富含火山灰土层具有特殊的物理力学性质和工程特性，其水平抗力系数的比例系数 m 的取值不清，途径该地区的高速铁路桩基水平承载特性不明。为此开展了火山灰堆积地区高速铁路桥梁单桩的水平静载试验，分析了该地区桩基的水平承载变形特性，综合分析了不同行业规范对 m值折减系数的具体要求，开展了富含火山灰土层m值的取值研究。研究结果表明:富含火山灰土层m值随水平荷载的增大呈非线性衰减，随水平位移的增大而近似呈幂函数形式衰减。获得了单桩水平临界荷载和极限水平承载力，并提出了考虑工作折减系数后的火山灰粉质黏土 m 的取值建议。研究成果可为我国富含火山灰土层m的合理取值和该地区高铁桥梁桩基水平承载力计算、安全评估提供重要参考。
Horizontal loading test on large diameter cast-in-place piles in deep volcanic ash accumulation area
Due to its special physico-mechanical properties and engineering characteristics,the lateral resistance coefficient m value of volcanic ash-rich soil layer is unclear,and the horizontal bearing characteristics of the pile foundation for high-speed railway in this area are unknown.Horizontal static loading test of high-speed railway bridge is carried out in volcanic ash accumulation area.The horizontal bearing deformation characteristics of pile are analyzed.Besides,the requirements on the reduction coefficient of m value in different design codes are comprehensively discussed,and the study on the m value of the volcanic ash-rich soil layer is also carried out.The results show that the m value of volcanic ash-rich soil layer decreases nonlinearly with the increase of horizontal load,and decreases approximately as power function with the increase of horizontal displacement.The horizontal critical load and ultimate horizontal bearing capacity of the single pile were obtained,and m value for volcanic ash-flour silty clay after considering the working reduction coefficient was proposed.The study results can provide important references for the reasonable value of m in the volcanic ash-rich soil layer in China and for the calculation of horizontal bearing capacity and safety assessment for bridges pile foundations of high-speed railway in this region.
万方数据
维普
