| 分级加载下组合渗流碎石桩-CFG桩复合地基固结解答 |
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| 引用本文： | 武崇福,李文雪,李文涛,芦建鑫,韩毅.分级加载下组合渗流碎石桩-CFG桩复合地基固结解答[J].中国公路学报,2022,35(8):140-150. |
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| 作者姓名： | 武崇福 李文雪 李文涛 芦建鑫 韩毅 |
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| 作者单位： | 1. 燕山大学 建筑工程与力学学院, 河北 秦皇岛 066004;2. 河北民族师范学院 旅游与航空学院, 河北 承德 067000;3. 北京交通大学 土木建筑工程学院, 北京 100044;4. 中交隧道局华中工程有限公司, 湖北 武汉 430014 |
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| 基金项目： | 河北省自然科学基金项目(E2020203075) |
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| 摘 要： | 为了进一步完善组合渗流排水桩-不排水桩复合地基固结理论,就分级加载下组合型复合地基的固结理论计算展开研究。以组合渗流碎石桩-CFG桩复合地基为研究对象,考虑碎石桩固结变形、不同桩体的涂抹效应和附加应力随深度与时间变化等因素,结合软土路基分级填筑的工程状况,运用解析法推导出分级加载下组合渗流碎石桩-CFG桩复合地基固结解析解,并得到任意时刻复合地基的整体平均固结度解答。进一步地,将本文解退化为瞬时加载下附加应力沿深度非均布条件下的解,大大简化了计算公式。运用MATLAB软件对本文解进行编程运算,以不同加载历程、附加应力沿深度分布的3种模式和桩土模量比为基本变量,绘制出相应工况下复合地基的整体平均固结度曲线,然后对计算结果进行参数分析。研究结果表明:采用与工程实际更为接近的分级加载模式,发现不同加载历程对复合地基固结速率的影响较大;分级加载下附加应力沿深度非均布的固结度曲线基本重合,表明考虑应力时效性的应力分布模式对复合地基固结速率影响不大,从而可以将固结度计算公式简化,易于工程应用;但是在不同的CFG桩土模量比下,附加应力沿深度分布模式的不同导致地基的最终沉降结果有较大差异,增大桩土模量比有助于减小复合地基变形量,缩小沉降差异,维持地基稳定。
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| 关 键 词： | 道路工程 复合地基 解析法 分级加载 附加应力 |
| 收稿时间： | 2020-12-22 |
Consolidation Solution of Composite Foundation of Composite Seepage Gravel Pile and CFG Pile Under Graded Loading |
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| WU Chong-fu,LI Wen-xue,LI Wen-tao,LU Jian-xin,HAN Yi.Consolidation Solution of Composite Foundation of Composite Seepage Gravel Pile and CFG Pile Under Graded Loading[J].China Journal of Highway and Transport,2022,35(8):140-150. |
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| Authors: | WU Chong-fu LI Wen-xue LI Wen-tao LU Jian-xin HAN Yi |
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| Affiliation: | 1. School of Civil Engineering and Mechanics, Yanshan University, Qinhuangdao 066004, Hebei, China;2. College of Tourism and Aviation Services, Hebei Normal University for Nationalities, Chengde 067000, Hebei, China;3. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China;4. Huazhong Engineering Co. Ltd., CCCC Tunnel Bureau, Wuhan 430014, Hubei, China |
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| Abstract: | To further improve the consolidation theory of composite foundations with drainage piles and undrained piles,the consolidation theory of a composite foundation under graded loading was studied.Taking the composite foundation of the composite seepage gravel pile and CFG pile as the research object,the consolidation deformation of the gravel pile,the smear effect of different piles,and the variation of additional stress with depth and time were considered.Combined with the engineering situation of soft soil subgrade grading filling,the analytical solution of composite foundation consolidation of composite seepage gravel pile CFG piles under grading loading was derived using an analytical method,and the solution of the overall average consolidation degree of the composite foundation at any time was obtained.Furthermore,the solution in this study was reduced to the solution under the condition that the additional stress is non-uniform along the depth under instantaneous loading,which greatly simplifies the calculation formula.MATLAB was used to program the solutions in this study.Considering different loading histories,three modes of additional stress distribution along the depth,and pile-soil modulus ratio as the basic variables,the overall average consolidation degree curves of the composite foundation under the corresponding working conditions was drawn,and the calculation results were analyzed.The results show that the consolidation rate of the composite foundation is greatly affected by different loading histories and the stress distribution mode considering the time effect of stress has little effect on the consolidation rate of the composite foundation;thus,the calculation formula for the consolidation degree can be simplified,which is easy for engineering applications;however,under different CFG pile-soil modulus ratios,the distribution pattern of additional stress along the depth leads to significant differences in the final settlement results of the foundation.Increasing the pile-soil modulus ratio helps to reduce the deformation of the composite foundation,reduce the settlement difference,and maintain the stability of the foundation. |
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| Keywords: | road engineering composite foundation analytical method graded loading additional stress |
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