海原地震石碑塬液化滑移地表特征形成机制探讨

Formation Mechanism of Surface Characteristics of Liquefaction-Triggered Sliding Flow in Haiyuan Earthquake Shibei Tableland

摘要:

海原大地震诱发石碑塬地区发生大规模液化滑移，因其多元地层结构和土体液化性质的差异，在滑移发生过程中形成节律性极强的后部似台盾，前、中部尺度差异性不强的波浪型地貌。而这种表性特征是滑移体成灾过程中发生模式的直观表达，因此，对其滑移体地表表性特征的形成机制分析是对该类致灾形式机制、机理研究分析一种理想研究角度的选择。文章结合实地调研、滑移体走向、地层剖面及前人对不同砂质黄土层的液化势判定成果，对波浪型峰谷地貌的峰、谷形成机制和运动特征进行细致的分析和探讨。

Abstract:

A large-scale sliding flow triggered by liquefaction in Shibeiyuan area was induced by Haiyuan earthquake. Due to the difference of multi-element stratum structure and soil liquefaction properties, the highly regular wavelike landform was formed during the sliding process. This phenotypic characteristic is an intuitive expression of the occurrence mode during the disaster-causing process of sliding bodies. Therefore, the formation mechanism analysis of the sliding body surface characteristics is an ideal approach for studying the mechanism and form of such disasters. In this paper, combined with field investigation, strike of slip body, stratigraphic profile, and previous determination of liquefaction potential of different sandy loess layers, the formation mechanism and movement characteristics of wavelike peak valley landform were analyzed and discussed in detail.