土工合成材料约束碎石桩承载特性研究
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摘要
土工合成材料约束碎石桩作为一种新型软土地基处理技术在工程中广泛应用,其单桩承载力取决于土工合成材料抗拉强度和土的工程性质。通过对土工合成材料、碎石桩及地基土的相互作用机理进行分析,提出了考虑土工合成材料约束拉力与土体围压的桩身强度计算方法,进而推导出考虑上部荷载作用的,由桩身强度控制的单桩极限承载力计算方法,并采用MATLAB编写了计算程序,根据得出的单桩极限承载力计算了土工合成材料拉力沿深度的分布,结合一算例说明了计算所需要的参数及计算过程,成果可为土工合成材料碎石桩的设计提供计算依据。
As a new soft soil foundation treatment technology, the geosynthetics-bound stone columns(GBSC) is widely used in engineering. The bearing capacity of GBSC is determined by the tensile strength of the geosynthetics and the property of the soil layer. The interaction mechanism of geosynthetic materials, stone columns and foundation soil is analyzed, The method for calculating the strength of GBSC is proposed considering the contribution of the constraint tension of geosynthetic materials and soil confining pressure, and then the method for the ultimate bearing capacity of GBSC is deduced in which the strength of GBSC and the action of the upper load are considered. A computer program is compiled to calculate the limit bearing capacity and tensile force of geosynthetic materials along the depth. An calculation example illustrates the required parameters and the calculation process. The achievement can be used for the bearing capacity design of geosynthetics-restrained stone columns.
As a new soft soil foundation treatment technology, the geosynthetics-bound stone columns(GBSC) is widely used in engineering. The bearing capacity of GBSC is determined by the tensile strength of the geosynthetics and the property of the soil layer. The interaction mechanism of geosynthetic materials, stone columns and foundation soil is analyzed, The method for calculating the strength of GBSC is proposed considering the contribution of the constraint tension of geosynthetic materials and soil confining pressure, and then the method for the ultimate bearing capacity of GBSC is deduced in which the strength of GBSC and the action of the upper load are considered. A computer program is compiled to calculate the limit bearing capacity and tensile force of geosynthetic materials along the depth. An calculation example illustrates the required parameters and the calculation process. The achievement can be used for the bearing capacity design of geosynthetics-restrained stone columns.
引文
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[3]GEDUHN M,RAITHEL M,KEMPFERT H G.Practical aspects of the design of deep geotextile coated sand columns for the foundation of a dike on very soft soils[C]//Landmarks in Earth Reinforcement.Lisse:Swets&Zeitlinger,2001:545-548.
[4]ALEXIEW D,BROKEMPER D,STEVE Lothspeich P E.Geotextile encased columns(GEC):load capacity,geotextile selection and pre-design graphs[C]//Geo-frontiers Congress2005.Austin,Texas,United States,2005.
[5]赵明华,何玮茜,衡帅,等.基于圆孔扩张理论的筋箍碎石桩承载力计算方法研究[J].岩土工程学报,2017,39(10):1785-1792.(ZHAO Ming-hua,HE Wei-xi,HENG Shuai,et al.Calculation method of geogrid-encased stone columns’bearing capacity based on cavity expansion theory[J].Chinese Journal of Geotechnical Engineering,2017,39(10):1785-1792.(in Chinese))
[6]PULKO B,MAJES B,LOGAR J.Geosynthetic-encased stone columns:analytical calculation model[J].Geotextiles and Geomembranes,2011,29(1):29-39.
[7]刘润,冯守中,魏秋晨,等.格栅碎石桩加固软基的机理及计算方法[J].天津大学学报,2009,42(9):784-789.(LIU Run,FENG Shou-zhong,WEI Qiu-chen.Mechanism and calculation method of geogrid gravel pile in soft soil foundation improvement[J].Journal of Tianjin University,2009,42(9):784-789.(in Chinese))
[2]AL-JOULANI N,BAUER G.E.Laboratory behavior of sleeve reinforced stone columns[C]//Geosynthetics‘95 Conference Proceedings.Nashville,1995:1111-1123.
[3]GEDUHN M,RAITHEL M,KEMPFERT H G.Practical aspects of the design of deep geotextile coated sand columns for the foundation of a dike on very soft soils[C]//Landmarks in Earth Reinforcement.Lisse:Swets&Zeitlinger,2001:545-548.
[4]ALEXIEW D,BROKEMPER D,STEVE Lothspeich P E.Geotextile encased columns(GEC):load capacity,geotextile selection and pre-design graphs[C]//Geo-frontiers Congress2005.Austin,Texas,United States,2005.
[5]赵明华,何玮茜,衡帅,等.基于圆孔扩张理论的筋箍碎石桩承载力计算方法研究[J].岩土工程学报,2017,39(10):1785-1792.(ZHAO Ming-hua,HE Wei-xi,HENG Shuai,et al.Calculation method of geogrid-encased stone columns’bearing capacity based on cavity expansion theory[J].Chinese Journal of Geotechnical Engineering,2017,39(10):1785-1792.(in Chinese))
[6]PULKO B,MAJES B,LOGAR J.Geosynthetic-encased stone columns:analytical calculation model[J].Geotextiles and Geomembranes,2011,29(1):29-39.
[7]刘润,冯守中,魏秋晨,等.格栅碎石桩加固软基的机理及计算方法[J].天津大学学报,2009,42(9):784-789.(LIU Run,FENG Shou-zhong,WEI Qiu-chen.Mechanism and calculation method of geogrid gravel pile in soft soil foundation improvement[J].Journal of Tianjin University,2009,42(9):784-789.(in Chinese))