土抗力法计算深基坑支护桩弯矩及实测分析

Soil resistance calculating method of deep foundation pit supporting pile and test analysis

通过在基坑支护桩中埋置应力计,跟踪测试基坑在开挖过程中桩身弯矩和桩顶位移的变化,研究支护桩荷载传递规律。同时选择上三角、全三角、梯形三种土压力分布模式,分别应用土抗力法的m法、c法和k法对支护桩的桩身弯矩进行了理论计算,并把计算结果与实测结果进行对比分析。结果表明:对于支护桩弯矩而言,无论采用何种土压力模式,m法的计算结果与实测结果相差较大;k法计算的最大正弯矩与实测值比较接近,但最大负弯矩偏大;c法计算的最大正弯矩偏于不安全,最大负弯矩过大。

Load transfer behavior of supporting pile for foundation excavation was studied through testing the change of bending moment of the pile with the deep foundation pit excavation program.Meanwhile,the moment and displacement of the pile were calculated by applying the soil resistance methods m, c and k and selecting earth pressure model of up triangle,triangle and trapezoid.The calculation and test results were compared and it got some conclusions.For the moments,the deviation of the calculation results and test results of the method m is relatively great.The results of the method k are checked fair well with the experimental data,but the maximum negative moment is bigger than measured value.The maximum positive bending moment by the method c is not safe and the maximum negative moment is so great.