/Acceptance Test/Stress and De-formation Characteristics引用本文复制引用
基金项目
青岛地质工程勘察院开放基金(2019-QDDZYKF05)
出版年
2024
NETL
NSTL
万方数据