考虑挤土和群桩效应的预制桩安全监控模型  

Safety monitoring model for extruding effect and group effect of precast piles

作　　者：陈志坚[1,2] 张雄文[1,3] 柳毅 李筱艳[1] 

机构地区：[1]河海大学土木工程学院,江苏南京210098 [2]中国矿业大学,北京100083 [3]苏通大桥建设指挥部,江苏南京226009 [4]天浦投资控股有限公司,上海200135

出　　处：《岩土力学》2004年第6期891-895,共5页Rock and Soil Mechanics

基　　金：国家重点基础研究发展规划项目资助(编号:2002CB412707)

摘　　要：在深入分析密集型静力压入式预制桩挤土效应和群桩效应的机理和不利影响的基础上,建立了确保地基土不因挤土效应而破坏的孔隙水压力监控模型,优化压桩线路和次序的超静孔压监控模型,确保基桩不因桩周土隆起而被拔断的基桩轴力监控模型,确保基桩不因挤土效应而产生弯折破坏以及桩间土不因群桩效应而产生剪切破坏的桩侧土压力监控模型。实测数据表明,在没有采取有效的降排水和卸压预防措施时,沉桩施工容易导致地基土强度失效和基桩拔断破坏。采取袋装砂井排水和碎石桩式降水井降水后,即使是透水性差的软土地基,也可使较大的超静孔压在1 d时间内消散70％。Mechanism and bad action of extruding effect and group effect for pressed piles are presented. Then, four monitoring models are founded to avoid failure of foundation pile and soil, including model of pore water pressure to prevent foundation soil from failure for the extruding effect of piles, model of excess pore pressure for optimization of pile sinking scheme, model of axial force to prevent foundation piles from tensile failure for the upheaved soil around piles, and model of lateral earth pressure to prevent foundation piles from flexural failure for extruding effect and to prevent foundation soil from shear failure for group effect. Observed data show that, without effective measure of water discharge and soil pressure relief, failure of soil and pile would happen in the progress of pile sinking. Soft soil foundation with weak permeability can diminish 70 percent of excess pore water pressure in one day by taking the measure of sand drain and discharging well in gravel pile.

关 键 词：预制桩 超静孔隙水压力 基桩轴力 桩侧土压力 承载力 监控模型 

分 类 号：TU473[建筑科学—结构工程]