荷载效应包括速率效应和疲劳效应两部分．速率效应使冻土的动强度和退荷回弹动弹模随应变速率加快而提高；疲劳效应使冻土的动强度随振频增加而下降，但在低应变速率下却使动强度略有提高．在高应变速率下动强度大于静强度，在低应变速度下动强度小于静强度，其间存在一个临界应变速率．通过动强度－破坏振次关系，可确定长期极限动强度． Load effects include the rate effect and fatigue effect in two parts. The velocity effect makes the dynamic strength of the frozen soil and the springback elastic modulus increase with the increase of the strain rate. The fatigue effect makes the dynamic strength of the frozen soil decrease with the increase of the vibration frequency, but increases the dynamic strength slightly at low strain rate . At high strain rates, the dynamic strength is greater than the static strength. At low strain rates, the dynamic strength is less than the static strength, and there is a critical strain rate between them. Long-term ultimate strength can be determined by the dynamic strength-failure relationship.