Coast Construction of Large Diameter Open Steel Pipe Pile Driving Analysis and Bearing Properties Research
-
摘要: 某电厂码头项目基础桩拟采用大直径开口钢管桩，为获取工程桩设计施工参数进行了工前试桩。试验过程中采用高应变动力测试和静载试验桩身内力测试等综合手段，对不同龄期钢管桩的受力及变形特性进行了综合测试分析。试桩研究得出如下成果：（1）通过统计端阻力占比判定试桩承载类型为摩擦桩；（2）通过观测桩管内外泥面差结合端阻–变形曲线特征判定试桩存在桩端蔽塞效应；（3）静载内力测试显示，随着荷载的不断增大，端阻发挥程度逐级快速增大，摩阻在0～12 m段出现软弱化区域，其余段整个加载过程表现为增强状态；（4）综合后3 m沉桩锤击数–承载力关系曲线和龄期–土体恢复系数关系曲线，得出钢管桩最终承载力的预判公式。Abstract: Large diameter open steel pipe pile is proposed to be used for the foundation pile of a power plant wharf project. In order to obtain the design and construction parameters of engineering pile, the pre-construction test pile was carried out. During the test, the stress and deformation characteristics of steel pipe piles at different ages are comprehensively tested and analyzed by means of high strain dynamic test, static load test pile internal force test and so on. The results of pile test research are as follows: (1) The bearing type of test pile is determined as friction pile by counting the proportion of end resistance; (2) By observing the difference of soil surface inside and outside the pile pipe and combining the characteristics of end resistance deformation curve, it is determined that the test pile has pile end clogging effect; (3) The static load internal force test shows that with the continuous increase of load, the exertion degree of end resistance increases rapidly step by step, the soft weakening area of friction resistance appears in the section of 0~12 m, and the whole loading process of other sections shows an enhanced state; (4) The prediction formula of the final bearing capacity of steel pipe pile is obtained by synthesizing the relationship curve between the number of blows and bearing capacity and the relationship curve between age and soil recovery coefficient of the upper 3 m pile.
-
表 1 地层力学参数
序号 S1(BK10) S2(BK07) 土层编号 极限侧摩阻/kPa 土层编号 极限侧摩阻/kPa 1 ② 6.06 ② 6.06 2 ③ 17.2 ③ 13.79 3 ③1 9.91 ③2 11.11 4 ③ 24.31 ③ 21.97 5 ④ 33.52 ④ 32.4 6 ④1 37.07 ⑤ 50.27 7 ④ 36.45 ⑤3 54.29 8 ⑤ 47.67 ⑤ 55.56 9 ⑤3 45.86 ⑤3 74.06 10 ⑤ 51.29 11 ⑤1 55.82 12 ⑤3 70.7 
下载: 导出CSV
表 4 桩周土体恢复情况统计
桩号 动力测试承载力/kN 最终土体恢复系数 初打 7 d复打 14 d复打 28 d复打 S1 5865.6 7298.4 7727.7 8012.4 1.366 S2 5770.8 7202.0 7685.2 7986.8 1.384
下载: 导出CSV
表 5 钢管桩闭塞效应判定
序号 Qp/As Qp/Asg 曲线变形 判定结果 1 <qpk或>qpk >qpk或接近 平缓 桩端闭塞 2 <<qpk <<qpk 陡峭聚变 桩端开口 3 <qpk 介于二者之间 半闭塞 注：桩端阻力为Qp；整桩桩端面积为As；钢管桩桩壁面积为Asg；勘察资料极限端阻标准值为qpk。
下载: 导出CSV
表 6 S1、S2闭塞效应判定结果
桩号 Qp/As Qp/Asg 判定结果 桩身内力测试结果判定 S1 460.9<2500 5879.0>2500 桩端闭塞 S2 427.8<2500 5456.7>2500 桩端闭塞 高应变动力测试结果判定 S1 467.4<2500 5961.8>2500 桩端闭塞 S2 413.2<2500 5270.0>2500 桩端闭塞
下载: 导出CSV
-
[1] 陈 凡, 徐天平, 陈久照, 等. 基桩质量检测技术[M]. 北京: 中国建筑工业出版社, 2003. [2] JTS 237—2017 水运工程地基基础试验检测技术规程[S]. 北京: 人民交通出版社股份有限公司, 2018. [3] DB13(J)/T 301—2019 基桩内力测试技术规范[S]. 北京: 中国建筑工业出版社, 2019. [4] 刘长健. 洋山三期大型钢管桩试桩及大型钢管桩承载力研究[D]. 北京: 清华大学, 2009. [5] 周厚林. 海上风电基础大直径钢管桩竖向承载特性研究[D]. 南京: 东南大学, 2016. [6] 胡兴昊,黄 邦,王 幸. 大直径钢管桩承载力恢复过程试验研究[J]. 水运工程,2018,(12):193-197,216. doi: 10.3969/j.issn.1002-4972.2018.12.035 [7] 贾德庆,陈 锋,吕 黄. 大直径开口钢管桩承载力特性的分析[J]. 水运工程,2004,(10):22-24,31. doi: 10.3969/j.issn.1002-4972.2004.10.006 [8] 王君辉,冯建国,张华平. 开口钢管桩桩基承载力桩端部分计算方法探讨[J]. 水运工程,2012,(1):49-53. doi: 10.3969/j.issn.1002-4972.2012.01.011 [9] 周立运,李普安. 武汉港外贸码头钢管桩动力和静力现场测试和分析[J]. 水运工程,1993,(1):12-17. [10] 张开伟,聂庆科,马清洲,等. 桩基静载试验内力及变形计算应用研究[J]. 施工技术,2017,(S1):152-156. [11] 梁金国,郅正华. 桩身竖向应力测试应用技术研究[J]. 工程勘察,2007,212(3):5-9. [12] ASTM. Standard Test Method for High-Strain Dynamic Testing of Deep Foundations: ASTM D4945-12 (2012)[S]. USA: American Society for Testing Materials, ASTM, 2012. [13] 刘万恩,蔡克俭,夏吉祥. 海上超长大钢管桩的高应变动力检测[J]. 工程勘察,2006,(S1):249-252. [14] 魏兴龙,左军成,段爱华. 开口钢管桩竖向承载力分析[J]. 人民长江,2011,42(11):32-34. [15] ASTM. Standard Test Methods for Deep Foundations Under Static Axial Compressive Load: ASTM D1143/D1143M-07 (2013) [S]. USA: American Society for Testing Materials, ASTM, 2013. [16] Bureau of Research Testing and Consultancy. Bangladesh National Building Code. BNBC 2015 [S]. Dhaka: Housing and Building Research Institute, 2015. -
图(7) / 表(7)
计量
- 文章访问数: 82
- HTML全文浏览量: 29
- PDF下载量: 19
- 被引次数: 0
