溜砂坡动力学特性实验及防治

溜砂坡是川藏公路中段较为严重的一种山地灾害。本文在自组织临界性理论的概念框架下，通过干燥沙石散粒体临界态单面坡沙堆实验，对溜砂坡的坍滑动力学特性进行了探索。实验发现，颗粒均匀的沙坡出现正态分布的、准周期的大规模“雪崩”，而颗粒非均匀的沙坡的坍滑重量表现为难以界分的、多样化的负幂率分布，大规模坍滑的绝对规模较小，呈现自组织临界行为。基于自组织临界性系统具有的普适性，提出了溜砂坡“频率一规模”关系等灾害演化的初步规律。溜砂坡坡顶来沙和坡脚制约作用削弱，是造成坍滑发展的主要原因。针对坍滑的“牵引式”形式和实际工程条件，设计了一种能稳定溜砂坡坡脚、对基础条件要求低的新型支挡防护结构。

Experiments on Sand-Sliding Slope and the Countermeasure

Sand-sliding slope is a kind of serious mountainous disasters along middle section of Sichuan-Tibet Highway. By means of sand-pile experiment with one slope, the sliding dynamic characteristics of sand-sliding slope in the critical state were discussed under the concept of self-organized criticality (SOC). It is discovered that the sand-pile which is built by the non-uniform sands shows SOC,the sliding scale is very diversified.Whereas the large-scale avalanches of the uniform sand-pile present Quasi-cycle and Normal distributions. Based on the universality of SOC systems, some regularities such as the relationship of frequency-scale of the avalanches were presented. It is suggested that the weathering granules slipping from the top continuously and the weaken stability in the slope foot are two main reasons to cause the avalanches of sand-sliding slope. The precipitation of sliding scale and occuring period of uniform granular slope is easer than non-uniform granular slope, but the sliding scale is greater. To counter the basic pattern of avalanches, the pulling-slip, a new type prevention construction with higher effect of stabilizing slope and lower requirement for the foundation was put forward. It is not only rational and cost-efficient, but also durable and secure.