冻结砂土在两级应力作用下的蠕变破坏性质

通过两级应力条件下冻结兰州砂土的蠕变试验发现，与单级应力条件下的蠕变破坏相比，第二级应力作用下冻结破坏时间增长，最小应变速率减小，即第一级应力对冻土有强化作用，在第一级应力作用时间相同时，这种强化作用的程度取决于第一级应力的大小，当第一级应力等于某临界值时，对冻土的强化作用最大。

Creep Failure Characteristics of Frozen Sand under Two-step Stress

This paper presents a series of creep tests of frozen soil under two-step stress. It is found that the creep failure time under two-step stress increases and the minimum strain rate decreases comparing with those under a single stress, i.e. the first step stress strenghenes frozen soil. At a same applying time of first step stress, the strenghened extent depends on the first step stress. When the first step stress is equal to a critical value, frozen soil is maaimally strenghened.