落石与坡面或者防护结构接触过程中冲击参量随时间变化特征是描述落石碰撞过程的重要指标，对于揭示落石与坡面相互作用机制以及采取合理的防护措施具有重要的意义。在现有的相关设计规范中，并没有给出关于落石冲击力时程关系的计算方法，仅参照有关规范或经验方法确定一个落石最大冲击力值。为此，首先基于线黏弹性接触理论，建立落石冲击地面力学模型，根据位移-速度组合初始条件以及速度-加速度组合初始条件分别推导得到两种落石冲击特征参量理论解析解；然后基于 ANSYS/LS-DYNA 非线性动力学软件，建立落石冲击地面三维数值模型，研究球体落石冲击地面力学特点；最后将理论结果对比室内试验和已有的研究成果，得出以下结论：（1）Hertz 弹性接触理论结果中各参量变化在加载阶段和恢复阶段均呈现对称的趋势，速度、加速度初始条件下的落石冲击特征参量和动力有限元法非常接近，而位移-速度初始条件组合并不适用于研究落石冲击下的动力特征；（2）不同速度和下落高度下，落石最大冲击力值随落石下落高度和冲击速度的增大而增加，而落石冲击作用时间随下落高度和冲击速度的增加而减小；（3）计算结果得到的落石最大冲击力以及落石冲击作用时间与室内试验结果和已有成果相接近，相比室内试验和有限元结果的震荡性，此结果更能体现落石冲击力变化规律； （4）多种冲击速度下，对比不同方法得到的落石最大冲击力，可知计算结果均在各种冲击力计算结果的范围内，具有很好的可靠性。考虑到现有研究理论的不足，难以求解落石冲击力时程关系，求解结果丰富了落石碰撞理论，可以指导工程有关落石灾害的防护设计。The time variation characteristic of impact parametersin the contact process between rockfall and slope or protective structure is animportant index to describe the process of rockfall collision. It issignificant to reveal the interaction mechanism between rockfall and slope andto take reasonable protective measures. In the existing relevant designspecifications

there are no calculation methods for the time historyrelationship of rockfall impact

and only a maximum value of rockfall impactforce is determined by referring to relevant specifications or empiricalmethods. Therefore

based on the linear viscoelastic contact theory

amechanical model of rockfall impact on the ground is established firstly; accordingto the different combined initial conditions

two theoretical analyticalsolutions of the characteristic parameters of rockfall impact are derivedrespectively. Then

based on the ANSYS/LS-DYNA nonlinear dynamics software

athree-dimensional numerical model is established

and the mechanicalcharacteristics of the rockfalls impacting the ground at different speeds arestudied. Finally

the theoretical results of this paper are compared with the indoortest and existing research results

and the following conclusions are drawn: 1)According to the Hertz elastic contact theory

the changes of variousparameters show a symmetrical trend during the loading stage and the recoverystage. The characteristic parameters of rockfall impact under the initialcondition combination of velocity-acceleration in this paper are very close tothe dynamic finite element method

and the initial condition combination ofdisplacement-velocity is not suitable for research on dynamic characteristics under the impact of rockfall. 2) At differentspeeds and falling heights

the maximum impact force value of the rockfallincreases with the increase of the falling height and impact velocity of therockfall

while the impact time of the rockfall decreases with the increase ofthe falling height and impact velocity. 3) The maximum impact force and impacttime of the rockfall obtained by the calculation in this paper are close to theindoor test and the existing results. Compared with the oscillation of the indoortest and the finite element results

the results of this paper can betterreflect the change law of the impact force of the rockfall. 4) Comparing the maximum impact forceof rockfall obtained by different methods under a variety of impact speeds

thecalculation results in this paper are all within the range of various impactforce calculation results

and have good reliability. The results of this paperenrich the rockfall collision theory

which can guide the protection design ofengineering related to rockfall disasters.