大型黄土古滑坡蠕变特性模拟  

Simulation of creep characteristics of large ancient loess landslide

作　　者：李昂[1] 周永根 叶万军[1] 孙兴华 马强 薛智轩 吕璐娜 方刚 LI Ang;ZHOU Yonggen;YE Wanjun;SUN Xinghua;MA Qiang;XUE Zhixuan;LYU Luna;FANG Gang(College of Civil and Architectural Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Shaanxi Transportation Planning and Design Institute,Xi’an 710065,China;Xi’an Research Institute of China Coal Technology and Engineering Group,Xi’an 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]陕西省交通规划设计研究院,陕西西安710065 [3]中煤科工集团西安研究院有限公司,陕西西安710054

出　　处：《西安科技大学学报》2023年第1期151-159,共9页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金项目(42072319);陕西省自然科学基础研究计划重点项目(2020JZ-52)。

摘　　要：为研究黄土古滑坡蠕变效应下长期稳定性问题,依托支党河特大桥桥区的黄土古滑坡,以原状黄土剪切蠕变试验为基础,采用数值模拟方法,分析削方卸载前后古滑坡体蠕变至2,10,30 a及100 a时的位移场及塑性区分布特征,对削方卸载后的古滑坡坡体进行现场监测,并与数值模拟结果进行对比。结果表明:随剪应力增加,原状黄土蠕变速率先减小后增大,先后经历衰减蠕变、等速蠕变及加速蠕变3个阶段,剪应力长期作用下,黏聚力及内摩擦角分别下降了16%,32%,蠕变效应明显;古滑坡坡体在10~100 a间出现了加速蠕变过程,位移量最大达到1.96 m,蠕变至30 a塑性区基本贯通,发生失稳破坏;在坡体大倾角位置削方卸载后,塑性区面积显著减小,蠕变10 a后,塑性区基本稳定且并未贯通,最大位移量仅为0.65 m,蠕变至100 a坡体也未发生失稳破坏。古滑坡表面及深部位移现场监测数据与数值模拟计算结果较为吻合,验证了蠕变试验及数值模拟结果的可靠性。To explore the long-term stability of loess ancient landslide under creep effect, taking the loess ancient landslide in the bridge area of Zhidang river bridge as the object, based on the shear creep experiment of undisturbed loess, the numerical simulation method was used to examine the displacement field and plastic zone distribution characteristics of ancient landslide body before and after cutting unloading for 2,10,30 a and 100 a.The results show that with the increase of shear stress, the creep rate of intact loess decreases first and then increases, and experiences three stages of attenuation, constant speed and accelerated creep respectively.Under the long-term action of shear stress, the cohesion and internal friction angle decrease by 16% and 32% respectively, and the creep effect is obvious.The accelerated creep process of the slope of the ancient landslide occurred between 10 and 100 a.The plastic zone was basically penetrated after 30 a of creep, the displacement reached 1.26 m, and the instability failure occurred.After unloading at the large inclination angle of the slope, the creep displacement and the plastic zone area decreased significantly, and no instability failure occurred in the slope until 100 a.The field monitoring data of surface and deep displacement of ancient landslide are in good agreement with the numerical simulation results, which verifies the reliability of creep test and numerical simulation results.The research provides a reference for the study of loess creep law and long-term stability of ancient landslide.

关 键 词：黄土古滑坡 数值模拟 蠕变效应 长期稳定性 现场监测 

分 类 号：TU444[建筑科学—岩土工程]