中文摘要：

建立了一种考虑桩侧阻软化的非线性指数荷载传递函数,并根据浙江地区实测工程资料,给出了各参数的取值方法及建议值。该侧阻软化函数中桩侧摩阻力残余值!f与峰值!u之比βs越小,软化现象越明显,残余强度越低;桩侧阻出现软化时的极限位移Su与桩侧阻跌落至残余强度时的桩土位移值Ss之比βc越大,软化现象越明显,残余强度越低。参数Su决定侧阻软化函数的临界点,即出现软化时的极限位移;参数!u决定了桩侧极限摩阻力值的大小。经过大量实测工程资料统计得出：βs约为0.84～0.98,结构性强的土质取小值;βc约为0.42～0.69,结构性强的土质取小值。应用本文提出的侧阻软化函数对实测工程进行计算,结果表明,计算值与实测值很接近,说明本文建立的侧阻软化函数能够很好地反映桩出现侧阻软化时的桩土荷载传递关系。

英文摘要：

A new nonlinear index load transfer model considering softening of pile shaft resistance is proposed.The proposed value of its parameters is given in accordance with engineering data in Zhejiang province.In this load transfer model,the degree of softening is higher with a smaller value of βs which equals to τ f/τ u and the degree of softening is higher with a bigger value of βc which equals to Su/Ss.The parameter Sudetermines the ultimate relative displacement,and the parameter τ u determines the ultimate friction resistance.According to the measured data,βs is about 0.84~0.98,and it is smaller for strong structural soil;βc is about 0.42~0.69,and it is larger for strong structural soil.The values calculated with the load transfer model from a project agree well with the test data.It indicates that the load transfer model considering softening of pile shaft resistance does well in simulating the curve of load transfer.