多年冻土区单桩竖向承载力在短期异常气候作用下的响应分析

由于全球气温升高，导致多年冻土逐渐退化，严重影响上部构筑物的稳定性。尤其在日渐复杂的气候环境下，极端天气、气候的频繁发生，使得多年冻土区的地基承载力的变化更加复杂。以多年冻土区某高温、高含冰量地段为例，考虑太阳辐射、冻土相变、大气对流、气候变暖等因素，通过数值方法计算分析了某单桩竖向承载力在短期异常气候作用下的响应。结果表明：短期异常变暖气候对桩基承载力有降低作用，主要体现在降低桩土界面冻结强度，对冻结面积的大小基本没有影响，气候变暖对冻结强度影响时间长而且不可消除；升温幅度越高，承载力降低越强；极寒极暖交替期间，桩基的承载力随着外界气温波动，寒暖期交替过后对桩基承载力基本没有影响。

Analysis of response of pile vertical bearing capacity to short-term climatic anomaly in permafrost regions

Significant climatic warming is in progress and causes degradation of permafrost and stability of superstructures. Especially under the more complex climate, frequently ultra weather and climate, the progress of bearing capacity in frozen ground is becoming more complex. taking a single pile in representative humid permafrost in Qinghai-Tibet plateau for example, considering the pile exposed in the air absorbs solar radiation, permafrost phase-change, natural air convection and global warming, the sensitivity of pile vertical bearing capacity to short-term climatic anomaly in permafrost regions is analyzed using finite element method. The numerical results show that the pile bearing capacity become lower under the short-term warmer climate because the decrease of adfreeze strength between pile and frozen ground, and no change of adfreeze area. The decrease influence is not fade away in the next years. The warmer climatic make the more decrease of bearing capacity. Under the colder climatic alternates with warmer climate, the pile bearing capacity is changed with outer air temperature, and regain normal after the climaticanomaly.