塑料套管管侧前注浆桩承载特性的现场试验研究

发布时间：2019-01-01 15:58

【摘要】：为提高塑料套管混凝土桩(简称TC桩)的承载性能,结合桩侧注浆技术,发展和形成了塑料套管管侧前注浆桩(简称TCSG桩)。通过现场试验,对TCSG桩、TC桩和扩径塑料套管混凝土桩(简称TCLD桩)3种桩型在不同时期进行了静载试验,并引入了3种易于应用的单桩沉降计算模型对各桩体的沉降进行了计算。试验结果和沉降模型计算分析表明:与TC桩相比,TCSG桩增加了8.3%~20.0%的承载力,并减小了19.8%~33.5%的沉降,而TCLD桩降低了10.0%~16.7%的承载力,且增加了13.2%~43.8%桩体的沉降;TCSG桩的轴力衰减速率大于TC和扩径的TCLD桩的,TCSG桩的前、后期的平均轴力衰减速率相差不大,TC桩后期的平均轴力衰减速率相比前期提高了1.1%~14.2%,而TCLD桩却降低了5.9%~21.9%;在前、后期静载时,TCSG桩在各级荷载下的平均单位侧摩阻力相比TC桩分别提高了14.5%~39.6%和9.2%~28.6%,扩径后的TCLD桩则分别降低了4.9%~11.8%和11.5%~30.7%;管侧前注浆后的TCSG桩的时效特性不显著,扩径后的TCLD桩的侧摩阻力随时间减小而端阻力则增大;基于桩土荷载传递的单桩沉降计算模型能够较好地预测塑料套管桩的沉降。
[Abstract]:In order to improve the bearing capacity of plastic casing concrete pile (TC pile for short), combined with pile side grouting technology, the plastic casing pipe side front grouting pile (TCSG pile) was developed and formed. Through field tests, three types of piles, TCSG pile, TC pile and expanded plastic casing concrete pile (TCLD pile), are tested under static load at different periods. The settlement of each pile is calculated by introducing three kinds of single pile settlement calculation models which are easy to be used. The test results and settlement model analysis show that compared with TC pile, the bearing capacity of TCSG pile is increased by 8.33%, and the settlement of TCSG pile is reduced by 33.5%, while the bearing capacity of TCLD pile is decreased by 10.0% and 16.7%, respectively. The settlement of the pile was increased by 13.2% and 43.8%. The attenuation rate of axial force of TCSG pile is larger than that of TC pile and TCLD pile with expanding diameter. The average axial force attenuation rate of TCSG pile is not different from that of TCSG pile, and the average axial force attenuation rate of TC pile in the latter stage is 1.1% higher than that of the earlier period. However, the TCLD pile decreased the value of 5.9% and 21.9%; In the former and later static loading, the average unit side friction of TCSG pile under various loads increased by 14.59.6% and 9.228.6%, respectively, compared with TC pile. The TCLD pile with enlarged diameter decreased by 4.9% and 11.50.70%, respectively. The aging characteristics of the TCSG pile after grouting on the pipe side are not significant, the side friction of the expanded TCLD pile decreases with time and the end resistance increases, and the settlement calculation model of the single pile based on pile-soil load transfer can better predict the settlement of the plastic sleeve pile.
【作者单位】：宁波大学建筑工程与环境学院建筑学系;河海大学岩土工程科学研究所;长江水利委员会水文局;
【基金】：浙江省自然科学基金青年基金项目(No.LQ15E080002) 国家自然科学基金面上项目(No.51478228)
【分类号】：TU473.1

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