硬岩中倾顺层边坡变形特征和破坏机制分析

RESEARCH ON DEFORMATION AND FAILURE MECHANISM OF MODERATE-DIP CATACLINAL HARDROCK SLOPE

由于线路设计的走向总体上平行于褶皱轴线方向,沪蓉西高速公路湖北省宜昌—恩施段遇到大量的顺层路堑边坡。在全部的顺层边坡中,岩层倾角为20°～60°的硬岩中倾顺层边坡占顺层边坡总量的30%,其稳定性问题和处治措施问题对于高速公路建设尤为重要。通过古树屋滑坡在滑坡起动之后全面的变形监测,分析硬岩中倾顺层边坡的变形特征。在此基础上,进一步研究该类边坡的失稳原因和破坏机制。研究结果显示,由于长期的风化、溶蚀、构造作用和坡体自重应力作用下,在一定深度范围内岩体节理和层面的泥质充填物的存在,抗剪强度的大幅度降低,是硬岩中倾顺层边坡产生滑动的控制性影响因素。对硬岩中倾顺层边坡的研究可以为湖北沪蓉西高速公路宜昌—恩施段的硬岩中倾顺层边坡顺层边坡和其他类似工程的稳定性评价及处治提供依据或参考。

Due to the trend of road paralleling to the axis of the folds,cataclinal slopes are abundant in Hurong Highway in Hubei Province. Of all these cataclinal slopes,the moderate-dip cataclinal hardrock slopes with the bedding plane dip angles ranging between 20° to 60° account for 30 percent,so the stability and treatment are very important to highway construction. Aiming at these problems,this paper presents the character of landform and engineering geology of these types of slopes,and the deformation characterization and sliding process are also analyzed by means of deformation monitoring. Based on the works,the failure mechanism of this type of slope is studied. The result indicates that the penetrative discontinuities have expanded intensely because of weathering,corrosion,tectonic effect and gravity for a long time,and are filled with mud in a certain depth,and thus its shear strength reduces,which is the dominate factor leading to sliding of the moderate-dip cataclinal slopes of hardrock. The conclusion may be useful for assessment of stability and treatment of Hurong Highway and similar engineering.