【摘要】 为了提高m法在试桩计算中的精度，提出了基于m法的横向受荷长桩三参数模型参数反演方法。假定地面处桩侧土抗力不为零、地基系数沿深度线性增加，将桩土相对刚度、桩的抗弯刚度、z₀作为参数，建立了横向受荷长桩三参数理论计算模型。假定αz₀,根据桩在地面处位移和转角实测值计算桩土相对刚度、桩的抗弯刚度和桩身最大弯矩。基于桩身最大弯矩计算值接近于实测值条件确定桩土参数，进而通过桩土参数计算桩身弯矩和土抗力并通过其分布情况验证反演方法的可行性。基于理论计算模型分析了剪力作用下αz₀变化对其他参数的影响，结果表明：随着αz₀的增大，桩土相对刚度、桩的抗弯刚度、桩身最大弯矩以及m值均减小，地面处土抗力和C值均增大，最大土抗力先减小后增大。算例分析表明：反演方法能够保证桩在地面处位移、转角、桩身最大弯矩及最大土抗力位置计算值与实测值相符。与现场试验实测值相比，土抗力最大误差在15%以内；与室内模型试验实测值相比，最大土抗力误差在5%以内；桩身弯矩和土抗力沿深度分布较m法合理。考虑地面处的土体抗力并将桩的抗弯刚度作为待定参数，能够更好地分析桩土的实际工作状况。更多还原

【Abstract】 To improve the computational accuracy of m method for test piles, the parameter inversion method for three-parameter model of laterally loaded long pile is proposed. It is assumed that the resistance of soil around pile is not zero at ground level, and the foundation coefficient increases linearly along depth. Regarding pile-soil relative stiffness, flexural rigidity, and z₀ as parameters, the theoretical model of three-parameter for laterally loaded long pile is established. According to the measured values of ground displacement and angle, the pile-soil relative stiffness, flexural rigidity, and maximum moment are calculated with assuming αz₀. Due to the calculated maximum bending moment is close to the measured value, the pile-soil parameters are determined. Then, the bending moment and soil resistance of piles are calculated with pile-soil parameters, and the feasibility of inversion method is verified by parameters distribution. The influence of αz₀ change on other parameters under shear force is analyzed based on the theoretical computation model. The result indicates that with the increase of αz₀, the pile-soil relative stiffness, flexural rigidity, maximum moment, and value of m all decrease. The ground soil resistance and the value of C both increase, but the maximum soil resistance decreases first then increases. The example analysis indicates that the theoretical values of ground displacement and angle, maximum moment, and position of maximum soil resistance are all same to the measured values by using inversion method. Compared with the measured values of field tests, the maximum error of soil resistance is within 15%, and the error of maximum soil resistance is within 5% compared with the measured value with indoor model test. The moment and soil resistance along depth are more reasonable than those by using m method. Considering ground soil resistance and regarding flexural rigidity as an undetermined parameter can preferably analyze practical working conditions between pile and soil.更多还原