基桩自平衡法双模内力测试研究与分析  

Analysis on Self-Balanced Method for the Bi-Directional Loading Test on Cast-In-Placed Bored Piles

作　　者：张召彬 韩文永 张开伟 李福来 郭洪林 谷立强 ZHANG Zhaobin;HAN Wenyong;ZHANG Kaiwei;LI Fulai;GUO Honglin;GU Liqiang(Hebei Shuangcheng Construction Engineering Testing Co.,Ltd.,Shijiazhuang 050221;China Hebei Construction&Geotechnical Investigation Group Co.Ltd.,Shijiazhuang 050000;Construction Co.Ltd.,China State Grid Hebei Electric Power Co.,Ltd.,Shijiazhuang,050031)

机构地区：[1]河北双诚建筑工程检测有限公司,石家庄050221 [2]中冀建勘集团有限公司,石家庄050000 [3]国网河北省电力有限公司建设公司,石家庄050000

出　　处：《土工基础》2023年第2期305-310,共6页Soil Engineering and Foundation

摘　　要：通过对灌注桩的双模内力测试与常规内力测试对比试验,分析基桩在双模受力时荷载-沉降曲线和桩的承载特性,并与常规内力测试进行比对。当试桩达到极限受力状态时,自平衡法双模测试极限端阻大于常规静载试验的测试极限端阻,摩阻分布规律基本一致,荷载箱上下侧摩阻发挥程度不同,上侧小于常规极限摩阻,下侧大于常规极限摩阻。利用桩顶位移与上部桩位移优化换算位移比规范简化法换算位移,更加精确有效;换算后的位移比常规静载试验位移略偏大,但是二者曲线走势基本一致,表明自平衡法双模内力测试结果能够提供工程桩设计的有效参考数据。The deformation-loading characteristics of the cast-in-place reinforced concrete piles are evaluated throughout the bi-directional loading tests and the loading results are compared with the conventional top-town loading test results.When the test pile reaches the limiting state,the tested end bearing resistance results from the bi-directional loading test is usually greater than that of from the conventional pile loading tests and the side friction values are similar in both testing methods.In the bi-directional loading tests,the side friction values are different in the upper portion and the lower portion of the testing device.Usually,the tested mobilized side friction in the upper portion is less than the limiting value tested in the conventional top-down loading tests and the mobilized value in the lower portion from the bi-directional loading test is greater than that of from the conventional loading test.An improved equivalent top-down loading-settlement curve conversion method is proposed by comparing the pile top settlement in the conventional loading test and the deflection in the upper shaft in the bi0directional loading test.It is found that the proposed method is more accurate than the code suggested method.Although the converted equivalent top-down settlement-loading curve predicts larger pile settlement than that of the conventional loading test,the deflection-loading curves from both test methods have similar trend and it is demonstrated that the bi-directional loading test can provide an effective loading test results for the pile design.

关 键 词：自平衡法 双模内力测试 等效转换 桩身压缩量 

分 类 号：TU413[建筑科学—岩土工程]