摘要
人工开挖是黄土地区滑坡形成的主要诱发因素之一,开挖导致斜坡一定范围内产生卸荷回弹和应力重分布,斜坡应力重新平衡的过程伴随着斜坡形变,甚至破坏。延安市宝塔区枣园镇阳崖滑坡为典型开挖诱发的黄土边坡,本文选取阳崖滑坡为地质原型,采用TLJ-500大型土工离心机对边坡坡脚开挖状态下变形破坏过程进行模拟试验,通过对模型控制点监测数据分析,研究边坡坡脚开挖前后坡体形变位移特征、坡体内部土压力响应特征以及边坡变形破坏机理。结果表明:坡脚开挖后临空面附近产生局部垮塌,其坡体位移、潜在滑移面以及拉张裂缝均由坡体前缘往后部渐进性变化发展。开挖后坡体内部产生明显的应力松弛,且越靠近开挖面卸荷效应越明显,开挖主要影响坡体的中前部分,对坡体后部影响较小甚至无影响,分析得知坡体变形破坏机理为典型的渐进后退式。
Artificial excavation is one of the main inducing factors of the landslide formation in loess area.It causes unloading rebound and stress redistribution within the scope of slopes.The process of slope stress rebalancing is followed by slope deformation,which even causes damage.The landslide happened at Baota Zaoyuan town in Yan'an city is a typical induced loess slope excavation.This paper chooses the Yangya landslide as the geological prototype.It uses the type of TLJ-500geotechnical centrifuge for the condition of excavation slope foot test to simulate the deformation and failure process.It studies the characteristics of the displacement of slope deformation before and after the excavation of the slope foot,slope soil pressure response and mechanism of slope deformation and destruction through analysis of the model monitoring data at monitoring points.Results show that partial collapse happens after the slope toe excavation near the international airport face.The slope displacement,shear stress concentration belt and tensile fracture increase progressively from the front part to the inner part of the slope.After excavation,the slope internal zone can produce obvious stress relaxation.The closer to the excavation face the more obvious effect of unloading.Excavation influences a majority of the front and middle parts of the main slope.So there is less or even no effect at the back slope,which means that slope deformation failure mechanism is the typical-steps-back type.
出处
《工程地质学报》
CSCD
北大核心
2016年第1期1-9,共9页
Journal of Engineering Geology
基金
中国地质调查局项目(1212011140005)
国家重点基础研究发展计划项目(2014CB744703)资助
关键词
开挖
黄土边坡
离心模拟试验
变形破坏机理
Excavation
Loess slope
Centrifugal simulation test
Deformation and failure mechanism
