基于动态空腔膨胀模型的土壤Mohr-Coulomb参数反演方法

Inversion method of soil Mohr-Coulomb parameters based on dynamic cavity expansion model

为实现土壤原位力学参数的精准、快速解译,定量评估军事装备机动性,本文利用冲击贯入过程中测得的阻力-速度曲线、加速度时程曲线、速度时程曲线以及贯入深度-初速度关系,基于动态空腔膨胀模型建立了土壤Mohr-Coulomb参数的反演方法。本文分析表明准确拟合贯入阻力系数是反演Mohr-Coulomb参数的关键,而利用冲击贯入过程中的速度时程曲线进行拟合能够对Mohr-Coulomb参数进行准确的反演。针对Forrestal等人报道的实验结果,利用本文方法对土壤内聚力进行反演的相对误差为2.14%,对土壤内摩擦角反演的相对误差为9.77%。本文进一步给出了动态空腔膨胀模型下Mohr-Coulomb参数反演的可解域,讨论了参数敏感性。本文提出的反演方法突破了传统半经验解译方法中物理图像不清晰、经验参数依赖性强的问题,可为复杂地质环境下土壤Mohr-Coulomb参数快速确定及土壤承载力评估提供一个新的方法和途径。

To achieve accurate and rapid interpretation of in-situ soil mechanical parameters and quantitatively evaluate military equipment mobility,an inversion method for soil Mohr-Coulomb parameters is established based on the dynamic cavity expansion model using the resistance-velocity relationship,acceleration and velocity curves,and the relationship between depth and initial velocity measured during the impact penetration process.It indicates that accurate fitting of the resistance coefficients is critical for interpreting Mohr-Coulomb parameters.Precise results could be derived using the measured velocity curve.Based on the experimental results reported by Forrestal et al.using the proposed method,the relative errors of soil cohesion and internal friction angle interpretation are 2.14%and 9.77%,respectively.Furthermore,the solution domain of the Mohr-Coulomb parameters under the dynamic cavity expansion model is revealed,and parameter sensitivity is investigated.The proposed inversion method resolves the problems of unclear physical images and strong parameter dependency in traditional semi-empirical interpretation methods.It could provide a new approach for rapidly determining soil Mohr-Coulomb parameters and assessing soil bearing capacity in complex geological environments.