Field Tests Study on Post-Grouting Cast-in-place Bored Piles in Soft Soil Area of Indonesia
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摘要: 后注浆钻孔灌注桩在软土地区工程中应用广泛，但对后注浆灌注桩承载特性的理论研究仍滞后于工程实践。依托印尼软土地区某工程，开展不同桩长普通钻孔灌注桩和后注浆钻孔灌注桩的现场试验。结果表明，后注浆钻孔灌注桩极限承载力是同条件下普通钻孔灌注桩的1.20～1.26倍，后注浆灌注桩的回弹率和弹性变形相应增加；研究区地质条件下后注浆水泥浆液上返高度约为12.4～13.8 m，桩端以下水泥浆下渗深度约为1.3～2.1 m（约为桩径的1.6～2.6倍）；后注浆灌注桩水泥浆上返高度以下桩侧和桩端以下岩土层的标贯击数较压浆前均显著提高，后注浆导致的桩侧摩阻力和桩端阻力的提高是钻孔灌注桩承载性能提高的主要因素。研究成果对指导印尼软土地区后注浆设计和施工具有一定的借鉴意义。Abstract: Post-grouting bored piles are widely used in soft soil engineering in Indonesia, but the theoretical research on the bearing characteristics of post-grouting bored piles still lags behind engineering practice. Based on a project in Indonesia's soft soil region, field tests of bored piles with different pile lengths and post-grouting bored piles were carried out. The results show that the ultimate bearing capacity of post-grouting bored piles is 1.20 to 1.26 times that of bored piles, and the rebound rate and elastic deformation of post-grouting bored piles are correspondingly increased. Under the geological conditions of the study area, the upward flow height of post-grouting cement slurry is 12.4~13.8 m, and the downward penetration depth of cement slurry below the pile tip is 1.3~2.1 m, which is 1.6~2.6 times the pile diameter. The blow counts of the standard penetration test (SPT) of the rock and soil layers below the cement slurry return height of the post-grouting pile and below the pile end are significantly increased compared to those before grouting. The improvement of the pile side friction resistance and pile end resistance caused by post-grouting is the main factor for improving the bearing performance of the bored pile. The research results have reference significance for the design and construction of post-grouting in soft soil areas in Indonesia.
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Key words:
- soft soil /
- cast-in-place bored pile /
- post-grouting /
- bearing performance /
- static loading test
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表 1 场地地层基本物理力学参数
层号 重度
γ/(kN·m−3)标贯击数 动探击数 压缩模量
Es/MPa黏聚力
c/kPa内摩擦角
φ/（°）地基承载力
特征值fak/kPa极限侧阻力标准值qsik/kPa 极限端阻力标准值qpk/kPa 灌注桩 ② 16.5 4 2.2 5 0 30 90 18 ③ 15.5 1 1 5 5 50 15 ③1 4 2 10 20 70 30 ③2 9 6 0 30 100 35 ④ 17.0 17 8 0 30 130 40 ⑤ 17.5 4 2.7 2 10 20 70 35 ⑥ 17.5 8 9.7 3 12 20 90 45 ⑦ 18.0 27 17.4 6 13 22 160 55 600 ⑧ 19.5 70 44.3 25 13 22 280 90 1200 ⑨ 20.5 71.3 30 350 150 1800 ⑩ 21.5 82.7 1000 180 2600 
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表 2 试桩参数表
桩号 桩径/mm 桩长/m 桩顶标高/m 桩端持力层 桩端压浆
情况S1 800 35 5.10 粉质黏土⑦层 否 S1' 是 S2 800 35 5.10 全风化凝灰岩⑧层 否 S2' 是 S3 800 24 5.10 粉质黏土⑦层 否 S3' 是 S4 800 24 5.10 粉质黏土⑦层 否 S4' 是 S5 800 39 5.10 强风化凝灰岩⑨层 否 S5' 是 S6 800 39 5.10 全风化凝灰岩⑧层 否 S6' 是
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表 3 试桩竖向极限承载力
桩号 桩长/m 桩端持力层 竖向极限承载力/kN 提高系数 S1 35 粉质黏土⑦层 3000 1.26 S1' 3780 S2 35 全风化凝灰岩⑧层 3300 1.20 S2' 3960 S3 24 粉质黏土⑦层 3000 1.26 S3' 3780 S4 24 粉质黏土⑦层 3150 1.26 S4' 3960 S5 39 强风化凝灰岩⑨层 5500 1.20 S5' 6600 S6 39 全风化凝灰岩⑧层 5500 1.26 S6' 6930
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表 4 试桩回弹量与回弹率统计表
桩号 最大沉降量
/mm最大回弹量
/mm回弹率
/%S1 50.28 4.46 8.87 S1' 55.11 7.15 12.97 S2 52.06 5.67 10.89 S2' 56.40 7.65 13.56 S3 48.76 4.65 9.54 S3' 51.46 6.30 12.24 S4 54.42 5.62 10.33 S4' 58.33 7.55 12.94 S5 51.11 6.63 12.97 S5' 52.81 6.61 12.52 S6 50.73 6.03 11.89 S6' 53.34 6.11 11.45
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表 5 桩侧压浆取芯结果
孔号 孔深
/m初见水泥浆
深度/m水泥浆终止
深度/m上返高度
/m桩端入渗
/mS1' 37.00 22.60 36.30 12.40 1.30 S2' 37.80 21.80 37.10 13.20 2.10 S3' 26.00 11.60 25.40 12.40 1.40 S4' 26.50 11.40 25.70 12.60 1.70 S5' 41.50 25.50 40.70 13.50 1.70 S6' 41.50 25.20 40.90 13.80 1.90
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表 6 不同试桩标贯击数对比
桩号 深度范围/m 标贯击数深度加权平均值 提高击数 S1 24～35 17 13.25 S1' 30.25 S2 23～30 15 12 S2' 27 S3 13～24.5 10.5 11.5 S3' 22 S4 13～24.5 14.25 13.5 S4' 27.75
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