地震折射层析法在青藏铁路路基开裂调查中的应用

青藏铁路有约500km路基处于冻土地带。铁路运行一年来，在少冰和多冰冻土段上的部分路基发生了开裂．影响到铁路安全。为了了解路基下冻土的分布状态，消除冻土变化对路基的影响，笔者采用了地震折射层析法勘查路基下冻土发生的变化。通过对这些资料的分析，发现路基下的冻土发生了变化，并推测这些发生在路基两侧的不对称、不均匀变化是造成路基开裂的主要原因。

The Application of Investigating the Roadbed Cracks of the Qinghai-Tibet Railway Using the Seismic Refraction Tomography Method

The Qinghai--Tibet Railway has more than 500kin the Roadbeds which are in the permafrost regions. After a year＇s railway running, the roadbeds on the frozen soil with less or more ice have had the roadbed cracks and affect the railroad security. In order to know the distribution of the frozen soil under the roadbeds and eliminate the influence of the changes of the frozen soil on the roadbeds, we have used the seismic refraction tomography method to investigate the changes that the frozen soil under the roadbed occurs. Through the data analysis, we discovered the frozen soil under the roadbed on both sides has had the changes and predicted the non--uniform and bilateral non--symmetry were the causes of the roadbed cracks.