Soil Compaction Effect of Bagged Grouting Piles in Saturated Soft Clay Subgrade
-
摘要: 为研究饱和软黏土路基条件下布袋注浆桩的挤土效应，以布袋注浆桩加固某饱和软黏土路基工程为例，通过现场试验对桩体成型过程中的桩周土体位移和超静孔隙水压力进行了分析. 运用测斜管监测了成桩时桩周土体的水平位移，得到了土体位移的分布特征和土体位移随注浆压力与时间的变化规律；运用孔压计监测了成桩时桩周土体中超静孔隙水压力，得到了超静孔隙水压力的分布规律与变化趋势. 试验结果表明：成桩后，桩周土体水平位移呈现“马鞍形”分布，在距离地表0.1～0.3倍和0.8～1.0倍的桩长位置处出现最大位移；桩体成型挤土产生水平位移的范围约为桩径的6倍；桩体养护成型后，标准施工下的注浆压力对挤土效应的影响甚微，同时桩周土体水平位移会出现明显回弹，回弹位移值为注浆当天的40%～60%；超静孔隙水压力在前10 d消散较快，超静孔隙水压比随土体与桩体间距离的增加而呈现近似于线性规律的衰减，其影响范围约为10倍桩径.Abstract: To study the soil compaction effect of bagged grouting piles in saturated soft clay roadbeds, field tests were conducted on roadbeds reinforced with bagged grouting piles to analyse the displacement of the soil and the applied super-static pore pressure occurring during pile formation. First, the horizontal displacement of the soil was monitored by using the inclined pipe, and the distribution characteristics of soil displacement and variation in soil displacement with grouting pressure and time were obtained. Second, the super-static pore pressure in the soil was monitored by using a sensor to measure the hole pressure, and the distribution and trend of the super-static pore pressure were obtained. The test results indicate that the horizontal displacement of the soil around the pile has a saddle-shaped distribution, and the soil exhibits maximum displacement at a distance of 0.1–0.3 times and 0.8–1.0 times the pile length. The range of influence of the horizontal displacement caused by soil compaction is approximately six times the pile diameter. After the pile has been cured, the grouting pressure has little influence on the compaction effect. Furthermore, after curing, the horizontal displacement of the soil around the pile shows a significant rebound, which amounts to approximately 40%–60% of the displacement on the day of grouting. The super-static pore pressure dissipates rapidly during the first 10 days and decreases linearly with increasing distance from the centre of the pile. The range of influence of the super-static pore pressure is approximately 10 times the pile diameter.
-
图 7 桩周土体超静孔隙水压力逐日变化值
Figure 7. Variation of super-static pore pressure with the number of days
图 8 超静孔隙水压比随径向距离变化
Figure 8. Variation of super-static pore pressure ratio with radial distance
表 1 土层性质参数与土层分布
Table 1. Soil properties and soil distribution
土层 压缩模量
/MPa泊松比 重度
/（kN•m–3）黏聚力
/kPa含水率
/%液限
/%塑限
/%摩擦角
/（°）层底标高
/m平均厚度
/m粉质黏土 3.37 0.30 18.9 18.0 34.5 37.8 22.8 18 –1.9 1.9 淤泥质粉质黏土 2.58 0.32 17.9 12.0 37.6 37.1 23.5 12 –5.2 3.3 淤泥质黏土 2.72 0.40 17.5 7.0 39.1 37.5 22.7 14 –10.3 5.4 粉质黏土 2.53 0.35 17.6 8.6 32.6 36.8 21.9 16 –13.2 2.9 粉土 6.80 0.25 19.1 10.8 31.4 36.5 21.1. 20 –15.8 2.6 粉质黏土 3.63 0.31 19.0 17.3 33.5 35.7 22.3 16 –19.1 3.3 粉砂夹粉质黏土 4.92 0.27 18.4 13.0 32.1 35.1 21.4 15 未穿透 – 
下载: 导出CSV
表 2 布袋注浆桩孔压计布置方案表
Table 2. Layout parameters of bagged grouting pile pore water pressure gauge
埋设深度/m 埋设土层 孔压计距离试验桩
中心的距离2D 4D 8D 5 淤泥质粉质黏土 u11 u21 u31 10 淤泥质黏土 u12 u22 u32 15 粉土 u13 u23 u33 20 粉砂夹粉质黏土 u14 u24 u34
下载: 导出CSV
表 3 各测点超静孔隙水压力值的变化与消散率
