| CM桩复合地基桩土应力比及垫层效应现场试验研究 |
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| 引用本文： | 张旭群,杨光华,陈 锐,温 勇,张玉成.CM桩复合地基桩土应力比及垫层效应现场试验研究[J].岩土力学,2015,36(Z1):357-361. |
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| 作者姓名： | 张旭群 杨光华 陈 锐 温 勇 张玉成 |
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| 作者单位： | 1. 哈尔滨工业大学 深圳研究生院，广东 深圳 518000；2. 广东省水利水电科学研究院，广东 广州 510000 |
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| 基金项目： | 国家自然科学基金（No.51378131）；广东省水利科技创新基金（No.2009-25）。 |
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| 摘 要： | 通过现场4桩大压板静载试验，布置土压力盒，测定并分析C桩（刚性桩）桩顶、M桩（亚刚性桩）桩顶和桩间土体应力，计算桩（C桩+M桩）土荷载分担比，分析CM桩复合地基静载试验过程中桩、土的受力特性。通过设置不同垫层厚度，对比大压板试验P-S曲线，结合单桩静载试验，分析CM桩复合地基垫层的破坏模式及垫层效应。试验结果表明，CM桩复合地基工作时C桩桩顶应力集中现象明显，C桩桩土应力比大于10，M桩桩土应力比小于10；随着试验加载,桩土应力比逐渐增大，C桩桩土应力比增大幅度大于M桩；在复合地基设计荷载条件下，桩土荷载分担比接近6:3:1；将M桩和桩间土体视为一整体，即地基处理后相对于C桩的“桩间土”，则桩土荷载分担比为6:4，设计较为合理；随着垫层厚度增大，CM桩复合地基沉降值增大；当C桩成桩质量较好时，垫层破坏模式为C桩桩顶刺入破坏，试验时应合理选取褥垫层的材料和厚度。
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| 关 键 词： | CM桩复合地基 现场试验 桩土应力比 荷载分担比 垫层效应 |
| 收稿时间： | 2015-03-10 |
Field test study of pile-soil stress ratio and cushion effect of CM-piles composite foundation |
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| ZHANG Xu-qun,YANG Guang-hua,CHEN Rui,WEN Yong,ZHANG Yu-cheng.Field test study of pile-soil stress ratio and cushion effect of CM-piles composite foundation[J].Rock and Soil Mechanics,2015,36(Z1):357-361. |
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| Authors: | ZHANG Xu-qun YANG Guang-hua CHEN Rui WEN Yong ZHANG Yu-cheng |
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| Institution: | 1. Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, Guangdong 518000, China;
2.Guangdong Research Institute of Water Resources and Hydropower, Guangzhou, Guangdong 510000, China |
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| Abstract: | During the four piles static load field test, soil pressure boxes are arranged. With the testing of stress on the top of C-piles namely the rigid piles, the top of M-piles namely the semirigid piles, and soil between piles, the piles-soil stress ratio and load sharing ratio are calculated. Then, the stress state of piles and soil during the CM-piles composite foundation static load test is analyzed. Besides, combining the large plate test P-S curve after setting different thicknesses of cushion layer with the single C-pile static load test, the failure mode and cushion effect are analyzed. The test results are as follows. First, when the CM-piles composite foundation is working, C-pile top stress concentration phenomenon is obvious as the pile-soil stress ratio of C-pile are more than 10, while that of M-pile are less than 10. As the test loading, piles-soil stress ratio increasing gradually, increasing rate of pile-soil stress ratio of C-pile is larger than that of M-pile. Second, under the conditions of design load of CM-piles composite foundation, load sharing ratio among C-piles, M-piles and soil is around 6:3:1. Considering M-piles and soil between piles as a whole, namely, after the foundation treatment, it is more reasonable for the soil between piles compared to C-piles to have a pile-soil load sharing ratio of 6:4. Third, as the thickness of cushion layer increases, the CM-piles composite foundation settlement values increase. While the quality of C-pile is better and cushion failure mode is pierced by C-pile, the material and thickness of cushion layer should be properly selected. |
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| Keywords: | CM-piles composite foundation field test piles-soil stress ratio load sharing ratio cushion effect |
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