基于Midas-GTS的不同开挖特征下破碎软岩边坡稳定性研究

Research on the Stability of Fractured Soft Rock Slope under Different Excavation Characteristics Based on Midas-GTS

边坡开挖后内部应力将重新调整分布,原有较稳定边坡常因开挖卸荷发生滑坡坍塌,而合理的开挖位置及坡比将有效减少此类灾害的损害程度。鉴于此,文章基于有限元软件Midas-GTS对破碎软岩边坡进行了不同坡比及位置的开挖模拟。结果表明:坡顶处开挖将提高边坡整体的稳定性,而坡脚处开挖则会降低边坡整体的稳定性,同时坡体中部处小坡比开挖对于边坡稳定性的影响较小;坡底和坡体中部处开挖坡比愈大边坡稳定系数愈小,而坡顶处开挖坡比愈大边坡稳定系数愈高;工程中对于软岩边坡坡顶进行开挖时应尽量提高开挖坡比,但要预防因直立开挖而产生的局部剪应力增高带,而在坡体中部及坡脚开挖时应减小开挖坡比或设置台阶分级开挖。

The internal stress distribution of the slope will be re-adjusted after excavation.The original stable slope often collapses due to excavation unloading.However,reasonable excavation location and slope ratio will effectively reduce the damage degree of such disasters.In view of this,the finite element software Midas-GTS is used to simulate the excavation of fractured soft rock slope at different slope ratios and location.The results show that the excavation at the top of the slope can improve the overall stability,while excavation at the bottom of the slope can reduce the overall stability.The influence of small slope in the middle of the slope is less than that of excavation.The larger the excavated slope ratio at the bottom and the middle of the slope,the lower the stability coefficient of the slope,while the larger the excavated slope ratio at the top,the higher the stability coefficient of the slope.The slope ratio of a soft rock slope should be increased as much as possible,but the local shear stress increase caused by vertical excavation should be prevented.The slope ratio should be reduced or steps should be provided in the middle of the slope and at the foot of the slope.