Table 3. Variation of super-static pore pressure and dissipation rate
孔压计
编号孔压计
埋深/m超静孔隙水压力
最大值/kPa消散率/% 10 d 28 d u11 5 98.4 73.4 79.4 u12 10 150.3 67.9 74.6 u13 15 235.9 74.4 80.0 u14 20 326.6 83.0 90.6 u21 5 63.1 73.5 83.4 u22 10 112.5 63.9 74.8 u23 15 166.6 74.5 81.9 u24 20 224.5 81.8 87.2 u31 5 28.4 70.1 84.9 u32 10 58.6 68.9 84.0 u33 15 84.8 73.0 87.9 u34 20 114.9 84.8 91.4
下载: 导出CSV
-
上海隧道工程股份有限公司. 柱状布袋注浆工法[R]. 上海: 上海隧道工程股份有限公司, 2004 龚晓南,李向红. 静力压桩挤土效应中的若干力学问题[J]. 工程力学,2001,17(4): 7-12GONG Xiaonan, LI Xianghong. Several mechanical problems in the compacting effect of jacked pile[J]. Engineering Mechanics, 2001, 17(4): 7-12 SEED H B, REESE L C. The action of soft clay along friction piles[J]. Transactions of ASCE, 1900, 122: 731-754 ROY M, BLANCHET R, TAVENASF, et al. Behavior of sensitive clay during pile driving[J]. Canadian Geotechnical Journal, 1981, 18(2): 67-85 COOKE R W, PRICE G. Strains and displacements around friction piles[C]//The 8th International Confe-rence on Soil Mechanics and Foundation Engineering. Moscow: ISSMGE, 1973: 53-60 周火垚,施建勇. 饱和软黏土中足尺静压桩挤土效应试验研究[J]. 岩土力学,2009,30(11): 3291-3296ZHOU Huoyao, SHI Jianyong. Saturated soft clay of full scale experimental study on compacting effect of jacked pile[J]. Rock and Soil Mechanics, 2009, 30(11): 3291-3296 雷华阳,李肖. 管桩挤土效应的现场试验和数值模拟[J]. 岩土力学,2012,33(4): 1006-1012LEI Huayang, LI Xiao. Field test and numerical simulation of soil squeezing effect of pipe pile[J]. Rock and Soil Mechanics, 2012, 33(4): 1006-1012 吴正宇,张电吉. 路基工程中布袋注浆桩的质量监测与分析[J]. 路基工程,2014(6): 137-141WU Zhengyu, ZHANG Dianji. Quality inspection and analysis of bag grouting pile in subgrade engineering[J]. Subgrade Engineering, 2014(6): 137-141 叶春林. 布袋灌注桩在深厚层夹层软基处理中的应用[J]. 铁道工程学报,2008(4): 25-32YE Chunlin. Application of bag grouting pile in soft foundation treatment of deep layer[J]. Journal of Railway Engineering Society, 2008(4): 25-32 李仰波. 布袋加筋注浆桩在软基加固处理中的应用研究[J]. 铁道工程学报,2014(12): 34-37LI Yangbo. Study on application of bag reinforced grouting pile in soft foundation reinforcement treatment[J]. Journal of Railway Engineering, 2014(12): 34-37 刘金龙,栾茂田,王吉利. 土工织物加固软土路基的机理分析[J]. 岩土力学,2007,28(5): 30-33LIU Jinlong, LUAN Maotian, WANG Gili. Mechanism analysis of soft soil subgrade reinforced by geotextile[J]. Rock and Soil Mechanics, 2007, 28(5): 30-33 杨敏,赵锡宏. 分层土中的单桩分析法[J]. 同济大学学报: 自然科学版,1992,20(4): 421-427YANG Min, ZHAO Xihong. An approach for a single pile in layered soil[J]. Journal of Tongji University: Natural Science, 1992, 20(4): 421-427 徐建平,周健,许朝阳. 沉桩挤土效应的模型试验研究[J]. 岩土力学,2000,21(3): 235-238XU Jianping, ZHOU Jian, XU Chaoyang. Model test of squeezing soil effect by sinking piles[J]. Rock and Soil Mechanics, 2000, 21(3): 235-238 HWANG J H, LIANG N, CHEN C S. Ground response during pile driving[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2001, 127(11): 939-949 YANG J, THAM L G, LEE P K. Observed per-formance of long steel H-piles jacked into sandy soils[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2006, 132(1): 24-35 -
下载:
点击查看大图
图(8) / 表(3)
计量
- 文章访问数: 392
- HTML全文浏览量: 143
- PDF下载量: 33
- 被引次数: 0